Clinical and laboratory profiles of refractory Mycoplasma pneumoniae pneumonia in children

Summary Objectives The purpose of this study was to explore the clinical and laboratory characteristics of children with refractory Mycoplasma pneumoniae pneumonia (RMPP). Methods Seventy-six children with RMPP and 26 children with non-refractory M. pneumoniae pneumonia (NRMPP), confirmed by both serology and fluorescent quantitation PCR in bronchoalveolar lavage fluid (BALF), were evaluated retrospectively. Results Compared to those with NRMPP, children with RMPP were older (66.6±39.0 vs. 48.4±35.4 months, p =0.038) and had a longer duration of fever (12.7±2.6 vs. 7.5±1.8 days) and hospital stay (12.1±3.2 vs. 7.4±2.9 days). Children with RMPP presented neutrophil infiltration both in serum and BALF, as well as severe pulmonary lesions with pleural effusion. Children with RMPP had a significantly higher M. pneumoniae DNA load in BALF compared to NRMPP patients, and the M. pneumoniae load in BALF was significantly correlated with neutrophils and inversely correlated with macrophages for both the NRMPP and RMPP groups. The serum concentrations of tumor necrosis factor alpha (median 114.5 pg/ml, range 49.1–897.9 pg/ml) and interferon gamma (median 376.9 pg/ml, range 221.4–1997.6 pg/ml) were significantly higher in children with RMPP compared to children with NRMPP. Conclusions This study indicates that a direct microbe effect and the subsequent induced excessive host immune response contribute in part to the progression of RMPP.