Cryoglobulinemia in kidney transplant recipients.
The aim of this study was to assess the presence of cryoglobulins, the constitution of the cryoprecipitate, as well as the possible etiology and clinical features in kidney transplant recipients. We excluded patients with clinical or laboratory evidence of autoimmune, liver or neoplasm disease, infections, blood transfusions or immunizations in the previous 3 months. Detection of cryoglobulins was obtained from the peripheral venous blood. In cases of cryoprecipitate formation it was analyzed using anti-IgG, anti-IgM, anti-IgA, anti-C3, and anti-C4 antibodies. The hepatitis C virus (HCV) was detected by the polymerase chain reaction. Thirty-nine patients were selected, of whom 23 were men and the overall mean age was 40.6 +/- 12.7 years. Cryoprecipitate was detected in 74.4% (29/39) patients. Among patients with or without cryoprecipitate formation, the serum creatinine values, the percentage of patients with proteinuria, and the posttransplantation times were similar. In patients with cryoglobulins, 37.9% (11/29) were HCV positive. The etiology was not determined for the other patients. The IgG, IgM, and IgA immunoglobulins and the complement fractions C3 and C4 were found in the cryoprecipitate. Their compositions were similar among patients with or without HCV. Few clinical features were associated with the presence of cryoglobulins, including deep venous thrombosis, cutaneous purpura and peripheral neuropathy. In conclusion, cryoglobulinemia was prevalent in kidney transplant recipients, but appeared to not affect graft function. HCV infection was the most frequently associated etiology and clinical features were infrequent.