These patients had been diagnosed as having HP because (1) they showed nonacute but unequivocal clincal symptoms related to the home environments, (2) their sera and BAL fluids had low but significant antibodies against several fungi detected by the enzyme-linked immunosorbent assay, and (3) their lung biopsy specimens showed granulomatous lung lesions.
In this study, we attempted to clarify the characteristics of HP with lung fibrosis regardless of antigens in the comparison of HP without lung fibrosis. The present study has shown the following: (1) CT scan could precisely predict pulmonary fibrosis because the histologic examinations of the TBLB materials confirmed fibrotic changes; (2) the classification of HP with or without pulmonary fibrosis was further substantiated by pulmonary function tests showing a restrictive impairment in the group of pulmonary fibrosis; (3) the onset of pulmonary fibrosis group was insidious; (4) an increase of lymphocytes in BAL fluids was much less in comparison with nonfibrosis group; and (5) CD8 + T-cell dominance of lymphocytes in BAL fluids was not observed in fibrosis group.
Mornex et al reported that CD4+ cell-dominant T lymphocytosis was observed in BAL fluids of HP when the exposure to antigens had been avoided for more than five days. Although CD4+ cell-dominant T lymphocytosis of the fibrosis group is similar to those patients after the avoidance of exposure, our observation regarding T cells in BAL fluids was obtained during continuous exposure to the antigen. The chronic stage of HP has been extensively characterized in the farmers lung, in which the principal findings were interstitial pulmonary fibrosis and CD4+ T-cell dominance in BAL fluids in several cases.