CLINICAL CHARACTERISTICS OF SUBACUTE THYROIDITIS CLASSIFIED ACCORDINGTO HUMAN-LEUKOCYTE ANTIGEN TYPING

We investigated human leukocyte antigen (HLA) class I and class II ant igens in 56 Japanese patients with subacute thyroiditis (SAT) who visi ted our out-patient clinic between 1988 and 1990. We found SAT to be a ssociated with not only HLA-B35 (40 patients; P < 0.000001; relative r isk, 18.02), but also with HLA-B67 antigens (9 patients; P < 0.00001; relative risk, 11.20). No heterozygotes of HLA-B35 or HLA-B67 were fou nd in any of the 56 patients with SAT. Either HLA-B35 or HLA-B67 antig en is found in 87% of patients with SAT. When season of onset and clin ical course of SAT were compared in the 49 patients with HLA-B35-posit ive SAT (B35-SAT) and HLA-B67-positive SAT (B67-SAT), we were able to identify certain characteristics: 1) B67-SAT often followed the course from transient thyrotoxicosis to a hypothyroid phase to a euthyroid p hase [6 of 9 B67-SAT (67%) us. 10 of 40 B35-SAT (25%); P < 0.05]; and 2) B67-SAT occurred mostly during the summer or autumn and at a higher rate than did B35-SAT [8 of 9 B67-SAT (89%) vs. 17 of 40 B35-SAT (43% )], whereas B35-SAT occurred throughout the year. We conclude that the re are at least two types of SAT that can be classified by association with either HLA-B35 or HLA-B67 antigens.