Isolated Anti-HBc in People Living with HIV: A 20-Year Experience from Istanbul, Turkey

Isolated anti-HBc positivity, defined as the presence of anti-HBc in the absence of HBsAg and anti-HBs, may reflect prior exposure to HBV, occult HBV infection, or a false-positive result. This study aimed to assess the prevalence of isolated anti-HBc positivity and its associated factors among PLWH in Istanbul, Turkey.

This retrospective cross-sectional study included adult People Living With HIV (PLWH) who underwent HBV serological testing between January 2000 and December 2019 at a tertiary hospital in Istanbul. Demographic and clinical characteristics were analyzed.

Among 386 PLWH, 8.8% (n = 34) had isolated anti-HBc positivity. Compared with HBV-seronegative PLWH (n = 194), these patients were older (48 [IQR 42-54] vs. 42 [35-50] years; p = 0.007), more likely to have BMI ≥ 25 kg/m² (p = 0.025), and to report smoking (p = 0.041), based on available data. Pre-ART HBV DNA testing was available in 13/34 (38.2%) patients with isolated anti-HBc, and all tested samples were HBV DNA-negative.

Isolated anti-HBc prevalence was 8.8% in PLWH; older age, BMI ≥25 kg/m², and smoking were more common in this group. Although no HBV DNA was detected in the tested subset, limited HBV DNA testing precluded estimation of OBI prevalence in this cohort.

Recognition of isolated anti-HBc positivity and occult HBV infection is important for ART selection and patient follow-up. Although isolated anti-HBc positivity was identified in 8.8% of this cohort, more systematic and risk-stratified HBV DNA assessment is needed to better define the true burden of occult HBV infection.