Disodium cromoglycate inhibits activation of human inflammatory cells in vitro

Recent clinical studies indicate that disodium cromoglycate (DSCG) may have a direct effect on inflammatory cells because the drug reversed various changes in leukocyte function, such as increased membrane-receptor expression and enhanced cytotoxic capacity observed in peripheral white blood cells from subjects with asthma undergoing allergen-inhalation challenge. In the present study, we have demonstrated that DSCG, at low concentrations (a concentration of drug required to produce 50% inhibition, approximately 10(-8) mol/L) and in a time-dependent fashion, directly inhibited the activation in vitro of human neutrophils, eosinophils, and monocytes. Peripheral blood leukocytes were incubated with the synthetic chemoattractant, formyl-methionyl-leucyl-phenylalanine (at an optimal concentration of 10(-8) mol/L), and activation was assessed by measuring increases in the percentages of complement and IgG (Fc) rosettes as well as the enhanced capacity of these cells to kill target organisms (schistosomula of Schistosoma mansoni). DSCG at a concentration of 10(-7) mol/L totally inhibited both the formyl-methionyl-leucyl-phenylalanine-induced enhancement of complement and IgG rosettes, as well as increased schistosomular killing. These observations indicate that DSCG directly inhibits the secretory properties of inflammatory cells and that in turn might have important implications in modulating mechanisms contributing to the inflammatory component of asthma and allergic disease. It may also help to explain why compounds with considerably greater mast cell stabilizing properties than DSCG have been so disappointing when they are evaluated clinically.