Expression of heat shock protein 72 by alveolar macrophages in hypersensitivity pneumonitis

The current study was done to look at a possible role of heat shock protein s (HSPs) in hypersensitivity pneumonitis (HP). The specific aims were to de termine whether there was a difference in the expression of HSP72 in alveol ar macrophages (AMs) between mice challenged with HP antigen and saline-tre ated control mice and between AMs obtained by bronchoalveolar lavage from 1 8 patients with HP and 11 normal subjects. The expression of HSP72 was stud ied under basal conditions and under a mild heat shock. HSP72 expression by AMs in response to in vitro stimulation with Saccharopolyspora rectivirgul a was lower in AMs of control mice than in those of HP animals. HSP72 was c onstitutively expressed in AMs of both normal and HP subjects. Densitometri c ratios showed that AMs from normal subjects responded to heat shock with a 39 degrees C-to-37 degrees C ratio of 1.72 +/- 0.18 (mean +/- SE), and AM s from HP patients responded with a ratio of 1.16 +/- 0.16 (P = 0.0377). Th is decreased induction by additional stress of AMs could lead to an altered immunoregulatory activity and account for the inflammation seen in HP.