Elevated Levels of Circulating Adhesion Molecules in IDDM Patients and in Subjects at Risk for IDDM

Serum levels of recently discovered circulating forms of adhesion molecules, ICAM-1 and L-selectin, were found to be elevated in IDDM patients and in subjects at risk for developing IDDM compared with 100 normal, nondiabetic blood donors. Both adhesion molecules were determined by sandwich ELISA. Serum concentrations of either clCAM-1 or cL-selectin were >2SD of normal mean in 10 of 14 recent-onset IDDM patients (P < 0.05). Serum levels of clCAM-1 and cL-selectin did not correlate. In first-degree relatives, elevated adhesion molecule levels were observed in the 6 ICA⁺ individuals and in the ICA⁻ individuals all (n = 14) with a genetic risk of IDDM (sharing HLA-DR3 and/or -DR4⁻ with the diabetic relative) but not in the HLA-DR3⁻ and/or -DR4⁻ relatives (n = 13). We conclude that elevated clCAM-1 and cL-selectin levels occur independently of ICA status and probably reflect ongoing immune processes in recent-onset IDDM patients and first-degree relatives at risk for IDDM.