Predictive value of CCL26 and CCR3 levels for prognosis assessment in children with Mycoplasma pneumoniae pneumonia treated with azithromycin.

Background: Mycoplasma pneumoniae pneumonia (MPP), a prevalent form of community-acquired pneumonia (CAP) in schoolchildren, frequently results in persistent fever or complications in 15-25% of cases despite azithromycin treatment. This highlights the urgent need for novel biomarkers to identify high-risk cases. This study aims to investigate the predictive value of serum C-C motif chemokine ligand 26 (CCL26) and C-C chemokine receptor 3 (CCR3) levels for treatment prognosis in children with MPP receiving azithromycin therapy.

Methods: Clinical data of 205 pediatric MPP patients treated in our hospital from February 2023 to February 2025 were collected. Serum levels of CCL26, CCR3, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and D-dimer (DD) were measured by enzyme-linked immunosorbent assay (ELISA), while Mycoplasma pneumoniae (MP) antibody titers were determined using passive agglutination. Pearson correlation analysis evaluated relationships between CCL26 and CCR3 and inflammatory cytokines (IL-6, TNF-α). Logistic regression identified risk factors for poor prognosis, with receiver operating characteristic (ROC) curve analysis assessing the predictive value of CCL26 and CCR3.

Results: Compared with healthy controls, MPP patients showed elevated serum CCL26, CCR3 and inflammatory cytokines (TNF-α, IL-6) both pre- and post-treatment (all P<0.05). These markers significantly decreased after therapy (all P<0.05). Pretreatment CCL26 and CCR3 levels positively correlated with inflammatory cytokines (P<0.05). Poor prognosis cases exhibited higher levels of CCL26, CCR3, TNF-α, IL-6, C-reactive protein (CRP), DD, MP antibody titers (≥1:160), fever duration (≥5 d), and peak temperature (≥38.5 °C) (P<0.05). Multivariate analysis identified MP antibody titer ≥1:160, elevated CCL26, CCR3, TNF-α, and IL-6 levels, fever ≥5 days, and temperature ≥38.5 °C as independent risk factors. The area under the curve (AUC) for CCL26 and CCR3 in predicting poor prognosis was 0.709 and 0.751, respectively, increasing to 0.798 when combined.

Conclusions: Serum CCL26 and CCR3 levels decrease following azithromycin treatment and demonstrate significant associations with inflammatory markers and clinical outcomes, serving as reliable predictors for poor prognosis in MPP patients.