Can mycoplasma DNA level and NK cell counts determine the sensitivity of mycoplasma pneumonia patients to macrolide antibiotics treatment at early stage

Purpose: Our study aimed to evaluate if DNA level of mycoplasma pneumoniae (MPDNA) and natural killer (NK) cell counts could differentiate macrolide-sensitive or macrolide-unresponsive mycoplasma pneumoniae pneumonia (MSMPP or MUMPP) children. Methods A total of 120 children with MPP admitted to our hospital from August 2022 to August 2023 were retrospectively included in our study. Based on their responses to macrolide antibiotics in 72 hours, they were classified into MSMPP and MUMPP groups. Data included white blood cell (WBC), neutrophil (N), lymphocytes (L), monocytes (M), platelet (PLT), C reactive protein (CRP), lactic dehydrogenase (LDH), procalcitonin (PCT), T cell (CD4 + and CD8+), B cell, NK cell levels. Moreover, lung consolidation and pleural effusion were also included. Univariate logistic analysis was performed to screen indicators that were significantly associated with MSMPP and MUMPP, and those indicators were further subjected to multivariate analysis. The receiver operator characteristic (ROC) curve and area under curve (AUC) were used to estimate predictive value of indicators. Results The age and sex between MSMPP and MUMPP groups had no significant difference. The level of L, PLT, total T cell, CD4 + T cell, CD8 + T cell, and NK cell were significantly higher whereas the MPDNA level was lower in MSMPP group than MUMPP group. Meanwhile, there were less cases with lung consolidation or pleural effusion in MSMPP group compared to MUMPP group. Multivariate analysis identified NK cell count as an independent risk factor for MUMPP patients. Moreover, the AUC of NK cell count for predicting MSMPP or MUMPP was 0.753. Conclusions In the MUMPP group, the level of lymphocytes including T cells was decreased and more lung complications were detected compared to the MSMPP group. We identified NK cell count as an independent risk factor for differentiating MUMPP. Meanwhile, the combination of NK cell counts and MPDNA level had robust ability for predicting MUMPP.