Evaluation of L-thyroxin therapy effects on serum IL-2, IL-4, IL-12, IFN-Gama cytokines in patient with hypothyroidism seconder to subclinical and overt Hashimoto

Hashimoto?s thyroiditis is a chronic autoimmune thyroiditis. It is the most common cause of primary hypothyroidism in adolescent period, via autoimmune thyroid tissue destruction and affecting 2% of the population. This disease is characterized by extensive lymphocytic infiltration in thyroid tissue.The pathogenesis of the Hashimoto?s thyroiditis involves a complex interaction between genetic predisposing factors and environmental factors. Genetic factors are associated with HLA-DR3 and HLA-DR5. Environmental factors are iodine intake, bacterial and viral infections, cytokines therapy and pregnancy. Th1-mediated cytotoxic immune response is the major pathogenic feature of this disease. Thus, cytokines such as IL-12, TNF-? and IFN-? are very important in the pathogenesis. On the other hand, apoptosis over TNF is other important pathogenic pathway.Sixty five patients with Hashimoto?s thyroiditis referred to Celal Bayar University Medical Faculty Endocrinology polyclinic were included in this study. All of the patients were female aged 18 to 73 (mean= 40.32 ± 13.5) years. After a 10-12 weeks L-thyroxin therapy period, all of the patients were turn into euthyroidic state. There was a statistically significant decrease ( p<0.0001 ) in the levels of TSH and increase in the levels of FT4 ( p<0.0001 ) at the same time. Also, the levels of anti-Tg ( p < 0.01 ) and anti-TPO ( p < 0,001 ) were significantly lower than pre-teatment period. Decreasing of the anti- TPO levels is greater than anti-Tg levels. In the post-treatment period, a statistically significant decrease was shown (p<0.001) for the IL-12 levels in our investigation and this case was announced only one published paper in the literature. This result was very important, because IL-12 was originated by Th-1 immune response. Decreasing of the IFN-? levels was not statistically significant (p=0.276). On the other hand, no changes were determined of the IL-2 and IL-4 levels.