IgM autoantibodies against two cellular antigens always appear in acute Epstein-Barr virus infection

Haemolysis in hepatitis A virus infections coinciding with the occurrence of autoantibodies against triosephosphate isomerase and the reactivation of latent persistent Epstein-Barr virus infection

Haemolysis has been observed frequently as a complication of acute hepatitis A virus (HAV) infection. However, the pathogenic mechanism has not been elucidated completely. In individual cases the detection of anti-erythrocyte antibodies of unknown specificity was described. The raised serum IgM fraction was shown to consist partially of autoantibodies. Previously, we detected autoantibodies of immunoglobulin class M directed against triosephosphate isomerase (IgM anti-TPI) in patients with infectious mononucleosis. These autoantibodies are able to induce haemolysis. In this study the occurrence of IgM anti-TPI in acute HAV infections and other viral diseases has been investigated. In 33 of 134 patients suffering from HAV infection (IgM anti-TPI was detected. Haematological and chemical data were available from seven of these 33 patients. Mild-to-moderate signs of haemolysis correlating with the IgM anti-TPI titre in the follow-up examinations were demonstrated. The presence of IgM anti-TPI in HAV infections is connected with a reactivation of a latent persistent EBV infection. In other viral infections both the detection of IgM anti-TPI and evidence of a reactivated EBV infection is rare. Thus, we anticipate that IgM anti-TPI antibodies occurring with the reactivation of a latent persistent EBV infection take part in provoking haemolysis in acute HAV infections.

Manganese superoxide dismutase as a target of autoantibodies in acute Epstein-Barr virus infection

Antibodies directed against the autoantigen p26 were detected in sera from 32 patients with acute Epstein-Barr virus (EBV) infection and clinical symptoms of infectious mononucleosis. P26 has now been identified as the enzyme manganese superoxide dismutase (MnSOD) by comparison of the NH2-terminal amino acid sequence. Antibodies against MnSOD belong to the immunoglobulin class M. They are not detectable in sera of patients with other herpesvirus infections. In the 32 patients investigated, the rise and fall of the autoantibodies coincides with the clinical symptoms. In vitro, the autoantibodies were shown to inhibit the dismutation of superoxide radicals by blocking MnSOD. As presented in the discussion this effect may contribute to the pathogenesis of acute EBV infection.

Affinity purification of antibodies from sera using polyvinylidenedifluoride (PVDF) membranes as coupling matrices for antigens presented by autoantibodies to triosephosphate isomerase

Polyvinylidenedifluoride (PVDF) membranes covered with antigen can be used for affinity purification of antibodies from sera. These antibodies serve as an appropriate substitute for monoclonal antibodies when performing cytological and analytical experiments with the respective antigen. The usefulness of this method is demonstrated with the purification of IgM autoantibodies produced against human triosephosphate isomerase in acute Epstein-Barr virus infection. Compared with the original serum, the specific activity of the purified antibodies was up to 1400-fold higher, and the recovery of the anti-triosephosphate isomerase activity between 25 and 33%.