HBsAg-negative and anti-HBc-positive in eosinophilic granulomatosis with polyangiitis: a retrospective pilot study.

We examined whether resolved hepatitis B virus (HBV) infection was associated with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), and affected AAV activity at diagnosis and prognosis during the follow-up. We reviewed the electronic medical records of 153 AAV patients, and included 91 hepatitis B surface antigen (HBsAg)-negative patients having results of both antibody to hepatitis B core antigen (anti-HBc) and surface antigen (anti-HBs). We collected clinical and laboratory data, Birmingham vasculitis activity score (BVAS) and five factor scores (FFS) at diagnosis and relapse rates during the follow-up. We divided patients into the two groups according to the presence of anti-HBc and compared variables between them in patients with AAV or those with each variant. The mean age and follow-up duration were 59.8 ± 15.2-year-old and 48.0 ± 47.5 months. Fifty patients (54.9%) had anti-HBc, and 61 patients (67.0%) had anti-HBs. Only thirty-six (39.6%) patients had ever experienced relapse after remission. There were no remarkable differences between HBsAg-negative AAV patients with and without anti-HBc. However, in eosinophilic granulomatosis with polyangiitis (EGPA) patients, patients with HBs-negative/anti-HBc-positive (resolved HBV infection) showed the higher initial mean BVAS and FFS (2009) than those without. Patients having anti-HBc exhibited significantly increased risk of relapse of EGPA than those having not (RR 16.0). Also, EGPA patients with HBs-negative/anti-HBc-positive showed meaningfully lower cumulative relapse-free survival rates than those without during the follow-up duration (p = 0.043). In conclusion, resolved HBV infection may importantly influence vasculitis activity at diagnosis and subsequently relapse after remission in EGPA patients.