重型再生障碍性贫血患者树突细胞亚群及其与淋巴细胞转录因子T-bet表达的相关性

Study on the dendritic cell subsets in peripheral blood and its relationship with the expressions of T- bet and GATA-3 in lymphocytes in severe aplastic anemia

目的探讨树突细胞（DC）亚群和淋巴细胞转录因子T-bet、GATA-3表达在获得性重型再生障碍性贫血（SAA）患者免疫失衡中的意义。方法采用流式细胞术检测29例SAA患者及16名健康人外周血DCl（HIA-DR^＋Lin^-CD11c^＋）、DC2（HLA-DR^＋Lin^-CD123^＋）数值及比例，半定量RT-PCR检测外周血T-bet mRNA和GATA-3 mRNA表达，ELISA法检测血浆IFNT、IL-4水平。结果SAA初治组、恢复组DC1占外周血单个核细胞比例分别为（0．44±0．24）％、（0．73±0．30）％，明显高于正常对照组[（0．29±0．10）％，P〈0．05]。三组DC2分别为（0．18±0．14）％、（0．28±0．20）％、（0．29±0．13）％，初治组低于对照组（P〈0．05）。SAA初治组、恢复组DC1／DC2比值分别为3．45±2．71、2．90±0．95，明显高于对照组（1．15±0．56），初治组与恢复组DC1／DC2比值差异无统计学意义（P〉0．05）。SAA初治组、恢复组及对照组T-bet的相对表达量分别为0．37±0．07、0．20±0．07、0．17±0．05，初治组明显高于恢复组和对照组（P〈0．05）。三组中GATA-3的相对表达量差异无统计学意义（P〉0．05）。初治组T-bet／GATA-3比值为0．72±0．13，明显高于恢复组（0．33±0．08）和对照组（0．35±0．11）。初治组血浆IFN7为（50．9±1．1）ng／L，明显高于恢复组[（49．7±0．9）ng／L]和正常对照组[（49．7±0．7）ng／L]。T-bet表达与DC1／DC2比值、IFNγ／水平呈显著正相关（r=0．445和r=0．402，P〈0．01）。结论DC1／DC2和T-bet／GATA-3比值失衡可作为判断SAA患者免疫状态的指标。T-bet的相对表达量与SAA患者的病情有关，病情好转后T-bet／GATA-3恢复平衡。SAA患者DC亚群恢复迟于血常规恢复，因此不可过早停用免疫抑制剂。

Objective To investigate the relationship between the dendritic cell （DC） subsets and transcriptive factors, T-bet, GATA-3, and immune imbalance in acquired severe aplastie anemia （SAA）. Methods The DC1 （ HLA-DR ^＋ Lin ^- CD11 e ^＋ ） and DC2 （ HLA-DR ^＋ Lin^ - CD123^ ＋ ） in peripheral blood mononuelear ceils （PBMNC） were measured with flow cytometry （ FCM）, the expressions of T-bet mRNA and GATA-3 mRNA in PBMNC with semiquantitative RT-PCR and the plasma level of IFNγ and IL-4 with ELISA in 29 SAA patients and 16 healthy controls. Results ①The percentages of DC1 in PBMNC were （0.44 ± 0.24）% and （0.73 ± 0.30）% in untreated and recovered SAA patients respectively, both were higher than that in controls （0.29 ± 0.10） % （ P 〈 0.05 ）. The percentage of DC2 in the untreated cases was lower than that of recovered ones or controls [（0. 18 ±0. 14） % vs （0.28 ±0.20） % and （0.29 ± 0.13） %] （P 〈 0.05 ）. DC1/DC2 ratios were 3.45 ± 2.71 and 2.90 ± 0.95 in untreated and recovered groups respectively, both were higher than that in controls （1.15 ± 0.56） （P 〈0.05 ）. No statistic difference in DC1/DC2 ratio was found between untreated and recovered patients （ P 〈 0.05 ）. ② The relative mRNA expression levels of trauscriptive factor T-bet were 0.37 ± 0.07, 0.20 ± 0.07 and 0.17 ± 0.05 in the above 3 groups, respectively, untreated group being higher than that of recovered group or healthy controls （P 〈 0.05）. There was no statistic difference of GATA-3 expression among the 3 groups （ P 〉 0.05 ）. T-bet/ GATA-3 ratio was 0.72 ± 0.13 in untreated group, being higher than that of recovered group （0.33 ± 0.08 ） or controls （0.35 ±0.11 ）. ③ The plasma level of IFN3, in the untreated group was （50.9 ± 1.1 ） ng/L, which was higher than that of recovered group [ （ 49.7 ± 0.9 ） ng/L ] or controls [ （ 49.7 ± 0.7 ） ng/L].④There was significant positive correlations between T-bet and DC1/DC2 ratio （ r = 0. 445, P 〈 0.01 ） , as well as between T-bet and IFNγ （ r = 0. 402, P 〈 0.01 ）. Conclusion Either DC1/DC2 or T-bet/GATA-3 ratio might become an index to estimate immune imbalance. High-expressed T-bet was related to the progress of SAA. In patients with SAA, DC1/DC2 ratio returns to normal range later than that of routine blood test does, indicating that immunosuppressive therapy should not be withdrawn too earlier.