Oral Abstract Session - Infectious Diseases & Transfusion Medicine
#OA2-AM25-SN-02 - HIV Serologic Reactivity in Long-term Treated Persons with HIV According to Timing of ART Initiation and Implications for Blood Safety
Vitalant Research Institute / UCSF San Francisco, California
Disclosure information not submitted.
Background/Case Studies: Fourth-generation antigen/antibody (Ag/Ab) combo assays are central to HIV donation screening, but their sensitivity may be diminished in donors with undisclosed infection status and exposure to antiretroviral drugs (ARV). Suppression of viral replication can blunt Ab responses and perturb typical diagnostic markers and yield inconclusive results, particularly in cases of persons with HIV (PWH) who initiate antiretroviral treatment (ART) during acute infection followed by further decay with long-term viral suppression. We evaluated the sensitivity of 2 Ag/Ab screening assays to detect early treated HIV infection.
Study
Design/Methods: We evaluated plasma samples from long term ART-suppressed PWH initiating ART at Fiebig stages 1–4 (n=345) in an early treatment cohort study with longitudinal follow-up, blood donors who tested nonreactive by NAT and serology, PWH who initiated ART in later infection (n=50), and blood donors screened NAT and serology reactive with viral load >1,000 copies/mL. Samples were tested using previously FDA approved assays: Alinity s HIV Ag/Ab Combo and VITROS Immunodiagnostic Products HIV Combo kits. We assessed reactivity, signal-to-cutoff (S/CO) ratios, and their correlation with HIV subtype, time on ART, and Fiebig stage at ART initiation.
Results/Findings: Reactivity in the early ART group was associated with progressively lower S/CO in both assays for treatment in earlier Fiebig stages and with no observation of waning at later timepoints. Serologic reactivity in samples from participants initiating ART at Fiebig 2 was somewhat lower for CRF01_AE (67%) than other HIV subtypes (91%) on the Alinity platform. In the late ART initiation group, S/CO values remained high for both assays even after prolonged ART, with higher S/CO values in samples from blood donors with presumably untreated infection. Lowering Alinity's S/CO cutoff from 1.0 to 0.5 modestly improved sensitivity in Fiebig 1 (27% to 40%) and Fiebig 2 (73% to 83%) groups with minimal impact on specificity (99.99% to 99.87%). Conclusions: PWH initiating ART during acute HIV infection demonstrate lower and sometimes nonreactive serologic profiles in commercial Ag/Ab assays even years after treatment initiation. Although these findings suggest limitations for infection detection in PWH who started ART during early infection, currently there is very little understanding or evidence of the infectivity of such donations. Although the risk of transfusion-transmitted HIV from virally suppressed, NAT-negative donors is likely low, further investigation is needed to fully assess residual transmission risk and implications for blood safety.
