Increasing Age Affected Polymorphonuclear Neutrophils in Prognosis of Mycoplasma pneumoniae Pneumonia

Abstract

Qianye Zhao,1,2,* Teng Zhang,2,* Beibei Zhu,1 Ying Bi,3 Shi-Wen Jiang,4 Yifan Zhu,1 Deyu Zhao,1 Feng Liu1 1Department of Respiratory Medicine, Children’s Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China; 2Department of Pediatrics, Lianyungang Maternal and Child Health Care Hospital, Lianyungang, Jiangsu, People’s Republic of China; 3Department of Respiratory Medicine, Xuzhou children’s Hospital, Xuzhou, Jiangsu, People’s Republic of China; 4Research Institute for Reproductive Health and Genetic Diseases, Center of Reproductive Medicine, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Deyu Zhao; Feng LiuDepartment of Respiratory Medicine, Children’s Hospital of Nanjing Medical University, No. 72, Guangzhou Road, Gulou District, Nanjing, Jiangsu, 210008, People’s Republic of ChinaTel [phone]; [phone]Fax [phone]Email [email protected]; [email protected]: It is well known that age is related to the incidence of Mycoplasma pneumoniae pneumonia (MPP), and how age and other factors contribute to MPP remains unclear. In this study, we investigate how age affects the prognosis of MPP.Patients and Methods: A total number of 1875 hospitalized children with pneumonia were enrolled in this study, including 52 children with refractory M. pneumoniae pneumonia (RMPP) and 298 children with non-RMPP. We used multiple logistic regression analysis to further identify the risk factors of RMPP, and found that age and polymorphonuclear neutrophils (PMNs) count were the key independent risk factors for the occurrence of RMPP. In order to improve specificity, 4.5 years old was taken as the cut-off value. Then, according to the cut-off value of age, 76 participants were recruited and divided into four groups: < 4.5y MPP group, ≥ 4.5y MPP group, < 4.5y health control (< 4.5yHC) and ≥ 4.5y HC group. We explored the diverse functions of primary PMNs from children of different ages with MPP at cellular level. Besides, we studied the relationship between lung injury and PMNs in mice model with MPP of different ages.Results: We found that the age and PMNs count of RMPP group were significantly higher than those of the non-RMPP group. Importantly, there is a linear correlation between the age of patients with RMPP and the percentage of PMNs. Further analysis showed that elderly patients infected with M. pneumoniae had more active PMNs function. Meanwhile, proteomics showed that children with M. pneumoniae infection in different age groups have differences in PMNs apoptosis, nicotinamide adenine dinucleotide phosphate, mitochondrial function and oxidative stress. Finally, we found that age is also involved in the pathogenesis of mouse model with MPP.Conclusion: We speculate that age may contribute to the development of RMPP.Keywords: refractory Mycoplasma pneumoniae pneumonia, Mycoplasma pneumoniae, polymorphonuclear neutrophils, reactive oxygen species, neutrophil extracellular traps

Keywords

• refractory mycoplasma pneumoniae pneumonia
• mycoplasma pneumoniae
• polymorphonuclear neutrophils
• reactive oxygen species
• neutrophil extracellular traps