Spontaneous in vitro immunoglobulin secretion at the diagnosis of insulin-dependent diabetes

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Abstract
Blood mononuclear cells obtained from 17 newly diagnosed insulin-dependent diabetic (IDDM) patients treated with insulin for 5-7 days were assessed for the number of spontaneous and pokeweed mitogen (PWM)-stimulated Ig-secreting cells in a reverse hemolytic plaque assay. The spontaneous in-vitro Ig secretion was evanescent and decreased in individual patients within 1-4 mo. of insulin treatment. Compared to matched controls, 53% (9/17) of the IDDM patients had an elevated spontaneous secretion of Ig 41% (7/17) for IgG, 35% (6/17) for IgM, and 35% (6/17) for IgA. The quantities of PWM-stimulated IgG, IgM, or IgA secreting cells in IDDM were comparable to the controls. The IDDM patients with spontaneous Ig secreting cells had higher fasting C-peptide levels compared to the patients with Ig-producing cells within the normal range (P < 0.05). The average titer of islet cell cytoplasmic antibodies was 1:26 in (9 of 9 were positive) patients with, compared to 1:1 in patients (4 of 8 were positive) without spontaneous secretion (P = 0.025). The clinical onset of IDDM apparently is associated with a polyclonal B lymphocyte activation. Higher levels of fasting C-peptide islet cell antibodies are associated with this immunoregulatory abnormality.