Correlation between islet cell antibodies and anti-cytomegalovirus IgM and IgG antibodies in healthy first-degree relatives of type 1 (insulin-dependent) diabetic patients

To investigate whether cytomegalovirus (CMV) infection may be related to islet cell antibodies (ICA) production and/or to insulin-dependent diabetes mellitus (IDDM) development, we have analyzed the prevalence of anti-CMV, IgM, and IgG antibodies and of ICA in 80 healthy siblings of IDDM patients (HSIDDP) and in 60 control subjects with negative familiar anamnesis of IDDM. HSIDDP and controls were also typed for HLA-A-B-C and DR antigens. IgM and IgG anti-CMV were detected by an ELISA method, whereas the ICA assay was performed by standard indirect immunofluorescence on 5-μm unfixed sections of human pancreas. HLA-A-B and C antigens were studied by standard microlymphocytotoxicity; DR antigens were also studied by a standard microlymphocytotoxicity on a B-enriched lymphocyte population. Our results indicate a significant association (P <0.0001) between high titers of anti-CMV IgG antibodies and ICA in HSDIDDP, whereas no correlation was found between the presence of any HLA-A-B-C and DR antigens and the prevalence of anti-CMV IgM and IgG antibodies and/or ICA. Thus, these data may support the hypothesis that a chronic CMV infection may be associated with ICA production whereas other factors seem to be needed for the complete development of type 1 diabetes.