妊娠早期孕妇CD_(56)^(bright)CD_(16)^-uNK、pNK细胞中CD_(44)的表达变化及意义

Expression and mechanism of CD_(44) on CD_(56)^(bright)CD_(16)^- uterine NK cells and peripheral NK cells in early pregnancy women

目的观察妊娠早期妇女CD56brightCD1-6子宫NK细胞(uNK细胞)和CD56brightCD1-6外周血NK细胞(pNK细胞)表面CD44的表达变化,探讨CD56brightCD1-6uNK细胞中CD44表达与母胎界面免疫耐受形成的关系。方法采集20例孕5~9周的正常妊娠妇女蜕膜和外周血以及20例正常非孕健康妇女外周血,用流式细胞仪检测其中CD56brightCD1-6NK细胞的数量及其表面CD44的表达。结果早期妊娠妇女子宫蜕膜淋巴细胞中CD56brightCD16-NK细胞占71.86%±6.22%,CD56brightCD16-uNK细胞中CD44的阳性表达率为34.65%±9.96%,显著低于CD56brightCD1-6pNK细胞的99.55%±0.35%,P<0.05。非孕期妇女CD56brightCD16-pNK细胞CD44阳性表达率为99.66%±0.29%,与妊娠早期孕妇相近,但孕早期妇女外周血CD56brightCD16-NK细胞CD44平均荧光强度(MFI)为241.71±62.41,正常未孕妇女为354.62±41.28,两者相比P<0.05。结论妊娠早期子宫蜕膜的淋巴细胞主要为CD56brightCD1-6uNK细胞。CD56brightCD1-6uNK细胞中CD44的表达明显低于pNK。这可能是妊娠早期维持母胎界面免疫耐受的重要因素。

Objective To investigate the expression of CD44 on uterine and peripheral blood CD56^brightCD16^- natural killer（NK） cells in early pregnancy women, and explore the relationship between expression of CD44 onuterine NK cells and immunotolerance at the fetal-maternal boundary. Methods Decidual lymphocytes and peripheral blood were obtained from 20 women during 5 - 9 weeks of normal pregnancy who were undergoing selective termination. Peripheral blood were obtained from 20 healthy nonpregnant women as control. FACS technology was used to detect CD44 on CD56^brightCD16^- NK cells number and CD44 expression. Results NK cells predominate, accounting for 70% of decidual lymphocytes. FACS results indicated that CD44 was significantly decreased in uterine NK cells as compared with that in peripheral blood NK cells, accounting for34.65% ± 9.96% and 99.55%± 0.35%, P 〈 0.05. Although the levels of CD44 in peripheral blood NK cells of pregnant women were similar to that in peripheral blood NK cells of non-pregnant women, accounting for 99.55% ± 0.35 % and 99.66% ± 0.29% respectively ,P 〈 0.05. Conclusions NK cells are the predominant lymphocytes during the first trimester of decidual tissue. These cells have a great different antigenic phenotype from peripheral blood NK cells. Uterine NK cells have low expression of CD44. This phenotype may be an important factor contributing to the immunotolerance at the fetal-maternal boundary during pregnancy.