Characterization of histamine releasing factors in diisocyanate-induced occupational asthma.
Lummus-ZL; Alam-R; Bernstein-JA; Bernstein-DI
Toxicology 1996 Jul; 111(1-3):191-206
Antigen specific histamine releasing factors (HRF), associated with diisocyanate (DI) induced asthma, were studied in 32 workers exposed to DI. All workers presented with occupational asthma (OA) associated with DI exposure. Venous blood was collected for characterization of peripheral blood mononuclear cells (PBMC), HRF, monocyte chemoattractant proteins (MCP), and the chemokine known as regulated on activation normal-T expressed and secreted (RANTES). Mean values for HRF in OA workers were greater than for asymptomatic exposed workers or unexposed controls after stimulation of PBMC with DI antigens. HRF was significantly associated with clinical diagnosis of OA. Specific immunoglobulin-E or immunoglobin-G antibody production did not correlate with OA. Hapten specific enhancement of HRF was significantly greater when PBMCs were stimulated in-vitro with the DI chemicals to which workers had been exposed. Immunoglobin-G antibodies, but not immunoglobulin-E, also demonstrated humoral immune response to DI antigens. Symptomatic workers showed higher mean production of antigen stimulated MCP and HRF than asymptomatic controls, but RANTES production was similar in both groups. A greater synthesis of antigen stimulated MCP messenger RNA occurred in an asthmatic worker than in a normal control. Purified T-cells from asymptomatic workers showed normal CD4/CD8 ratios (2.2), whereas low CD4/CD8 ratios (1.0 to 1.4) occurred in OA workers. The study confirmed that PBMC of workers with known OA induced by DI can be stimulated in-vitro to produce basophil activating HRF and MCP. The authors conclude that the HRF bioassay appears to detect a cell mediated immune response to DI haptens in workers with DI induced OA.
NIOSH-Publication; NIOSH-Grant; Pulmonary-system-disorders; Occupational-exposure; Occupational-hazards; Occupational-diseases; Occupational-health; Humans; Bronchial-asthma; Airway-resistance; Respiratory-irritants
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University of Cincinnati, Cincinnati, Ohio