# Immune Dysregulation and Cytokine Profiling in Acute Mycoplasma pneumoniae Pneumonia

## TL;DR

This study explores how the immune system and cytokines contribute to lung inflammation in acute Mycoplasma pneumoniae pneumonia using a mouse model.

## Contribution

The study identifies a cytokine storm and myeloid cell involvement in acute M. pneumoniae pneumonia using a preclinical model.

## Key findings

- Severe lung inflammation with neutrophil and macrophage infiltration was observed in the MPP model.
- 36 cytokines, including IL-1β, IL-6, and IL-17A, were significantly upregulated in bronchoalveolar lavage fluid.
- Enriched pathways related to cytokine signaling and IL-17 suggest potential therapeutic targets for MPP.

## Abstract

Mycoplasma pneumoniae pneumonia (MPP) is a common respiratory infection characterized by significant inflammatory responses and lung tissue injury. However, the precise immunological mechanisms and temporal dynamics of key cytokines driving pulmonary inflammation in MPP are still unclear. This study aimed to investigate the underlying immunological mechanisms and cytokine dynamics in MPP. We established an acute MPP murine model via intranasal administration of M. pneumoniae. This model recapitulates key features of human MPP, such as robust airway inflammation and cytokine production. Comprehensive analyses were conducted, including histopathology, flow cytometry, and cytokine profiling. Results showed severe inflammatory responses with prominent infiltration of neutrophils and macrophages in lung tissue, whereas monocyte populations were significantly reduced, indicating a shift towards myeloid cell predominance. Notably, 36 cytokines, including pro-inflammatory interleukins (IL-1β, IL-6, IL-17A) and chemokines, were statistically significantly upregulated in bronchoalveolar lavage fluid compared to the normal group, highlighting a cytokine storm associated with lung inflammation and tissue damage. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis further revealed enriched pathways related to cytokine-cytokine receptor interactions and IL-17 signaling, suggesting potential therapeutic targets. In conclusion, this study preclinical provides insights into the innate immune response and cytokine-driven pathology in acute MPP, underscoring the pivotal roles of myeloid cells and pro-inflammatory cytokines. Future research should focus on clinical validation of these findings to assess their translational potential and the exploration of immunomodulatory strategies informed by this model to mitigate MPP severity.