Serum IgG, IgM, and IgA Antibody Response against Cytomegalovirus-Specific Proteins in Renal Transplant Recipients during Primary and Secon-dary/Recurrent Infection as Determined by Immunoblotting Technique

A total of 190 selected serum samples from 30 kidney graft recipients obtained in temporal connection with the first occurrence of CMV-pp65-antigen positive leukocytes or IgM-anti-CMV-antibodies were analysed by immunoblot (IB) in a blinded manner. In all sera the number of IgG, IgM and IgA specificities against 8 defined CMV polypeptides and the intensity of reactions were measured. In 12 pretransplant CVM-IgG-EIA(Abbott)-positive recipients antibodies to 150, 78 and 65 kD polypeptides were detectable in 100% of the patients, followed by antibodies to 52 and 38 kD polypeptides in 83% and finally antibodies to 60, 42 and 28 kD polypeptides in 50 – 58% of the patients. The strongest reactions were seen against the 150 kD polypeptide. In 7 out of 18 patients (38.9%) of the pretransplant CMV-IgG-EIA-negative group antibodies to 65 kD polypeptide could be detected by IB. Therefore, the grouping of recipients as CMV antibody positive or negative strongly depends on the test system used. After prophylactic or therapeutic use of human gammaglobulins all recipients became blot positive immediately after infusion. The strongest reaction intensities were found against the 150 kD polypeptide followed by 52, 65 and 38 kD. In 12 recipients suffering from primary CMV infection IgM responses to 65, 52 and 38 kD polypeptides were found in 100%. Most recipients developed also an IgM response to the 150 kD glycoprotein in the course of infection. All recipients with a positive IgM reaction also produced IgA-anti-CMV- antibodies at the same time. The strongest reaction was directed against the 65 kD polypeptide, followed by reactions against 52, 38 and 150 kD polypeptides. With respect to the time point of antigen detection in peripheral blood leukocytes we observed both an increase in number of blot positive recipients and an increase in reaction intensity immediately after occurrence of pp65 positive leukocytes. Remarkable IgM as well as IgA activities were directed against 65, 52 and 38 kD polypeptides. All 12 recipients suffering from CMV reactivation produced IgM responses to 150, 52 and 38 kD polypeptide, most recipients also to 78, 65, 42 and 28 kD polypeptides. All recipients with a positive IgM reaction produced at the same time also IgA-anti-CMV-antibodies. The strongest reaction was directed against the 65 kD polypeptide, followed by reactions to 52, 38 and 150 kD polypeptides. It is worth noticing that in about 70% of recipients suffering from CMV reactivations IgM-antibodies to 150, 52 and 42 kD polypeptides and IgA-antibodies to 52 kD polypeptide could be de