1131 Dominance of Th1-response in children with refractory mycoplasma pneumoniae pneumonia

Wednesday, 14 October 2015
Hall D1 Foyer (Floor 3) (Coex Convention Center)

Jun Bao, MD , Pediatric Respirology, Xinhua Hospital, Shanghai, China

Yi-Xiao Bao, MD , Xinhua Hospital, Shanghai, China

Background To investigate DNA copy numbers of Mycoplasma pneumoniae and expressions of helper T (Th) cell producing cytokines in bronchoalveolar lavage fluid (BALF) from children with refractory MP pneumonia (MPP).

Methods Of the 90 enrolled children with MPP, 30 cases were assigned as refractory MPP who failed to respond to at least 1-week treatment with macrolide antibiotics, while the other 60 cases were common MPP. A total of 30 children with congenital bronchial atresia or stenosis were included as controls. ELISA was used to assess BALF levels of IFN-γ, IL-4, IL-8 and TNF-α. RT-PCR was used to determine MP-DNA copy numbers in BALF.

ResultsCompared with the common MPP group, the refractory MPP group had a significantly higher MP-DNA copy number (3715352 ± 3162 vs. 2570 ± 5495; /ml; P<0.01). Children with refractory MPP achieved significantly increased BALF levels of IFN-γ, IL-8 and TNF-α than those with common MPP and the controls (40.55 ± 22.03 vs. 29.71 ± 11.18 vs. 27.54 ± 9.80; 213.58 ± 80.05 vs. 169.83 ± 83.56 vs. 79.50 ± 55.47; 240.90 ± 68.33 vs. 121.85 ± 63.15 vs. 101.33 ± 42.56; pg/ml; P<0.01). No significant difference in BALF levels of IL-4 was found among the three groups (23.00 ± 11.24 vs. 21.96 ± 11.94 vs. 17.61 ± 10.55; pg/ml; P>0.05).

Conclusion Refractory MPP may be associated with high MP load. Th1 mediated response may be dominant in the development of refractory MPP.