Incidence of autoimmune thyroiditis in interferon-alpha treated and untreated patients with chronic hepatitis C virus infection.
OBJECTIVE
To clarify the relationship between interferon-alpha (IFN-alpha) therapy and autoimmune thyroiditis in chronic hepatitis C virus (HCV) infection, we investigated a selected number of patients without basal thyroid dysfunctions.


METHODS
130 patients (average age: 20-70), with chronic HCV infection and without basal clinical and laboratory signs of autoimmune thyroiditis were divided into two groups: IFN-alpha treated (A) and untreated (B) patients. Group A received IFN-alpha (three million U.I./3 times a week) for six months; group B was followed for the same period. Thyroid peroxidase and thyroglobulin autoantibodies were measured by radioimmunoassay; thyroid function was measured by radioimmunoassay (free thyroxine and triiodothyronine) and immunoradiometric assay (thyroid stimulating hormone).


RESULTS
After a 6-month period, thyroid autoantibodies positivity was documented in 21.1% of group A and in 10.3% of group B patients, both statistically relevant (p<0.001 and p<0.011, respectively). The comparison between the two groups was not statistically relevant (p=0.142).


CONCLUSIONS
Our study showed a prevalence of de novo thyroid autoimmunity in chronic HCV patients treated with IFN-alpha, confirming previous data in literature. The lack of a significant difference between treated and untreated patients strongly suggests that the anti-thyroid autoimmune response is linked to the HCV infection itself. Moreover, IFN-alpha therapy probably does not represent a risk factor in renewing the autoimmune processes of the thyroid gland. Thyroid function and autoantibodies must be systematically monitored in patients with HCV infection, especially in female and IFN-alpha treated population, not only to verify the possible thyroid abnormalities but also to rule out concomitant autoimmune diseases.
Rocco
A
A
Dept. of Medical Patophysiology, University of Rome La Sapienza, Italy. arocco48@libero.it
Gargano
S
S
Provenzano
A
A
Nardone
M
M
De Sanctis
G M
GM
Altavilla
N
N
Chircu
L V
LV
Grimaldi
F
F
D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000009:adverse effects / Q000627:therapeutic use; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D016898:Interferon-alpha / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013967:Thyroiditis, Autoimmune / Q000175:diagnosis / Q000453:epidemiology*
D000998:Antiviral Agents; D016898:Interferon-alpha