Association of HTLV-I with Autoimmune Thyroiditis in Patients withMyelopathy/tropical Spastic Paraparesisand in HTLV-I Carriers

There are some reports about the association of autoimmune thyroid diseases with human T cell leukemia virus type I (HTLV-I) infection. The objective of this study was to estimate the seroprevalence rates of anti-thyroid antibodies in HTLV-I carriers and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients in Mashhad, north east of Iran, to determine any association between HTLV-I infection and Hashimoto’s thyroiditis (HT). A total of 46 HTLV-I infected patients (24 patients with HAM/TSP and 22 asymptomatic carriers) and 40 HTLV-I seronegative healthy individuals were screened for the presence of thyroid autoantibodies. The diagnosis of HT was based on the presence of positive thyroid autoantibodies (Anti thyroid peroxidase and/or Anti thyroglobulin) and at least one of two additional criteria (hypothyroidism and/or goiter). Analysis of data was done, using Fisher-Exact test by statistical software SPSS version 13.0. A P value below 0.05 was considered statistically significant. Positivity for thyroid autoantibodies was found in 14 (63.6%) of 22 asymptomatic carriers, 6 (25%) of 24 patients with HAM/TSP and 3 (7.5%) of 40 HTLV-I seronegative healthy individuals. HT found in 45.4% of asymptomatic carriers, 25% of HAM/TSP patients and 5% of seronegative healthy individuals. This study demonstrates a high prevalence of HT in the HAM/TSP patients and the HTLV-I carriers in Mashhad. Our findings suggest an association between HTLV-I infection and HT in our region.