EVIDENCE OF INCREASED HISTAMINE LEVELS IN LUNG LAVAGE FLUIDS FROM PATIENTS WITH CRYPTOGENIC FIBROSING ALVEOLITIS

Abstract

A significant increase in histamine [HA] in lung lavage fluids from a group of 33 patients with lone cryptogenic fibrosing alveolitis (lone CFA) and from a group of 13 patients having CFA in association with other connective tissue disorders, when compared with findings for 13 smoking patient controls without peripheral lung disease (P < 0.001, P < 0.05, respectively) is reported. The increases were independent of smoking or treatment. Significant correlations were obtained between the raised HA levels in CFA and increased levels of albumin and increased counts of neutrophils and eosinophils in the lavage fluids, and with more pronounced fibrosis in CFA lung biopsies. Thus HA is associated with inflammation features relating to progressive or more severe disease. No significant increase in HA was observed in a group of 22 patients with sarcoidosis, although 21 had evidence of disease involving the lung parenchyma. There were significantly higher levels in the patients with X-ray evidence of upper lobe contraction, suggestive of fibrosis (P < 0.025). The levels also showed a correlation with increasing lavage neutrophil counts (P < 0.005), a feature also associated with X-ray evidence of contraction in this group. Mast cells were readily identified in biopsies from 12 CFA patients suggesting that these cells may provide 1 possible source of histamine in CFA lungs. HA and/or possibly other substances derived from mast cells may play some role in amplifying inflammation associated with pulmonary fibrosis.