Absence of macrophage humoral recognition factor(s) in patients with carcinoma.

Abstract Phagocytosis by macrophages requires that certain humoral recognition factors (HRF) be present in order for the macrophage to discriminate between "self", "altered self", and "non-self." Rat liver slices in an incubation medium consisting of rat serum and heparin phagocytized approximately 17 per cent of gelatinized reticuloendothelial (RE) test lipid emulsion per 100 mg. of tissue. Normal human serum in the presence of heparin was as effective as rat serum in promoting phagocytosis by rat liver slices, indicating that human HRF can also enhance the phagocytic activity of the rat macrophage. In contrast, liver slices incubated in serum derived from 17 patients with untreated carcinoma, both metastatic and nonmetastatic, manifested a 90 per cent reduction of particle uptake, denoting essential loss of HRF activity. Of 6 subjects, following radiation or surgical therapy, 5 manifested four- to six-fold elevations of HRF activity as assessed by the capability of their serum to support Kupffer cell phagocytosis. Patients with other clinical disorders, such as pneumonia and diabetes, were found to have essentially normal HRF activity. These findings denote that neoplastic disease in man is associated with profound decreases in HRF activity. In view of the partial restoration of HRF activity with treatment, it is suggested that the loss of humoral recognition factors may be an important element in neoplasia.