To study the humoral immune response to bovine serum albumin (BSA) and ovalbumin (OA) in children with newly diagnosed insulin-dependent diabetes mellitus (IDDM).
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.
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.
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.