The aim of this study was to assess circulating soluble L (sL) and soluble E (sE) selectins adhesion molecules in acute myeloid leukemia (AML) blasts in order to evaluate their clinical significance. Fifty patients with AML (4 M0, 8 M1, 16 M2, 5 M3, 7 M4, 6 M5, 4 M6) were included in this study. sL and sE selectins were evaluated at diagnosis, remission and in relapsed patients; whole membrane expression of L and E selectins by AML blast was investigated only at diagnosis. In addition, 15 normal persons were studied as a control group. sL and sE selectins were significantly higher in AML patients at diagnosis when compared to controls (P<0.01), but less at remission (P<0.01). Furthermore, elevated sL and sE selectin levels were detected in patients with AML at relapse. sE and sL selectins were significantly higher in AML patients with extramedullary infiltration as compared to patients without extramedullary disease (P<0.001). Membrane expression of L selectin was positive in 20% of AML patients. However, none of the patients showed significant E selectin expression. Patients with higher sE and sL selectins at diagnosis have high probability of relapse compared to those with normal levels (P<0.01 and <0.001, respectively). The overall relapse predictability of sE and sL selectins was 84%. Moreover, patients with higher sE and sL selectins levels had shorter event free survival than patients with lower levels (P<0.001 for both). The overall mortality prediction using sE, sL, and cellular L selectin was 96%.
In conclusion: (1) AML blast cell express and release sL selectins but not sE selectin, (2) sE and sL selectins and cellular L selectin may be useful prognostic markers in evaluating AML patients at diagnosis.