ENHANCED GENERATION OF REACTIVE OXYGEN SPECIES IN MONOCYTES FROM PATIENTS WITH COMMON VARIABLE IMMUNODEFICIENCY

Monocyte and macrophage dysfunction may be important for both immunopa thogenesis and clinical manifestations in subgroups of patients with p rimary hypogammaglobulinaemia. In the present study we examined the ab ility to generate reactive oxygen species (ROS) in isolated monocytes from these patients by two different methods: superoxide dismutase (SO D) inhibitable cytochrome c reduction by O-2(-) and nitroblue tetrazol ium (NBT) reduction. Monocytes from patients with common variable immu nodeficiency (CVI) demonstrated significantly enhanced ROS generation both unstimulated and stimulated (unopsonized zymosan and phorbol myri state acetate (PMA)). The enhanced oxidative burst response in CVI pat ients was found both with and without serum containing medium. Further more, serum from CVI patients did significantly enhance the oxidative burst response in monocytes from healthy blood donors compared with th e effect of control serum. The enhanced ROS generation in CVI patients was significantly correlated with elevated serum levels of neopterin, reduced numbers of CD4(+) lymphocytes in peripheral blood and occurre nce of splenomegaly. In contrast to the CVI group, monocytes from pati ents with X-linked agammaglobulinaemia (XLA) did not show enhanced ROS generation. The increased oxidative burst response in monocytes from CVI patients most probably reflects in vivo activation of these cells. Our observations indicate the presence of a subgroup of CVI patients characterized by chronic immune activation particularly of monocytes. The enhanced ROS generation might be involved in immunopathogenesis (e .g. T cell dysfunction) and in the pathogenesis of clinical manifestat ions (e.g. malignancies and autoimmune disorders) in these patients.