重型再生障碍性贫血患者外周血树突细胞亚群及共刺激分子表达的研究

Study on the peripheral blood dendritic cells subtypes and the expression of co-stimulating molecules on dendritic cells and B cells in severe aplastic anemia patients

目的了解重型再生障碍性贫血(SAA)患者在免疫抑制治疗(IST)前、后外周血树突细胞(DC)亚群数量、比值的变化,测定外周血 T 细胞激活协同分子(CD80、CD86、CD40)在树突细胞及 B细胞表面的表达。方法用单克隆抗体三标法和流式细胞术检测26例发病期和13例 IST 后恢复的SAA 患者外周血髓系 DC 前体(pDC1)与淋系 DC 前体(pDC2)的数量、比例,并与15名正常对照比较。其中10例患者检测了治疗前、后2个月的 pDC1与 pDC2的数量。检测16例 SAA 患者及12名正常对照外刷血 DC 及 B 淋巴细胞表面 CD80、CD86、CD40的表达。结果正常对照组外周血 pDC 总量、pDC1、pDC2及 pDC1/pDC2比值分别为(0.72±0.08)%,(0.41±0.05)%,(0.30±0.05)%,1.58±0.18:而初发 SAA 患者为(0.96±0.18)%,(0.67±0.13)%.(0.32±0.06)%,2.70±0.32,pDC1显著增多(P<0.05),pDC1/pDC2比例明显失衡(P<0.01);恢复期 SAA 患者上述指标下降为(0.77±0.13)%,(0.43±0.10)%,(0.34±0.09)%,1.78±0.36,与正常对照组无差异(P 值均>0.05)。10例 SAA 患者治疗前 pDC1、pDC2及 pDC1/pDC2比值分别为(0.87±0.31)%,(0.35±0.09)%,2.65±0.40,治疗2个月后分别为(0.24±0.09)%,(0.14±0.04)%,2.16±0.26,pDC1、pDC2显著下降(P值均<0.05)。正常对照组外周血 DC 表面 CD80、CD86、CD40的表达分别为(1.61±0.84)%,(11.97±4.31)%,(0.56±0.45)%,而 SAA 患者分别为(9.14±4.08)%,(29.84±3.02)%,(7.04±3.79)%,SAA 患者 DC 表面 CD86表达明显高于正常对照(P<0.05)。正常对照组外周血淋巴细胞CD19、CD80、CD86、CD40的表达分别为(9.38±0.92)%,(2.57±0.44)%,(1.86±0.32)%,(7.34±1.22)%;而 SAA 患者分别为(11.12±2.26)%,(5.17±0.68)%,(5.98±0.96)%,(8.85±2.49)%,CD80^+细胞、CD86^+细胞比例明显高于正常对照(P 值分别为<0.05和0.01)。正常对照外周血 B 淋巴细胞 CD80、CD86、CD40的表达分别为(28.22±3.56)%,(8.04±0.66)%,(81.6±6.48)%;而 SAA患者分别为(23.06±3.73)%,(20.46±2.78)%,(81.57±5.29)%,SAA 患者 B 淋巴细胞上 CD86表达明显高于正常对照组(P<0.05)。结论 SAA 患耆 pDC 亚群明显异常,与 Th1细胞激活有关的pDC1明显增多,这种变化与 SAA 病情密切相关。SAA 患者 T 细胞活化所需要的共刺激信号 B7-2途径处于高度激活状态,这可能是导致 T 细胞异常激活的机制之一。

Objective To investigate the quantities of monocyte-derived dendritic cell precursors （pDC1） and plasmacytoid dendritic cell precursors （pDC2） in peripheral blood mononuclear ceils （PBMC） of severe aplastic anemia （SAA） patients before and after immune suppressive therapy （IST）, the ratio of the pDC1 to pDC2, and the expression of co-stimulating molecules （CD80, CD86, CD40） on dendritic cells （DC） and B ceils in SAA patients. Methods By means of three color monoclonal antibody labeling technology, the quantities and ratio of pDC1 and pDC2 in PBMC were detected in 26 SAA patients at active phase, 13 at recovery phase and 15 normal controls respectively. The aforementioned parameters of 10 SAA patients were tested before and 2 months after IST. The expression of CD80, CD86 and CD40 on DC and B lymphocytes were detected in 16 SAA patients and 15 normal controls. Results The percentages of pDC1 and the ratio of pDC1/pDC2 of controls were （0.41 ± 0.05）% and 1.58 ±0.18 respectively, and those of SAA patients at active phase were （0.67 ± 0. 13） % and 2.70 ± 0.32 respectively, [ pDC1 （ P 〈 0.05） ; pDC1/ pDC2 ratio （P 〈 0.01 ） 1. The aforementioned parameters in convalescent SAA patients decreased to （0.43 ± 0.10） %, and 1.78 ± 0.36 respectively, being no difference from those of normal controls. The percentages of pDC1 and pDC2 in 10 SAA patients were（0.87 ± 0.31 ）%, and （0.35 ± 0.09）%, before IST, and （ 0.24 ± 0.09） %, （0.14 ± 0.04） % , after IST, being significantly decreased （ P 〈 0.05 ）. The percentages of CD86 expression on DC of controls was （11.97 ± 4.31 ）% , and that of SAA patients was （29.84 ± 3.02） % （P 〈 0.05 ）. The percentages of CD80, CD40 and CD86 expression on lymphocytes of controls were （2.57 ±0.44）%, （7.34 ± 1.22）% and （ 1.86 ± 1.11 ）%, respectively, and those of SAA patients were （5.17 ± 0.68） %, （8.85 ± 2.94） % and （5.98 ± 0.96） % respectively （ P 〈 0. 05, P 〈 0.01 ）. The percentage of CD86 expression on B lymphocytes in controls was 8.04 ± 0.66%, and in SAA patients was （20.46 ± 2.78 ） %, （ P 〈 0.05 ）. Conclusion The pDC subtypes were abnormal and the percentage of pDC1 is increased in SAA patients, which are associated with stage of this disease. DC and B Lymphocytes in SAA patients upregulated expression of costimulatory molecules （CD86） which cause the T lymphocyte abnormally activated.