IL-2 is the up-regulating cytokine, which stimulates primarily the cell-mediated inflammatory response by promoting growth, proliferation and differentiation of T cells, B cells, natural killer (NK) cells, monocytes and macrophages. It is secreted mainly by activated T cells. IL-2 induces activation and rapid clonal expansion of mature T cells, and cytokine production in T cells, including interferon (IFN)-g and IL-4; 1 growth of B cells and immunoglobulin (Ig) J-chain switching and secretion of IgM in B cells; 2 proliferation, production of IFN-g and cytolytic activity of NK cells; 3 proliferation and differentiation of macrophage precursors; 4 and cytolytic activity of monocytes. 5 In contrast to IL-2, IL-10 (known as the cytokine synthesis inhibitory and macrophage deactivating factor) down-regulates the immune reactions accompanying acute inflammation and limits the duration of inflammatory responses. IL-10 can also promote and regulate chronic inflammatory processes. IL-10 is produced by a variety of cell types, including CD4 ' T cells, activated CD8 ' T cells and activated B cells. The main anti-inflammatory activities of IL-10 */ namely, inhibition of cytokine production in macrophages, neutrophils, T cells and NK cells, 6 Á 9 and inhibition of the macrophage Á/monocyte activation and the antigen presentation abilities of these cells 10 */lead to the resolution of inflammation. However, if the acute inflammatory process has not been resolved, IL-10 can induce humoral inflammatory reactions such as the immunoglobulin isotype switching in B cells 11, 12 and differentiation of B cells into plasma cells, 13 and thus promote switching of inflammation in the chronic stage.