IgG and IgM autoantiidiotype antibodies against antibody to HBsAg in chronic hepatitis B

The potential role of HLA-G in the pathogenesis of HBV infection: Immunosuppressive or immunoprotective?

The non-classical human leukocyte antigens (HLA)-G could be generally considered as a potent tolerogenic molecule, which modulates immune responses. HLA-G due to the immunosuppressive properties may play an important role in the pathogenesis of infections related to the liver. HLA-G may display two distinct activities in the pathological conditions so that it could be protective in the autoimmune and inflammatory diseases or could be suppressive of the immune system in the infections or cancers. HLA-G might be used as a novel therapeutic target for liver diseases in the future. Indeed, new therapeutic agents targeting HLA-G expression or antibodies which block HLA-G activity are being developed and tested. However, further consideration of the HLA-G function in liver disease is required. This review aims to summarize the role of HLA-G in the liver of patients with HBV infection.

IgM antibody to hepatitis C virus in acute and chronic hepatitis C

To assess possible role of testing for IgM-specific antibody in the diagnosis and monitoring of patients with hepatitis C, we tested sera from 14 patients with acute and 97 patients with chronic non-A, non-B hepatitis for IgG and IgM antibody to hepatitis C virus. IgG antibody to hepatitis C virus was detected in 93% of acute cases and 91% of chronic cases. Of the 101 patients with IgG antibody to hepatitis C virus, 57% had IgM antibody to hepatitis C virus. None of the 20 healthy subjects or 40 patients with acute or chronic hepatitis A or hepatitis B had IgM antibody to hepatitis C virus. At the onset of clinical symptoms in acute hepatitis C, IgG antibody to hepatitis C virus was detected in 8 (57%) and IgM antibody to hepatitis C virus in 9 of 14 patients (64%). Eventually, both IgG and IgM antibody to hepatitis C virus became detectable in 13 of 14 patients with acute hepatitis C. Seven patients with antibody to hepatitis C virus resolved the acute infection within 6 mo and all seven cleared IgM antibody to hepatitis C virus, whereas two cleared IgG antibody to hepatitis C virus. Six patients had a chronic outcome of the acute infection and IgM antibody to hepatitis C virus persisted in detectable amounts for more than 6 mo in all (mean = 15.5 mo). Among 88 patients with chronic non-A, non-B hepatitis with IgG antibody to hepatitis C virus, IgM antibody to hepatitis C virus was detected in 45 (51%).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in anti-idiotype antibodies against anti-HBs during recombinant interferon treatment of chronic hepatitis B

To determine the possible changes in the presence and level of anti-idiotype (anti-Id) antibodies against anti-HBs induced by recombinant interferon (rIFN) therapy in chronic hepatitis B virus (HBV) infection, a study of patients under rIFN treatment has been carried out. A total of 62 (38 treated and 24 controls), HBeAg and HBV-DNA positive HBsAg carriers were tested serially for the presence of IgG and IgM anti-Id antibodies. According to serological evolution, treated patients were divided in responders (HBeAg and HBV-DNA became negative) (n = 18) and nonresponders (n = 20). Control patients were also classified as having spontaneous seroconversion (n = 11) and without changes (n = 13). Basally all patients had IgG and IgM anti-Id. At the end of the follow-up period (15th month), a significant decrease was observed in the percentage of cases positive to anti-Id among rIFN-responders (IgG, 67%, p less than 0.01; IgM, 44%, p less than 0.001). In contrast, only one nonresponder lost IgM anti-Id during the study. Among controls, only one with spontaneous loss of HBV-DNA and HBeAg clearance became negative to both IgG and IgM anti-Id. In addition, in the basal sample, the rIFN-responders had significantly lower anti-Id levels than the nonresponders (p less than 0.05). Similar results were obtained when comparing the controls with or without spontaneous response (p less than 0.05). Furthermore, a significant decrease in the anti-Id levels among the rIFN responders at the 9th month was detected (p less than 0.01). In summary, the anti-Id antibodies decreased significantly in patients who became HBV-DNA negative following rIFN administration. This result confirms the close relationship between HBV replication and the anti-idiotype against anti-HBs.

Immunology of hepatitis B virus infections

Acute or chronic hepatitis B virus infection is often associated with symptoms which are probably caused by immune complexes, such as vasculitis, glomerulonephritis and arthritis. The immune complexes found in such patients contain excessive viral proteins. The functions of these proteins and the immune response to them during various states of infection are discussed.