[Study of thrombopoietin and its receptor C-mpl in acute leukemia].

OBJECTIVE

To study the expression of C-mpl gene in acute leukemia (AL) and its implication and investigate the effect of recombinant human thrombopoietin (rhTpo) on acute leukemic cells as well as its relation to C-mpl expression.

METHODS

C-mpl expression was detected in 43 AL patients by using semi-quantitative reverse transcription polymerase chain reaction and the effect of rhTpo on acute leukemia cells by MTT assay.

RESULTS

C-mpl was expressed in 22 of 35 patients with acute myeloblastic leukemia (AML), but did not in 8 patients with ALL. The percentage of C-mpl expression (16/22, 72.7%) was significantly higher in CD34 positive AML patients than in CD34 negative group (4/12, 33.3%, P = 0.031), and was higher in patients with M2b, M3 and M4EO than in those with other AML subtypes (40.0% vs 80.0%, P = 0.019). The complete remission rate in C-mpl positive AML patients was lower than that in negative patients (70.0% vs 81.8%, P = 0.394), although the difference was not significant. In 9 of 28 cases of AML, the in vitro treatment with rhTpo induced proliferation of leukemia cells. Among these 28 patients, leukemic cells from 8 of 17 (47.0%) patients expressing C-mpl responded to rhTpo, but only the cells from one of 11 (9.1%) non-expressing patients did. The rhTpo induced proliferation of AML cells was enhanced when combined with IL-3, GM-CSF or SCF.

CONCLUSIONS

C-mpl was expressed in some AML, but did not in ALL. Tpo could induce AML cells to proliferate and the effect was augmented when combined with other hematopoietic growth factors.