Monocyte-macrophage (M-M) functions in asymptomatic hemophiliacs and supertransfused thalassemics.
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Patients suffering from acquired immune deficiency syndrome (AIDS) succumb to opportunistic infections due to a generalized failure of their cell-mediated immune defenses. The monocyte-macrophage (M-M) system plays an important role in host defense against viruses, protozoa, mycobacteria, and tumours, all potentially involved in the terminal stages of AIDS. We studied M-M functions in 55 asymptomatic hemophiliacs, 20 supertransfused thalassemics, and 9 von Willebrand's syndrome patients over a period of 17 months to establish the part played by chronic repeated blood component transfusions on the macrophage defense system. We found a significant impairment of chemotaxis in 24 out of 55 hemophiliacs, 13 out of 20 thalassemics, and 4 out of 9 von Willebrand's patients. In contrast, Candida pseudotropicalis killing was markedly increased in all 3 patient groups, while Candida phagocytosis was most significantly diminished in thalassemics. Fc-receptor-dependent erythrophagocytosis showed wide variations in all patients, with a significant decrease only in thalassemics. Phorbol ester-activated nitroblue tetrazolium (NBT) reduction to formazan was normal in most cases, but background spontaneous NBT was often much higher than in the controls. Monocyte adhesion to plastic appeared impaired in hemophiliacs and von Willebrand's Syndrome patients, yet was of no statistical significance. It thus appears that continuous, repeated blood component transfusions cause an alteration of M-M functions. This may be either due to chronic, recurrent antigenic stimulation by foreign proteins transfused, or oncogenic and known immune suppressive viruses, like cytomegalovirus, Epstein-Barr virus, hepatitis, and human T cell lymphotropic virus III. This in turn may increase susceptibility to AIDS.
