Specific IgM of cytomegaloviruses and primary infection in kidney transplant patients

: In 20 renal transplant recipients suffering from symptomatic CMV infection we looked if a specific IgM response was indicative of a primary infection. By an ELISA technique we investigated the specific IgG and IgM in a pair of sera taken at the time of the transplantation and later at the time of the CMV isolation. For 7 out of 8 patients exhibiting an IgM response in the late serum, the pretransplant serum did not contain either IgG or IgM specific antibodies. Therefore the specific IgM response was associated in 7 out of 8 patients with a primary CMV infection. Nevertheless in 6 other primary infected patients no specific IgM response was detected. Otherwise rheumatoid factors appeared in each primary infected patient developing a specific IgG response, with or without specific IgM response.