Estimation of the Seroconversion Duration of HIV-1 Antibodies in Individuals With Recent Infection in China

Abstract

The identification of recent HIV-1 infection is clinically important for the effective treatment and prevention of transmission. However, the window period for seroconversion with respect to various HIV-1 antibodies is not well characterized. In addition, the routine HIV testing algorithms are not particularly appropriate for the identification of recent HIV-1 infection. In this study, we enrolled individuals who showed seroconversion from negative Western blot (WB) or indeterminate WB results and analyzed the window periods for appearance of HIV-1 antibodies. A total of 10,934 individuals with suspected HIV infection were tested by Wuhan CDC between 2012 and 2017; of these, 40 individuals with initial negative WB and 102 individuals with initial indeterminate WB who showed positive WB results within 100 days were included in the analysis. The mean time for seroconversion was 43.90 (95% confidence interval [CI]: 37.30-50.50) days and 42.15 (95% CI: 37.99-46.30) days, respectively. The time duration for p31 seroconversion among people with negative WB and indeterminate WB was 58.11 (95% CI, 44.30-71.92) days and 51.91 (95% CI, 44.55-59.28) days, respectively, both of which were significantly longer (p = 0.0169) than those in people without p31 seroconversion. A similar difference was observed with respect to p66 seroconversion, with a window time of 53.53 (95% CI, 43.54-63.52) days and 47.87 (95% CI, 43.16-52.57) days among people with negative WB and indeterminate WB, respectively. These data suggest that HIV-1 antibody p66, like p31, may serve as a potential serological marker for distinguishing Fiebig stage V and stage VI at day 70 post-infection.

Keywords: HIV/AIDS; Western blot bands; recent HIV-1 infection; seroconversion; viral marker.

FIGURE 1

Schematic illustration of the study design and patient selection criteria. During the study reference period (2012–2017), 10934 individuals with suspected HIV infection were screened with two Ag-Ab ELISA kits and confirmed by Western blot in Wuhan CDC. Of these, 59 patients and 124 patients with negative WB and indeterminate WB, respectively, showed seroconversion (including 7 patients who initially seroconverted from negative to indeterminate WB and finally to positive WB). After exclusion of patients who seroconverted after ≥100 days, 40 patients with negative WB and 102 patients with indeterminate WB who showed seroconversion were included in the analysis. WB, Western blot; Neg, negative; Ind, indeterminate; Pos, positive; CI, confidence interval. ^∗Including non-reactive for two ELISA kits and WB.

FIGURE 2

Comparison of the seroconversion duration of different WB bands in HIV-1 positive individuals who seroconverted from negative WB. The time interval (days) between two sampling dates of negative WB and positive WB bands, including p66, p51, p31, gp120, gp41, and p17, were calculated; seroconversion rates for subjects with and without the above bands were compared using the Student’s t-test (GraphPad Instat Statistical Software). Thick horizontal bars indicate the median, boxes show quartiles, and whiskers show full range.

FIGURE 3

Comparison of the seroconversion duration of different WB bands in HIV-1 positive individuals who seroconverted from indeterminate WB. The time interval (days) between two sampling dates of indeterminate WB and positive WB bands, including p66, p51, p31, gp120, gp41, and p17, were calculated. Seroconversion rates for subjects with and without the above bands were compared using the Student’s t-test (GraphPad Instat Statistical Software). Thick horizontal bars indicate the median, boxes show quartiles, and whiskers show full range.

FIGURE 4

Comparison of the seroconversion for HIV-1 positive individuals who converted from negative WB and indeterminate WB. The time interval (days) between two sampling dates of negative/indeterminate WB and positive WB bands, including p66, p51, p31, gp120, gp41, and p17, were calculated. Seroconversion duration for subjects with above bands who seroconverted from negative and indeterminate WB was compared using the Student’s t-test (GraphPad Instat Statistical Software). Thick horizontal bars indicate the median, boxes show quartiles, and whiskers show full range. Neg, negative; Ind, indeterminate.