Quantitative cytochemistry of human leukocyte elastase compared with plasma elastase and acute phase proteins in inflammatory diseases.

Plasma levels of human leukocyte elastase, a serine proteinase stored in the azurophilic granules of polymorphonuclear granulocytes, increase in the early stages of several inflammatory diseases. We studied the intracellular enzyme activity by cytochemical quantitative image analysis and the amount of elastase released in plasma by an automatic immunoactivation immunoassay method in 66 patients with inflammatory diseases and in a control group. The patients were divided into two groups with infective disease (severe and moderate) and one group with non-infective inflammation. Intracellular activity and plasmatic levels of elastase were also compared with other inflammatory markers, i.e. erythrocyte sedimentation rate, C-reactive protein, alpha 1-antitrypsin, haptoglobin, alpha 1-acid glycoprotein and fibrinogen. Our studies suggest that plasma and leukocyte elastase are correlated both with etiology and with the severity of the inflammation.