Immune-mediated interactions during macrophage development in non-Hodgkin's lymphoma

As part of an investigation of mononuclear phagocytes in malignant lymphoma, measurement of immune-mediated erythrophagocytosis and rosette formation was carried out on cells grown in suspension culture at the monocyte (Day 0) and macrophage (Day 6) stages; the culture medium contained autologous serum. Cells were derived from 10 patients with untreated non-Hodgkin's lymphoma (NHL) and from 12 normal individuals. The results were subjected to Analysis of Variance and demonstrated a significant difference between the two groups with respect to erythrophagocytosis but not to rosette formation. In the NHL group, the proportion of erythrophagocytic cells showed no significant increase between the monocyte and macrophage stages (0.07 to 0.09), in contrast to the marked increase seen in the normal group (0.09 to 0.24). In a pilot investigation to examine the possible role of factors in the serum, cells derived from the NHL patients were cultured with serum from healthy donors; they showed no significant difference in the immune-mediated functions from those grown in autologous serum. Overall, the results provide further quantitative evidence of defective macrophage maturation in NHL, presumably reflecting the compromise of host defence mechanisms.