研究急性髓样白血病（AML）患者骨髓中CD200的表达情况及与临床疗效关系的相关研究。

将51例急性髓样白血病患者根据初发时白细胞计数分为高白细胞组（18例）与非高白细胞组（33例），根据化疗效果分为完全缓解组（31例）和未缓解组（20例），同期选取51例缺铁性贫血或巨幼细胞贫血患者为对照组。采用流式细胞术检测AML患者化疗前后CD200、Foxp3⁺/CD4⁺的表达，酶联免疫吸附试验检测AML患者及对照组患者外周血白细胞介素17（IL-17）、IL-4和干扰素γ的水平。同时，采用Pearson线性相关分析研究AML患者中CD200表达水平与化疗前后血清IL-17、IL-4、干扰素γ水平及骨髓中Foxp3⁺/CD4⁺水平的关系。

高白细胞组患者CD200阳性表达率明显高于非高白细胞组患者[（4.8 ± 2.8）% vs.（3.7 ± 2.2）%，t = 4.961，P < 0.001]。未缓解组患者较完全缓解组患者明显偏高[（4.8 ± 2.6）% vs.（3.1 ± 1.6）%，t = 5.716，P < 0.001]。对照组患者与AML患者化疗前比较，IL-17及干扰素γ水平均明显升高（t = 26.970，P < 0.001；t = 4.370，P < 0.001），IL-4水平及Foxp3⁺/CD4⁺细胞均明显降低（t = 9.965，P < 0.001；t = 7.346，P < 0.001）。而对照组患者与AML患者化疗后比较，仅IL-17及IL-4水平比较，差异有统计学意义（t = 8.897，P < 0.001；t = 3.965，P < 0.001）。与AML患者化疗前比较，化疗后IL-17 [（147 ± 42）ng/L vs.（332 ± 68）ng/L，t = 15.920，P < 0.001]及干扰素γ [（24 ± 8）μg/L vs.（31 ± 12）μg/L，t = 3.576，P < 0.001]水平均明显升高，IL-4水平[（142 ± 54）μg/L vs.（84 ± 31）μg/L，t = 6.644，P < 0.001]及Foxp3⁺/CD4⁺细胞[（7.5 ± 2.4）% vs.（5.2 ± 2.4）%，t = 5.330，P < 0.001]均明显降低。Pearson线性相关分析发现，CD200表达水平仅与化疗后骨髓中Foxp3⁺/CD4⁺水平呈正相关（r = 0.347，P = 0.012）。

CD200可能通过抑制免疫相关因子影响AML患者临床疗效。

To study the expression of CD200 in acute myeloid leukemia (AML) bone marrow stem cells and its clinical efficacy.

Totally 51 AML patients were divided into the high white blood cell group (18 cases) and non-high white blood cell group (33 cases) according to whether the initial white blood cell count > 100 × 10⁹/L. The 51 AML patients also were divided into the complete response group (31 cases) and the non-response group (20 cases) after the first chemotherapy, and 51 iron-deficiency anemia or megaloblastic anemia patients were selected as the control group at the same time. The expression of CD200 and Foxp3⁺/CD4⁺ before and after the first chemotherapy were detected by flow cytometry in AML patients. The levels of interleukin-17 (IL-17), IL-4 and interferon-gamma (IFN-γ) in the peripheral blood before and after chemotherapy were detected by enzyme-linked immunosorbent assay (ELISA) in AML patients and control group. The Pearson correlation was used to analyze the relationship between expression of CD200 in AML patients and IL-17, IL-4, IFN-γ and Foxp3⁺/CD4⁺ before and after chemotherapy.

The positive rate of CD200 in the high white blood cell group were much higher than those in the non-high white blood cell group [(4.8 ± 2.8)% vs. (3.7 ± 2.2)%, t = 4.961, P < 0.001], and the positive rate of CD200 in the non-response group also increased as compared with the complete response group [(4.8 ± 2.6)% vs. (3.1 ± 1.6)%, t = 5.716, P < 0.001]. In the control group, the levels of IL-17 and IFN-γ were significantly higher (t = 26.970, P < 0.001; t = 4.370, P < 0.001), the IL-4 and Foxp3⁺/CD4⁺ were much lower (t = 9.965, P < 0.001; t = 7.346, P < 0.001) than those in AML patients before chemotherapy. And statistically significant differences were observed only in the levels of IL-17 and IL-4 between the control group and AML patients after chemotherapy (t = 8.897, P < 0.001; t = 3.965, P < 0.001). Compared with the AML patients before chemotherapy, the IL-17 [(147 ± 42) ng/L vs. (332 ± 68) ng/L, t = 15.920, P < 0.001] and IFN-γ [(24 ± 8) μg/L vs. (31 ± 12) μg/L, t = 3.576, P < 0.001] increased markedly, the IL-4 [(142 ± 54) μg/L vs. (84 ± 31) μg/L, t = 6.644, P < 0.001] and Foxp3⁺/CD4⁺ [(7.5 ± 2.4)% vs. (5.2 ± 2.4)%, t = 5.330, P < 0.001] decreased obviously after chemotherapy. The expression of CD200 in AML patients was only correlated with Foxp3⁺/CD4⁺ levels after chemotherapy (r = 0.347, P = 0.012).

The espression of CD200 can affect the clinical efficacy in AML patients by suppressing the immune-related factors.