Alpha 1-protease inhibitor in serous effusions: differences in lectin crossed immuno-affinoelectrophoresis precipitin profiles between benign and malignant disease.

Differences in the lectin crossed immuno-affinoelectrophoresis (LCIE) precipitin profile of the antiprotease alpha 1-protease inhibitor (alpha 1-PI) have been detected between serous effusions of benign and malignant origin. Extra proteins with antigenicity towards anti-human alpha 1-PI appear in both malignant pleural effusions and malignant ascitic fluid caused by ovarian cancer that are not detected in effusions of benign origin. These compounds may be protease-antiprotease complexes caused by tumour excretion of proteases into the serous effusions.