RESUMO
L-selectin plays a critical role in the initiation of normal leukocyte attachment to activated endothelium. It is expressed on most normal leukocytes and is also detectable on blast cells in ALL and AML. The shed form of L-selectin (sL-selectin) is found in plasma. High plasma sL-selectin levels were detectable in patients with AML and correlated with disease activity and poor prognosis. Little information is available on the clinical and prognostic significance of sL-selectin in ALL. The study was undertaken to determine sL-selectin levels during clinical course of patients with ALL and AML and to assess its role as a disease activity and prognostic factor. Heparinized plasma was obtained from 83 patients with newly diagnosed acute leukemia, including 30 with ALL, 50 with AML, 3 with biphenotypic leukemia and 19 healthy people. For some patients additional samples were taken in complete remission (CR) and relapse. sL-selectin was assayed using an ELISA method. The mean plasma sL-selectin concentration in all patients with acute leukemia was significantly higher than and in normals. Concentration of s-selectin L in patients with CR was significantly lower than at presentation and in the range of normals. sL-selectin plasma concentration in relapse was comparable to that from diagnosis. There was no significant difference in sL-selectin concentration between patients who entered CR after induction treatment and without CR. Patients with extramedullary disease had higher sL-selectin than patients without that manifestation. Monitoring of the sL-selectin concentration maybe useful for evaluating leukemia activity in both ALL and AML patients.