title: Exacerbation of thyroid autoimmunity by interferon alpha treatment in patients with chronic viral hepatitis: our studies and review of the literature.
abstract: In the present studies, the long term effects of IFN alpha on thyroid function and thyroid autoantibodies were evaluated in 42 patients with chronic viral hepatitis type C treated with IFN alpha for at least 4 months. Before IFN treatment, 41 patients tested were all euthyroid. Five (12%) out of 24 patients tested had positive tests for thyroid autoantibodies. MCHA/TPOAb was detected in all 5 and TGHA/TGAb in 3 out of these 5 patients. Six to 10 x 10(6) units (U) of recombinant or natural IFN alpha were given intramuscularly daily for the first 2 to 4 weeks, followed by 3 to 10 x 10(6) U thrice weekly for the subsequent 14 to 22 weeks. Thyroid dysfunction and/or rises in titers of thyroid autoantibodies were observed in 6 patients during IFN alpha treatment; clinically overt thyroid dysfunctions, destructive thyroiditis and thyrotoxicosis of unidentified etiology, developed in 2 patients 4 to 5 months after start of IFN treatment, subclinical hypothyroidism with a slight increase in serum TSH concentrations but no serum thyroid hormone alternations was observed in 2 patients, and increases in titers of thyroid autoantibodies without thyroid dysfunction were found in 2 patients. Thus, IFN alpha exacerbated thyroid autoimmunity exclusively in all patients with positive tests for thyroid autoantibodies prior to treatment, but did not induce thyroid autoimmunity in thyroid autoantibody-negative patients. These data suggest that the prolonged IFN alpha therapy can lead to exacerbation of thyroid autoimmunity in susceptible (thyroid autoantibody-positive) patients.
authors.affiliation: First Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nagayama
authors.forename: K
authors.initials: K
authors.lastname: Ohta
authors.forename: M
authors.initials: M
authors.lastname: Tsuruta
authors.forename: A
authors.initials: A
authors.lastname: Takeshita
authors.forename: H
authors.initials: H
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Hamasaki
authors.forename: K
authors.initials: K
authors.lastname: Ashizawa
authors.forename: K
authors.initials: K
authors.lastname: Nakata
authors.forename: N
authors.initials: N
authors.lastname: Yokoyama
authors.forename: S
authors.initials: S
authors.lastname: Nagataki
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis*; D002908:Chronic Disease; D005260:Female; D006526:Hepatitis C / Q000150:complications / Q000628:therapy*; D006801:Humans; D007370:Interferon Type I / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins; D013959:Thyroid Diseases / Q000209:etiology* / Q000276:immunology; D013961:Thyroid Gland / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D007370:Interferon Type I; D011994:Recombinant Proteins