To investigate the expression levels of serum sICAM-1 and their clinical significances in patients with hyperleukocytic acute leukemia(HLAL).The serum levels of sICAM-1 in 30 hyperleukocytic acute leukemia and 20 non-hyperleukocytic acute leukemia were detected by ELISA,compared with 20 healthy persons as the control group.The expression of sICAM-1 in patients with hyperleukocytic acute leukemia and non-hyperleukocytic acute leukemia were significantly higher than those in control group,expecially in hyperleukocytic acute leukemia.Over expression of sICAM-1 may play a key role in the genesis and progression of hyperleukocytic acute leukemia.