Atopy: a risk factor of refractory mycoplasma pneumoniae pneumonia?

ObjectiveTo investigate the relationship of pathogen DNA copies with clinic and laboratory features among children with Mycoplasma pneumoniae (MP) pneumonia. MethodsA total of 95 enrolled children with MP pneumonia were assigned into the high-MP-load group (>10(6)/mL) and the low-MP-load group (10(6)/mL) according to MP-DNA copies in bronchoalveolar lavage fluid (BALF). Clinical characteristics and any allergy history were collected. Aeroallergens and food allergens were detected with a skin test. Serum IgE and eosinophil cationic protein (ECP) were assessed using enzyme immunoassay. BALF levels of IL-4, IFN-, IL-8 and TNF- were assessed by ELISA. ResultsCompared with the low-MP-load group, 72.7% in the high-MP-load group developed refractory MP pneumonia who failed to respond to at least 1-week treatment with macrolides (72.7% vs 41.9%, P=0.005). More children in the high-load group than those in the low-load group presented with extrapulmonary manifestations, lung consolidation, pleural effusion and atopic conditions including any allergy history, positive findings of aeroallergen test and increased serum IgE and ECP (P<0.05). A significant higher BALF IL-4 level was seen in the high-load group versus the low-load group (23.0011.24 vs 14.68 +/- 7.12; pg/mL; P<0.01). There were no significant differences in BALF levels of IFN-, IL-8 and TNF- between the two groups (P>0.05). ConclusionAtopy may be a risk factor for the presence and severity of refractory MP pneumonia due to the high pathogen load in airway.