PROSPECTIVE-STUDY ON THYROID AUTOIMMUNITY AND DYSFUNCTION RELATED TO CHRONIC HEPATITIS-C AND INTERFERON THERAPY

This study was designed to assess patients with chronic hepatitis C (C HC) for the presence of thyroid autoimmunity and dysfunction, to evalu ate the risk of thyroid disorders associated with interferon (IFN) the rapy, and to survey the outcome of possible treatment-related thyroid injury. Out of 104 consecutive untreated patients (30 women and 74 men ; mean age, 52.7 years), 8 (7.7%) were found seropositive for thyroid autoantibodies (ThyAb), whereas seropositivity in healthy controls was 1/98 (1.3%). The relative increase in risk of developing thyroid auto immunity associated with CHC was 760% (95% Cl, 220-1300%). No patients had abnormalities of thyroid function tests, but on IFN treatment, 3/ 3 patients showed a rapid over-range rise in circulating thyrotropin, which returned to normal after therapy discontinuation. In the other 5 seropositive patients who refused treatment, thyroid function remaine d normal. Out of the 58 initially seronegative patients who consented to IFN treatment, 9 (15.5%) developed thyroid autoimmunity. Seven of t hem (77,7%) had thyroid dysfunction: hypothyroidism in 4 cases, transi ent thyrotoxicosis in 2 cases. The last patient developed TSH-receptor antibodies and Graves' disease, requiring methimazole therapy. Thyroi d function recovered in the former 6 cases following IFN discontinuati on. In the 28 initially seronegative patients who refused IFN and part icipated in a preliminary tauroursodeoxy-cholic acid trial, antithyrog lobulin antibodies alone appeared in one case, but no thyroid dysfunct ion was observed. The relative risk of thyroid autoimmune disorder ass ociated with IFN therapy was 342% (28-636%). The patients with CHC wer e unlikely to develop thyroid dysfunction in the absence of IFN therap y, in spite of being ThyAb seropositive. Moreover, a considerable prop ortion of seronegative patients, when IFN-treated, developed thyroid a utoimmunity and then thyroid dysfunction, Both in seropositive and ser onegative patients immediate IFN discontinuation normalized thyroid fu nction and hormone replacement therapy was not necessary. (C) 1997, Ed itrice Kurtis.