Influence of immunosuppressive therapy with azathioprine and prednisolone on serum-immunoglobulin concentration in renal transplanted patients.

Serological diagnosis of infectious diseases are based on the assumption that a change in virus-specific antibody - titer reflects the response to a certain viral infection due to changes in the concentration of the respective virus - specific antibodies. On the other hand immunosuppressive medication interacts with that system responsible in producing antigen-specific antibodies. This study was outlined therefore to follow the variation of the concentration of serum immunoglobulins of classes IgG and IgM with regard to a better evaluation of virus-specific antibody titers especially for those viruses that remain persistent after a primary infection and an reactivate. The study followed ten patients after allogenic cadaver kidney transplantation under immunosuppressive medication with azathioprine and corticosteroids. Concentration of serum-IgG and -IgM protein was continuously measured for 6 months after transplantation along with measurement of virus-specific antibody-titers with enzyme immunoassay (Elisa) especially for cytomegalovirus. The results show a drastic decrease in serum immunoglobulins IgG and IgM - the lowest concentration being reached 25-50 days after transplantation. The concentration of IgG increased thereafter if no severe infectious diseases occurred during the post-transplant period. The concentration of IgM seems to react more sensitively upon infectious processes. In general, virus-specific antibody-titers (IgG) follow the sometimes drastic variation in the respective immunoglobulin class. It therefore reveals that antigen-specific antibody-titers in those patients should be controlled continuously during the time after transplantation for better evaluation of titer variations that eventually occur in correlation to the absolute concentration of the immunoglobulin class.