再生障碍性贫血患儿CD_4^+ CD_(25)^+T细胞及TGF-β1 Flt-3L水平变化的意义

Changes and significance of CD_4^+ CD_(25)^+ regulatory T cells,transforming growth factor-β1 and Flt-3 ligand in children with aplastic anemia.

目的评价免疫调节T细胞和细胞因子在再生障碍性贫血(再障)细胞免疫功能紊乱中的作用。方法2004-02—2005-06中山大学第二附属医院采用流式细胞术检测27例特发性再障患儿骨髓及外周血淋巴细胞亚群和CD+4CD2+5T细胞水平,ELISA检测骨髓转化生长因子(TGFβ-1)和F lt-3L水平,并与正常儿童对照。结果与对照组比较,初诊再障患儿外周血和骨髓CD+8T细胞均显著增高(P<0.05),重型再障(SAA)组伴外周血CD3-CD+56NK细胞及骨髓B细胞显著下降(P<0.05)。初诊SAA组骨髓CD+4CD+25T细胞[(7.5±3.4)%]显著高于对照组[(4.3±0.9)%,P<0.05],初诊SAA组及轻型再障(MAA)组骨髓CD+4CD2+5/CD+4比值分别为(28.9±11.1)%和(28.2±9.4)%,均显著高于对照组[(17.4±0.9)%,P均<0.05],骨髓TGFβ-1分别为(2.2±1.7)μg/L和(2.0±0.6)μg/L,均较对照组[(4.4±0.9)μg/L]显著降低(分别为P<0.01、P<0.05),而F lt-3L水平分别为(1031.1±321.8)ng/L和(694.7±424.7)ng/L,均较对照组[(63.0±37.5)ng/L]显著增高(P均<0.01)。缓解期SAA儿童除外周血CD8+T细胞仍较对照组显著增高外,其余上述指标均接近正常水平。相关分析显示,骨髓CD4+CD+25T细胞与CD+3CD+4T细胞呈显著正相关(r分别为0.495、0.540,P<0.01);F lt-3L与骨髓CD+3、CD+4、CD+8T细胞及CD+4CD+25T细胞均呈显著正相关(r分别为0.732、0.542、0.688、0.405,P分别<0.01、0.01、0.01、0.05),而TGFβ-1与骨髓CD+8T细胞和F lt-3L水平呈显著负相关(r分别为-0.431、-0.482,P分别<0.05、<0.01)。结论儿童再障发病与CD+4CD+25T细胞数量缺乏无关,骨髓TGFβ-1水平显著降低和F lt-3L水平显著增高可能在再障儿童T淋巴细胞数量增多和功能紊乱中起重要作用。

Objective To investigate the roles of immune regulatory T cells and cytokines in immune disorders in pediatric aplastic anemia（AA）. Methods Lymphocyte subsets and CD4^＋ CD25^＋ cells in bone marrow（BM） and peripheral blood （PB） were detected by FACS,and the levels of TGF-β1 and Fh-3L in BM were measured by ELISA in 27 patients with idiopathic pediatric AA and controls. Results Compared to controls,the frequencies of CD3^＋ CD8^＋ cells in BM and PB increased significantly in untreated AA patients,and the frequencies of NK in PB and B cells in BM decreased significantly in untreated SAA. The frequency of CD4^＋ CD25^＋ cells in untreated SAA group [ （ 7.5 ± 3.4 ） % ] was higher than that in controls [ （4. 3 ±0. 9） %, P 〈0. 05]. The ratio of CD4^＋ CD25^＋/ CD4^＋ in BM of untreated SAA group [ （28.9 ± 11.1 ） % ] and MAA group [ （ 28.2 ± 9.4 ） % ] was higher than that of controls [ （ 17.4 ± 0. 9 ） %, P 〈 0. 05, respectively ]. The levels of TGF-β1 in untreated SAA group [ （ 2.2 ± 1.7 ）μg/L] and MAA group [ （ 2. 0 ± 0. 6 ） μg/L] were lower than that in controls[ （4. 4 ± 0. 9 ） μg/L, P 〈 0. 01, 〈 0. 05, respectively]. Flt-3L in SAA group [ （ 1031. 1 ± 321.8 ） ng/L] and MAA group [ （694. 7 ± 424. 7 ） ng/L] was higher than that in controls [ （63.0 ± 37.5 ） ng/L, P 〈 0. 01, respectively]. In recovered SAA patients treated by immunosuppressive therapy, all of the above but the frequency of CD3^＋ CD8^＋ cells in PB returned to normal levels. There was significant positive relationship between CD4^＋ CD25^＋ and CD3^＋, CDf CD4^＋ cells （ r =0. 495,0. 540, P 〈 0. 01, respectively ） , as well as between Flt-3 L and CD3^＋, CD3^＋ CD4^＋ , CD3^＋ CD8^＋, CD4^＋ CD25^＋ cells in BM （r =0. 732,0. 542,0. 688,0. 405, P .〈0. O1, 〈0. 01, 〈0. 01, 〈0. 05,respectively）. Negative relations were found between TGF-β1 and Flt-3L, CD3^＋ CD8^＋ cells （ r = - 0. 431, -0. 482, P 〈0. 05, 〈 0. 01, respectively ）. Conclusion These results indicate that pediatric AA is not related to CD4^＋ CD25^＋ regulatory T cells deficiency. The decreased TGF-β1 and increased Flt-3L in BM may play an important role in T lymphocytes proliferation and function disorders in pediatric AA.