Study of soluble CD44 and its expression by mononuclear cells in children with acute lymphoblastic leukemia: its relation to prognostic factors.

To measure sCD44 and its expression in ALL children before and after induction of remission (day 28) and their relation to prognostic factors. Newly diagnosed 30 ALL pediatric patients were examined for sCD44 by ELISA and CD44 expression by flowcytometry and their levels after induction of remission. We correlated them to age, sex, TLC, Hb, platelet count, blast % in PB and BM, Immunophenotyping, and LDH. CD44 expression in ALL patients at the time of diagnosis ranged from 0 - 98% with a mean +/- SD of (41.23 +/- 23.99) and in the control group (range 0 - 11 with a mean +/- SD of 5.5 +/- 6.58), the % of expression was significantly higher in ALL patients than control group (P = 0.001). CD44 expression was significantly decreased by induction of remission (P = 0.001). sCD44 concentration in ALL patients at the time of diagnosis ranged from 105- 449 ng/dl with a mean +/- SD of (246.5 +/- 99.51) and in the control group (range 103 -243 ng/dl with a mean +/- SD of 160.65 +/- 37.12), sCD44 was significantly higher in ALL patients than control group (P = 0.001). sCD44 was significantly decreased after induction of remission (P = 0.001). LDH was elevated in the patients group than the control, (P = 0.001). In conclusion, LDH level at time of ALL diagnosis is an important risk determinant and correlate with degree of anemia, high TLC and high PB absolute blast count. High sCD44 level at the time of diagnosis and rapid decline in its level after treatment suggesting that sCD44 may be a good marker for prognosis and a marker for monitoring response to therapy, a second elevation of sCD44 level after its decline by therapy may suggest ALL relapse. Elevated CD44 expression in ALL patients may mediate lymphoblast metastatic migration.