Association between human leukocyte antigen (HLA) and interferon- induced thyroid diseases in four patients with HCV-related chronic hepatitis.

The interferon-alpha (IFN-alpha) therapy for HCV hepatitis may exacerbate or induce underlying thyroid disorders. Besides viral factors, the human leukocyte antigen (HLA) may be an independent risk factor. We evaluated fifteen patients with HCV chronic hepatitis during a period of 40 months. At the enrollment, all the patients were negative for thyroid disorders, excluding one patient with subclinical hypothyroidism. Eleven patients received IFN-alpha therapy. The HLA system was examined in every patient, evaluating antigens (n=40) of locus A, B and Cw and alleles (n=19) of locus DRB1* and DQB1*. The HLA system was also examined in healthy subjects (n=107) as a control group. The HCV genotype distribution in patients was: 1b=20%, 2a=60%, 3a=20%. Four IFN-treated patients presented clinical thyroid disorders, including autoimmune hypothyroidism (n=2), transient thyrotoxicosis (n=1) and subacute thyroiditis (n=1). The HLA susceptibility to thyroid disorders (antigen/allele frequency) in the whole group of patients was not different in respect to controls and normal Italian population. The patients with HCV chronic hepatitis that developed thyroid diseases after IFN- treatment had a double and specific association with the HLA system (Mantel-Haenszel X(c)(2)=4.706, p<0.05). This case report suggests that HLA system examination is an important and promising diagnostic aspect that may be considered in order to evaluate the appearance of thyroid disorders during the IFN-alpha treatment for HCV-related chronic hepatitis.