["Diabetic rosettes": a cellular immunity marker in subjects at risk for type I diabetes].

The authors have previously described a marker of cell-mediated, called "diabetic rosettes", revealed by the increased binding of CD3 CD4 lymphocytes from type I diabetic patients to beta-cell membrane antigens, as compared to lymphocytes from control subjects. In the present study, they have detected such "diabetic rosettes" in some subjects at risk for type I diabetes. The mean value of lymphocytes adhering to beta (RINm5F)-cells (beta-CL) was statistically higher in those subjects at risk than in control blood bank donors (p = 0.003). When a positive test was arbitrarily defined as a value of beta-CL higher than the 95th percentile of controls, 20 p. cent of the subjects at risk were classified as beta-CL+. No difference was observed between two subgroups of subjects at risk: first degree relatives of type I diabetic patients, and non-diabetic subjects with transient hyperglycaemia. "Diabetic rosettes" were associated with HLA DR 3/4 heterozygosity (p less than 0.04) and with a "low" acute insulin release to IV glucose (p = 0.05). They were not associated with islet-cell antibodies, insulin autoantibodies, or "activated" (HLA DR+) T-lymphocytes. The authors suggest that "diabetic rosettes" represent a marker of cellular immunity in some subjects at risk for type I diabetes.