Endogenous secretion of insulin and its relationship with immunogenetic markers in infants with insulin-dependent diabetes mellitus

The level of C-peptide is a marker determining the clinical course of insulin-dependent diabetes mellitus (IDDM). The factors influencing the volume of residual endogenous secretion of insulin in IDDM patients are not yet well known. In order to elucidate the effect of HLA-phenotype on the residual function .of pancreatic beta-cells and the course of diabetes, 114 children, 55 boys and 59 girls aged 8 months to 6.5 years, suffering from IDDM, were examined. HLA phenotype was detected by the standard microlymphocytotoxic test. Fifty-nine HLA antigens of classes I and II, locuses A, B, DR, DQ were taken into consideration. Basal and radial C-peptide was assessed by radioimmunoassay. The pancreatic insulin-secretory function was found reduced in young patients with IDDM. The mean values of C- peptide were 0.13 ± 0.01 nmol/liter. Residual secretion of insulin was revealed in 56.2% of children. HLA markers of high risk of IDDM development in the first yeais of life were revealed: DQw3. DR3/4. DR4, DR3, B8 antigens. The markers of high risk of diabetes DR3 and DR4, and moreover, DR3/4. as well as the age by the disease onset and duration of IDDM were found to influence the size and duration of functioning of beta-cells.