CD8^+CD57^+T细胞在体外对MDS骨髓造血的影响

In vitro effects of CD8^+CD57^+T lymphocytes on hematopoiesis in myelodysplastic syndrome

目的观察异常激活的CD8 T细胞(CD8+CD57+T细胞)在体外对骨髓增生异常综合征(MDS)造血情况的影响。方法用免疫磁珠体外剔除44例中低危MDS患者(MDS组)及5例正常人(正常对照组)骨髓单个核细胞(BMNC)中CD8+CD57+T细胞,对剔除和加回CD8+CD57+T细胞(4倍)的BMNC分别培养,比较培养后细胞集落的生长情况和克隆细胞比例,观察培养前后髓系细胞标志的变化。结果①在MDS组中,剔除CD8+CD57+T细胞培养后,18例可见集落和集簇均有生成;7例仅见集簇生长;19例仅见细胞密集分布。加回CD8+CD57+T细胞的BMNC培养后,MDS组均无集落和集簇生成,且细胞密度明显低于剔除CD8+CD57+T细胞的BMNC。正常对照组剔除和加回CD8+CD57+T细胞的BMNC培养后,均有集落生成,集落计数无统计学差异。②2例单纯+8异常低危MDS病例,剔除CD8+CD57+T细胞培养后,+8克隆细胞比例较培养前增加;2例20q-异常的初治病例,剔除CD8+CD57+T细胞培养后,异常克隆细胞比例较培养前增加。③MDS组BMNC中CD34+、CD33+和CD13+细胞百分比均高于正常对照组(P<0.05),剔除CD8+CD57+T细胞培养后,CD34+和CD33+细胞百分比均低于培养前(P<0.05),而CD13+细胞百分比与培养前比较无统计学差异(P>0.05)。正常对照组的CD34+、CD33+和CD13+细胞百分比在剔除培养前后差异无统计学意义(P>0.05)。结论在体外选择性剔除骨髓中CD8+CD57+T细胞,可以增加MDS患者骨髓体外集落形成,且集落中髓系细胞明显向较成熟阶段分化,提示CD8+CD57+T细胞可能通过免疫途径参与骨髓无效造血。而剔除CD8+CD57+T细胞造成克隆细胞明显增加,提示其介导的免疫过程主要是针对MDS骨髓恶性克隆细胞。

Objective To observe the in vitro effects of abnormally activated CD8 T lymphocytes （CD8^＋CD57^＋T lymphoeytes） on hematopoesis in myelodysplastie syndrome （MDS）. Methods Bone marrow mononuelear ceils （BMNC） from 44 patients with low-grade MDS（MDS group） and 5 normal controls（normal control group） were depleted of CD8^＋CD57^＋T lymphoeytes using magnetic sorting. BMNC with depleted CD8^＋CD57^＋T lymphocytes and plused CD8^＋CD57^＋T lymphocytes （4 folds） were cultured separately, and the number of colony-forming unit （CFU）, the percentage of clonal ceils and the change in myeloid cell markers were compared, respectively. Results In MDS group, after culture with CD8^＋CD57^＋T lymphocyte depletion, 18 patients exhibited significantly increased generation of CFU, and cell clusters formed in 7 patients, while no CFU or cell clusters formed in the other 19 patients among whom only more intensified cell density was observed. No CFU formed after culture with CD8^＋CD57^＋T lymphocyte plus in MDS group, and the cell density was significantly lower than that of CD8^＋CD57^＋T lymphocytedepleted BMNC. There was generation of CFU in cultures initiated with both CD8^＋CD57^＋T lymphocyte-depleted BMNC and CD8^＋CD57^＋T lymphocyte-plused BMNC in normal control group. After depletion of CD8^＋CD57^＋T lymphoeytes, 2 patients with low-grade MDS and trisomy 8 had increased percentage of trisomy 8 clones after culture, and 2 patients with 20q- had increased percentage of abnormal clones. The percentages of CD34^＋, CD33^＋ and CD13^＋ cells in BMNC of MDS group were significantly higher than those in normal control group （P 〈0.05）. After culture with CD8^＋CD57^＋T lymphocyte depletion, the percentages of CD34^＋ and CD33^＋ cells in MDS group decreased （P 〈 0.05）, while there was no significant change in that of CD33^＋ cells（P 〉 0.05）. There was no significant difference in the percentages of CD34^＋,CD33^＋ and CD13 ^＋ cells in normal control group before culture and after culture（ P 〉 0.05）. Conclusion The in vitro selective depletion of CD8^＋CD57^＋T lymphocytes may increase bone marrow CFU in MDS, and myeloid cells in CFU may differentiate into more mature ones, indicating that CD8^＋CD57^＋T lymphocytes may participate in the ineffective hematopoesis through immunological mechanism. The depletion of CD8^＋CD57^＋T lymphocytes may increase the number of cell clones, indicating the immunological mechanism may mainly involve the bone marrow malignant clones in MDS.