Isotype and antigen analysis of immune complexes isolated from the sera of heart transplant recipients

Serial isotype analysis of circulating immune complexes in heart transplant recipients treated with heterologous antithymocyte globulin or cyclosporin A showed a predominance of IgM and IgA antibodies. Kinetic data showed that the proportion of IgM immune complexes tended to rise over the first six weeks post-transplant, while that of IgG complexes fell. The contribution from IgA complexes to the total showed no discernible temporal directionality. Serum immunoglobulin determinations also showed significant elevations, and these were found to be associated with bacterial or viral infections. The immune complexes were isolated from patients' sera by chromatographic methods, dissociated in acid, then analysed for the presence of specific antigens. The results showed that the immune complexes contained antigenic material reactive with antibodies to equine IgG and herpes simplex virus type I. Specific detection of viral/anti-viral immune complexes may be useful in indicating the presence of sub-clinical infection.