J. Murayama et al., LUNG FIBROSIS IN HYPERSENSITIVITY PNEUMONITIS - ASSOCIATION WITH CD4+BUT NOT CD8+ CELL DOMINANT ALVEOLITIS AND INSIDIOUS ONSET, Chest, 104(1), 1993, pp. 38-43
Seventeen cases of hypersensitivity pneumonitis (HP) at a symptomatic
phase were categorized into two groups based on computed tomographic (
CT) findings and histologic features of transbronchial lung biopsy spe
cimens, HP accompanied by lung fibrosis (fibrosis group), and HP unacc
ompanied by lung fibrosis (nonfibrosis group). The fibrosis group comp
rised bird fancier's lung and HP of unknown etiology, whereas the nonf
ibrosis group mainly comprised summer-type HP. Comparison of results o
f pulmonary function tests between these two groups confirmed a restri
ctive impairment in the fibrosis group. Analyses of cellular component
s of bronchoalveolar lavage (BAL) fluids revealed lymphocytes, especia
lly CD8+ T lymphocytes, were significantly increased in the nonfibrosi
s group in comparison with the fibrosis group, whereas CD4+ T cells we
re increased to the same level in the both groups. Analyses of the ons
et of disease showed that acute onset was observed mainly in nonfibros
is group and strongly correlated with increased CD8+ T lymphocytes in
BAL fluids, while insidious onset was related to lung fibrosis and rel
atively increased CD4+ T lymphocytes in BAL fluids. These findings rai
se the possibility that highly elevated CD8+ T cells might have a prot
ective effect on pulmonary fibrosis or that relatively increased CD4T cells might play an important role in the pathogenesis of pulmonary
fibrosis of HP at the chronic phase.