PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (26)
 

Clipboard (0)
None

Select a Filter Below

Year of Publication
more »
Document Types
1.  Immunoadjuvant Prednisolone Therapy for HIV-Associated Tuberculosis: A Phase 2 Clinical Trial in Uganda 
The Journal of infectious diseases  2005;191(6):856-865.
Background
Human immunodeficiency virus (HIV)–infected patients with tuberculosis (TB) respond to effective antituberculous therapy, but their prognosis remains poor. Mounting evidence from clinical studies supports the concept of copathogenesis in which immune activation that is triggered by TB and mediated by cytokines stimulates viral replication and worsens HIV infection, especially when immune function is preserved.
Methods
We performed a phase 2, randomized, double-blind, placebo-controlled clinical trial in Kampala, Uganda, to determine whether immunoadjuvant prednisolone therapy in HIV-infected patients with TB who have CD4+ T cell counts ≥200 cells/μL is safe and effective at increasing CD4+ T cell counts.
Results
Short-term prednisolone therapy reduced levels of immune activation and tended to produce higher CD4+ T cell counts. Although prednisolone therapy was associated with a more rapid clearance of Mycobacterium tuberculosis from the sputum, it was also associated with a transient increase in HIV RNA levels, which receded when prednisolone therapy was discontinued. The intervention worsened underlying hypertension and caused fluid retention and hyperglycemia.
Conclusion
The benefits of prednisolone therapy on immune activation and CD4+ T cell counts do not outweigh the risks of adverse events in HIV-infected patients with TB and preserved immune function.
doi:10.1086/427995
PMCID: PMC4515766  PMID: 15717259
2.  Prevalence of latent tuberculosis infection and associated risk factors in an urban African setting 
BMC Infectious Diseases  2015;15:165.
Background
Nearly one third of the world is infected with latent tuberculosis infection (LTBI) and a vast pool of individuals with LTBI persists in developing countries, posing a major barrier to global TB control. The aim of the present study was to determine the prevalence of LTBI and the associated risk factors among adults in Kampala, Uganda.
Methods
We performed a secondary analysis from a door-to-door cross-sectional survey of chronic cough conducted from January 2008 to June 2009. Urban residents of Rubaga community in Kampala aged 15 years and older who had received Tuberculin skin testing (TST) were included in the analysis. The primary outcome was LTBI defined as a TST with induration 10 mm or greater. Multivariable logistic regression analyses were used to assess the risk factors associated with LTBI.
Results
A total of 290 participants were tested with TST, 283 had their tests read and 7 didn’t have the TST read because of failure to trace them within 48–72 hours. Of the participants with TST results, 68% were female, 75% were 15–34 years, 83% had attained at least 13 years of education, 12% were smokers, 50% were currently married, 57% left home for school or employment, 21% were HIV positive and 65% reported chronic cough of 2 weeks or longer. The overall prevalence of LTBI was 49% [95% CI 44–55] with some age-and sex-specific differences. On multivariable analysis, leaving home for school or employment, aOR = 1.72; [95%CI: 1.05, 2.81] and age 25–34, aOR = 1.94; [95%CI: 1.12, 3.38]; 35 years and older, aOR = 3.12; [95%CI: 1.65, 5.88] were significant risk factors of LTBI.
Conclusion
The prevalence of LTBI was high in this urban African setting. Leaving home for school or employment and older age were factors significantly associated with LTBI in this setting. This suggests a potential role of expansion of one’s social network outside the home and cumulative risk of exposure to TB with age in the acquisition of LTBI. Our results provide support for LTBI screening and preventive treatment programs of these sub-groups in order to enhance TB control.
doi:10.1186/s12879-015-0904-1
PMCID: PMC4392742  PMID: 25879423
Latent tuberculosis infection; Tuberculin skin testing; TB control
3.  Cost-Effectiveness Analysis of Community Active Case Finding and Household Contact Investigation for Tuberculosis Case Detection in Urban Africa 
PLoS ONE  2015;10(2):e0117009.
Introduction
Case detection by passive case finding (PCF) strategy alone is inadequate for detecting all tuberculosis (TB) cases in high burden settings especially Sub-Saharan Africa. Alternative case detection strategies such as community Active Case Finding (ACF) and Household Contact Investigations (HCI) are effective but empirical evidence of their cost-effectiveness is sparse. The objective of this study was to determine whether adding ACF or HCI compared with standard PCF alone represent cost-effective alternative TB case detection strategies in urban Africa.
Methods
A static decision modeling framework was used to examine the costs and effectiveness of three TB case detection strategies: PCF alone, PCF+ACF, and PCF+HCI. Probability and cost estimates were obtained from National TB program data, primary studies conducted in Uganda, published literature and expert opinions. The analysis was performed from the societal and provider perspectives over a 1.5 year time-frame. The main effectiveness measure was the number of true TB cases detected and the outcome was incremental cost-effectiveness ratios (ICERs) expressed as cost in 2013 US$ per additional true TB case detected.
Results
Compared to PCF alone, the PCF+HCI strategy was cost-effective at US$443.62 per additional TB case detected. However, PCF+ACF was not cost-effective at US$1492.95 per additional TB case detected. Sensitivity analyses showed that PCF+ACF would be cost-effective if the prevalence of chronic cough in the population screened by ACF increased 10-fold from 4% to 40% and if the program costs for ACF were reduced by 50%.
Conclusions
Under our baseline assumptions, the addition of HCI to an existing PCF program presented a more cost-effective strategy than the addition of ACF in the context of an African city. Therefore, implementation of household contact investigations as a part of the recommended TB control strategy should be prioritized.
doi:10.1371/journal.pone.0117009
PMCID: PMC4319733  PMID: 25658592
4.  Tuberculosis risk factors among tuberculosis patients in Kampala, Uganda: implications for tuberculosis control 
BMC Public Health  2015;15:13.
Background
Slow decline in the incidence of tuberculosis (TB) has been observed in most high TB burden countries. Knowledge of the prevalence of different TB risk factors can help expand TB control strategies. However with the exception of Human Immunodeficiency Virus (HIV) the prevalence of the other TB risk factors are poorly studied in Uganda. We aimed to determine the prevalence of different TB risk factors and TB disease presentation among TB patients in Kampala Uganda.
Methods
We assessed 365 adult TB patients and used descriptive statistics to summarize their socio-demographic, clinical, radiological, sputum mycobacteriology and TB risk factors (HIV, diabetes, TB contact, alcohol use, tobacco smoking, poverty and overcrowding) data.
Results
A total of 158 (43.3%) patients were male and the median age was 29 (IQR 28–30). Majority of the patients (89.2%) had pulmonary TB, 86.9% were new and 13.2% were retreatment. Wasting (i.e. body mass index of <18.5 kg/m2) was found in 38.5% of the patients and 63% presented with cough. Constitutional symptoms (fever, anorexia, night sweats and weight loss) were reported by 32.1%. Most patients (78.6%) presented with non-cavity lung parenchyma disease (infiltrates, nodules, masses) but 35.2% had cavity disease. Pleural disease was detected in 19.3% of patients. Positive smear microscopy and culture (irrespective of month of treatment) was found in 52.7% and 36.5% of patients respectively. Any drug resistance was detected in 21.1% of patients while multidrug resistance (MDR) TB defined as resistance to rifampicin and isoniazid was detected in 6.3% of patients. All MDR patients were new patients.
The prevalence of TB risk factors were as follows: HIV 41.4%, diabetes 5.4%, close contact 11.5%, family history 17.5%, smoking 26.37%, poverty 39.5%, overcrowding 57.3% and alcohol use 50.7%. Overcrowding increased smear positive rate, prevalence ratio 1.22, p = 0.09 but all the other studied risk factors did not affect clinical, radiological and mycobacteriological study patient characteristics.
Conclusions
Among TB patients in Kampala, Uganda, there is high prevalence of the known TB risk factors. Targeting reducing their prevalence may lead to better TB control in the country. Tuberculosis, risk factors, Uganda.
doi:10.1186/s12889-015-1376-3
PMCID: PMC4311451  PMID: 25604986
5.  Contact Investigation for Active Tuberculosis Among Child Contacts in Uganda 
In a large prospective study in Kampala, Uganda, we found that case investigation can be effective (10% yield) in early detection of active tuberculosis in children <15 years old, with 71% culture confirmation.
Background. Tuberculosis is a large source of morbidity and mortality among children. However, limited studies characterize childhood tuberculosis disease, and contact investigation is rarely implemented in high-burden settings. In one of the largest pediatric tuberculosis contact investigation studies in a resource-limited setting, we assessed the yield of contact tracing on childhood tuberculosis and indicators for disease progression in Uganda.
Methods. Child contacts aged <15 years in Kampala, Uganda, were enrolled from July 2002 to June 2009 and evaluated for tuberculosis disease via clinical, radiographic, and laboratory methods for up to 24 months.
Results. Seven hundred sixty-one child contacts were included in the analysis. Prevalence of tuberculosis in our child population was 10%, of which 71% were culture-confirmed positive. There were no cases of disseminated tuberculosis, and 483 of 490 children (99%) started on isoniazid preventative therapy did not develop disease. Multivariable testing suggested risk factors including human immunodeficiency virus (HIV) status (odds ratio [OR], 7.90; P < .001), and baseline positive tuberculin skin test (OR, 2.21; P = .03); BCG vaccination was particularly protective, especially among children aged ≤5 years (OR, 0.23; P < .001). Adult index characteristics such as sex, HIV status, and extent or severity of disease were not associated with childhood disease.
Conclusions. Contact tracing for children in high-burden settings is able to identify a large percentage of culture-confirmed positive tuberculosis cases before dissemination of disease, while suggesting factors for disease progression to identify who may benefit from targeted screening.
doi:10.1093/cid/cit645
PMCID: PMC3840405  PMID: 24077055
pediatric; child; tuberculosis; risk factors; contact tracing
6.  Cough Aerosols of Mycobacterium tuberculosis Predict New Infection. A Household Contact Study 
Rationale: Airborne transmission of Mycobacterium tuberculosis results from incompletely characterized host, bacterial, and environmental factors. Sputum smear microscopy is associated with considerable variability in transmission.
Objectives: To evaluate the use of cough-generated aerosols of M. tuberculosis to predict recent transmission.
Methods: Patients with pulmonary tuberculosis (TB) underwent a standard evaluation and collection of cough aerosol cultures of M. tuberculosis. We assessed household contacts for new M. tuberculosis infection. We used multivariable logistic regression analysis with cluster adjustment to analyze predictors of new infection.
Measurements and Main Results: From May 2009 to January 2011, we enrolled 96 sputum culture-positive index TB cases and their 442 contacts. Only 43 (45%) patients with TB yielded M. tuberculosis in aerosols. Contacts of patients with TB who produced high aerosols (≥10 CFU) were more likely to have a new infection compared with contacts from low-aerosol (1–9 CFU) and aerosol-negative cases (69%, 25%, and 30%, respectively; P = 0.009). A high-aerosol patient with TB was the only predictor of new M. tuberculosis infection in unadjusted (odds ratio, 5.18; 95% confidence interval, 1.52–17.61) and adjusted analyses (odds ratio, 4.81; 95% confidence interval, 1.20–19.23). Contacts of patients with TB with no aerosols versus low and high aerosols had differential tuberculin skin test and interferon-γ release assay responses.
Conclusions: Cough aerosols of M. tuberculosis are produced by a minority of patients with TB but predict transmission better than sputum smear microscopy or culture. Cough aerosols may help identify the most infectious patients with TB and thus improve the cost-effectiveness of TB control programs.
doi:10.1164/rccm.201208-1422OC
PMCID: PMC3707366  PMID: 23306539
Mycobacterium tuberculosis; cough-generated aerosols; natural human transmission; household contact study
7.  Treatment Outcomes of New Tuberculosis Patients Hospitalized in Kampala, Uganda: A Prospective Cohort Study 
PLoS ONE  2014;9(3):e90614.
Background
In most resource limited settings, new tuberculosis (TB) patients are usually treated as outpatients. We sought to investigate the reasons for hospitalisation and the predictors of poor treatment outcomes and mortality in a cohort of hospitalized new TB patients in Kampala, Uganda
Methods and findings
Ninety-six new TB patients hospitalised between 2003 and 2006 were enrolled and followed for two years. Thirty two were HIV-uninfected and 64 were HIV-infected. Among the HIV-uninfected, the commonest reasons for hospitalization were low Karnofsky score (47%) and need for diagnostic evaluation (25%). HIV-infected patients were commonly hospitalized due to low Karnofsky score (72%), concurrent illness (16%) and diagnostic evaluation (14%). Eleven HIV uninfected patients died (mortality rate 19.7 per 100 person-years) while 41 deaths occurred among the HIV-infected patients (mortality rate 46.9 per 100 person years). In all patients an unsuccessful treatment outcome (treatment failure, death during the treatment period or an unknown outcome) was associated with duration of TB symptoms, with the odds of an unsuccessful outcome decreasing with increasing duration. Among HIV-infected patients, an unsuccessful treatment outcome was also associated with male sex (P = 0.004) and age (P = 0.034). Low Karnofsky score (aHR = 8.93, 95% CI 1.88 – 42.40, P = 0.001) was the only factor significantly associated with mortality among the HIV-uninfected. Mortality among the HIV-infected was associated with the composite variable of CD4 and ART use, with patients with baseline CD4 below 200 cells/µL who were not on ART at a greater risk of death than those who were on ART, and low Karnofsky score (aHR = 2.02, 95% CI 1.02 – 4.01, P = 0.045).
Conclusion
Poor health status is a common cause of hospitalisation for new TB patients. Mortality in this study was very high and associated with advanced HIV Disease and no use of ART.
doi:10.1371/journal.pone.0090614
PMCID: PMC3948371  PMID: 24608875
8.  Wasting among Uganda men with pulmonary tuberculosis is associated with linear regain in lean tissue mass during and after treatment in contrast to women with wasting who regain fat tissue mass: prospective cohort study 
Background
Nutritional changes during and after tuberculosis treatment have not been well described. We therefore determined the effect of wasting on rate of mean change in lean tissue and fat mass as measured by bioelectrical impedance analysis (BIA), and mean change in body mass index (BMI) during and after tuberculosis treatment.
Methods
In a prospective cohort study of 717 adult patients, BMI and height-normalized indices of lean tissue (LMI) and fat mass (FMI) as measured by BIA were assessed at baseline, 3, 12, and 24 months.
Results
Men with wasting at baseline regained LMI at a greater rate than FMI (4.55 kg/m2 (95% confidence interval (CI): 1.26, 7.83 versus 3.16 (95% CI: 0.80, 5.52)) per month, respectively during initial tuberculosis therapy. In contrast, women with wasting regained FMI at greater rate than LMI (3.55 kg/m2 (95% CI: 0.40, 6.70) versus 2.07 (95% CI: -0.74, 4.88)), respectively. Men with wasting regained BMI at a rate of 6.45 kg/m2 (95% CI: 3.02, 9.87) in the first three months whereas women, had a rate of 3.30 kg/m2 (95% CI: -0.11, 6.72). There were minimal changes in body composition after month 3 and during months 12 to 24.
Conclusion
Wasted tuberculosis patients regain weight with treatment but the type of gain differs by gender and patients may remain underweight after the initial phase of treatment.
doi:10.1186/1471-2334-14-24
PMCID: PMC3922730  PMID: 24410970
Tuberculosis; HIV; Wasting; Lean tissue mass index; Fat mass index; Body mass index; Gender
9.  Elucidating Emergence and Transmission of Multidrug-Resistant Tuberculosis in Treatment Experienced Patients by Whole Genome Sequencing 
PLoS ONE  2013;8(12):e83012.
Background
Understanding the emergence and spread of multidrug-resistant tuberculosis (MDR-TB) is crucial for its control. MDR-TB in previously treated patients is generally attributed to the selection of drug resistant mutants during inadequate therapy rather than transmission of a resistant strain. Traditional genotyping methods are not sufficient to distinguish strains in populations with a high burden of tuberculosis and it has previously been difficult to assess the degree of transmission in these settings. We have used whole genome analysis to investigate M. tuberculosis strains isolated from treatment experienced patients with MDR-TB in Uganda over a period of four years.
Methods and Findings
We used high throughput genome sequencing technology to investigate small polymorphisms and large deletions in 51 Mycobacterium tuberculosis samples from 41 treatment-experienced TB patients attending a TB referral and treatment clinic in Kampala. This was a convenience sample representing 69% of MDR-TB cases identified over the four year period. Low polymorphism was observed in longitudinal samples from individual patients (2-15 SNPs). Clusters of samples with less than 50 SNPs variation were examined. Three clusters comprising a total of 8 patients were found with almost identical genetic profiles, including mutations predictive for resistance to rifampicin and isoniazid, suggesting transmission of MDR-TB. Two patients with previous drug susceptible disease were found to have acquired MDR strains, one of which shared its genotype with an isolate from another patient in the cohort.
Conclusions
Whole genome sequence analysis identified MDR-TB strains that were shared by more than one patient. The transmission of multidrug-resistant disease in this cohort of retreatment patients emphasises the importance of early detection and need for infection control. Consideration should be given to rapid testing for drug resistance in patients undergoing treatment to monitor the emergence of resistance and permit early intervention to avoid onward transmission.
doi:10.1371/journal.pone.0083012
PMCID: PMC3859632  PMID: 24349420
10.  Mycobacterium tuberculosis Specific CD8+ T Cells Rapidly Decline with Antituberculosis Treatment 
PLoS ONE  2013;8(12):e81564.
Rationale
Biomarkers associated with response to therapy in tuberculosis could have broad clinical utility. We postulated that the frequency of Mycobacterium tuberculosis (Mtb) specific CD8+ T cells, by virtue of detecting intracellular infection, could be a surrogate marker of response to therapy and would decrease during effective antituberculosis treatment.
Objectives: We sought to determine the relationship of Mtb specific CD4+ T cells and CD8+ T cells with duration of antituberculosis treatment.
Materials and Methods
We performed a prospective cohort study, enrolling between June 2008 and August 2010, of HIV-uninfected Ugandan adults (n = 50) with acid-fast bacillus smear-positive, culture confirmed pulmonary TB at the onset of antituberculosis treatment and the Mtb specific CD4+ and CD8+ T cell responses to ESAT-6 and CFP-10 were measured by IFN-γ ELISPOT at enrollment, week 8 and 24.
Results
There was a significant difference in the Mtb specific CD8+ T response, but not the CD4+ T cell response, over 24 weeks of antituberculosis treatment (p<0.0001), with an early difference observed at 8 weeks of therapy (p = 0.023). At 24 weeks, the estimated Mtb specific CD8+ T cell response decreased by 58%. In contrast, there was no significant difference in the Mtb specific CD4+ T cell during the treatment. The Mtb specific CD4+ T cell response, but not the CD8+ response, was negatively impacted by the body mass index.
Conclusions
Our data provide evidence that the Mtb specific CD8+ T cell response declines with antituberculosis treatment and could be a surrogate marker of response to therapy. Additional research is needed to determine if the Mtb specific CD8+ T cell response can detect early treatment failure, relapse, or to predict disease progression.
doi:10.1371/journal.pone.0081564
PMCID: PMC3852504  PMID: 24324704
11.  Aetiology of Pulmonary Symptoms in HIV-Infected Smear Negative Recurrent PTB Suspects in Kampala, Uganda: A Cross-Sectional Study 
PLoS ONE  2013;8(12):e82257.
Introduction
Previously treated TB patients with pulmonary symptoms are often considered recurrent TB suspects in the resource-limited settings, where investigations are limited to microscopy and chest x-ray. Category II anti-TB drugs may be inappropriate and may expose patients to pill burden, drug toxicities and drug-drug interactions.
Objective
To determine the causes of pulmonary symptoms in HIV-infected smear negative recurrent pulmonary tuberculosis suspects at Mulago Hospital, Kampala.
Methods
Between March 2008 and December 2011, induced sputum samples of 178 consented HIV-infected smear negative recurrent TB suspects in Kampala were subjected to MGIT and LJ cultures for mycobacteria at TB Reference Laboratory, Kampala. Processed sputum samples were also tested by PCR to detect 18S rRNA gene of P.jirovecii and cultured for other bacteria.
Results
Bacteria, M. tuberculosis and Pneumocystis jirovecii were detected in 27%, 18% and 6.7% of patients respectively and 53.4% of the specimens had no microorganisms. S. pneumoniae, M. catarrhalis and H. influenzae were 100% susceptible to chloramphenicol and erythromycin but co-trimoxazole resistant.
Conclusion
At least 81.5% of participants had no microbiologically-confirmed TB. However our findings call for thorough investigation of HIV-infected smear negative recurrent TB suspects to guide cost effective treatment.
doi:10.1371/journal.pone.0082257
PMCID: PMC3849471  PMID: 24312650
12.  Variability of Infectious Aerosols Produced during Coughing by Patients with Pulmonary Tuberculosis 
Rationale: Mycobacterium tuberculosis is transmitted by infectious aerosols, but assessing infectiousness currently relies on sputum microscopy that does not accurately predict the variability in transmission.
Objectives: To evaluate the feasibility of collecting cough aerosols and the risk factors for infectious aerosol production from patients with pulmonary tuberculosis (TB) in a resource-limited setting.
Methods: We enrolled subjects with suspected TB in Kampala, Uganda and collected clinical, radiographic, and microbiological data in addition to cough aerosol cultures. A subset of 38 subjects was studied on 2 or 3 consecutive days to assess reproducibility.
Measurements and Main Results: M. tuberculosis was cultured from cough aerosols of 28 of 101 (27.7%; 95% confidence interval [CI], 19.9–37.1%) subjects with culture-confirmed TB, with a median 16 aerosol cfu (range, 1–701) in 10 minutes of coughing. Nearly all (96.4%) cultivable particles were 0.65 to 4.7 μm in size. Positive aerosol cultures were associated with higher Karnofsky performance scores (P = 0.016), higher sputum acid-fast bacilli smear microscopy grades (P = 0.007), lower days to positive in liquid culture (P = 0.004), stronger cough (P = 0.016), and fewer days on TB treatment (P = 0.047). In multivariable analyses, cough aerosol cultures were associated with a salivary/mucosalivary (compared with purulent/mucopurulent) appearance of sputum (odds ratio, 4.42; 95% CI, 1.23–21.43) and low days to positive (per 1-d decrease; odds ratio, 1.17; 95% CI, 1.07–1.33). The within-test (kappa, 0.81; 95% CI, 0.68–0.94) and interday test (kappa, 0.62; 95% CI, 0.43–0.82) reproducibility were high.
Conclusions: A minority of patients with TB (28%) produced culturable cough aerosols. Collection of cough aerosol cultures is feasible and reproducible in a resource-limited setting.
doi:10.1164/rccm.201203-0444OC
PMCID: PMC3443801  PMID: 22798319
tuberculosis; cough; air microbiology; infectious disease transmission; infection control
13.  Lean Tissue Mass Wasting is Associated with Increased Risk of Mortality among Women with Pulmonary Tuberculosis in Urban Uganda 
Annals of Epidemiology  2012;22(7):466-473.
Objective
We assessed the impact of wasting on survival in tuberculosis patients using precise height-normalized lean tissue mass index (LMI) estimated by bioelectrical impedance analysis and body mass index (BMI).
Methods
In a retrospective cohort study, 747 adult pulmonary tuberculosis patients who were screened for HIV and nutritional status were followed for survival.
Results
Of 747 patients, 310 had baseline wasting by BMI (kg/m2) and 103 by LMI (kg/m2). Total deaths were 105. Among men with reduced BMI, risk of death was 70% higher (hazard ratio (HR) = 1.7, 95% CI 1.03, 2.81) than in men with normal BMI. Survival did not differ by LMI among men (HR = 1.1; 95% CI: 0.5, 2.9). In women, both the BMI and LMI were associated with survival. Among women with reduced BMI, risk of death was 80% higher (HR = 1.8; 95% CI: 0.9, 3.5) than in women with normal BMI; risk of death was 5-fold higher (HR = 5.0; 95% CI: 1.6, 15.9) for women with low LMI compared to women with normal LMI.
Conclusion
Wasting assessed by reduced BMI is associated with an increased risk for death among both men and women whereas reduced LMI is among women with tuberculosis.
doi:10.1016/j.annepidem.2012.04.007
PMCID: PMC3377556  PMID: 22575813
Tuberculosis; survival; wasting; lean tissue mass index; body mass index; bioelectrical impedance analysis
14.  Influence of efavirenz pharmacokinetics and pharmacogenetics on neuropsychological disorders in Ugandan HIV-positive patients with or without tuberculosis: a prospective cohort study 
BMC Infectious Diseases  2013;13:261.
Background
HIV infection, anti-tuberculosis and efavirenz therapy are associated with neuropsychological effects. We evaluated the influence of rifampicin cotreatment, efavirenz pharmacokinetics and pharmacogenetics on neuropsychiatric disorders in Ugandan HIV patients with or without tuberculosis coinfection.
Methods
197 treatment naïve Ugandan HIV patients, of whom 138 were TB co-infected, enrolled prospectively and received efavirenz based HAART. TB-HIV confected patients received concomitant rifampicin based anti-TB therapy. Genotypes for CYP2B6 (*6, *11), CYP3A5 (*3, *6, *7), ABCB1 (c.3435C>T and c.4036 A/G rs3842), CYP2A6 (*9, *17) and NR1I3 rs3003596 T/C were determined. Efavirenz plasma concentrations were serially quantified at 3rd day, 1st, 2nd, 4th, 6th, 8th and 12th weeks during therapy. Efavirenz neuropsychiatric symptoms were evaluated in terms of sleep disorders, hallucinations and cognitive effects at baseline, at two and twelve weeks of efavirenz treatment using a modified Mini Mental State Examination (MMSE) score.
Results
During the first twelve weeks of ART, 73.6% of the patients experienced at least one efavirenz related neuropsychiatric symptom. Commonest symptoms experienced were sleep disorders 60.5% (n=124) and hallucination 30.7% (n=63). Neuropsychiatric symptoms during HAART were significantly predicted by efavirenz plasma concentrations consistently. Rifampicin cotreatment reduced plasma efavirenz concentrations significantly only during the first week but not afterwards. There was no significant difference in the incidence of neuropsychiatric symptoms between patients receiving efavirenz with or without rifampicin cotreatment. CYP2B6*6 and ABCB1 c.4036 A/G genotype significantly predicted efavirenz concentrations. The tendency of CYP2B6*6 genotype association with higher incidence of having vivid dream (p=0.05), insomnia (p=0.19) and tactile hallucination (p=0.09) was observed mainly at week-2.
Conclusions
Efavirenz related neuropsychiatric symptoms are common among Ugandan HIV patients receiving ART and is mainly predicted by higher efavirenz plasma concentrations and CYP2B6 genotype but not by rifampicin based anti-TB co-treatment.
doi:10.1186/1471-2334-13-261
PMCID: PMC3680019  PMID: 23734829
Efavirenz; Neuropsychiatric toxicity; Rifampicin; CYP2B6; HIV; Tuberculosis; CNS; Antiretroviral therapy; Ugandans
15.  M. tuberculosis microbiologic and clinical treatment outcomes in a randomized trial of immediate vs. CD4 initiated antiretroviral therapy in HIV-infected adults with high CD4 cell counts 
In a prospective randomized, controlled trial of ART during TB treatment versus TB treatment alone in Ugandan patients with CD4 >350 cells/μL, ART did not accelerate microbiologic, radiographic or clinical responses to TB therapy. 18% of participants had positive sputum smears after 5 months of TB therapy despite negative cultures.
doi:10.1086/654799
PMCID: PMC2919368  PMID: 20569064
Tuberculosis; HIV; antiretroviral therapy
16.  Effectiveness of the Standard WHO Recommended Retreatment Regimen (Category II) for Tuberculosis in Kampala, Uganda: A Prospective Cohort Study 
PLoS Medicine  2011;8(3):e1000427.
Prospective evaluation of the effectiveness of the WHO-recommended standardized retreatment regimen for tuberculosis by Edward Jones-López and colleagues reveals an unacceptable proportion of unsuccessful outcomes.
Background
Each year, 10%–20% of patients with tuberculosis (TB) in low- and middle-income countries present with previously treated TB and are empirically started on a World Health Organization (WHO)-recommended standardized retreatment regimen. The effectiveness of this retreatment regimen has not been systematically evaluated.
Methods and Findings
From July 2003 to January 2007, we enrolled smear-positive, pulmonary TB patients into a prospective cohort to study treatment outcomes and mortality during and after treatment with the standardized retreatment regimen. Median time of follow-up was 21 months (interquartile range 12–33 months). A total of 29/148 (20%) HIV-uninfected and 37/140 (26%) HIV-infected patients had an unsuccessful treatment outcome. In a multiple logistic regression analysis to adjust for confounding, factors associated with an unsuccessful treatment outcome were poor adherence (adjusted odds ratio [aOR] associated with missing half or more of scheduled doses 2.39; 95% confidence interval (CI) 1.10–5.22), HIV infection (2.16; 1.01–4.61), age (aOR for 10-year increase 1.59; 1.13–2.25), and duration of TB symptoms (aOR for 1-month increase 1.12; 1.04–1.20). All patients with multidrug-resistant TB had an unsuccessful treatment outcome. HIV-infected individuals were more likely to die than HIV-uninfected individuals (p<0.0001). Multidrug-resistant TB at enrolment was the only common risk factor for death during follow-up for both HIV-infected (adjusted hazard ratio [aHR] 17.9; 6.0–53.4) and HIV-uninfected (14.7; 4.1–52.2) individuals. Other risk factors for death during follow-up among HIV-infected patients were CD4<50 cells/ml and no antiretroviral treatment (aHR 7.4, compared to patients with CD4≥200; 3.0–18.8) and Karnofsky score <70 (2.1; 1.1–4.1); and among HIV-uninfected patients were poor adherence (missing half or more of doses) (3.5; 1.1–10.6) and duration of TB symptoms (aHR for a 1-month increase 1.9; 1.0–3.5).
Conclusions
The recommended regimen for retreatment TB in Uganda yields an unacceptable proportion of unsuccessful outcomes. There is a need to evaluate new treatment strategies in these patients.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
One-third of the world's population is currently infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB), and 5%–10% of HIV-uninfected individuals will go on to develop disease and become infectious. The risk of progression from infection to disease in HIV infected is much higher. If left untreated, each person with active TB may infect 10 to 15 people every year, reinforcing the public health priority of controlling TB through adequate treatment. Patients with a previous history of TB treatment are a major concern for TB programs throughout the world because these patients are at a much higher risk of harboring a form of TB that is resistant to the drugs most frequently used, resulting in poorer treatment outcomes and significantly complicating current management strategies. More then 1 million people in over 90 countries need to be “re-treated” after failing, interrupting, or relapsing from previous TB treatment.
Every year, 10%–20% of people with TB in low- and middle-income countries are started on a standardized five-drug retreatment regimen as recommended by the World Health Organization (WHO). Yet, unlike treatment regimens for newly diagnosed TB patients, the recommended retreatment regimen (also known as the category II regimen) has never been properly evaluated in randomized clinical trials or prospective cohort studies. Rather, this regimen was recommended by experts before the current situation of widespread drug-resistant TB and HIV infection.
Why Was This Study Done?
WHO surveillance data suggest that the retreatment regimen is successful in about 70% of patients, but retrospective studies that have evaluated the regimen's efficacy showed variable treatment responses with success rates ranging from 26% to 92%. However, these studies have generally only assessed outcomes at the completion of the retreatment regimen, and few have examined the risk of TB recurrence, especially in people who are also infected with HIV and so are more likely to experience TB recurrence—an issue of particular concern in sub-Saharan Africa. Therefore, in this study based in Kampala, Uganda, the researchers conducted a prospective cohort study to assess treatment and survival outcomes in patients previously treated for TB and to identify factors associated with poor outcomes. Given the overwhelming contribution of HIV infection to death, the researchers categorized their survival analysis by HIV status.
What Did the Researchers Do and Find?
The researchers recruited consecutive smear-positive TB patients who were admitted to Mulago Hospital, Kampala, Uganda, for the retreatment of TB with the standard retreatment regimen between July 2003 and January 2007. Eligible patients received daily directly observed therapy and after hospital discharge, were seen every month during their 8-month TB-retreatment course. Home health visitors assessed treatment adherence through treatment card review, monthly pill counts, and patient self-report. After the completion of the retreatment regimen, patients were evaluated for TB recurrence every 3 months for a median of 21 months. The researchers then used a statistical model to identify treatment outcomes and mortality HIV-uninfected and HIV-infected patients.
The researchers found that 29/148 (20%) of HIV-uninfected and 37/140 (26%) of HIV-infected patients had an unsuccessful treatment outcome. Factors associated with an unsuccessful treatment outcome were poor adherence, HIV infection, increasing age, and duration of TB symptoms. All patients with multidrug resistant TB, a form of TB that is resistant to the two most important drugs used to treat TB, had an unsuccessful treatment outcome. In addition, HIV-infected subjects were more likely to die than HIV-uninfected subjects (p<0.0001), and having multidrug resistant TB at enrollment was the only common risk factor for death during follow-up for both HIV-infected and HIV uninfected patients. Other risk factors for death among HIV-infected patients were CD4<50 cells/ml and no antiretroviral therapy treatment and among HIV-uninfected patients were poor adherence and duration of TB symptoms.
What Do These Findings Mean?
The researchers found that although 70%–80% of patients had a successful treatment outcome on completion of antituberculous therapy (a result that compares well with retrospective studies), the standard retreatment regimen had low treatment response rates and was associated with poor long-term outcomes in certain subgroups of patients, particularly those with multidrug resistant TB and HIV.
These findings indicate that the standard retreatment approach to TB as implemented in low- and middle-income settings is inadequate and stress the importance of a new, more effective, strategies. Improved access to rapid diagnostics for TB drug-resistance, second-line TB treatment, and antiretroviral therapy is urgently needed, along with a strong evidence base to guide clinicians and policy makers on how best to use these tools.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000427.
The World Health Organization has information on TB, TB retreatment, and multidrug-resistant TB
WHO also provides information on TB/HIV coinfection
The Stop TB Partnership provides information on the global plan to stop TB
doi:10.1371/journal.pmed.1000427
PMCID: PMC3058098  PMID: 21423586
17.  Body Composition among HIV-seropositive and HIV-seronegative Adult Patients with Pulmonary Tuberculosis in Uganda 
Annals of epidemiology  2010;20(3):210-216.
Purpose
We determined whether human immunodeficiency virus (HIV) infection affects body cell mass and fat mass wasting among adults with pulmonary tuberculosis (PTB).
Methods
We screened 967 Ugandan adults for PTB and HIV infection in a cross-sectional study. We compared anthropometric and bioelectric impedance analysis (BIA) body composition parameters among HIV-seropositive and HIV-seronegative men and women with or without PTB using a non-parametric test.
Results
We found that poor nutritional status associated with TB differed among men and women. Anthropometric and BIA body composition did not differ between HIV-seropositive and HIV-seronegative patients regardless of gender. Average weight group difference in men comprised of body cell mass and fat mass in equal proportions of 43%. In women, average weight group difference comprised predominantly of fat mass of 73% and body cell mass of 13%. Compared to individuals without TB, patients with TB had lower body mass index, weight, body cell mass, and fat mass regardless of gender and HIV status.
Conclusions
Gender but not HIV status was associated with body composition changes in TB. Tuberculosis appears to be the dominant factor driving the wasting process among co-infected patients.
doi:10.1016/j.annepidem.2009.11.001
PMCID: PMC2824615  PMID: 20159491
Tuberculosis; HIV; bioelectrical impedance; gender; wasting; body composition
18.  Detection of multiple strains of Mycobacterium tuberculosis using MIRU-VNTR in patients with pulmonary tuberculosis in Kampala, Uganda 
BMC Infectious Diseases  2010;10:349.
Background
Many studies using DNA fingerprinting to differentiate Mycobacterium tuberculosis (MTB) strains reveal single strains in cultures, suggesting that most disease is caused by infection with a single strain. However, recent studies using molecular epidemiological tools that amplify multiple targets have demonstrated simultaneous infection with multiple strains of MTB. We aimed to determine the prevalence of MTB multiple strain infections in Kampala, and the impact of these infections on clinical presentation of tuberculosis (TB) and response to treatment.
Methods
A total of 113 consecutive smear and culture positive patients who previously enrolled in a house-hold contact study were included in this study. To determine whether infection with multiple MTB strains has a clinical impact on the initial presentation of patients, retrospective patient data (baseline clinical, radiological and drug susceptibility profiles) was obtained. To determine presence of infections with multiple MTB strains, MIRU-VNTR (Mycobacterial Interspersed Repetitive Unit-Variable-Number Tandem Repeats) -PCR was performed on genomic DNA extracted from MTB cultures of smear positive sputum samples at baseline, second and fifth months.
Results
Of 113 patients, eight (7.1%) had infection with multiple MTB strains, coupled with a high rate of HIV infection (37.5% versus 12.6%, p = 0.049). The remaining patients (105) were infected with single MTB strains. The proportions of patients with MTB smear positive cultures after two and five months of treatment were similar. There was no difference between the two groups for other variables.
Conclusion
Infection with multiple MTB strains occurs among patients with first episode of pulmonary tuberculosis in Kampala, in a setting with high TB incidence. Infection with multiple MTB strains had little impact on the clinical course for individual patients. This is the first MIRU-VNTR-based study from in an East African country.
doi:10.1186/1471-2334-10-349
PMCID: PMC3004912  PMID: 21143966
19.  Shortening Treatment in Adults with Noncavitary Tuberculosis and 2-Month Culture Conversion 
Rationale: Cavitary disease and delayed culture conversion have been associated with relapse. Combining patient characteristics and measures of bacteriologic response might allow treatment shortening with current drugs in some patients.
Objectives: To assess whether treatment could be shortened from 6 to 4 months in patients with noncavitary tuberculosis whose sputum cultures converted to negative after 2 months.
Methods: This study was a randomized, open-label equivalence trial. HIV-uninfected adults with noncavitary tuberculosis were treated daily with isoniazid, rifampin, pyrazinamide, and ethambutol for 2 months, followed by 2 months of isoniazid and rifampin. After 4 months, patients with drug-susceptible TB whose sputum cultures on solid media were negative after 8 weeks of treatment were randomly assigned to continue treatment for 2 more months or to stop treatment. Patients were followed for relapse for 30 months after beginning treatment.
Measurements and Main Results: Enrollment was stopped by the safety monitoring committee after 394 patients were enrolled due to apparent increased risk for relapse in the 4-month arm. A total of 370 patients were eligible for per protocol analysis. Thirteen patients in the 4-month arm relapsed, compared with three subjects in the 6-month arm (7.0 vs. 1.6%; risk difference, 0.054; 95% confidence interval with Hauck-Anderson correction, 0.01–0.10).
Conclusion: Shortening treatment from 6 to 4 months in adults with noncavitary disease and culture conversion after 2 months using current drugs resulted in a greater relapse rate. The combination of noncavitary disease and 2-month culture conversion was insufficient to identify patients with decreased risk for relapse.
doi:10.1164/rccm.200904-0536OC
PMCID: PMC2742745  PMID: 19542476
tuberculosis; antitubercular agents; isoniazid; rifampin
20.  Rate and Amplification of Drug Resistance among Previously-Treated Patients with Tuberculosis in Kampala, Uganda 
Background
Drug-resistant Mycobacterium tuberculosis has emerged as a global threat. In resource-constrained settings, patients with a history of tuberculosis (TB) treatment may have drug-resistant disease and may experience poor outcomes. There is a need to measure the extent of and risk factors for drug resistance in such patients.
Methods
From July 2003 through November 2006, we enrolled 410 previously treated patients with TB in Kampala, Uganda. We measured the prevalence of resistance to first- and second-line drugs and analyzed risk factors associated with baseline and acquired drug resistance.
Results
The prevalence of multidrug-resistant TB was 12.7% (95% confidence interval [95% CI], 9.6%–16.3%). Resistance to second-line drugs was low. Factors associated with multidrug-resistant TB at enrollment included a history of treatment failure (odds ratio, 23.6; 95% CI, 7.7–72.4), multiple previous TB episodes (odds ratio, 15.6; 95% CI, 5.0–49.1), and cavities present on chest radiograph (odds ratio, 5.9; 95% CI, 1.2–29.5). Among a cohort of 250 patients, 5.2% (95% CI, 2.8%–8.7%) were infected with M. tuberculosis that developed additional drug resistance. Amplification of drug resistance was associated with existing drug resistance at baseline (P<.01) and delayed sputum culture conversion (P<.01).
Conclusions
The burden of drug resistance in previously treated patients with TB in Uganda is sizeable, and the risk of generating additional drug resistance is significant. There is an urgent need to improve the treatment for such patients in low-income countries.
doi:10.1086/592252
PMCID: PMC2883442  PMID: 18808360
21.  Impact of pulmonary tuberculosis on survival of HIV-infected adults: a prospective epidemiologic study in Uganda 
AIDS (London, England)  2000;14(9):1219-1228.
Background
Retrospective cohort studies of tuberculosis suggest that active tuberculosis accelerates the progression of HIV infection. The validity of these findings has been questioned because of their retrospective design, diverse study populations, variable compliance with anti-tuberculous therapy and use of anti-retroviral medication. To assess the impact of tuberculosis on survival in HIV infection we performed a prospective study among HIV-infected Ugandan adults with and without tuberculosis.
Methods
In a prospective cohort study, 230 patients with HIV-associated tuberculosis and 442 HIV-infected subjects without tuberculosis were followed for a mean duration of 19 months for survival. To assess changes in viral load over 1 year, 20 pairs of tuberculosis cases and controls were selected and matched according to baseline CD4 lymphocyte count, age, sex and tuberculin skin test status.
Results
During the follow-up period, 63 out of of 230 tuberculosis cases (28%) died compared with 85 out of 442 controls (19%), with a crude risk ratio of 1.4 [95% confidence interval (CI), 1.07–1.87]. Most deaths occurred in patients with CD4 lymphocyte counts < 200 × 106 cells/l at baseline (n = 99) and occurred with similar frequency in the tuberculosis cases (46%) and the controls (44%). When the CD4 lymphocyte count was > 200 × 106 /l, however, the relative risk of death in HIV-associated tuberculosis was 2.1 (95% CI, 1.27–3.62) compared with subjects without tuberculosis. For subjects with a CD4 lymphocyte count > 200 × 106/l, the 1-year survival proportion was slightly lower in the cases than in the controls (0.91 versus 0.96), but by 2 years the survival proportion was significantly lower in the cases than in the controls (0.84 versus 0.91; P < 0.02; log-rank test). For subjects with a CD4 lymphocyte count of 200 × 106 cells/l or fewer, the survival proportion at 1 year for the controls was lower than cases (0.59 versus 0.64), but this difference was not statistically significant (P = 0.53; logrank test). After adjusting for age, sex, tuberculin skin test status, CD4 lymphocyte count, and history of HIV-related infections, the overall relative hazard for death associated with tuberculosis was 1.81 (95% CI, 1.24–2.65). In a nested Cox regression model, the relative hazard for death was 3.0 (95% CI, 1.62–5.63) for subjects with CD4 lymphocyte counts > 200 × 106/l and 1.5 (95% CI, 0.99–2.40) for subjects with a CD4 lymphocyte count of 200 × 106/l or fewer.
Conclusion
The findings from this prospective study indicate that active tuberculosis exerts its greatest effect on survival in the early stages of HIV infection, when there is a reserve capacity of the host immune response. These observations provide a theoretical basis for the treatment of latent tuberculous infection in HIV-infected persons.
PMCID: PMC2869086  PMID: 10894287
HIV-1; tuberculosis; survival; Africa; prospective cohort study
22.  IMMUNE CORRELATES OF ACUTE MYCOBACTERIUM TUBERCULOSIS INFECTION IN HOUSEHOLD CONTACTS IN KAMPALA, UGANDA 
To determine immunologic and epidemiologic correlates of acute Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis cases, we performed a prospective, community-based cohort study of index cases and their household contacts in Kampala, Uganda. Contacts were evaluated for tuberculin skin test (TST) conversion over two years. Interferon-γ expression was measured using a whole blood assay after stimulating with M. tuberculosis culture-filtrate. In 222 contacts with a TST less than 5 mm at baseline, the one-year rate of TST conversion was 27%. The TST conversion was associated with the infectiousness of the index case and proximity of contact. Interferon-γ levels at baseline were greater among TST converters compared with those who did not convert. The risk of TST conversion increased four-fold as the baseline interferon-γ increased 10-fold, but only in contacts with BCG vaccination. In household contacts of tuberculosis, interferon-γ responses to non-specific mycobacterial antigens may be used to make an early diagnosis of tuberculosis infection, especially in resource-limited settings where bacille Calmette-Guérin vaccination is commonly used.
PMCID: PMC2869089  PMID: 16837709
23.  Effect of Tuberculosis Preventive Therapy on HIV Disease Progression and Survival in HIV-Infected Adults 
HIV clinical trials  2006;7(4):172-183.
Purpose:
To determine whether tuberculosis (TB) preventive therapies alter the rate of disease progression to AIDS or death and to identify significant prognostic factors for HIV disease progression to AIDS.
Method:
In a randomized placebo-controlled trial in Kampala, Uganda, 2,736 purified protein derivative (PPD)-positive and anergic HIV-infected adults were randomly assigned to four and two regimens, respectively. PPD-positive patients were treated with isoniazid (INH) for 6 months (6H; n = 536), INH plus rifampicin for 3 months (3HR; n = 556), INH plus rifampicin plus pyrazinamide for 3 months (3HRZ; n = 462), or placebo for 6 months (n = 464). Anergic participants were treated with 6H (n = 395) or placebo (n = 323).
Results:
During follow-up, 404 cases progressed to AIDS and 577 deaths occurred. The cumulative incidence of the AIDS progression was greater in the anergic cohort compared to the PPD-positive cohort (p < .0001). Among PPD-positive patients, the relative risk of the AIDS progression with INH alone was 0.95 (95% CI 0.68–1.32); with 3HR it was 0.83 (95% CI 0.59–1.17); and with 3HRZ it was 0.76 (95% CI 0.52–1.08), controlling for significant baseline predictors. Among anergic patients, the relative risk of the AIDS progression was 0.81 (95% CI 0.56–1.15). Survival was greater in the PPD-positive cohort compared to the anergic cohort (p = .0001).
Conclusion:
The number of signs or symptoms at baseline and anergic status are associated with increasing morbidity and mortality. Even though the tuberculosis preventive therapies were effective in reducing the incidence of TB for HIV-infected adults, their benefit of delaying HIV disease progression to AIDS was not observed.
doi:10.1310/hct0704-172
PMCID: PMC2860292  PMID: 17065029
disease progression; HIV/AIDS; natural history; prevention; survival; tuberculosis
24.  Comparison of rapid tests for detection of rifampicin-resistant Mycobacterium tuberculosis in Kampala, Uganda 
Background
Drug resistant tuberculosis (TB) is a growing concern worldwide. Rapid detection of resistance expedites appropriate intervention to control the disease. Several technologies have recently been reported to detect rifampicin resistant Mycobacterium tuberculosis directly in sputum samples. These include phenotypic culture based methods, tests for gene mutations and tests based on bacteriophage replication. The aim of the present study was to assess the feasibility of implementing technology for rapid detection of rifampicin resistance in a high disease burden setting in Africa.
Methods
Sputum specimens from re-treatment TB patients presenting to the Mulago Hospital National TB Treatment Centre in Kampala, Uganda, were examined by conventional methods and simultaneously used in one of the four direct susceptibility tests, namely direct BACTEC 460, Etest, "in-house" phage test, and INNO- Rif.TB. The reference method was the BACTEC 460 indirect culture drug susceptibility testing. Test performance, cost and turn around times were assessed.
Results
In comparison with indirect BACTEC 460, the respective sensitivities and specificities for detecting rifampicin resistance were 100% and 100% for direct BACTEC and the Etest, 94% and 95% for the phage test, and 87% and 87% for the Inno-LiPA assay. Turn around times ranged from an average of 3 days for the INNO-LiPA and phage tests, 8 days for the direct BACTEC 460 and 20 days for the Etest. All methods were faster than the indirect BACTEC 460 which had a mean turn around time of 24 days. The cost per test, including labour ranged from $18.60 to $41.92 (USD).
Conclusion
All four rapid technologies were shown capable of detecting rifampicin resistance directly from sputum. The LiPA proved rapid, but was the most expensive. It was noted, however, that the LiPA test allows sterilization of samples prior to testing thereby reducing the risk of accidental laboratory transmission. In contrast the Etest was low cost, but slow and would be of limited assistance when treating patients. The phage test was the least reproducible test studied with failure rate of 27%. The test preferred by the laboratory personnel, direct BACTEC 460, requires further study to determine its accuracy in real-time treatment decisions in Uganda.
doi:10.1186/1471-2334-9-139
PMCID: PMC2744678  PMID: 19709423
25.  Whole Blood Interferon-Gamma Responses to Mycobacterium tuberculosis Antigens in Young Household Contacts of Persons with Tuberculosis in Uganda 
PLoS ONE  2008;3(10):e3407.
Background
Due to immunologic immaturity, IFN-γ-producing T cell responses may be decreased in young children compared to adults, thus we hypothesized that IFN-γ responses to mycobacterial antigens in household contacts exposed to Mycobacterium tuberculosis (Mtb) would be impaired in young children relative to adults. The objective of this study was to compare whole blood IFN-γ production in response to mycobacterial antigens between children and adults in Uganda.
Methodology/Principal Findings
We studied household contacts of persons with culture-positive pulmonary tuberculosis (TB) enrolled in a cohort study conducted in Kampala, Uganda. Whole blood IFN-γ production in response to Mtb culture-filtrate antigens was measured by ELISA and compared between infants (<2 years old, n = 80), young children (2 <5 years old, n = 216), older children (5 <15 years old, n = 443) and adults (≥15 years old, n = 528). We evaluated the relationship between IFN-γ responses and the tuberculin skin test (TST), and between IFN-γ responses and epidemiologic factors that reflect exposure to Mtb, and the effect of prior BCG vaccination on IFN-γ responses. Young household contacts demonstrated robust IFN-γ responses comparable to those of adults that were associated with TST and known risk factors for infection. There was no effect of prior BCG immunization on the IFN-γ response.
Conclusions/Significance
Young children in a TB endemic setting can mount robust IFN-γ responses generally comparable to those of adults, and as in adults, these responses correlated with the TST and known epidemiologic risk factors for Mtb infection.
doi:10.1371/journal.pone.0003407
PMCID: PMC2560997  PMID: 18923705

Results 1-25 (26)