| Research background Acute promyelocytic leukemia is a special type of acute myeloid leukemia. Its clinical characteristics include abnormal hyperplasiao of promyelocytic cells in bone marrow, severe bleeding tendency,15/17 chromosome ectopic and (or) PML/RAR alpha fusion gene transcription. It was regarded as the most dangerous subtype of leukemia. In recent years, because of application of all trans retinoic acid and arsenic trioxide, the prognosis of patients with acute promyelocytic leukemia has been significantly improved. But there is still a part of patients with poor prognosis. At present, there are many studies about the prognostic factors of APL. In which, the following prognostic factors have been recognized:the elder age, high white blood cell count, obvious bleeding tendency etc. As for the relationship between immunophenotype and prognosis of acute promyelocytic leukemia, currently reported inconsistent results. There is still some controversy. Among them, the positive expression of CD34 effect on the prognosis of acute promyelocytic leukemia patients with favorable attention. According to some foreign literature reports, the complete remission rate, overall survival, event free survival rate of CD34+ APL patients was significantly lower than that of CD34- patients. But some studies have shown that CD34 has no obvious effection on the prognosis of the patients with APL. However, the domestic research on the relationship between CD34 and prognosis of APL are still lacking as so far.Objective This study analysed clinical and follow-up data of 64 cases of APL patients. To explore the relationship between the expression of CD34 and clinical characteristics or biological characteristics and its impact on the disease outcome in patients with acute promyelocytic leukemia. In order to estimate the prognosis of newly diagnosed patients by immunological markers, so as to guide the clinical treatment, further improve the therapeutic effect of APL and prolong the survival time of patients.Methods Sixty-four patients with APL, from December 2009 to October 2013 in our hospital were studied retrospectively. To demonstrate the relationship between its antigen expression and clinical features. Univariate analysis of the potential factors influencing survival of these patients was carried out with the Chi-square test and Log-Rank method.Result CD34 was expressed in 12 (18.8%) of cases with higher expression in PML/RARa-S (9/19,47.4%)compared to PML/RARa-L isoform. CD34+ cases were often associated with CD2+, HLA-DR+(7/13,53.8%vs 5/8,62.5%). In addition, CD34 expression was significantly associated with decreased incidence of complete remission, overall survival and event-free survival. The overall survival and event-free survival and of patients with WBCs count≥10×109/L was inferior to patients with WBCs count≤10×109/L. The EFS of patients with CD2+ or PML/RARa-S isoform was inferior to patients with CD2" or PML/RARa-L isoform, but no significant differences were observed in overall survival between CD2+ and CD2- or between PML/RARa-L isoform and PML/RARa-S isoform groups.Conclusion There is no significant difference between CD34+ group and CD34- group in gender, age, WBCs count, PLTs count, classification of risk, Hb level and percentage of promyelocytic cells in bone marrow. In newly diagnosed APL, CD34 used to co-express with CD2, HLA-DR. And CD34 is highly expressed in PML/RARa-S APL patients. The CR rate, OS rate and EFS rate of CD34+ APL patients was significantly lower than that of group CD34-.Immunophenotypic analysis for CD34 could distinguish an APL subset with different biological characteristics and adverse prognostic outcome. |
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