Abstract
Human polymorphonuclear leukocytes, when incubated in vitro with cigarette smoke condensate, release .beta.-glucuronidase, acid phosphatase and elastase and fail to exclude trypsan blue. The released elastase is active on an elastin substrate even in the continuing presence of cigarette smoke condensate. When mixtures of human polymorphonuclear leukocytes and cigarette smoke condensate are instilled into rat lungs in vivo, the elastase is also released and can be traced to connective tissue targets by immunohistochemical and enzyme-histochemical techniques.