Mast cell response to formaldehyde. 1. Modulation of mediator release.

To examine the effects of the atmospheric pollutant formaldehyde on functionally distinct mast cells, peritoneal mast cells (PMC), intestinal mucosal mast cells (IMMC) and mouse bone-marrow-derived mast cells (BMMC) were incubated with various concentrations of formaldehyde. Pretreatment for 30 min with up to 100 micrograms/ml formaldehyde was not cytotoxic to mast cells. Formaldehyde (1-10 micrograms/ml) alone induced low levels of histamine release (< 10%) from IMMC and BMMC. Antigen-induced histamine release was significantly increased in both PMC pretreated with low concentrations of formaldehyde (5-20 micrograms/ml) and BMMC pretreated with 10 micrograms/ml formaldehyde but decreased in PMC pretreated with a higher concentration (100 micrograms/ml) of formaldehyde. By contrast, antigen-induced histamine release was decreased in IMMC pretreated with formaldehyde in a dose-dependent manner. Histamine release stimulated with A23187 was also increased in PMC pretreated with a low concentration (10 micrograms/ml) of formaldehyde but decreased in those pretreated with a higher concentration (100 micrograms/ml) of formaldehyde. Pretreatment with 10 micrograms/ml formaldehyde significantly enhanced beta-hexosaminidase release from PMC stimulated with antigen or A23187. Compared to sham-treated PMC, PMC pretreated with formaldehyde expressed a markedly depressed natural cytotoxicity for the tumor target WEHI-164 (an assay of tumor necrosis factor alpha activity). These results suggest that formaldehyde modifies various mast cell functions through alterations in cellular metabolism. Such effects may be important in respiratory and other diseases associated with formaldehyde exposure.