Kimura's disease is characterized by subcutaneous masses, eosinophilia, and markedly elevated serum immunoglobulin E, suggesting that T helper (Th)2 cells may play a role in the pathogenesis. We investigated Th2 cytokine synthesis by mononuclear cells and possible Th1/Th2 subpopulations in Kimura's disease. Peripheral blood samples were obtained from seven patients with Kimura's disease and CD4(+) T-cell subpopulations separated by CD45RO and CD62L were isolated. Purified cells were stimulated with PHA or anti-CD3 mAb, and the cytokine levels were measured by Cytometric Bead Array kit. Peripheral blood mononuclear cells in the majority of the patients produced Th2 cytokines such as interleukin (IL)-3, IL-4, IL-5, IL-13 or GM-CSF higher than those of controls. The ratio of CD45RO(+) CD62L(+) cells in CD4(+) T cells was increased in six out of seven patients compared to age-matched controls. Especially, patient 1 had remarkably increased levels of CD45RO(+) CD62L(+) population in CD4(+) T cells. In addition, IL-4 production levels by CD45RO(+) CD62L(+) CD4(+) T cells of patients 1 and 2 were higher than those of their CD45RO(+) CD62L(-) CD4(+) T cells, in the same manner as those by a normal control. Taken together, the synthesis of Th2 cytokines and CD62L-positive subpopulation in CD45RO(+) CD4(+) T cells, which may represent characteristics of Th2, are increased in patients with Kimura's disease, suggesting that deviation to Th2 may involve in pathogenesis of the disease.