Nedocromil sodium and cromolyn (sodium cromoglycate) selectively inhibit antibody-dependent granulocyte-mediated cytotoxicity.

Nedocromil sodium and cromolyn (sodium cromoglycate) are prophylactic agents in asthma which were initially found to be inhibitors of mast cell activation. Recent evidence has suggested that their effects on granulocyte-mediated reactions may contribute to their therapeutic effects. Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF) enhance the activity of granulocytes in antibody-dependent cell-mediated cytotoxicity (ADCC). Preincubation of purified neutrophils or eosinophils with nedocromil sodium or cromolyn partially inhibited their ability to mediate ADCC when stimulated by GM-CSF or TNF. Preincubation with nedocromil sodium did not alter the ability of neutrophils to produce superoxide or release lysozyme in response to soluble or phagocytic stimuli, and GM-CSF-enhanced superoxide production triggered by chemotactic peptide was not altered in such drug-treated neutrophils. After nedocromil sodium treatment, neutrophils showed no consistent changes in TNF-stimulated adherence to either plastic culture wells or umbilical vein endothelium. These findings demonstrate that nedocromil sodium and cromolyn directly and selectively affect the function of granulocytes in vitro. While drug-treated granulocytes were impaired in immune-directed cytotoxicity stimulated by GM-CSF or TNF, activation of other granulocyte functions by the same stimuli was intact.