Anti-inflammatory effect of spontaneous lymphoma in SJL/J mice

Histiocytic lymphomas develop spontaneously in about 80% of SJL/J mice between the ages of 8 and 14 months. These animals were used for the determination of whether spontaneously arising cancers compromise monocyte function similar to the monocyte defects described during growth of transplanted tumors. SJL/J mice with tumors accumulated significantly fewer macrophages than did age-matched animals without tumors either on sc implanted filters or in peritoneal exudates induced by phytohemagglutinin. There was no corresponding defect in polymorphonuclear neutrophil responses. Whereas no apparent correlation existed between tumor size and degree of inhibition, animals without demonstrable tumors had no inflammatory defects. Aging did not alter the inflammatory response to implanted filters but increased both the resident peritoneal macrophage population and the total macrophage yield to phytohemagglutinin provocation. When given transplants of histiocytic lymphomas, young SJL/J mice developed similar inflammatory defects. This study represents the first demonstration that spontaneous tumors, in addition to transplanted tumors, produce abnormalities in monocyte inflammatory responses.