Background:
@EN IDDM is a disease generally occurring in children and characterized by an absolute deficiency of insulin caused by destruction of the pancreatic beta cells through an autoimmune mechanism. In the Asian populations, it has been known that
clinical
and immunologic characteristics of IDDM are quite different from those of Caucasians, say low prevalence of Islet Cell antibody(ICA). Anti-glutainic acid decarboxylase autoantibodies(anti-GAD), now recognized as one of the other major serological
markers for autoimmune type IDDM appear to be more prdictive of IDDM in Caucasoids than in Asians. However, if we admit IDDM is mainly caused by autoimmune destruction of pancreatic beta cells, the prevalence of autoimmune markers in recent-onset
IDDM
patients in Korea maybe getting close to that in Caucasians. The objective of the present study was to evaluate the prevalence of these immunologic markers in IDDM patients and their prediabetic relatives from Korea applying a newly developed
anti-GAD
assay.
@ES Methods:
@EN Since not only the detection of these autoantibodies is rather complicated and time-consuming.but the incorrect patient definitionmay lead to false conclusion on the immunologic characteristics of IDDM in Korea, we developed a new
radioimmunopercipitation assay using purified enzymatically active pig brain GAD and measured the prevalence of anti-GAD and ICA in 131 cases of IDDM, whose age at diagnosis were less than 15(mean age at diagnosis : 7.9 yr, mean duration of IDDM
:
4.5
yrs) and their 96 first-degree relatives.
@ES Results :
@EN The overall prevalence of anti-GAD antibodies was 57%(73 of 127) in patients with Korean IDDM, whereas 3 of 73 their first0degree relatives had positive antibodies. The frequency of ICA(+) was 43% in IDDM patients, whereas 1.2% of the
relatives
had
ICA(+). Prevalences of anti-GAD and ICA in recent-onset cases(duration < 1 yr) were 75% and 87.5%, respectively. Among those who were positive for anti-GAD, their onset age were significantly high. No statistically significant diffeences in sex
ratio,
duration of disease, and the frequencies of diabetic ketoacidosis were found comparing anti-GAD(+) patients to the anti-GAD(-). We found a significant. But not strong association between the titers of anti-GAD and ICA.
@ES Conclusion :
@EN From this, we could assess that autoantibodies are present at comparable sensitivity and specificityin Korean IDDM patients, especially in recent-onset cases. Caucasian immunologic markers for IDDM might also confer disease susceptibility
among
Koreans, but low prevalence of them in the first-degree relatives may suggest that these prediabetic diagnostic markers are unlikely to give much benefit, when we perform these assays on the population levels.
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