CHILDREN WITH NEWLY-DIAGNOSED IDDM HAVE INCREASED LEVELS OF ANTIBODIES TO BOVINE SERUM-ALBUMIN BUT NOT TO OVALBUMIN

OBJECTlVE- To study the humoral immune response to bovine serum albumin (BSA) and ovalbumin (OA) in children with newly diagnosed insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN AND METHODS- We examined serum samples from 505 children 0.8-14.9 years of age with newly diagnosed IDDM for antibodies to BSA and OA by enzyme-linked immunosorbent assay (ELISA). We also had two control groups: 85 unrelated control children (0.8-7.1 years of age) and 395 nondiabetic siblings (3.0-14.9 years of age). The specificity of antibodies detected in ELISA was confirmed by immunoblotting in a subset of sera with varying levels of antibodies. RESULTS- Diabetic children <7 years of age had a significantly higher level of IgG (immunoglobulin) antibodies to BSA than did unrelated control children (P < 0.0001). The difference was greatest in the youngest group of children, 0.8-2.9 years of age. IgA antibodies to BSA were detected more frequently among diabetic than control children (P = 0.0009). Levels of IgG and IgA antibodies to ovalbumin did not differ between diabetic and control children. Diabetic children 3.0-14.9 years of age also had higher levels of IgG and IgA antibodies to BSA than did their age- and sex-matched nondiabetic siblings (P = 0.02 and P < 0.0001, respectively). Those siblings who contracted IDDM during the follow-up period (n = 15) had a measurable level of IgA antibodies to BSA more often than did those who remained nondiabetic (60 and 34%, respectively; P = 0.04). Neither before nor after diagnosis of IDDM was there any significant trend in antibody levels. CONCLUSIONS- A high level of antibodies to BSA commonly associates with IDDM, whereas the humoral immune response to OA is similar in diabetic and nondiabetic children.