Bone marrow stromal cells regulate marrow haematopoiesis by secreting interleukins (IL) such as IL-8. Lipid mediators modulate IL-8 synthesis in numerous cell types. We have investigated the effects of 5 lipid mediators (PAF, PGE 2 , LTB 4 , 12-HETE and 15-HETE) on the spontaneous and cytokine-induced IL-8 synthesis by human bone marrow stromal cells. By using reverse-transcriptase polymerase chain reaction (RT-PCR) we demonstrate that these cells constitutively express IL-8 transcripts. By using a specific ELISA, we found that the production of IL-8 by marrow stromal cells is enhanced after stimulation with 12-HETE (1μM) both in serum-free and serum-containing culture medium. LTB 4 (1μM) enhances IL-8 production only in serum-supplemented medium. PAF, PGE 2 and 15-HETE (1μM to 0.1nM) have no effect on the spontaneous and serum-induced production of IL-8 by human bone marrow stromal cells. PGE 2 (1μM or 10nM) reduces marrow stromal cell IL-8 synthesis in response to IL-1α or TNF-α. In contrast, PAF, 12-HETE, 15-HETE and LTB 4 have no effect. In conclusion, various lipid mediators modulate the spontaneous, serum- or cytokine-induced IL-8 synthesis by bone marrow stromal cells, highlighting, for the first time, their potential role in the regulation of IL-8 production within the human bone marrow.