The mutual cooperation of blood platelets and lymphocytes in the development of autoimmune thyroid diseases.

Autoimmune thyroid diseases include several distinct clinical entities, mainly Graves' disease and Hashimoto's thyroiditis. An incompetent immune response directed against the body's own tissues, and the production of antibodies against specific cell antigens accompanied by chronic inflammation, all occur in autoimmune thyroid diseases. The autoimmune process is induced by genetic and environmental factors that are difficult to identify and generates the development of concomitant diseases in other systems. Leukocyte activation and overproduction of inflammatory mediators, as well as improper levels of thyroid hormones, play an essential role in the chronic course of these diseases. The development of autoimmune thyroid diseases results from the impairment of the regulatory and suppressor functions of T-cells or NK cells and activation of B cells, or from the changes in the number of those cells. Many reports have shown the significant role of platelet-leukocyte interaction in inflammation. Autoantibodies react with target antigens in different kinds of cells, including blood platelets, and autoimmune processes can modulate the mutual cooperation of blood platelets and lymphocytes. The activity of blood platelets and lymphocytes is reciprocally regulated. It has been suggested that blood platelets can influence lymphocyte function by direct contact with receptors, and indirectly via soluble mediators. The interactions of platelet-immune cells (neutrophils, monocytes, lymphocyte and dendritic cells) can have a potent enhancing effect on immune cells functions.