Thyroid autoimmunity and function before, during anf after interferon alpha-2b therapy in chronic hepatitis C

In order to study thyroid function and autoimmunity in HCV+ patients and to evaluate if a prolonged treatment with αIFN can induce or exacerbate immune thyreopaties, we assessed, in a group of 24 HCV+ patients (14 M, 10 F; mean age 51.2 range 30-70 years), thyroid function and auto immunity with peroxidase antigen (TPOAb, RIA), TSH receptor antibodies (TRAb, RRA) and thyreoglobulin (TgAb, Haemoagglutination). All patients were euthyroid at basal determination; TPO Ab were mildly positive in 3 patients. 14 patients (5 M, 9 F; mean age 47.2 range 30-59 years) required αIFN-2b therapy; TSH, TROAb, TRAb and TGAb were assessed at 2, 4, 6, 9 and 12 months of therapy; FT3 and FT4 were determined during therapy only in case of rising of auto immunity, significant change of TSH level or development of clinical signs of thyreopaties. During therapy in one patient TGAb became transiently detectable without reaching pathological signifcance; in four other patients TRAb rose from undetectable level to borderline values. No changes were found in thyroid function tests and none of these patients became symptomatic for thyroid disease. In one patient positive for TROAb before treatment a severe hyperthyroidism, such to require discontinuation of IFN therapy and a treatment with metimazole, accompanied by increased levels of thyroid antibodies occurred at the 4th month of therapy. These results suggest that the prevalence of thyroid auto immunity in HCV+ patients is lower than in previous reports and similar to prevalence found in general population; IFN treatment is frequently associated with fluctuation of thyroid autoimmunity and can enhance a pre-existing predisposition for thyroid autoimmunity.