Abstract:

Objective　To investigate the changes in cell classification levels in bronchoalveolar lavage fluid (BALF) of children diagnosed with Mycoplasma pneumoniae pneumonia (MPP). Methods　This study was a prospective cohort study. During the period spanning January to June 2022, a cohort of 30 children diagnosed with acute MPP who were admitted to the Department of Pediatrics and Pediatric Intensive Care Unit (PICU) at the First Affiliated Hospital of Xinxiang Medical University and underwent bronchoalveolar lavage were enrolled as the study group. Concurrently, 9 children presenting with uncomplicated bronchial foreign bodies were recruited as the control group. In the study group, there were 15 boys and 15 girls, aged (6.6±2.5) years. In the control group, there were 6 boys and 3 girls, aged (5.7±5.4) years. Wright-Giemsa stain coupled with microscopic examination served as the analytical tools to scrutinize alterations in the proportion of BALF cell classifications in children and their potential association with extrapulmonary manifestations. χ² test, independent sample t test, and rank sum test were used. Results　The levels of neutrophil percentage, C-reactive protein, D-dimer, and lactate dehydrogenase in blood routine of the study group were higher than those of the control group [71.05 (56.40, 79.83)% vs. 46.50 (34.50, 62.45)%, 17.47 (4.86, 37.65) mg/L vs. 1.00 (0.17, 1.64) mg/L, 1.75 (0.80, 4.23) mg/L vs. 0.60 (0.55, 0.75) mg/L, 342 (269, 482) U/L vs. 245 (181, 284) U/L], while the percentage of lymphocytes in blood routine was lower than that of the control group [23.45 (13.55, 34.95)% vs. 43.20 (33.10, 58.55)%], with statistically significant differences (all P<0.05). The percentage of BALF neutrophils in the study group was higher than that in the control group [46.00 (38.00, 55.00)% vs. 1.00 (0.01, 1.75)%], while the percentage of macrophages was lower than that in the control group [43.00 (33.87, 51.00)% vs. 87.50 (85.00, 90.00)%], with statistically significant differences (both P<0.05). According to the presence or absence of extrapulmonary manifestations, the study group was divided into 23 cases without extrapulmonary manifestations and 7 cases with extrapulmonary manifestations (2 cases with kidney damage, liver damage, and myocardial damage, 3 cases with kidney damage and myocardial damage, 1 case with kidney damage, and 1 case with myocardial damage). The levels of calcitonin, serum amyloid A, lactate dehydrogenase and aspartate aminotransferase in the group with extrapulmonary manifestations were higher than those in the group without extrapulmonary manifestations [0.74 (0.42, 3.59) µg/L vs. 0.35 (0.19, 0.68) µg/L, 464.9 (172.8, 655.6) mg/L vs. 134.9 (41.0, 431.0) mg/L, 697.0 (469.0, 1 177.0) U/L vs. 296.0 (255.0, 417.0) U/L, 54.0 (42.0, 109.0) U/L vs. 30.0 (22.0, 37.0) U/L], the length of hospital stay was longer than that in the group without extrapulmonary manifestations [19.00 (18.00, 22.00) d vs. 11.00 (7.00, 16.00) d], and the percentage of BALF lymphocytes and albumin level were lower than those in the group without extrapulmonary manifestations [10.50 (9.50, 11.00)% vs. 13.00 (10.00, 14.50)%, 33.9 (27.3, 40.2) g/L vs. 40.3 (37.1, 42.3) g/L], with statistically significant differences (all P<0.05). Spearman correlation analysis showed that the percentage of BALF lymphocytes was negatively correlated with extrapulmonary manifestations (r=-0.334, P=0.038). Conclusion　BALF composition in children experiencing acute MPP predominantly consists of neutrophils. Moreover, there exists a correlation wherein a decrease in the percentage of BALF lymphocytes corresponds with an elevated occurrence of extrapulmonary manifestations.

Key words:

Mycoplasma pneumoniae pneumonia, Bronchoalveolar lavage fluid, Cytological morphology, Children

摘要：

目的　研究细胞分类水平在肺炎支原体肺炎（MPP）患儿支气管肺泡灌洗液（BALF）中的变化。方法　本研究为前瞻性队列研究。选取2022年1—6月新乡医学院第一附属医院儿科及儿科重症监护室（PICU）收治并行支气管肺泡灌洗的急性期MPP患儿30例作为研究组和未合并感染的支气管异物患儿9例作为对照组。研究组中男15例、女15例，年龄（6.6±2.5）岁；对照组中男6例、女3例，年龄（5.7±5.4）岁。采用瑞氏-姬姆萨染色后镜检分析患儿BALF细胞分类百分比水平的变化及其与肺外表现的相关性。采用χ²检验、独立样本t检验、秩和检验。结果　研究组患儿的血常规中性粒细胞百分比、C反应蛋白、D-二聚体和乳酸脱氢酶水平均高于对照组［71.05（56.40，79.83）%比46.50（34.50，62.45）%、17.47（4.86，37.65）mg/L比1.00（0.17，1.64）mg/L、1.75（0.80，4.23）mg/L比0.60（0.55，0.75）mg/L、342（269，482）U/L比245（181，284）U/L］，血常规淋巴细胞百分比低于对照组［23.45（13.55，34.95）%比43.20（33.10，58.55）%］，差异均有统计学意义（均P<0.05）；研究组的BALF中性粒细胞百分比高于对照组［46.00（38.00，55.00）%比1.00（0.01，1.75）%］，巨噬细胞百分比低于对照组［43.00（33.87，51.00）%比87.50（85.00，90.00）%］，差异均有统计学意义（均P<0.05）。依据有无肺外表现，将研究组分为无肺外表现组23例和有肺外表现组7例（肾损害、肝损害、心肌损害2例，肾损害、心肌损害3例，肾损害1例，心肌损害1例）；有肺外表现组患儿的降钙素、血清淀粉样蛋白A、乳酸脱氢酶、天冬氨酸氨基转移酶均高于无肺外表现组［0.74（0.42，3.59）µg/L比0.35（0.19，0.68）µg/L、464.9（172.8，655.6）mg/L比134.9（41.0，431.0）mg/L、697.0（469.0，1 177.0）U/L比296.0（255.0，417.0）U/L、54.0（42.0，109.0）U/L比30.0（22.0，37.0）U/L］，住院时间长于无肺外表现组［19.00（18.00，22.00）d比11.00（7.00，16.00）d］，BALF淋巴细胞百分比、白蛋白水平均低于无肺外表现组［10.50（9.50，11.00）%比13.00（10.00，14.50）%、33.9（27.3，40.2）g/L比40.3（37.1，42.3）g/L］，差异均有统计学意义（均P<0.05）。Spearman相关性分析显示，BALF淋巴细胞百分比与肺外表现呈负相关（r=-0.334，P=0.038）。结论　急性期MPP患儿的BALF以中性粒细胞为主；BALF淋巴细胞百分比越低，肺外表现的发生率越高。

关键词:

肺炎支原体肺炎, 支气管肺泡灌洗液, 细胞形态, 儿童