OBJECTIVETo investigate the efficacy, safety and possible mechanism of rhIL-11 in the management of chemotherapy-induced thrombocytopenia in acute leukemia.

METHODSThirty-two acute leukemia patients were enrolled in the study. rhIL-11 was given when platelet count dropped below 30 x 10(9)/L after chemotherapy, at 1.5 mg/d, ih, for 7-14 days or withdrawn when the increase of platelet count was more than 50 x 10(9)/L. Serum IL-11 level was determined by ELISA, IL-11R alpha gene expression by RT-PCR. Efficacy and safety data were collected and their correlation with serum IL-11 and IL-11Ralpha expression were analyzed.

RESULTSThe platelet counts on day 7 and 14 after medication were (63.40 +/- 7.24) x 10(9)/L and (98.70 +/- 9.37) x 10(9)/L for 32 patients in IL-11 group [26 complete remission (CR), 2 partial remission (PR), 4 non-remission (NR)] and (42.50 +/- 6.38) x 10(9)/L and (70.30 +/- 7.12) x 10(9)/L for the control group (20 CR, 3 PR, 5 NR). There were 10 patients who received platelet transfusion (16-32 U) in IL-11 group and 19 patients (32-48 U) in control group. Compared with the IL-11 group a delay of platelet recovery was observed in controls (P < 0.05). IL-11 was generally well tolerated. Five experienced transient atrial arrhythmia and relieved after extenuation or withdrawal. The responders' serum IL-11 level of pre-medication was (21.81 +/- 1.88) ng/L, lower than that of non-responders (P < 0.05). IL-11Ralpha level was 0.3552 +/- 0.0224, higher than that of non-responders (P < 0.05). No correlation was observed among serum IL-11, IL-11Ralpha expression, platelet count, and megakaryocyte number.

CONCLUSIONSrhIL-11 can safely accelerate the recovery of chemotherapy-induced thrombocytopenia in acute leukemia. The serum IL-11 level and IL-11Ralpha of mononuclear cells might predict the efficacy of rhIL-11.