Predictive value of ig Mycoplasma pneumoniae-DNA, high-density lipoprotein, natural killer cell, and platelet levels for diagnosing severe M. pneumoniae pneumonia in children.

Objective: The present study aimed to assess the predictive value of Ig Mycoplasma pneumoniae (MP)-DNA, high-density lipoprotein (HDL), natural killer (NK) cell, and platelet (PLT) levels for the diagnosis of severe MP pneumonia (SMPP) in children with MP pneumonia (MPP).

Methods: Children with MPP admitted to our hospital from August 2022 to February 2024 were selected and assigned to the non-SMPP (NSMPP) and SMPP groups according to whether they had severe pneumonia. The following parameters were analyzed and compared between the two groups by the rank-sum test: age; Ig MP-DNA level; white blood cell, neutrophil (N), and monocyte counts; platelet (PLT), C-reactive protein (CRP), lactate dehydrogenase (LDH), triglycerides, high-density lipoprotein (HDL), low-density lipoprotein, and procalcitonin levels; and levels of T cells, CD4⁺ T cells, CD8⁺ T cells, B cells, and NK cells. The chi-square test was used to analyze differences in these variables between genders. One-way analysis of variance was used to select significant variables (P < 0.1) from the abovementioned ones, and the selected variables were analyzed by multivariate analysis of variance to detect independent risk factors. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) value were determined for the independent risk factors.

Results: The two groups showed significant differences in the levels of Ig MP-DNA, N, PLT, CRP, LDH, HDL, CD8⁺ T cells, and NK cells. PLT and Ig MP-DNA levels were positively correlated with the risk of SMPP development; however, HDL and NK levels showed a negative correlation. The AUC values for Ig MP-DNA + HDL, Ig MP-DNA + NK, Ig MP-DNA + PLT, NK + HDL, NK + PLT, and PLT + HDL were 0.825, 0.812, 0.813, 0.724, 0.717, and 0.701, respectively.

Conclusion: The combination of variables, including Ig MP-DNA + HDL, Ig MP-DNA + NK, and Ig MP-DNA + PLT, can predict whether MPP children would develop SMPP.