Abstract: Objective To explore the levels of detection of T cell subsets,IgE and regulated upon activation normal T cell expressed and secreted(RANTES) in infants with refractory Mycoplasma pneumoniae pneumonia（RMPP） and their role in pathogenesis of RMPP.
Methods A total of 190 children with Mycoplasma pneumoniae pneumonia were chosen as research subjects,who were treated in children′s Hospital Affiliated to Zhengzhou University from Feb.2019 to Aug.2022.They were divided into experimental group (95 children with RMPP),pneumonia group (95 children with Mycoplasma pneumoniae pneumonia) and control group (90 children suspected with tracheostenosis but without pulmonary infection).The expression of CD4+,CD8+ T cells of T cell subsets of peripheral blood were detected by flow cytometry.The level of IgE and RANTES were assayed with ELISA technique in their serum and bronchoalveolar lavage fluid.Results (1)The differences in CD4+ and CD8+ T cell expression rates among experimental group,pneumonia group and control group were not statistically significant(P>0.05).The CD4/CD8 ratio in experimental group was higher than that in pneumonia group and control group (all P<0.05).(2) Level of IgE in serum and bronchoalveolar lavage fluid in the experimental group was much higher than that in pneumonia group（P<0.05） and control group（P<0.01） and it was higher in pneumonia group than in control group in their serum and bronchoalveolar lavage fluid（P<0.05）.(3) Level of RANTES in the experimental group was much higher than that in pneumonia group（P<0.05） and control group（P<0.01） and it was higher in pneumonia group than in control group in their serum and bronchoalveolar lavage fluid（P<0.05）.Conclusion
T cell subsets,IgE and RANTES are involved in the pathogenesis of RMPP to the regimen of latter two can be used as early detection indicators of RMPP,to optimize the regimen of clinical diagnosis and treatment.

Key words:

Refractory Mycoplasma pneumoniae pneumonia, Flow cytometry, T cell subsets, IgE, Regulated upon activation normal T cell expressed and secreted