Background & objectives:
Red blood cell alloimmunization is common in patients receiving multiple blood transfusions. Since the probability of repeat transfusion increases with longer life expectancy, it is important to study to which extent alloimmunized patients with a history of transfusion are prone to form alloantibodies after transfusion events. The aim of this study was to retrospectively analyze the alloimmunization against RBCs among transfused patients who were to undergo elective surgery in Tehran, Iran.
A total of 3092 occasionally transfused patients, who were to undergo elective surgery, in four hospitals in Tehran were included in the study. For patients with alloantibodies, the data about sex, date of birth, history of transfusion, surgery, abortion and alloantibody specificity were collected.
Clinically significant alloantibodies were found in 30 patients. The presence of positive antibodies in the patients for whom cross-match had been done was one per cent. Most of them had surgery history or transfusion record during the preceding year. The three most frequent alloantibodies were anti-K (23.53%), anti- E (20.59%) and anti-c (17.56%).
Interpretation & conclusions:
The most common clinically significant alloantibodies identified in men and women were anti-K and anti-E, respectively. The most common causes of alloimmunization for men were surgery history and transfusion record and for women pregnancy.
Alloimmuization; RBC antigens and antibodies; serological testing; transfusion-surgery
Red blood cell (RBC) alloantibodies may be formed following exposure to RBC antigens. In most cases, the alloimmunization develops during pregnancy or from previous blood transfusions. The RBC antigens and their alloantibodies vary among different human populations and ethnic groups, and they do have a clinical significance for their adverse immunological reactions.
This study aimed at studying the prevalence of RBC alloantibodies at the Blood Transfusion Unit of Hospital Raja Perempuan Zainab II in Kota Bharu, Malaysia.
Patients and Methods:
A cross-sectional study was performed utilizing data obtained in the years 2007 and 2008. Data of antibody screening tests from 5719 patients were examined.
Results and Discussion:
The overall prevalence of alloimmunization was 65 (1.13%). The majority of these had a single alloantibody (76.9%), whereas the remaining 23.1% had multiple antibodies. The anti-E antibody comprised the most common alloantibody (24.6%) followed by the anti-Lewis (a) antibodies (18.5%) and the anti-M antibody (13.8%). There were more female recipients than males.
It was concluded that the findings of this work have been comparable with other published works, and that the main factors associated with alloantibody formation were multiple transfusions and pregnancies. The study also emphasizes the necessity for carrying out immunohematology studies prior to every blood transfusion especially in cases that require multiple transfusions for a long period of time such as in thalassemia patients.
RBC antigens; alloantibodies; blood transfusion
Alloimmunization to minor red blood cell (RBC) antigens occurs commonly in sickle cell disease (SCD). Patients with alloimmunization demonstrate increased risk for new alloantibody formation with subsequent transfusion. Alloimmunization to human leukocyte antigens (HLA) can occur with RBC transfusion and may result in graft rejection during stem cell or organ transplantation. The prevalence and risk factors for HLA alloimmunization in multiply transfused pediatric SCD patients are unknown.
A cross-sectional study of HLA alloimmunization in SCD patients aged 3–21 years with a history of ≥3 RBC transfusions was performed to test the hypothesis that HLA alloimmunization is associated with RBC alloimmunization. Antibodies to class I and class II HLA were measured by Flow Panel Reactive Antibody (FlowPRA®).
Seventy-three SCD patients (30 with RBC antibodies) were tested. HLA antibodies were detected in 25/73 (34%) patients; class I HLA antibodies occurred in 24/73 (33%) and class II HLA antibodies occurred in 3 (4%). Among patients with RBC antibodies, 16/30 (53%) had HLA antibodies, while 9/43 (21%) patients without RBC antibodies had HLA antibodies (OR 4.32 [1.6–12.1]). In a multivariate analysis, antibodies to RBC antigens were an independent predictor of HLA alloimmunization (P =0.041). The association of RBC and HLA immunization was strongest among patients with no history of chronic transfusion therapy.
This analysis is the first description of HLA alloimmunization in pediatric SCD patients who receive primarily leukoreduced RBC transfusions and demonstrates that HLA alloimmunization tendency is associated with antibodies to RBC antigens.
alloimmunization; human leukocyte antigen (HLA); sickle cell disease; transfusion
Red blood cell alloimmunization is a major complication of transfusion therapy. Host immune markers that can predict antibody responders remain poorly described. As regulatory T cells (Tregs) play a role in alloimmunization in mouse models, we analyzed the Treg compartment of a cohort of chronically transfused patients with sickle cell disease (SCD, n = 22) and β-thalassemia major (n = 8) with and without alloantibodies. We found reduced Treg activity in alloantibody responders compared with nonresponders as seen in mice. Higher circulating anti-inflammatory IL-10 levels and lower IFN-γ levels were detected in non-alloimmunized SCD patients. Stimulated sorted CD4+ cells from half of the alloimmunized patients had increased frequency of IL-4 expression compared with nonresponders, indicating a skewed T helper (Th) 2 humoral immune response in a subgroup of antibody responders. All patients had increased Th17 responses, suggesting an underlying inflammatory state. Although small, our study indicates an altered immunoregulatory state in alloantibody responders which may help future identification of potential molecular risk factors for alloimmunization.
Serological safety is an integral part of overall safety for blood banks. Emphasis is on the use of routinue Red Blood Cell (RBC) antibody screen test, at set time intervals, to reduce risks related to alloantibodies. Also emphasis is on importance of issuing antigen negative blood to alloantibody positive patients. Effect of using leucodepleted blood on the rate of alloimmunization is highlighted. The concept of provision of phenotypically matched blood is suggested.
Materials and Methods:
Antibody screen test is important to select appropriate blood for transfusion. Repeat antibody screen testing, except if time interval between the earlier and subsequent transfusion was less than 72 hours, followed by antibody identification, if required, was performed in patients being treated with repeat multiple blood transfusions. Between February 2008 and June 2009, repeat samples of 306 multi-transfused patients were analyzed. Search for irregular antibodies and reading of results was conducted using RBC panels (three-cell panel of Column Agglutination Technology (CAT) and two cell panel of the Solid Phase Red Cell Adherence Technology (SPRCAT). Specificities of antibodies were investigated using appropriate panels, 11 cell panel of CAT and 16 cell panel of SPRCA. These technologies, detecting agglutination in columns and reactions in solid phase, evaluate the attachment of irregular incomplete antibody to antigen in the first phase of immunological reaction more directly and hence improve the reading of agglutination. Three to four log leuco reduced red blood cells were transfused to patients in the study using blood collection bags with integral filters.
Alloimmunization rate of 4.24% was detected from 306 multiply transfused patients tested and followed up. The Transfusion therapy may become significantly complicated.
Red cell antibody screening and identification and subsequent issue of antigen negative blood have a significant role in improving blood safety. Centers that have incorporated antibody screen test and identification have ensured safe transfusion. Identified patients should be flagged in a database and information shared. Such patients can be given carry-on cards and educated about the names of the identified antibodies. Full red cell phenotyping of individuals, patients and donors, can be feasibility.
Antibody screen Test; antibody identification; cell panel
Several irregular red blood cell alloantibodies, produced by alloimmunization of antigens in transfusions or pregnancies, have clinical importance because they cause hemolysis in the fetus and newborn and in transfused patients.
a prospective analysis of patients treated by the surgical and clinical emergency services of Hospital de Clínicas of the Universidade Federal do Triângulo Mineiro (HC/UFTM), Brazil was performed to correlate alloimmunization to clinical and epidemiological data.
Blood samples of 143 patients with initial negative antibody screening were collected at intervals for up to 15 months after the transfusion of packed red blood cells. Samples were submitted to irregular antibody testing and, when positive, to the identification and serial titration of alloantibodies. The Fisher Exact test and Odds Ratio were employed to compare proportions.
Fifteen (10.49%) patients produced antibodies within six months of transfusion. However, for 60% of these individuals, the titers decreased and disappeared by 15 months after transfusion. Anti-K antibodies and alloantibodies against antigens of the Rh system were the most common; the highest titer was 1:32 (anti-K). There was an evident correlation with the number of transfusions.
Given the high incidence of clinically important red blood cell alloantibodies in patients transfused in surgical and clinical emergency services, we suggest that phenotyping and pre-transfusion compatibilization for C, c, E, e (Rh system) and K (Kell system) antigens should be extended to all patients with programmed surgeries or acute clinical events that do not need emergency transfusions.
Blood transfusion; Blood group antigens; Hemolysis; Immunophenotyping; Emergencies
The objective of this study was to explore the frequency of red cell alloantibodies and autoantibodies among β-thalassaemia patients who received regular transfusions.
Material and methods
This study included 501 patients with β-thalassaemia. This work planned to study the presence of alloantibodies and autoantibodies to different red cell antigens in multitransfused thalassaemia patients using the ID. Card micro typing system.
Of a total of 501 β-thalassaemia patients included in the study, 11.3% of patients developed alloantibodies; 9.7% of these alloantibodies were clinically significant. The most common alloantibodies were anti-K, anti-E and anti-C. The rate of incidence of these alloantibodies was 3.9%, 3.3% and 1.7% respectively. Autoantibodies occurred in 28.8% of the patients and 22.1% of these antibodies were typed IgG. There was a significant association between splenectomy with alloimmunization and autoantibody formation (p = 0.03, p = 0.001 respectively). There was no significant association between alloantibody, autoantibody formation and number of transfused packed red cells.
Alloimmunization to minor erythrocyte antigens and erythrocyte autoantibodies of variable clinical significance are frequent findings in transfused β-thalassaemia patients. There is an association between absence of the spleen and the presence of alloimmunization and autoantibody formation.
β-thalassaemia; alloimmunization; autoantibodies
The development of irregular serum antibodies (alloantibodies) following massive transfusion was studied in 144 patients who had undergone cardiac valve replacement. An overall incidence of alloimmunization of 8·3% was found. Of the 15 antibodies detected nine were Rhesus anti-E and four anti-Kell. The incidence of anti-E formation in Rhesus E-negative patients was 11·4%; the corresponding figure for anti-Kell was 3·2%. The results suggest that the risk of allo-immunization is directly related to the volume of blood transfused, and Rhesus E-negative persons appear to be at particular risk.
Australia (Au) antigen investigations were also carried out in 102 of these cases. Three patients were Au antigen positive, one of them developing acute hepatitis. In each case no Au antigen could be detected in the donor blood that was used.
It is suggested that tests for alloantibodies and for the Australia antigen should become part of the routine follow-up of any patient receiving massive transfusion.
Transfusion therapy is currently an effective therapeutic intervention in a number of diseases, including sickle cell disease. However, its use is complicated by a high incidence of red blood cell (RBC) alloimmunization in the transfusion recipients. The identification of T regulatory cells (Tregs) among the CD4+CD25+ T cell subset as key regulators of peripheral tolerance in mice as well as humans has opened an exciting era in the prevention and treatment of autoimmune disease and for improving organ transplantation. However, their potential in inducing transfusion tolerance remains to be explored. We used red cells from mice transgenic for human glycophorin A blood group antigen as donor cells and transfused wild-type mice to induce alloantibodies, as an experimental system to study RBC alloimmunization. We found that depletion with anti-CD25 enhanced the alloantibody production, indicating that CD25 Tregs play an important role in regulation of alloantibody responses. More importantly, adoptive transfer of purified population of CD4+CD25+ but not CD4+CD25– cells from naïve mice prevented the induction of IgG and IgM alloantibody production in transfusion recipients, with a concomitant reduction in activated splenic B cells and macrophages. Similarly, adoptive transfer of purified populations of CD4+CD25+ cells from naïve mice into naïve syngeneic recipients inhibited the anti-Ig response to rat RBCs in the recipients but transfer of control CD4+CD25– cells did not. Altogether, our results demonstrate that Tregs participate in the control of trans-fusion-associated RBC alloantibody responses, opening up the possibility that Treg immunotherapy may be exploited for suppressing transfusion immunization events.
Alloantibodies of clinical importance can cause transfusion reactions or hemolytic disease of the fetus and newborn (HDFN). The frequencies of these antibodies have not been reported in our locality.
To determine the frequency of occurrence of alloantibodies among pregnant women in Port Harcourt, Nigeria.
Settings and Design:
This is a prospective study, which was carried out in the Braithwaite Memorial Specialist Hospital, Port Harcourt, Nigeria.
Materials and Methods:
Screening and identification of red blood cell alloantibodies was done on the sera of 500 pregnant women using the DiaMed, DiaCell, and DiaPanel reagents (Cressier, Switzerland). ABO and Rh blood groups were done using antisera bought from Biotec (Ipswich, UK).
Alloantibodies were identified in the serum of 17 of the 500 (3.4%) pregnant women. The specificity of the antibodies was as follows: anti-C 6 (1.2%), anti-E 3 (0.6%), anti-Jsb 3 (0.6%), and anti-K 5 (1.0%). No anti-D was identified despite 8.6% of the study population being Rhesus D (Rh D) negative. The distribution of the antibodies was found to be independent of the blood groups of the participants (χ2 = 4.050, P = 0.670). Blood group O constituted the highest percentage (48.0%).
This study has identified the presence of non-Rh D antibodies to the proportion of 3.4%. Rh D antibody was absent in this population irrespective of the relatively high percentage of Rh D negative women. There is a need to determine the actual risk these antibodies may pose to the antenatal women and to include antibody screening and identification in routine antenatal care.
Alloantibodies; frequencies; non-Rh D antibodies; HDFN; Nigeria
In this study, we report the first Korean case of an anti-Gerbich (Ge) alloantibody to a high-incidence antigen that belongs to the Ge blood group system. The alloantibody was detected in a middle-aged Korean woman who did not have a history of transfusion. Her blood type was B+, and findings from the antibody screening test revealed 1+ reactivity in all panels except the autocontrol. The cross-matching test showed incompatible results with all 5 packed red blood cells. Additional blood type antigen and antibody tests confirmed the anti-Ge alloantibody. While rare, cases of hemolytic transfusion reaction or hemolytic disease in newborns due to anti-Ge have been recently reported in the literature. Therefore, additional further studies on alloantibodies to high-incidence antigens, including anti-Ge, are necessary in the future.
Ge; Blood group antigens; Transfusion
Although red cell transfusions are lifesavers for patients with thalassemia, they are responsible for a series of complications and expose the patients to a variety of risks.
Material and Methods:
This cross-sectional study included 464 Egyptian beta(β) thalassemia major patients whose age ranged between 10 months and 31 years (mean 10.2 ± 6.6 years). All patients were subjected to thorough history taking with special emphasis on blood transfusions regarding rate of blood transfusion, type of received blood, and history of previous transfusion reactions in addition to type of chelation and compliance to iron chelation therapy and history of diabetes. Serum ferritin and pretransfusion hemoglobin assessment were done for all patients.
The mean pretransfusion hemoglobin level was 5.7 ± 1.16 g/dl. Allergic reactions were observed in 3.9% of the patients during the period of the study, while the history of previous allergic reaction was given by 72% of the patients. Deferiprone showed better compliance (58.6%) than deferoxamine (26.3%). The prevalence of diabetes was 10.1% among the studied group. On comparing diabetics to nondiabetics, serum ferritin, transfusion intervals, and age were statistically higher among diabetics (P<0.001).
Lower pretransfusion hemoglobin and high rate of prevalence of diabetes, in addition to better compliance to deferiprone than deferoxamine, were detected among the patients.
β-thalassemia; blood transfusion; allergic transfusion reactions; Iron chelators
The thalassemias are among the most common genetic disorders worldwide, occurring more frequently in the Mediterranean region. The aim of this study was to determined frequency of sensory-neural hearing loss in major ß- thalassemias transfusion dependent patients in south of Iran.
A cross sectional study on 308 cases of major beta-thalassemia patients referring to Thalassemia Center of Shiraz University of Medical Sciences between 2006–2007 years. The diagnosis of ß- thalassemia major was based on clinical history, complete blood count and hemoglobine electrophoresis. Clinical data such as serum ferritin level, deferoxamine (DFO) dose, mean daily doses of DFO (mg/kg) and audiometric variables was recorded.
Out of 308 cases, 283 (96.5%) had normal hearing and 10 (3.5%) sensorineural hearing loss. There was no statically significant difference between two groups regarding mean age, weight, age at the first blood transfusion, age at the first DFO infusion.
We found the lowest incidence of sensorineural hearing loss in a large population of patients suffered from major thalassemia who received DFO. We show that DFO is not ototoxic at a low dose. When considering all related literature, as a whole there has been much critical misrepresentation about DFO ototoxicity.
Thalassemia; Sensorineural Hearing Loss; Blood Transfusion; Deferoxamine; Ferritin
The ideal management of thalassemia involves a multidisciplinary therapeutic team approach and should be preferably done at a comprehensive thalassemia care center with all sorts of specialists and the backup of a well-equipped blood bank. However, in developing country like ours, these facilities are not available in rural set up. So, a situation where conservative therapy with regular blood transfusion is the only choice left to innumerable thalassemic children.
To evaluate the existing conservative management protocol of Beta-thalassemia major patients in the setup of a subdivision level Government Hospital of rural West Bengal, India.
Materials and Methods:
The study was performed between December 2009 and December 2011. Beta-thalassemia major patients, registered in blood bank for moderate transfusion regimen, were taken in study. All the patients were screened for Transfusion Transmittable Infections at the time of registration and thereafter periodically every six months. Iron chelation therapy was given simultaneously with transfusion at a dose of 20 to 40 mg/kg/day for six days. The patients were advised to follow up with chelation therapy at home by daily infusion with a goal of maintaining serum ferritin level below 1000 ng/ml. Over this long period of study, the patients were periodically evaluated for complications.
The average blood requirement (ml/kg/year) in 1-5 years, 6-10 years, and 11-15 years were 110, 150, and 180, respectively. Incidence of Hepatitis C Virus infection in 1-5 years and 6-10 years were 1.75% and 2.08%, respectively. It is well seen that serum ferritin level increase with ascending age as does the blood consumption.
Conservative management may be the best alternative and at times the only hope for patients in developing country like ours. However, in order to decrease the disease load, steps need to be taken to introduce preventive measures.
Beta-thalassemia major; blood transfusion; conservative management; iron chelation; prevention program
Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC) transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands), dilated myocardiopathy, liver fibrosis and cirrhosis). Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes), gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely, deletions in the beta globin gene on chromosome 11, leading to reduced (beta+) or absent (beta0) synthesis of the beta chains of hemoglobin (Hb). Transmission is autosomal recessive; however, dominant mutations have also been reported. Diagnosis of thalassemia is based on hematologic and molecular genetic testing. Differential diagnosis is usually straightforward but may include genetic sideroblastic anemias, congenital dyserythropoietic anemias, and other conditions with high levels of HbF (such as juvenile myelomonocytic leukemia and aplastic anemia). Genetic counseling is recommended and prenatal diagnosis may be offered. Treatment of thalassemia major includes regular RBC transfusions, iron chelation and management of secondary complications of iron overload. In some circumstances, spleen removal may be required. Bone marrow transplantation remains the only definitive cure currently available. Individuals with thalassemia intermedia may require splenectomy, folic acid supplementation, treatment of extramedullary erythropoietic masses and leg ulcers, prevention and therapy of thromboembolic events. Prognosis for individuals with beta-thalassemia has improved substantially in the last 20 years following recent medical advances in transfusion, iron chelation and bone marrow transplantation therapy. However, cardiac disease remains the main cause of death in patients with iron overload.
Hepatitis C virus (HCV) is the major cause of post-transfusion hepatitis infection (PTH). Patients with thalassemia major are at high risk of hepatitis C due to the blood transfusion from donors infected by HCV. The aim of this study was to detect the prevalence of anti-HCV antibodies and risk factors in multitransfused thalassemic patients in Isfahan-Iran to establish more preventive strategies.
This study was conducted to assess the patients with beta-thalassemia in Isfahan hospitals during 1996-2011 for HCV infection. A structured interview questionnaire was developed by the trained researcher to collect the demographic and risk factors. Statistical analysis was done by Chi-square test, Mann-Withney and multiple logistic regressions using SPSS software, version 15.
466 patients with major thalassemia participated in this study. The mean age of patients was 17.46 ± 8.3. Two hundred and seventy (58.3%) and 193 (41.7%) of participants were male and female, respectively. The prevalence of HCV was estimated 8% among thalassemia patients. History of surgery, history of dental procedure, number of units transfused per month, number of transfusion per month and duration of transfusion had significant association with HCV seropositivity in univariate analysis. There were no statistical significant risk factors for HCV seropositivity in multiple logistic regression models.
Our findings revealed that blood transfusion was the main risk factors for HCV infection among beta-thalassemic patients. Therefore, more blood donor screening programs and effective screening techniques are needed to prevent transmission of HCV infection among beta-thalassemic patients.
Beta-thalassemia; HCV infection; Iran
The aim of this study was to evaluate the frequency of red blood cell (RBC) alloantibodies in surgical patients.
Blood samples of 18,980 Chinese surgical patients were collected and tested between January 2009 and September 2010. For patients with RBC alloantibodies, sequences of antibodies were identified with the DiaMed Asia antibody screening system. Data regarding sex, age, transfusion history, pregnancy history, and alloantibody specificity were collected.
39 alloantibodies were identified from 18,980 samples, yielding a prevalence of 0.21%. The most frequently identified alloantibodies were Rhesus system antibodies (28/39, 71.8%), including anti-E (17/39; 1 anti-E accompanied by anti-Fyb), anti-c (5/39), anti-cE (2/39), anti-Cw (1/39), anti-D (1/39), and anti-e (1/39). Other antibodies included anti-M (5/39), anti-Lea (2/39), anti-Leb (1/39), anti-K+S (1/39), anti-JKa (1/39), and anti-JSa (1/39). The frequency of alloantibodies was greater in females than in males (31 vs. 8).
The results show a higher prevalence of RBC alloantibodies in females than in males. Anti-E was the most common alloantibody identified in this Chinese surgical population and was also more frequent in females compared to males.
Red blood cells; Alloantibody; Surgery
Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin. This disorder results in excessive destruction of red blood cells, and there is no effective treatment. Patients require lifelong blood transfusion, usually started within 6 to 12 months of birth of patient, which on other hand has its own complications. It is a chronic disease that manifests so early in life that it leads to psychological and social problems for parents . We focused on parents to assess the impact of their child’s disease.
To determine the psychosocial problems of parents of thalassemic children.
This cross sectional study was conducted among the parents of thalassemic children attending THALASSEMIA CENTRE, BAHAVAL VICTORIA HOSPITAL (BVH), BAHAWALPUR, PAKISTAN during the year 2011. A self designed questionnaire was used that contained questions regarding psychological and social aspects. Patient Health Questionnaire-9 (PHQ-9) was used to assess the depression of parents of thalassemic children.
Of the 100 parents interviewed, the majority were mothers (71%) , with a mean age of 32 ± 8.07 years for both sexes. 29 percent of the parents had moderate to severe depression, 16 percent had sleep disturbances. 56 percent were downgraded by relatives. There was a significant relationship between respondent education and depression (p < 0.05).
A substantial number of parents have psychosocial problems due to the disease of their child. Parent counseling is needed on regular basis.
Parents; Psychological morbidity; Thalassemia; Social relationship; Adjustment disorder; Pakistan
Naturally occurring alloantibodies produced against A and B red cell antigens in cats can cause acute hemolytic transfusion reactions. Blood incompatibilities, unrelated to the AB blood group system, have also been suspected after blood transfusions through routine crossmatch testing or as a result of hemolytic transfusion reactions.
Incompatible crossmatch results among AB compatible cats signify the presence of a naturally occurring alloantibody against a newly identified blood antigen in a group of previously never transfused blood donor cats. The associated alloantibody is clinically important based upon a hemolytic transfusion reaction after inadvertent transfusion of red cells expressing this red cell antigen in a feline renal transplant recipient that lacks this red cell antigen.
Blood donor and nonblood donor cats were evaluated for the presence of auto- and alloantibodies using direct antiglobulin and crossmatch tests, respectively, and were blood typed for AB blood group status. Both standard tube and novel gel column techniques were used.
Plasma from 3 of 65 cats and 1 feline renal transplant recipient caused incompatible crossmatch test results with AB compatible erythrocytes indicating these cats formed an alloantibody against a red cell antigen they lack, termed Mik. The 3 donors and the renal transplant recipient were crossmatch-compatible with one another. Tube and gel column crossmatch test results were similar.
Conclusions and Clinical Importance
The absence of this novel Mik red cell antigen can be associated with naturally occurring anti-Mik alloantibodies and can elicit an acute hemolytic transfusion reaction after an AB-matched blood transfusion.
Blood type; Cat; Gel column crossmatch; Hemolytic transfusion reaction; Renal transplant
Apart from inhibitor development in patients with hemophilia (PWH) the old problems of blood borne viral infections and red cell alloimmunization still persist in PWH from developing countries. This study was planned to detect the presence of inhibitors in our PWH and to determine the presence of transfusion transmitted infections (TTI) markers and clinically significant red cell alloantibodies in these patients.
Materials and Methods:
One hundred fourteen PWH were screened for various laboratory tests. Screening for inhibitors was done by mixing study. Blood grouping, TTI testing and red cell alloantibody detection were done as per the departmental standard operating procedures.
Out of 114 patients evaluated 98(86%) had hemophilia A and remaining 16(14%) had hemophilia B. Five (5.1%) patients of hemophilia A were positive on inhibitor screening. On Bethesda assay, one patient was high responder (14.4 BU/ml) and rest 4 were low responders (<5 BU/ml). Overall, 19 PWH were positive for TTI markers and two had clinically significant red cell alloantibody (anti-E and anti-Jkb).
This is probably first comprehensive study from our state on laboratory testing in PWH. The specialty of Transfusion Medicine can be a core part of hemophilia care. The overall prevalence of inhibitors in our hemophilia A patients was 5.1%, which is less as compared to majority of published studies.
Hemophilia; inhibitor; transfusion-related complications
Despite progress made in the prevention of transfusion-transmitted infections (TTI) over the last few years, they continue to be a problem in many parts of the world, particularly in multitransfused patients.
The aim of this study was to estimate the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), and to evaluate the screening and vaccination program among our cohort of multitransfused children from Qena, Upper Egypt.
Patients and Methods
One-hundred children suffering from diseases requiring repeated blood transfusions were included in the study. They were classified into group 1, which included 67 children with thalassemia, and group 2, which included 33 children with hemophilia. Screening for hepatitis B surface antigen, hepatitis B surface antibody, hepatitis B core antibody and antibody to HCV was done using a second-generation enzyme-linked immunosorbent assay technique.
Only 12% of all patients were either acutely or chronically infected with HBV. 46% were immune due to previous vaccination, whereas 39% of patients were not protected from HBV infection. HCV antibodies were positive in 45% of cases. Seventy-eight patients had a complete hepatitis B vaccination in the form of three doses as documented by birth certificate. Thirty-six patients mentioned history suggestive of hepatitis. The prevalence of the studied hepatitis markers was similar in both the thalassemia and hemophilia groups of children.
Transfusion-transmitted hepatitis is still a major problem for multitransfused children in Egypt. More effort is required to reduce the infection rate through proper screening of blood and blood products, strict emphasis on receiving the vaccine, regular follow-up for those children with a hepatitis B antibody titer, and providing booster doses for those in need.
Child; Hepatitis; Transfusion; Egypt
To evaluate the rate of seropositivity to hepatitis B and C and Human Immunodeficiency Virus (HIV) infections among children with β-thalassemia major receiving multiple transfusions in Ahmedabad, India, compared with healthy controls.
Materials and Methods:
The study was performed during January 2007 to January 2009 on multi-transfused children suffering with β-thalassemia major registered in the Prathama Blood Centre, Ahmedabad; Jeevandeep hospital, Ahmedabad; and Red Cross Blood Centre, Ahmedabad, and investigated for the prevalence and development of transfusion-transmitted infections. Hepatitis B surface Antigen (HBsAg), anti-Hepatitis C Virus (HCV) Antibodies (Ab), and HIV Ab were checked using a fourth-generation Enzyme-Linked Immunosorbent Assay (ELISA). Positive tests were confirmed by western blots. Healthy blood donors were used for the control group.
Hepatitis B surface antigen, anti-HCV Ab, and HIV Ab were positive in one of 96 (1.04%; 95% Confidence Interval (CI) = 0.17–1.3), 24 of 96 (25%; 95% CI = 11.4–14.2), and one of 96 (1.04%; 95% CI = 0.12–1.3), respectively. The rate of anti-HCV Ab was significantly higher in multi-transfused children suffering with β-thalassemia major. In thalassemia patients, the rate of positive anti-HCV Ab was significantly higher than that for positive HBsAg (P<0.001) and HIV Ab (P<0.001).
It is concluded that HCV is the current major problem in multi-transfused children with thalassemia major and more careful pretransfusion screening of blood for anti-HCV must be introduced in blood centers.
Hepatitis B; hepatitis C; Human immunodeficiency virus; β-thalassemia major; seroprevalence
Hepatitis C is prevalent among thalassemia patients in Iran. It is mainly transfusion mediated, in particular among patients treated before 1996 when blood screening was introduced.
The current study aimed to investigate why patients still seroconvert to anti-HCV in Iranian thalassemia centers.
Patients and Methods
During 2006-2007 sera were sampled from 217 anti-HCV positive thalassemia patients at nine thalassemia centers in Tehran and Amol city, where 34 (16%) patients had been infected after 1996. The HCV subtype could be determined by sequencing and phylogenetic analysis of partial NS5B and/or 5׳NCR-core region in 130 strains.
1a (53%) was predominant followed by 3a (30%), 1b (15%), and one strain each of 2k, 3k and 4a. Phylogenetic analysis revealed 19 clades with up to five strains diverging with less than six nucleotides from each other within subtypes 1a and 3a. Strains in seven clades were from nine patients infected between 1999 and 2005 and similar to strains from eight patients infected before 1996, indicating ongoing transmission at the centers. Further epidemiological investigation revealed that 28 patients infected with strains within the same clade had frequently been transfused at the same shift sitting on the same bed. An additional eight patients with related strains had frequently been transfused simultaneously in the same room.
The results suggest nosocomial transmission at these thalassemia centers both before and after the introduction of blood screening. Further training of staff and strict adherence to preventive measures are thus essential to reduce the incidence of new HCV infections.
Hepatitis C; Thalassemia; Iran
Red blood cell (RBC) alloimmunization can be a serious complication of blood transfusion, but factors influencing the development of alloantibodies are only partially understood. Within FDA-approved time limits, RBCs are generally transfused without regard to length of storage. However, recent studies have raised concerns that RBCs stored for more than 14 days have altered biologic properties that may affect medical outcomes. To test the hypothesis that storage time alters RBC immunogenicity, we utilized a murine model of RBC storage and alloimmunization.
STUDY DESIGN AND METHODS
Blood from transgenic HOD donor mice, which express a model antigen (hen egg lysozyme [HEL]) specifically on RBCs, was filter leukoreduced and stored for 14 days under conditions similar to those used for human RBCs. Fresh or 14-day-stored RBCs were transfused into wild-type recipients. The stability of the HOD antigen and post-transfusion RBC survival were analyzed by flow cytometry. RBC alloimmunization was monitored by measuring circulating anti-HEL immunoglobulin levels.
Transfusion of 14-day-stored, leukoreduced HOD RBCs resulted in 10- to 100-fold higher levels of anti-HEL alloantibodies as detected by enzyme-linked immunosorbent assay than transfusion of freshly collected, leukoreduced RBCs. RBC expression of the HOD antigen was stable during storage.
These findings demonstrate that HOD murine RBCs become more immunogenic with storage and generate the rationale for clinical trials to test if the same phenomenon is observed in humans. Length of storage of RBCs may represent a previously unappreciated variable in whether or not a transfusion recipient becomes alloimmunized.
Increased rates of RBC alloimmunization in patients with sickle cell disease may be due to transfusion frequency, genetic predisposition, or immune dysregulation. To test the hypothesis that sickle cell pathophysiology influences RBC alloimmunization, we utilized two transgenic mouse models of sickle cell disease.
Study Design and Methods
Transgenic sickle mice, which express human α and βS globin, were transfused with fresh or 14-day stored RBCs containing the HOD (hen egg lysozyme, ovalbumin, and human Duffyb) antigen; some recipients were inflamed with poly (I:C) prior to transfusion. Anti-HOD alloantibody responses were subsequently measured by ELISA and flow crossmatch; a cohort of recipients had post-transfusion serum cytokines measured by bead array.
Both Berkeley and Townes homozygous (SS) and heterozygous (AS) mice had similar rates and magnitude of anti-HOD RBC alloimmunization following fresh HOD RBC transfusion compared with control animals; under no tested condition did homozygous SS recipients make higher levels of alloantibodies than control animals. Unexpectedly, homozygous SS recipients had blunted cytokine responses and lower levels of anti-HOD alloantibodies following transfusion of 14-day stored RBCs, compared with control animals.
In sum, homozygous βS expression and the ensuing disease state are not alone sufficient to enhance RBC alloimmunization to transfused HOD RBCs in 2 distinct humanized murine models of sickle cell disease under the conditions examined. These data suggest other factors may contribute to the high rates of RBC alloimmunization observed in humans with sickle cell disease.
red blood cells (sickle cell disease); alloimmunization; transfusion medicine