In vitro cytokine secretion and maturation phenotype of lymphoma-associated splenic macrophages.

In this study, cytokine secretion capacity and maturation phenotype of human lymphoma-associated splenic macrophages (LASM) were evaluated in a long-term culture. Sixteen spleens from malignant lymphoma patients and five control spleens were investigated. Splenic macrophages (SM) were isolated by teflon adherence and cultured for 6-48 days. Secretion of IL-1 alpha, IL-6 and TNF alpha was measured by ELISA following maximal stimulation with LPS and IFN-gamma, and cytokine mRNA expression was detected by in situ hybridization. Immunohistochemical expression of maturation-associated antigens was evaluated semiquantitatively. Cytokine secretion capacity was significantly altered in LASM which exhibited reduced TNF alpha and IL-6, but elevated IL-1 alpha secretion when compared to control SM. Alterations of cytokine secretion capacity were associated with a modification of LASM maturation phenotype, showing impaired expression of early and chronic/late inflammatory markers. These findings obtained from a long-term culture model suggest that malignant lymphomas induce lasting modifications of cytokine secretion and maturation patterns in LASM.