Gill, C. accompanied by an increase in the proportion of AIDS among females. In S?o Paulo, as well as Fudosteine in the rest of Brazil, the male/female ratio among AIDS cases reported for individuals older than 12 years has fallen from 6:1 in the middle 1980s to less than 2:1 in 2002 and 2003 (21, 22). Monitoring the spread of HIV among healthy, sexually active women is an important element in tracking epidemic trends among heterosexual people and in supporting strategies for the prevention of mother-to-child HIV transmission. According to the Brazilian Ministry of Health cross-sectional sentinel serosurveys, conducted since 1997, HIV seroprevalence among delivering mothers has ranged from 0.00 to 2.41% (95% confidence intervals [CI] range from 0.00 to 4.74%), depending on year of evaluation, geographic region, and age groups (23). An assessment of incident infections (recently acquired infections) might provide useful information to better understand the epidemic dynamics among this low-prevalence segment of the population, potentially in real time for prevention strategies. The serologic testing algorithm for recent HIV seroconversion (STARHS) (14), also referred to as the detuned enzyme immunoassay (EIA), employs a sensitive-less sensitive EIA testing strategy and has been used to estimate HIV incidence from HIV-reactive serum samples (3-5, 9-17, 24-26, 30-33). Other laboratory tools, also based on antibody assays, have been evaluated for the detection of recent HIV infections by assessing specific reactivity against virus antigens (8, 18-20, 28). In the present study, we applied the STARHS in a cross-sectional analysis to estimate seroincidence among specimens from pregnant women (PW) from S?o Paulo, Brazil, and investigate the correlation of standard Western blot (WB) assay band patterns with the results of the STARHS. We tested, unlinked and anonymously, 106 anti-HIV-positive serum samples from PW seeking antenatal care in public clinics in S?o Paulo from 1991 to 2002. Serum samples were obtained from the serum bank of the Serology Section of the Adolfo Lutz Institute (IAL), S?o Paulo, and comprise all 93 HIV-seroreactive specimens from PW received for confirmatory purposes from 1991 to 2002 and 13 of 14 (92.9%) HIV-seroreactive specimens from 4,247 PW who attended for testing purposes from 1999 to 2002. Recent HIV seroconversion (within the previous 170 days) was evaluated by employing the Organon Teknika/bioMrieux Vironostika HIV type 1 (HIV-1) less sensitive EIA (33). Estimates of HIV incidence were calculated for the 1999-to-2002 period by means of mathematical modeling proposed by Janssen et al. (14). An HIV-1 Western blot assay (Genelabs Diagnostics, Singapore) was performed according to the Fudosteine manufacturer’s instructions. Each serum strip was interpreted and its banding patterns were scored in a blind fashion to avoid bias. Bivariate Fudosteine analysis was employed to assess the association (2 test) between STARHS results and the independent variables: age groups (by 5-year strata) and WB banding profiles. A stepwise forward-based procedure was employed in a multiple logistic regression model analysis. Based on adjusted odds ratios (OR), a final logistic regression model was evaluated. This study is a part of the project IAL/CCD-BM 28/01, approved by the IAL Committee for Ethics in Research, in accordance with Brazilian policies for research involving human subjects. By applying the STARHS strategy, we found 18 of 106 specimens (17.0%) with putative recent infection reactivity. This overall proportion of HIV infections is similar to rates reported by other authors also evaluating low-risk populations (14, 19), although we observed that 30.8% of specimens (4 of 13) showed a reactivity pattern consistent with recent Rabbit Polyclonal to SirT1 infection for the most recent years studied (1999 to 2002) (Table ?(Table1).1). The estimated annual HIV seroincidence, calculated for the 1999-to-2002 period, was Fudosteine 0.22 per 100 PW per year (95% CI, 0.04 to 0.61 per 100 PW per year) (Table ?(Table1).1). Unfortunately, information on the number of HIV screening tests performed on samples received from 1991 to 1998 was limited, which hindered the evaluation of the incidence trends. TABLE 1. Recent HIV-1 infections according to age group and year and HIV incidence data from 1999 to 2002= 0.708 (2 test). cFebruary to December 1991. dIncluding 4,247 samples received for testing and 4 samples received for confirmation purposes only. eJanuary to April 2002. No significant association between STARHS results and age groups could be found (= 0.708). Except for the PW aged 35 to 39 years, for which only established infections were identified, similar proportions of recent HIV infections were observed. With regard to antibody reactivity profiles, a negative or indeterminate pattern for one of the gp41, p31, p51, p66, and gp120 regions was a predictor of recent HIV-1 seroconversion (OR = 108.75, 0.001; OR = 7.36, 0.001; OR = 4.03, = 0.015; OR = 4.46, = 0.023; and OR = 5.38, = 0.105, respectively). After multiple logistic regression model analysis, only gp41 remained an independent factor associated with recent HIV-1.