SEROLOGICAL EVALUATION OF THE ROLE OF CYTOMEGALOVIRUS IN THE PATHOGENESIS OF IDDM - A PROSPECTIVE-STUDY

To study the possible temporal association between primary cytomegalov irus infection and the appearance of islet cell autoantibodies or the development of insulin-dependent diabetes mellitus (IDDM) cytomegalovi rus antibodies were analysed from follow-up sera of 46 initially non-d iabetic siblings of diabetic children who either manifested clinical I DDM (22 siblings) or turned islet cell antibody positive (24 siblings) during the prospective observation (mean follow-up time 2.9 years). S econdly, cytomegalovirus antibodies were analysed during pregnancy in 96 mothers whose child presented with IDDM before the age of 7 years a nd in 96 control mothers who gave birth to a non-diabetic child. Third ly, a case-control series including 90 newly-diagnosed young children with IDDM and their 90 control subjects was analysed. No seroconversio ns were found in cytomegalovirus antibodies during the follow-up of th e 46 siblings indicating no temporal association with islet cell antib ody seroconversion or manifestation of clinical diabetes. During the f ollowup 17 (37%) siblings were constantly seronegative and 29 (63%) se ropositive for cytomegalovirus IgG and there was no difference between islet cell antibody positive and negative siblings. Cytomegalovirus I gG and IgM were not different in pregnant mothers who gave birth to a subsequently diabetic child compared to control mothers, or in newly-d iagnosed diabetic children compared to control children. Cytomegalovir us IgA was higher in newly-diagnosed diabetic children than in control children (p < 0.005). This difference disappeared when only cytomegal ovirus IgG positive individuals were analysed. No correlation was foun d between islet cell antibodies and cytomegalovirus antibodies in newl y-diagnosed diabetic patients. The results do not support the hypothes is that primary cytomegalovirus infections could initiate the cascade leading to autoimmune destruction of the beta cells.