Cell biological roles of IL-10 in myeloma cells

IL-10,along with interleukin(IL)-6,are considered two of the most important cytokines that regulate the proliferation and cellular characteristics of myeloma cells. It remains unclear from the clinical data how levels of IL-10 in serum at various stages of myeloma are related to clinical manifestations of this disease. Several studies have reported that IL-10 affects myeloma cells by stimulating secondary signals for cell proliferation through oncostatin M (OSM)and IL-11. In experiments using human myeloma cell lines that were established in our laboratory,IL-10 seemed to be expressed in half of myelomas simulta-neously with OSM,and was correlated with c-maf,a transcription factor that has been known to be overexpressed in myelomas with t (14;16)(q32;q23). In addition,IL-10 abolishes all trans-retinoic acid (ATRA)-induced growth inhibition of myeloma cells. The expression and production of IL-10 in myeloma patients may be important for sub-categorization and to establish case-oriented therapies. Key words myeloma,interleukin 10,c-maf,ATRA,gene expressio