Fluorescent antibody studies of alpha-1-antitrypsin in adult human lung.

The histologic distribution of alpha-1-antitrypsin in frozen sections prepared from four specimens of human lung was determined by the indirect fluorescent antibody technic. Three of the specimens were obtained directly from surgical procedures and were peripheral tissue excised with tumors. The tumors were a mixed-cell "scar cancer" (Case 1), a bronchiolar carcinoma (Case 2), and a benign hemartoma (Case 3). The fourth specimen (Case 4) was obtained at autopsy following death by myocardial infarction. Specific fluorescence for alpha-1-antitrypsin was observed lining the terminal airways and alveoli throughout the sections from Cases 1 and 4. In specimens from Cases 2 and 3, a few focal areas of specific fluorescence were observed. The results of this study suggest that alpha-1-antitrypsin may be distributed in lung in variable concentration in association with pulmonary surfactant.