Human papillomavirus antibody response following HAART initiation among MSM. AIDS
Antibodies to high-risk human papilloma virus (HPV) L1 protein are considered as markers of cumulative HPV exposure, whereas antibodies against HPV E6 protein have been shown to be highly specific markers for HPV-related cancer. In this study, Combes et al. aimed to describe pre and post-highly active antiretroviral therapy (HAART) HPV-L1 and HPV-E6 antibody response in HIV-positive MSM, and the meaning of this response for subsequent HPV-related cancer risk.
Antibodies were tested using a multiplex HPV-serology assay. For each individual, two serum samples, one at HAART initiation (pre-HAART) and another 24 months later (post-HAART), were tested. Identification of HPV-related cancer included data linkage with Swiss cancer registries.
Pre-HAART, 127 (45.2%) participants were seropositive for any high-risk HPV-L1, and 91 (32.4%) were HPV16-L1-seropositive. Only one participant was positive for HPV16-E6. Post-HAART, seropositivity for any high-risk HPV-L1 increased to 170 (60.5%), and HPV16-L1-seropositivity to 135 (48%). Two more individuals seroconverted to HPV16-E6 positivity. Factors associated with seroconversion were low CD4+ cell count [OR 5.28] and low CD4+/CD8+ ratio [OR 6.56] at HAART initiation. Anal cancer incidence was 63/100’000 person-years for post-HAART HPV16-E6 seronegatives versus 3’956/100’000 person-years in seropositives, corresponding to a statistically significant incidence rate ratio of 63.1.
In conclusion, the authors described for the first time, that HAART is associated with seroconversion and increasing titers of HPV-antibodies. Although numbers of cancer cases were small, HAART-related seroconversion seemed to improve the ability of HPV16-L1 and E6 antibody status to discriminate future anal cancer risk.