Epstein-Barr virus serology and isoelectrofocusing pattern of serum immunoglobulins in cyclosporin or placebo-treated type I diabetics.

Epstein-Barr virus (EBV) serology was serially studied for a period of 18 months in 49 recently diagnosed type I diabetics randomly assigned to receive cyclosporin (CsA) (n = 25) or placebo (n = 24). Additionally, isoelectrofocusing of serum (IEF) was serially performed in 59 CsA- and 38 placebo-treated diabetics, over a 36 month period (687 sera) in order to detect restriction of heterogeneity of circulating immunoglobulins. Patients were continuously treated with CsA at a dose of 7.5-10 mg/day during the first 6 months and a dose not exceeding 5 mg/kg/day, thereafter. Before treatment anti-EBV antibody levels were in the normal range for the whole group. In the placebo group, Epstein-Barr nuclear antigen (EBNA) and viral capsid antigens (VCA) IgG were moderately raised during the first 6 months in comparison with baseline level (0.33 +/- 0.13 and 0.30 +/- 0.18 two-fold dilutions respectively). In contrast, in the CsA group, EBNA and VCA IgG decreased slightly (0.26 +/- 0.16 and 0.26 +/- 0.17 dilutions). Changes between the two groups at 3 and 6 months were significantly different (P less than 0.05), but the difference disappeared subsequently. No significant changes in anti-early antigen (EA) IgG and in EA and VCA IgA were observed. No IEF abnormalities appeared in the CsA group. One CsA-treated patient who was initially EBV seronegative developed normal serological signs of recent EBV infection at 12 months without restriction of immunoglobulin heterogeneity or clinical symptoms of infectious mononucleosis. This study indicates that CsA, at moderate dosage, slightly reduces the titer of pre-existing anti-EBV antibodies but does not alter the response to recent EBV infection. These results do not provide any evidence of clinically latent EBV-induced benign or malignant lymphocyte proliferation.