Both T helper and T cytotoxic lymphocytes can be divided into subpopulations on the basis of their cytokine production (Th1/Th2), Tc1/Tc2). It is confirmed by numerous studies and clinical investigations that the abnormal ratio of the lymphocyte subpopulations can play pathogenic role in some disorders. In organ specific autoimmun diseases Th1 dominance and in atopic diseases Th2 dominance can be observed.

Atopic dermatitis is a very common, chronic, recurring, multifactorial disease and Th2 lymphocyte dominance has an imporatant role in the pathogenesis. This Th2 dominance is mostly characterized by elevated IL-4 and decreased IFN-g production, but some recent data in the literature emphasize also the importance of IL-13 production. In the case of patients with chronic idiopathic urticaria and polymyositis dermatomyositis (PM/DM) little is known about the intracellular cytokine production of peripheral blood lymphocytes.

In the present study our aim is to measure the serum immunglobulin levels, the lymphocyte subpopulations, the number of activated T cells, the ratio of Th1/Th2 and Tc1/Tc2 lymphocytes an also to detect the soluble cytokine levels in the sera of patients with atopic dermatitis, chronic idiopathic urticaria and PM/DM. We also plan to carry out histological investigations.