Abstract: Objective To investigate the distribution difference of T lymphocyte subsets in common and refractory mycoplasma pneumonia and its impact on treatment. Methods Two hundred children with mycoplasma pneumonia hospitalized from October 2023 to January 2024 were retrospectively reviewed and divided into common mycoplasma pneumonia group and refractory mycoplasma pneumonia group (n=100 each) according to the severity of disease and treatment. The distribution of T cell immunophenotypes CD4⁺, CD8⁺ and CD4⁺/CD8⁺ were compared between common mycoplasma pneumonia and refractory mycoplasma pneumonia. The predictive value of CD4⁺, CD8⁺ counting, CD4⁺/CD8⁺ and combined detection on the occurrence of refractory mycoplasma pneumonia were analyzed. Results Compared with the common mycoplasma pneumonia group, the refractory mycoplasma pneumonia group had more school-age children, longer fever duration and hospital stay (P＜0.05). Compared with the common mycoplasma pneumonia group, CD4⁺ expression was slightly decreased in the refractory mycoplasma pneumonia group, but there was no statistical significance between the two groups;CD8⁺ expression was significantly increased while CD4⁺/CD8⁺ expression was significantly decreased (P＜0.05). Receiver operating characteristic curve (ROC) showed that CD4⁺ (AUC=0.532, 95% CI=0.455-0.608), CD8⁺ (AUC=0.592, 95% CI=0.515-0.666), CD4⁺/CD8⁺ (AUC=0.579, 95% CI=0.502-0.653) and combined detection (AUC=0.607, 95% CI=0.531-0.680). Conclusions Compared with the common mycoplasma pneumonia group, CD4⁺ expression is slightly decreased, CD8⁺ expression is significantly increased, and CD4⁺/CD8⁺ expression is significantly decreased in the refractory mycoplasma pneumonia group. All these indicators hold certain value in predicting the occurrence of refractory mycoplasma pneumonia, with combined detection demonstrating higher predictive value.

Key words: mycoplasma pneumonia, common mycoplasma pneumonia, refractory mycoplasma pneumonia, CD4⁺T lymphocytes, CD8⁺T lymphocytes