Heterophile antibodies segregate in families and are associated with protection from type 1 diabetes.

Markedly elevated levels of serum IL-4 were reported previously in 50% of a small group of type 1 diabetes nonprogessors. To determine the patterns of expression for this phenotype, a larger cohort of 58 families containing type 1 diabetic patients was examined. Analysis of the two-site ELISA assay used to measure serum IL-4 revealed evidence for heterophile antibodies, i.e., nonanalyte substances in serum capable of binding antibodies mutivalently and providing erroneous analyte (e.g., IL-4) quantification. Interestingly, relatives without type 1 diabetes were significantly more likely to have this phenotype than were patients with the disease (P = 0.003). In addition, the trait appears to have clustered within certain families and was associated with the protective MHC allele DQB1*0602 (P = 0.008). These results suggest that heterophile antibodies represent an in vivo trait associated with self-tolerance and nonprogression to diabetes.