Histocompatibility lymphocytic antigen (HLA) typing in patients with acute exacerbation of Hashimoto's thyroiditis.

Histocompatibility lymphocytic antigen (HLA) typing was performed in 6 patients with acute exacerbation of Hashimoto's thyroiditis whose diagnoses were established on the basis of typical histological findings, and was compared with those of 12 with subacute thyroiditis, 33 with general Hashimoto's thyroiditis and also with a control group. There was a high incidence of BW35 in patients with subacute thyroiditis, although it was only seen in 1 of 6 patients with acute exacerbation. The difference was statistically significant (p less than 0.01). Four of 6 patients with acute exacerbation had DR2 and none of them had DR4, which was the reverse of the findings for Hashimoto's thyroiditis patients in general, and the difference in the incidence of DR2 was significant (p less than 0.001). None of the HLA types in patients with acute exacerbation was significantly different from those of the control group. In conclusion, HLA typing in patients with acute exacerbation was different from those of subacute thyroiditis and general Hashimoto's thyroiditis. Acute exacerbation was considered to involve quite a limited and rather unique population among patients with Hashimoto's thyroiditis.