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.

Antiviral treatment with alpha interferon up-regulates CD14 on liver macrophages and its soluble form in patients with chronic hepatitis B.

To investigate whether therapy with alpha interferon (IFN-alpha) induces changes in intrahepatic antigen-presenting cells (APCs), we obtained liver biopsy specimens before, during, and after therapy with IFN-alpha from chronic hepatitis B patients whose viral load had already been reduced by at least 8 weeks of treatment with lamivudine. HLA-DR, CD1a, and CD83 were not modified by the therapy. The intralobular expression of CD68 on Kupffer cells remained stable, denoting no changes in the number of resident macrophages during IFN-alpha treatment. In contrast, CD14 was weakly expressed in the absence of IFN-alpha and was significantly up-regulated during therapy. At the same time, the levels of soluble CD14 and interleukin-10 in plasma increased significantly. In vitro, monocytes maintained in the presence of IFN-alpha differentiated into macrophages or dendritic cells with higher levels of expression of CD14 than that for the control cultures. During therapy with IFN-alpha, T-cell infiltration in the portal spaces was reduced, mainly due to a significant decrease in the number of CD8(+) T cells. These findings show that IFN-alpha is biologically active on APCs in vivo and in vitro and suggest that this newly described regulatory function, together with the already known inhibitory effects on lymphocytes, may cooperate to reduce inflammation and consequent tissue damage in patients with chronic viral hepatitis.

Hepatitis B virus-specific T cell response in chronic hepatitis B patients treated with lamivudine and interferon-alpha.

AIMS: The goal of the present study was to assess the impact combination antiviral therapy has on immune responses in chronic hepatitis B. MATERIALS AND METHODS: T cell responses were studied in 16 chronically hepatitis B virus (HBV)-infected patients treated with sequential, partially overlapping, lamivudine-interferon (IFN)-alpha combination therapy. RESULTS: HBcAg-specific lymphoproliferative response (LPR) was transiently detected in four of five patients who achieved virus suppression (HBV DNA < 10(4) genome equivalents/ml) at end of dual therapy, and then reverted to pre-treatment viral load after therapy discontinuation. In contrast, no significant HBcAg-specific LPR was detected in 8 patients who did not attain profound HBV suppression, as well as in three patients who experienced no HBV DNA rebound after therapy discontinuation. CONCLUSIONS: This pilot study suggests that restored viral replication after pharmacological suppression drives the immune response to HBV in chronically infected patients. Further characterization of the adaptive immunity and its regulatory mechanisms at time of therapy discontinuation appears therefore necessary in controlled trials.