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 (CHC) for the presence of thyroid autoimmunity and dysfunction, to evaluate the risk of thyroid disorders associated with interferon (IFN) therapy, 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 autoimmunity associated with CHC was 760% (95% CI, 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 remained normal. Out of the 58 initially seronegative patients who consented to IFN treatment, 9 (15.5%) developed thyroid autoimmunity. Seven of them (77.7%) had thyroid dysfunction: hypothyroidism in 4 cases, transient thyrotoxicosis in 2 cases. The last patient developed TSH-receptor antibodies and Graves' disease, requiring methimazole therapy. Thyroid function recovered in the former 6 cases following IFN discontinuation. In the 28 initially seronegative patients who refused IFN and participated in a preliminary tauroursodeoxycholic acid trial, antithyroglobulin antibodies alone appeared in one case, but no thyroid dysfunction was observed. The relative risk of thyroid autoimmune disorder associated with IFN therapy was 342% (28-636%). The patients with CHC were unlikely to develop thyroid dysfunction in the absence of IFN therapy, in spite of being ThyAb seropositive. Moreover, a considerable proportion of seronegative patients, when IFN-treated, developed thyroid autoimmunity and then thyroid dysfunction. Both in seropositive and seronegative patients immediate IFN discontinuation normalized thyroid function and hormone replacement therapy was not necessary.
Custro
N
N
Istituto di Medicina Interna e Geriatria, University of Palermo, Italy.
Montalto
G
G
Scafidi
V
V
Soresi
M
M
Gallo
S
S
Tripi
S
S
Notarbartolo
A
A
D000328:Adult; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000209:etiology*; D005260:Female; D006526:Hepatitis C / Q000276:immunology / Q000628:therapy*; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000009:adverse effects* / Q000627:therapeutic use; D007453:Iodide Peroxidase / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011994:Recombinant Proteins; D013959:Thyroid Diseases / Q000276:immunology* / Q000503:physiopathology; D013961:Thyroid Gland / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D001323:Autoantibodies; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins; D014284:Triiodothyronine; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine