Abstract

Human pulmonary macrophages from heavy smokers usually (17/21 cases) contain sea blue inclusion material in the cytoplasm. In non-smokers, sea blue material is rarely evident (1/21 cases). The sea blue material observed has the same properties as sea blue material identified in other conditions (viz, Sudan black and PAS positivity and autofluorescence). Evidence is presented which suggests that pulmonary macrophages from smokers contain extra surfactant and that it is this phospholipid complex that accounts for the sea blue reaction observed.