Combined HDV RNA and Anti-HDV measurement for the management of HBV/HDV coinfection

BACKGROUND AIMS: Virologic profiling is mandatory for the clinical management of Hepatitis-B-surface-Antigen (HBsAg) carriers, positive for antibody against Hepatitis-Delta-Virus (anti-HDV). We analysed the correlations between serum HDV RNA, anti-HDV, HBV-markers and liver disease in a single centre cohort study. APPROACH RESULTS: Virologic, biochemical, imaging/histologic characteristics were studied in 146 consecutive HBsAg/anti-HDV carriers at baseline; in 31 Interferon-treated patients HDV/HBV markers were measured at end of therapy (EOT), 24 weeks after EOT and end of follow-up (EOF). HDV RNA was quantified by Altostar-Quantification-Kit (Altona Diagnostics) and anti-HDV by 10-fold endpoint dilutions (Liaison-XL-Murex anti-HDV, DiaSorin). Liver disease was absent in 9/10 (90%) HDV RNA negative/anti-HDV positive (all ≤1:100) and 2/136 (1.5%) viremic individuals (HDV RNA<500 IU/mL and anti-HDV≤1:100). The remaining 134 had liver disease (CHD), 110 (82.0%) cirrhosis; all but one had anti-HDV≥1:1,000; HDV RNA levels were higher in cirrhotics [5.86 (4.93-6.43) vs 5.01 (3.58-5.79) Log IU/mL, p=0.004], viremia peaking in early [6.02 (5.21-6.56) Log IU/mL] versus advanced cirrhosis [5.44 (4.71-6.06) Log IU/mL, p=0.006]. HDV RNA correlated with anti-HDV, HBsAg, HBcrAg and ALT (p<0.001). At multivariate HDV RNA independently associated with liver disease stage (β=0.244, p=0.003), ALT (β=0.220, p=0.001), and HBsAg levels (β=0.515, p<0.001). All but one of the 16 IFN responders had anti-HDV≤1:100 at EOF; all relapsers/non responders had anti-HDV≥1:1,000. CONCLUSIONS: Combined HDV RNA and anti-HDV quantification provides complementary information for characterizing HBV/HDV infection and monitoring treatment response. Declining anti-HDV levels associate with virological control. These results prompt prospective multicentre studies of their role in the clinical and therapeutic management of patients with HBV/HDV coinfection.