The importance of granulocyte elastase in haematological diagnosis.

PMN elastase is a useful additional parameter in the differential diagnosis of the leukaemias. In all patients with myelocytic leukaemias there were elevated levels of elastase-alpha 1-proteinase inhibitor (E-alpha 1PI), while in the lymphatic leukaemias complexed elastase levels were decreased. The highest values were found in the peripheral blood plasma and bone marrow plasma of patients with CML. Despite high E-alpha 1PI concentrations there were no signs of bleeding or consumption of plasmatic coagulation factors. In AML a wide range of E-alpha 1PI levels was observed, extending from slightly elevated to four hundred-fold increased. In myeloblastic leukaemias without maturation (FAB M 1) the concentrations of complexed elastase remained below 150 ng/ml. In myeloblastic leukaemias with maturation (FAB M2) the E-alpha 1PI values ranged between 214 ng/ml and 850 ng/ml (means = 402 +/- 69), and in myelo-monoblastic leukaemias (FAB M4) between 450 ng/ml and 720 ng/ml (means = 663 +/- 72). The only case of promyelocytic leukaemia (FAB M 3) exhibited an extremely high value of 4,550 ng/ml, while a monocytic leukaemia (FAB M5) showed an extremely low value of 5 ng/ml. During cytostatic therapy there was a rapid decrease in levels of complexed elastase, with E-alpha 1PI values returning to normal in remission. In recidivating cases there was an increase of E-alpha 1PI levels in AML and a decrease in ALL. There was a correlation between the E-alpha 1PI concentrations in peripheral plasma and leukaemic bone marrow infiltration, so providing a good basis for monitoring remission from leukaemia and indicating relapse. It was also interesting to observe an extremely low E-alpha 1PI level (5 ng/ml) in patients with myelodysplasia. Under Decortin/Plenastril therapy the concentration rose to 50 ng/ml. An E-alpha 1PI level of 10 ng per ml was observed in one case of Ranitidine agranulocytosis. Under corticoid therapy the value returned to normal within eight days.