T-lymphocyte subsets in peripheral blood and lung lavage in idiopathic pulmonary fibrosis and sarcoidosis: Analysis by monoclonal antibodies and flow cytometry

Abstract

Thymus-dependent (T) lymphocytes may contribute to the pathogenesis of human interstitial lung disease. In order to determine whether alterations of immunoregulatory T cells occur in patients with idiopathic pulmonary fibrosis (IPF) and sarcoidosis, we characterized T lymphocytes in peripheral blood ( n = 8 and 11, respectively) and lung lavage ( n = 4 and 6, respectively) in untreated patients with these diseases. In IPF, we found a decreased percentage, but normal total count of circulating OKT3 + (mature) and OKT4 + (inducer/helper) cells compared to normal controls. We observed a normal percentage and total count of circulating OKT8 + (cytotoxic/suppressor) cells. The ratio of OKT4 + to OKT8 + ( 4 8 ) lymphocytes, reflecting the balance of immunoregulatory cells, was normal in peripheral blood. Comparing peripheral blood to lung lavage, we noted a lower proportion of OKT4 + cells and a higher proportion of OKT8 + cells in lung lavage. The 4 8 ratio in lung lavage tended to be low compared to blood. In contrast, we found in sarcoidosis patients a decrease in both percentage and total circulating OKT3 +, OKT4 +, and OKT8 + cells as compared to normal. In lung lavage, there was an increase in OKT3 + cells, due to an increase in the OKT4 + subset. The percentage of OKT8 + cells in lung lavage was low. Compared to blood the 4 8 ratio was high in lung lavage. Thus, a number of alterations in circulating and lavage T cells were found both in patients with IPF and sarcoidosis. These results suggest that immunoregulatory abnormalities contribute to pathogenesis of these disorders.