Soluble Fas and Fas ligand and prognosis in children with acute lymphoblastic leukemia

The soluble forms of Fas and its ligand (sFas and sFasL) correlate with disease progression in various malignancies. We compared serum levels of sFas and sFasL in children with acute lymphoblastic leukemia and healthy children to determine the prognostic significance of these molecules. Serum levels of sFas and sFasL were measured with an enzyme-linked immunosorbent assay in 48 patients with newly diagnosed childhood acute lymphoblastic leukemia and 38 healthy children. Cut-off values of sFas and sFasL levels were based on their levels in controls. Clinical and laboratory characteristics were recorded on admission. The mean serum concentration of sFas was 243 +/- 40 pg/mL in patients and 238 +/- 29 pg/mL in controls. Serum levels of sFasL were 4.33 +/- 0.25 ng/mL in patients and 4.27 +/- 0.11 ng/mL in controls. Neither difference was significant. Based on the cut-off value, 12.5% of the patients were positive for sFas, and 16.6% were positive for sFasL. Survival was significantly longer in sFasL-positive patients (394 +/- 69.6 vs. 254 +/- 24.3 days) and the duration of complete remission was also longer (380 +/- 65.0 vs. 246 +/- 26.0 days) than in sFasL-negative patients (P < 0.02), indicating the important role of this molecule in the response to therapy. Higher sFas levels were associated with hepatosplenomegaly (P < 0.047). In conclusion, sFasL positivity was associated with a favorable outcome in ALL patients.