['Dendritic cells (DC) have been suggested to play an important role in the pathogenesis of rheumatoid arthritis (RA). Agents that inhibit DC differentiation and function may have a therapeutic value in the treatment of RA.', 'To examine the effect of the non-steroidal anti-oestrogens toremifene and tamoxifen on the differentiation of synovial fluid (SF) macrophages into DC.', 'SF macrophages from patients with RA were cultured with interleukin (IL)-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF) in the presence or absence of anti-oestrogens. The expression of cell surface markers on SF antigen-presenting cells (APC) was studied by flow cytometry. The capacity of SF APC to stimulate allogeneic T cells was studied using the mixed lymphocyte reaction. The production of tumour necrosis factor-alpha, IL-10 and transforming growth factor-beta1 was studied using ELISA.', 'Anti-oestrogens inhibited the differentiation of SF macrophages into DC and the capacity of SF macrophage-derived DC to stimulate allogeneic T cells.'] Do non-steroidal anti-oestrogens inhibit the differentiation of synovial macrophages into dendritic cells?