Evaulation of the efficacy of the combination of multiple autoantibodies to islet-specific antigens in Korean type 1 diabetic patients

Abstract

With the recent cloning and recombinant expression of novel islet autoantigens, it is possible to investigate whether the quantitative expression of autoantibodies to these molecules is correlated with the semiquantitative titration of islet cell antibodies (ICA). To estimate the regional difference in the degree of association between these autoantibodies, autoantibodies reacting with ICA512/IA-2 (ICA512) and GAD65 in addition to ICA were analyzed in 131 Korean children with type 1 diabetes. Among the 131 type 1 diabetes patients, 36% was ICA512-positive, 56% was anti-GAD65-positive, and 43% was ICA-positive. However, in a subset of these with recent onset (<1 year), the prevalence of ICA512, anti-GAD65, and ICA were 75%, 75%, and 87.5% respectively. ICA512 as well as anti-GAD65 were significantly associated with the presence of ICA. Among type 1 diabetes patients, 69% had one or more and 43% had two or more of these antibodies. Autoantibodies to ICA512 and anti-GAD65 were observed in 40 and in 41 of 56 ICA-positive subjects, respectively. Furthermore, ICA512 or anti-GAD65 were positive in 97% (34 of 35) and 100% (22 of 22) of patients with ICA levels ≥20 JDF-u and ≥40 JDF-u, respectively. The titer of ICA correlated with those of ICA512 (r=0.41, p<0.001) and anti-GAD65 (r=0.49, p<0.001). Both the prevalences and the titers of ICA512 or anti-GAD65 were strongly correlated with those of ICA even in Korean type 1 diabetes patients. ICA512 and anti-GAD65 in combination may be considered to be an alternative to ICA.