Study on acute HIV-1 infection in men who have sex with men in Tianjin

Abstract

Objective: To understand the immunological and virological characteristics of HIV-1 infected men who have sex with men (MSM) in the acute phase in Tianjin and evaluate the effects of the fourth generation HIV ELISA and the P24 ELISA for acute HIV-1 infected samples. Methods: From October 2015 to October 2016, MSM were recruited through the community-based organizations in Tianjin. All the participants received rapid HIV test, positive samples were confirmed by Western Blot and negative samples underwent pooled nucleic acid testing. The participants with HIV-1 RNA reactive result underwent testing for viral load and T-cell count after second blood collection. Acute HIV-1 infection was defined as negative rapid HIV test result and the positive results of two HIV RNA tests, then the sensitivity were compared between the fourth generation HIV ELISA and the P24 ELISA to detect the initial HIV-1 RNA positive samples. Results: Among 3 016 MSM screened, 193 were positive in rapid HIV test. Western blot testing indicated that 179 cases were HIV positive, 7 cases were HIV indeterminate and 7 cases were negative. Of 2 823 sero-negative cases, 17 were acute HIV-1 infections. The HIV-1 infection rate was 6.53% (197/3 016) and the acute HIV-1 infection rate was 0.56% (17/3 016), with an average viral load of (5.63±1.50) log(10) copies/ml, an average CD(4) count of (442.82±268.17) cells/μl, an average CD(8) count of (1 069.65±668.22) cells/μl and an average CD(4)/CD(8) ratio of (0.49±0.25). Higher viral load, CD(4) and CD(4)/CD(8) ratio were seen in the acute HIV-1 infection group compared with the chronic HIV-1 infection group (U=148, P<0.01; U=272, P=0.042 and t=3.147, P=0.005). Demographic characteristics were similar between two groups, except the occupation (χ(2)=11.016, P=0.026). The sensitivity of P24 ELISA was higher than the fourth generation HIV ELISA in the HIV-1 detection for acute infection (Fisher's exact test, P=0.017). Conclusions: MSM are at risk for acute HIV-1 infection. Screening for acute HIV-1 infection with P24 ELISA would increase the sensitivity of diagnosis and reduce HIV transmission in MSM.