Evidence for raised K-cell levels in type-I diabetes.

The proportion of blood mononuclear cells forming low-affinity rosettes with sheep erythrocytes (K cells) was abnormally high in 13 (57%) of 23 children with classical type-1 diabetes at diagnosis but normal in children who had had diabetes for more than a year. A raised proportion of K cells was also found in 5 out of 10 unaffected siblings with islet-cell antibodies and at least one HLA haplotype in common with the diabetic proband; and in 10 (45%) of 22 subjects with type-1 diabetes and co-existent autoimmune thyroid disease irrespective of the duration of diabetes or the presence of islet-cell antibodies. These findings may be new evidence for lymphocyte-mediated beta-cell destruction and support the idea of immunogenetic heterogeneity within type-1 diabetes.