PRODUCTION AND ROLES OF IL-6, IL-10, AND IL-13 IN B-LYMPHOCYTE MALIGNANCIES AND IN B-LYMPHOCYTE HYPERACTIVITY OF HIV-INFECTION AND AUTOIMMUNITY

We analyzed the production and the roles of IL-6, IL-10, and IL-13 in B-lymphoid malignancies and in specific diseases with B-lymphocyte hyp eractivity. Both IL-13 and IL-10 genes are expressed in B-cell lymphom as. However, their contribution to tumor progression is unclear, In ce rtain lymphoproliferative disorders that develop in transplanted patie nts, IL-6 is produced by malignant cells and is a major factor of thei r proliferation. In other lymphomas, the IL-6 gene is expressed only i n malignancies where differentiated malignant cells are present, In th ese lymphomas, IL-6 is produced by stromal cells, and the malignant ce lls express the IL-6 receptor. In patients with HIV infection, the lev el of production of IL-6, IL-10, and IL-13 is not higher than those of other conditions with immune activation. However, IL-6 contributes to increased production of IgG and IgA in vivo. In Castleman's disease, IL-6 is produced in the lymph node germinal centers, partly originatin g from follicular dendritic cells, which may explain some of the patho genesis of this disease, In systemic lupus erythematosus, the critical cytokine is IL-10, which is produced in large amounts by B lymphocyte s and monocytes and is responsible for autoantibody production. Taken together, these data emphasize the roles of IL-6 and IL-10, usually pr oduced by nonlymphoid cells, on B lymphocytes, either malignant or hyp eractivated. (C) 1997 Academic Press, Inc.