Two cohorts were recruited for this study, 62 high-risk women and 33 low-risk women. Their demographic data have been published elsewhere and can be found in Table (15
). Semen was detected in eight samples but was not associated with any of the findings studied, so these samples were included in the analyses (Table ).
Summary of demographics, sexual partners, and practices of study participants
Effects of BV and vaginal leukocytes on SLPI and Lf levels
The mean Lf concentration in the high-risk group was 204 ng/ml (standard deviation = 75 ng/ml; range, 19 to 371 ng/ml), which was significantly higher than the mean in the low-risk cohort, which was 160 ng/ml (standard deviation = 70 ng/ml; range, 13 to 252 ng/ml; Fig. ) (P = 0.007). The mean SLPI concentration in the high-risk group was 9,987 pg/ml (standard deviation = 3,292 pg/ml; range, 1,832 to 21,469 pg/ml), which did not differ significantly from that of the low-risk cohort, with a mean concentration of 9,257 pg/ml (standard deviation = 1,892 pg/ml; range, 4,670 to 11,727 pg/ml; Fig. ). Subgroups of 26 high-risk and 11 low-risk women were also tested for RANTES levels. For these studies, paired endocervical fluid samples collected before and after BV treatment were studied. Since BV was absent in the low-risk women, we compared posttreatment samples from the high-risk cohort with low-risk samples. The RANTES levels in cervical fluid were 316.6 ± 175 pg/ml in the low-risk women. In the high-risk women with BV, the RANTES level was 2,428.4 ± 9,307.1 pg/ml, and posttreatment it was 331.3 ± 632.0 pg/ml (Fig. ). The difference was significant (P = 0.05). However, 17 women had a reduction in RANTES levels with treatment, compared to 9 who had increased RANTES levels following treatment. There was no significant difference between the posttreatment levels in the high-risk and low-risk groups. However, the high-risk group is represented by women with a range of risk behaviors. We further defined a higher-risk group of women who reported having had >10 partners in 6 months and using condoms sometimes or never. When we compared these women to the remainder of the high-risk cohort, they had significantly higher RANTES levels (P = 0.03).
Effects of cohort and BV on Lf concentrations in CVL fluid. The data shown are means and 95% confidence intervals (error bars). (A) For the cohort effect, the P value is 0.007. (B) For the BV effect, the P value is 0.004.
FIG. 2. Effects of cohort and BV on SLPI concentrations in CVL fluid. The data shown are means and 95% confidence intervals (error bars). (A) For the cohort effect, the P value shows no statistical significance. (B) For the BV effect, the P value is 0.04. (more ...)
FIG. 3. The mean RANTES levels of the pre- and posttreatment subgroups were 2,428.4 ± 9,307.1 pg/ml and 331.3 ± 632.0 pg/ml (P = 0.05), respectively. Seventeen women had decreased RANTES levels posttreatment, and nine had increased levels. (more ...)
The concentrations of SLPI and Lf in the presence or absence of BV or vaginal leukocytes are given in Table . It appears that the presence of BV decreases the mean SLPI concentration (P = 0.04; Fig. ) but increases the mean Lf concentration (P = 0.004; Fig. ). In addition, increased levels of leukocytes are associated with a decrease in SLPI (statistically insignificant, P = 0.25) and an increase in Lf (P = 0.0002).
A number of other cofactors that might influence the concentrations of SLPI and Lf were analyzed. With the exception of BV, none of the other risk factors studied was significantly associated with the concentration of SLPI (data not shown). On the other hand, as shown in Table , several risk factors, when considered individually, are significantly associated with the concentration of Lf. These include BV, the presence of red blood cells, the presence of leukocytes, and vaginitis, which includes both BV and Trichomonas infection. The phase of the menstrual cycle was not associated with either SLPI or Lf. In the multivariate analysis, after adjustment for the risk group, only the levels of leukocytes in the CVL fluid specimen remained strongly associated with the concentration of Lf (P < 0.0001). None of the other risk factors, including BV, were still associated with the concentration of Lf at a significance level of 0.05. In general, this suggests that most of the effects of the risk factors are explained by the risk group and the levels of leukocytes. The effects of leukocytes on the Lf concentration were similar for both the low- and high-risk groups (Table , analysis 2).
Association between Lf and other factors by linear regression modelsa
Several risk behaviors were positively associated with Lf concentrations as part of the overall cohort effect but were not independently associated with the Lf concentration after adjustment for the cohort effect. It appears that the effect of risky behavior on Lf is largely accounted for by the variable “exchange of sex for drugs, money, or shelter” when the effect of leukocytes in the CVL fluid specimen is adjusted for. We collected data on contraceptive and antibiotic use. Only seven participants used hormonal contraceptives. There was no association between type of contraception and either SLPI or Lf. None of the participants reported antibiotic use at the time these samples were taken.
The concentration of SLPI in the CVL fluid samples was not associated with risk behavior. However, the presence of bacterial vaginosis was negatively associated with the SPLI concentration (P = 0.04).