Serial Changes in Serum Eosinophil-associated Mediators between Atopic and Non-atopic Children after Mycoplasma pneumoniae pneumonia

PURPOSE Mycoplasma pneumoniae pneumonia (MP) is associated with the exacerbation, timing, and onset of asthma. The goal of this study was to elucidate the impact of MP on eosinophil-related hyper-reactive amplification in atopic children. METHODS We studied 48 patients with MP (26 atopic, 22 non-atopic), between 3 and 12 years of age. Serial changes in blood eosinophil counts, serum interleukin-5 (IL-5), and serum eosinophil cationic protein (ECP) levels were measured in atopic and non-atopic children with MP upon admission, recovery, and at 2 months post-recovery. Serum IL-5 and ECP levels were measured by enzyme-linked immunosorbent assays; eosinophil counts were measured using an autoanalyzer. RESULTS Serial changes in serum IL-5, ECP, and total eosinophil counts were significantly higher in atopic patients, relative to non-atopic controls (P≤0.001). Serum IL-5 and ECP levels were significantly higher in atopic patients at all three time points tested, while eosinophil counts were higher in the clinical recovery and follow-up phases, but not in the acute phase. Furthermore, among atopic patients, serum ECP levels were significantly higher in the recovery and follow-up phases than in the acute phase. CONCLUSIONS The present study demonstrated significant differences in eosinophil counts, serum IL-5, and serum ECP levels between atopic and non-atopic children with MP at admission, recovery, and 2 months after clinical recovery. These outcomes are suggestive of eosinophil-related hyperreactivity in atopic children, with this status maintained for at least 2 months after MP.