目的检测新生儿细菌性肺炎患者外周血总自然杀伤细胞(NK细胞)及其各亚群百分率的变化,探讨NK细胞在其发病中的临床意义。方法采用流式细胞术检测38例新生儿细菌性肺炎患者及18例正常新生儿的总NK细胞及其各亚群占外周血总淋巴细胞百分率,住院天数在10 d以内(含10 d)为A组、住院天数10 d以上为B组;入院时外周血白细胞的数量<5.0×109/L或>20.0×109/L者为重度感染组,5.0×109/L<外周血白细胞数量<20.0×109/L者为轻度感染组。结果新生儿细菌性肺炎患者外周血总NK细胞及CD3-CD56negCD16bright百分率低于正常新生儿(P<0.01),但NK细胞CD3-CD56bright CD16neg/dim及CD3-CD56dimCD16bright亚群差异无统计学意义。A组CD3-CD56negCD16bright亚群百分率低于正常新生儿(P<0.01),而总NK细胞及其他亚群则差异无统计学意义。B组总NK细胞及CD3-CD56negCD16bright亚群百分率低于正常新生儿(P<0.01),且B组总NK细胞及各亚群百分率低于A组(P<0.05)。重度感染组总NK细胞及其各亚群百分率明显低于轻度感染组,差异有统计学意义(P<0.05)。结论新生儿细菌性肺炎患者病情越重住院时间越长,总NK细胞及其各亚群百分率越低。 Objective To detect the changes of total natural killer cells (NK cells) and their subsets in peripheral blood of neonatal bacterial pneumonia, and to explore the clinical significance of NK cells in the pathogenesis. Methods Flow cytometry was used to detect the percentage of total NK cells in 38 neonates with bacterial pneumonia and 18 normal neonates. The percentage of total NK cells in peripheral blood was less than 10 days (including 10 days) In group A, the days of hospitalization were more than 10 days in group B. The number of peripheral blood leukocytes on admission was <5.0 × 109 / L or> 20.0 × 109 / L in severe infection group, 5.0 × 109 / L