Using immunoenzymatic techniques (ELISA) we measured serum levels of IL-2, sIL-2R, IAA and anti-islet cell antibodies (ICA-IgG; ICSA) in 33 young patients with newly diagnosed IDDM (all within 30 days since onset of clinical symptoms) compared to control subjects. In 15 of 33 patients (46%) we found extremely low circulating levels of IL2 (< 2 U/ml); levels within the range 2-10 U/ml were found in 10 patients (30%). In 23 of 30 control subjects (76%) low values of IL2 (< 2,5 U/ml) were detected. Serum levels of sIL-2R were markedly increased in 24 (72%) young diabetic patients observed in the earliest phases of the disease (846 +/- 212 U/ml). The 72% of this group (18/25) showed IL-2 levels < 10 U/ml. In 86% of control subject (26/33) we found sIL-2R in the normal range of concentration (358 +/- 94 U/ml). We found IAA in 36% (12/33) of diabetic patients. In 11 of 12 subjects showing IAA+ were detected increased circulating sIL-2R levels. Positivity for ICA-IgG was found in 7 of 33 diabetic patients (21%), and 13 of them (39%) resulted ICSA+. Our findings suggest that serum levels of IL-2, sIL-2R and IAA can serve as reliable serologic markers of immune system activation in the earliest phases of IDDM. The monitoring of these parameters combined with ICA and ICSA in subjects at risk and in the earliest phases of the disease would be useful to prevent the irreversible beta-cellular damage.
