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 prevalences 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
autoantibodies.
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 > or =20 JDF-u and > or =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.