# Peripheral blood inflammatory cytokines linked to clinical outcomes in Mycoplasma pneumoniae pneumonia

## TL;DR

This study found that specific inflammatory cytokines in the blood of children with Mycoplasma pneumoniae pneumonia are linked to poor clinical outcomes, suggesting they could help predict disease severity.

## Contribution

The study presents the largest cohort to date examining inflammatory cytokines in MPP, identifying key cytokines associated with adverse outcomes.

## Key findings

- Elevated levels of IL-2, IL-4, IL-10, and IL-17 are associated with severe and refractory MPP.
- IFN-γ and IL-6 are upregulated in poor-prognosis groups and correlate with clinical markers like CRP and D-dimer.
- Cytokine profiles could improve early diagnosis and management of adverse MPP outcomes.

## Abstract

Mycoplasma pneumoniae pneumonia (MPP) can result in a variety of poor prognoses. A retrospective cohort study of MPP patients admitted to the Children’s Hospital of Nanjing Medical University from 1 January 2021 to 1 April 2024 was carried out to evaluate the association between 12 peripheral blood inflammatory cytokines and clinical outcomes. 2,391 patients were enrolled and divided into four outcome-based groups: severe MPP (SMPP), refractory MPP (RMPP), necrotizing pneumonia (NP), and pulmonary embolism (PE). The levels of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-10 (IL-10), and interleukin-17 were elevated in the poor-prognosis groups of SMPP and RMPP. Interferon-γ (IFN-γ) was upregulated in the poor-prognosis groups of RMPP, and it was an influencing factor for the prognoses. Interleukin-6 (IL-6) was upregulated in the NP and PE groups, and it was an influencing factor for NP. Correlation analysis showed strong positive correlations among the 12 inflammatory variables. IFN-γ, IL-6, and IL-10 were positively correlated with C-reactive protein, neutrophil-to-lymphocyte ratio, D-dimer, and lactate dehydrogenase. These findings suggest that inflammatory cytokines may serve as potential indicators for predicting different prognoses of MPP.

The number of patients in our clinical research cohort is the largest to date in studies focusing on Mycoplasma pneumonia (MPP) and inflammatory cytokines. Specifically, we established a prospective cohort study involving 2,391 patients, systematically collecting clinical data and peripheral blood samples to explore the association between peripheral blood inflammatory cytokine levels and clinical outcomes of MPP. Our findings hold substantial clinical significance: patients with poor MPP outcomes exhibited a markedly stronger pulmonary immunoinflammatory response, shedding new light on the underlying mechanisms driving disease progression. Importantly, incorporating cytokine profiles into routine clinical monitoring and early diagnosis could facilitate timely identification and targeted management of adverse MPP prognoses.