Converging and diverging properties of human interleukin-4 and interleukin-10.

IL-4 and IL-10 are both produced by activated TH2 cells as well as basophil/mast cells. In addition, IL-10 is secreted by activated B cells, monocytes/macrophages and keratinocytes. IL-4 and IL-10 act in concert to induce activated B lymphocytes to grow, switch isotype and ultimately differentiate into antibody producing plasma cells. Both IL-4 and IL-10 inhibit the secretion of proinflammatory cytokines by monocytes/macrophages and neutrophils. While IL-4 enhances the presentation of antigen by monocytes/macrophages and dendritic cells, IL-10 inhibits it. IL-4 and IL-10 can either stimulate or inhibit T cell proliferation. While both cytokines may prove useful in the management of inflammatory disorders, IL-4 is presently used in clinical trials that relate to its antitumor effects.