Feasibility and safety of research sigmoid colon biopsy in a cohort of Thai men who have sex with men with acute HIV-1

BACKGROUND: The gut-associated lymphoid tissue (GALT) is a major reservoir of HIV-1 established early in acute HIV-1 infection (AHI). Sampling tissue from GALT can provide information about viral reservoirs and immune responses but may be complicated during AHI for reasons such as high viral replication, CD4 T cell depletion and immune activation. Risk of adverse events (AEs) associated with research sigmoid colon biopsies was assessed in participants with AHI in Bangkok, Thailand. METHODS: Between 2009 and 2016, 170 biopsies collected from the sigmoid colon were performed during AHI and at follow-up visits (median 24 weeks post AHI diagnosis). Adverse event incidence was evaluated, as well as the associations of procedure timing, repetition and clinical parameters with AE risk. Negative binomial regression models were used to calculate incidence rate ratios and 95% confidence intervals. RESULTS: Among 103 participants (median age of 27 years, 97.1% male, 96.1% men who have sex with men), 87 sigmoidoscopies were completed during AHI and 83 at a follow-up visit. Approximately 30 biopsies were obtained per procedure for assessment of colonic viral load and HIV-1 reservoir, immunohistochemistry or phenotypic assays. All 11 AEs were grade 1 (6.5%) and included abdominal discomfort (n = 5, 2.9%), mild rectal bleeding (n = 5, 2.9%) and difficulty passing stool (n = 1, 0.6%). Biopsy-related AE risk was not significantly associated with age, HIV-1 RNA, CD4 T cell count, or number and time of biopsy. CONCLUSIONS: Complications of sigmoidoscopy with biopsy in participants with AHI were infrequent and mild. Longitudinal sampling of the sigmoid colon to evaluate the gut-associated HIV-1 reservoir can be safely performed as part of research studies.