Objective: To study the postnatal changes in lymphocyte subsets in early preterm infants and the effect of perinatal factors on lymphocyte subsets.
Methods: A total of 61 early preterm infants were enrolled. Flow cytometry was used to measure the absolute counts of lymphocytes and lymphocyte subsets at 1, 7, 14, and 28 days after birth, as well as at 6 months after birth for 17 of these early preterm infants. The effects of perinatal factors, such as antepartum use of hormone, intrauterine infection, gestational age at birth, and Ureaplasma urealyticum (UU) colonization, on lymphocyte subsets were analyzed.
Results: The absolute counts of lymphocyte subsets except natural killer (NK) cells were lowest at birth, increased rapidly at 1 week after birth, and reached the levels in healthy infants at 6 months; the count of NK cells remained at a low level and increased significantly at 6 months after birth. Compared with those with a gestational age of <28 weeks, the early preterm infants with a gestational age of ≥28 weeks had significantly higher absolute counts of T cells, T helper (Th) cells, and NK cells at 7 days after birth, a significantly higher absolute count of T cells at 14 days after birth, and significantly higher absolute counts of lymphocytes and Th cells at 28 days after birth (P<0.05). Compared with the group not using hormone, the group using hormone showed a significantly higher absolute count of T cells at 7 days after birth and significantly higher absolute counts of lymphocytes and all subsets at 14 days after birth (P<0.05). There was no significant difference in lymphocyte subsets at 1 day after birth between the intrauterine infection and non-infection groups (P>0.05); the intrauterine infection group had significantly higher absolute counts of B cells at 7 and 14 days after birth than the non-infection group. Compared those without UU colonization, the infants with UU colonization had significantly higher absolute counts of lymphocytes, T cells, Th cells, and Ts cells at 1 day after birth and a significantly higher absolute count of B cells at 14 days after birth.
Conclusions: Early preterm infants have deficiencies in innate immune cells at birth and normal levels at about 6 months after birth. Various perinatal factors including antepartum use of hormone, gestational age at birth, intrauterine infection, and UU colonization have long-term effects on lymphocyte subsets in early preterm infants.
目的: 了解早期早产儿淋巴细胞亚群变化趋势及围产因素的影响。
方法: 流式细胞术检测61例早期早产儿生后第1、7、14、28天以及其中17例早期早产儿出生后6个月的淋巴细胞亚群水平。分析围产期因素的影响。
结果: 早期早产儿出生时除自然杀伤（NK）细胞外各亚群淋巴细胞绝对计数均处于最低水平，1周时迅速升高，6个月升至正常；NK细胞至6个月方增高。与胎龄＜28周早期早产儿比较，≥ 28周的早期早产儿第7天的T细胞、辅助性T（Th）细胞、NK细胞，以及第14天的T细胞和第28天的淋巴细胞、Th细胞绝对计数较高（P＜0.05）。与母亲产前未使用激素组相比，激素组第7天的抑制性T（Ts）细胞和第14天的淋巴细胞及所有亚群淋巴细胞水平均较高（P＜0.05）。宫内感染组与非宫内感染组出生第1天的淋巴细胞亚群差异无统计学意义（P > 0.05）；第7、14天的B细胞绝对计数以宫内感染组较高（P＜0.05）。解脲支原体（UU）定植组第1天的淋巴细胞、T、Th、Ts细胞以及14天的B细胞绝对计数水平高于非定植组（P＜0.05）。
结论: 早期早产儿出生时免疫细胞数量不足，以后逐渐增高，6个月左右达正常。母亲产前使用激素以及出生胎龄、宫内感染、UU定植等多种围产因素对早期早儿淋巴细胞亚群水平有较长时间的影响。