HLA antigens in patients with interferon-α-induced autoimmune thyroid disorders in chronic hepatitis C

Background/Aims: To determine the immunological predisposition to autoimmune thyroid disorders induced by interferon-α therapy, human leukocyte antigen (HLA) was analyzed in patients with chronic hepatitis C who developed autoimmune thyroid disorders during or after treatment with interferon-α. Methods: Four hundred and thirty-nine patients with chronic hepatitis C (278 males and 161 females, aged 20–73 years) were treated with interferon-α (natural-α, 169; α-2a, 82; α-2b, 188) for 24 weeks. Results: Seventeen of 439 (3.9%) patients developed symptomatic autoimmune thyroid disorders; these included nine cases of hyperthyroidism and eight cases of hypothyroidism. The incidence of HLA-A2, B46 and Cw7 increased in patients with interferon-α-induced autoimmune thyroid disorders. Especially, the incidence of HLA-A2 (15/17; 88.2%) was significantly higher than that observed in the general population in Japan (corrected p-value (pc): pc<0.003). The odds ratios for the relative risk of the autoimmune thyroid disorders were A2, 10.6 [95% confidence interval, 2.4–46.5]; B46, 4.8 [1.6–14.0]; and Cw7, 3.0 [1.1–7.9]. Conclusions: Our study revealed that HLA-A2 is highly linked to the autoimmune thyroid disorders induced by interferon-α-therapy in patients with chronic hepatitis C.