免疫相关性血细胞减少症患者CD4(+) T淋巴细胞中CD70表达水平及其启动子甲基化水平研究

OBJECTIVE: To study the expression of CD70 and the methylation level of CD70 promoter in immuno-related pancytopenia (IRP) patients, and explore the role of CD70 in the pathogenesis of IRP. METHODS: Thirty-five IRP patients and fifteen healthy donors were enrolled in this study. Peripheral blood mononuclear cells were isolated from venous blood by density gradient centrifugation, and CD4(+) T cells were isolated by immunomagnetic beads. The mRNA level and the percentage of CD70 of CD4(+) T cells were measured by real-time quantitative polymerase chain reaction (RT-PCR) and flow cytometry respectively. Methylation-Specific PCR (MSP) was performed to determine the methylation level of CD70 promoter. RESULTS: The percentage of CD70 expression on CD4(+) T cells of untreated IRP patients [(7.46±1.51)%] was significantly higher than that of recovered ones [(5.95±1.34)%] and normal controls [(1.83±0.60)%], and that of recovered IRP patients was significantly higher than of normal controls (P<0.05). The relative expressions of CD70 mRNA in CD4(+) T cells were 2.314 (0.200–6.084), 1.021 (0.135–3.434), 0.353 (0.008–2.258) in three groups respectively. The differences among untreated IRP patients, recovered IRP patients and normal controls were significant (P<0.05). The CD70 promoter methylation level in CD4(+) T cells of all IRP patients was significantly lower than that of normal controls (P<0.05). The expression of CD70 positively correlated to the ratio of CD5(+) B cells (r=0.533, P<0.01). CONCLUSION: The overexpression of CD70 may lead to immunologic disarrangement of patients, which may play important role in the pathogenesis of IRP.