Lung inflammatory cells after exposure to mouldy hay.

To investigate the inflammatory cell response after exposure to mouldy hay, guinea pigs were exposed to an aerosol of spores from mouldy hay. Lung wall (LW) and lung lavage (LL) cells were counted after 5 weeks of daily exposures. At 5 weeks both LW and LL macrophages, lymphocytes and neutrophils increased. The LL cell increase was proportionally higher. At 12 weeks, the increase in the number of cells was slightly less than at 5 weeks. After cessation of exposure, macrophages and lymphocytes remained elevated up to 7 days whereas neutrophils rapidly decreased to normal values. This animal inhalation model of early allergic alveolitis could be used to evaluate the importance of different exposure conditions and various agents in the dust.