AUTOANTIBODIES AGAINST AROMATIC L-AMINO-ACID DECARBOXYLASE IN AUTOIMMUNE POLYENDOCRINE SYNDROME TYPE-I

Patients with autoimmune polyendocrine syndrome type I(APS I) have aut oantibodies against the enzyme aromatic L-amino acid decarboxylase (AA DC) of pancreatic beta-cells. The aim of the present study was to inve stigate the presence of anti-AADC antibodies in a large cohort of pati ents with APS I, and in patients with isolated insulin-dependent diabe tes mellitus (IDDM). We found autoantibodies against AADC in 35 of 69 patients (51%) with APS I but in none of 138 patients with isolated ID DM or 91 healthy controls. Among the patients with APS I, anti-AADC an tibodies were more often found in those with hepatitis (11/12, 92%), t han in those without hepatitis (24/57, 42%) (P = 0.003). Similarly, of 15 patients with vitiligo, 12 (80%) had anti-AADC antibodies, compare d with 23/54 (43%) without vitiligo (P = 0.021). Of the 9 APS I patien ts with IDDM, 5 had antibodies against both AADC and glutamate decarbo xylase, 2 against AADC only, and 2 against glutamate decarboxylase onl y. Interestingly, AADC is present in relatively large amounts in the l iver, where its function is unknown. Thus, an autoimmune reactivity ag ainst AADC may be involved in the pathogenesis of autoimmune chronic a ctive hepatitis and vitiligo in APS I patients, whereas the role of AA DC in the development of IDDM in these patients remains to be determin ed.