Identification of tyrosine hydroxylase as an autoantigen in autoimmune polyendocrine syndrome type I

Patients with the autosomal recessively inherited autoimmune polyendocrine syndrome type I (APS I) have autoantibodies directed against several endocr ine and nonendocrine organs. In this study a new autoantigen related to thi s syndrome, tyrosine hydroxylase, was identified in sera from patients with alopecia areata through immunoscreening of a scalp cDNA library. Immunorea ctivity against in vitro expressed tyrosine hydroxylase was found in 41 (44 %) of the 94 APS I patients studied and this reactivity correlated with the presence of alopecia areata (P = 0.02). These findings further stress the importance of enzymes involved in neurotransmitter biosynthesis as importan t immune targets in APS I. (C) 2000 Academic Press.