Stress-Inflammation Dysregulation and Biomarker Dynamics in Pediatric Mycoplasma Pneumoniae Pneumonia

Summary

Elevated LDH and D-dimer levels in pediatric Mycoplasma pneumoniae pneumonia were linked to systemic inflammation, psychological stress, and prognostic outcomes. High MP-DNA loads predicted longer hospitalization. Findings highlight LDH and D-dimer as valuable biomarkers for early risk stratification, enabling improved clinical management and identification of high-risk pediatric patients.

Abstract

Mycoplasma pneumoniae pneumonia (MPP) is a common pediatric infection frequently accompanied by systemic inflammation and psychological stress; however, its potential bidirectional relationship remains poorly defined. We retrospectively analyzed 120 hospitalized children aged 5-12 years using the Child Stress Questionnaire (CSQ), inflammatory mediators (CRP, IL-6), and three clinical biomarkers (LDH, D-dimer, MP-DNA load). Elevated LDH and D-dimer were significantly associated with higher CSQ scores (r = 0.67, p < 0.01) and more severe inflammatory responses. Children with prolonged illness (>7 days) and high MP-DNA load had markedly higher stress scores (mean 38 vs. 25, p < 0.01). LDH ≥ 450 U/L independently predicted extended hospitalization (OR = 2.1, 95% CI: 1.2-3.7), and ROC analysis demonstrated strong discriminative power for severe complications (AUC = 0.89, 95% CI: 0.83-0.95; sensitivity = 82%, specificity = 81%). These findings support a bidirectional link between psychological stress and immune dysregulation in pediatric MPP and highlight LDH and D-dimer as practical biomarkers for early identification of high-risk children.

Introduction

Mycoplasma pneumoniae (MP) is among the most common causes of community-acquired pneumonia in children, accounting for a substantial proportion of respiratory hospitalizations worldwide^1,2. Beyond pulmonary involvement, MP infection frequently elicits systemic immune responses that may result in extrapulmonary complications and delayed recovery³. In pediatric populations, immune function is closely linked to psychological well-being, as acute illness and hospitalization can trigger chronic stress responses that disrupt endocrine-immune balance^4,

Protocol

This study was approved by the Institutional Ethics Committee of Anhui Provincial Children's Hospital. Written informed consent was obtained from the parents or legal guardians of all participants prior to data collection. All procedures involving patient samples were conducted in accordance with institutional biosafety regulations and internationally recognized ethical standards. The equipment and software used are listed in the Table of Materials.

1. Study design

This retrospective cohort study enrolled children aged 5-12 years with confirmed Mycoplasma pneumoniae (MP) pneumonia betw....

Results

The overall study design and workflow are summarized in Figure 1. LDH demonstrated superior accuracy for predicting severe complications (AUC = 0.89, 95% CI: 0.83-0.95) compared with CRP (AUC = 0.76) and IL-6 (AUC = 0.72). The optimal cutoff for LDH was 450 U/L, yielding a sensitivity of 82% and a specificity of 81%. Logistic regression confirmed that LDH ≥ 450 U/L was independently associated with prolonged hospitalization (OR = 2.1, 95% CI: 1.2-3.7). Persis.......

Discussion

Mycoplasma pneumoniae (MP) pneumonia in children is a heterogeneous disease, with immunoinflammatory dysregulation acting as a central determinant of severity and recovery. This dysregulation arises from interactions between host immune responses and MP virulence factors, shaping both disease course and treatment responses. Clinical biomarkers, therefore, represent indispensable tools for patient stratification, treatment guidance, and prognosis.

CRP serves as a frontline marker of ac.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Child Stress Questionnaire (CSQ)	Not specified		Psychometric assessment of stress
CRP assay kit	Siemens Healthineers	11537224 (Atellica CH hCRP2, 720 tests)	Measurement of C-reactive protein
D-dimer assay kit	Diagnostica Stago	00515 (STAÂ- Liatest D-Di kit)	Measurement of plasma D-dimer levels
IBM SPSS Statistics version 28.0	IBM Corp., Armonk, NY, USA		Data analysis
IL-6 assay kit	Roche Diagnostics	09015612190 (cobas e 801 pack); 09015612500 (100 tests)	Measurement of interleukin-6
LDH assay kit	Not specified	MAK066 (MilliporeSigma LDH Activity Assay Kit)	Measurement of lactate dehydrogenase activity
Pediatric flexible bronchoscope (e.g., BF-P190)	Olympus	BF-P190 (model/order no.)	Bronchoalveolar lavage collection
Pulse oximeter	Not specified	Not provided	Measurement of oxygen saturation