Abstract:

Objective To investigate the upper respiratory tract bacterial species and T helper cell 17（Th17）/regulatory T cell（Treg）cytokine level changes in patients with neutrophilic asthma. Methods A total of 106 patients with neutrophilic asthma admitted to the Second People's Hospital of Jiaozuo City from May 2020 to May 2023 were enrolled as research group，and 106 healthy subjects were enrolled as control group. The subjects in the both groups were determined for upper respiratory tract bacterial species. Flow cytometry was used to determine T lymphocyte populations and Th17/Treg. Enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of interleukin（IL）-6，IL-10 and IL-17. The rate scattering turbidimetry method was applied to determine immunoglobulins（Ig）. Results Totally，169 isolates of bacteria were isolated from research group，of which Neisseria had the highest determination rate，followed by Streptococcus pneumoniae，Staphylococcus epidermidis and Streptococcus A. A total of 56 isolates of bacteria were isolated from control group，with the highest determination rate being Streptococcus A，followed by Streptococcus epidermidis and Neisseria. The CD4⁺T cell percentage and CD4⁺/CD8⁺ ratio in research group were lower than those in control group （P<0.05）. The Th17 percentage，Treg percentage，Th17/Treg ratio，IL-6，IL-10 and IL-17 levels in research group were higher than those in control group （P<0.05）. There was no statistical significance in the levels of IgG，IgA and IgM between research and control groups （P>0.05）. Conclusions The upper respiratory tract bacteria in patients with neutrophilic asthma is dysregulated，mainly Neisseria，and the levels of Th17/Treg are abnormally elevated.

Key words: Bacterium, T helper cell 17, Regulatory T cell, Neutrophilic asthma, Upper respiratory tract