Nedocromil sodium inhibition of IgE-mediated activation of human mononuclear phagocytes and platelets from asthmatics.

The demonstration of a specific receptor for IgE on non-mast cell or basophil leucocytes, such as mononuclear phagocytes, eosinophils and platelets, suggests that these cells may participate directly in immunological disorders of allergy. In this study, inhibition by nedocromil sodium of IgE-dependent activation of human alveolar macrophages, blood monocytes and platelets was investigated. Nedocromil sodium produced an inhibition of IgE-mediated generation of cytotoxic molecules from monocytes and platelets together with a concomitant inhibition of their oxidative metabolism, measured by chemiluminescence. In addition, nedocromil sodium reduced the ability of alveolar macrophages to synthesise and release mediators, estimated by beta-glucuronidase activity. Furthermore, nedocromil sodium inhibited the abnormal response to aspirin of platelets from aspirin-sensitive asthmatics at therapeutic concentrations. These studies confirm that nedocromil sodium acts on a cell compartment other than the classical mast cell population in IgE-dependent allergy and asthma.