The role of T-lymphocyte subpopulation in bronchoalveolar lavage in pulmonary parenchyma diseases.

Cellularity and T-lymphocyte to T-lymphocyte subpopulation ratio were examined in 37 cases of interstitial pulmonary disease as well as in two healthy subjects in bronchoalveolar lavage (BAL) using monoclonal antibody indirect immunofluorescence technique. In BAL, active sarcoidosis cases (n = 18) were found to have increased T-lymphocytes of helper phenotype (CD4) accompanied by a markedly heightened CD4/CD8 proportion. Conversely, T-lymphocytes of the suppressor cytotoxic phenotype (CD8) with markedly reduced CD4/CD8 proportion predominated in the BAL of cases with hypersensitive pneumonitis (HP). Case group having sarcoidosis (S) after corticosteroid therapy (n = 11) showed a reduction in the proportion of T-lymphocytes (CD4) as well as in that of CD4/CD8 in BAL. An analysis of T-lymphocytic subpopulation in BAL could be helpful in diagnosing pulmonary interstitial disease, and give an insight into disease activity.