Polyarteritis nodosa associated with hepatitis B virus infection. The role of antiviral treatment and mutations in the hepatitis B virus genome.

Polyarteritis nodosa (PAN) is a systemic inflammatory disease causing vasculitis of medium sized and small arteries. Circulating immune complexes containing viral proteins have been implicated in the pathogenesis of hepatitis B virus (HBV) related PAN and several immunosuppressive and antiviral regimens have been used with varying success. In our hospital seven HBV positive patients with a confirmed diagnosis of PAN could be identified between 1984 and 2001. Most patients had an acute HBV infection and all patients were treated with prednisone. A combination of prednisone and antiviral therapy with alpha-interferon (IFN) was used only in the last four patients. HBV DNA was isolated from serum samples obtained before treatment from the four IFN treated patients and amplified by using the polymerase chain reaction technique. None of the patients without, but two of four with antiviral therapy exhibited HBsAg seroconversion. In three out of four patients HBV DNA decreased rapidly after starting IFN therapy. Clinical remission of PAN was observed in three of the four treated patients, but in none of the three patients who were not receiving antiviral medication. Analysis of the HBV genome revealed no mutations that could be associated with PAN. In one patient a stop codon in the pre-core region and a double mutation A1762T-G1764A were found during antiviral therapy. We did not find HBV heterogeneity predisposing to the development of PAN. In our group of patients it appeared that clinical remission of PAN was primarily related to spontaneous or therapy induced loss of HBV DNA replication. The combined administration of a priming steroid course and IFN appears to be an improvement over prednisone monotherapy and should be considered for every patient with HBV related PAN. The efficacy of new generation nucleoside analogues should be further elucidated in future studies.