Changes and significance of TLR7/9 and IFN-Ⅰ levels in children with severe mycoplasma pneumoniae pneumonia

Abstract

Objective To investigate the changes and significance of Toll-like receptor 7 （TLR7）， TLR9 and type I interferon （IFN-Ⅰ） in children with severe mycoplasma pneumoniae pneumonia （SMPP）. Methods 80 children with mycoplasma pneumoniae pneumonia （MPP） were divided into the non-severe MPP （MPP group） and SMPP groups （SMPP group）. 26 healthy children who underwent outpatient physical examination were chosen as the control group. Serum samples in each group were collected. In the SMPP group， bronchoalveolar lavage fluid （BALF） on the affected and contralateral sides of 26 children with unilateral lung consolidation， atelectasis， lung abscess or lung tissue necrosis on imaging examination were collected. The levels of TLR7， TLR9， myeloid differentiation factor 88 （MyD88）， interferon-α （IFN-α） and IFN-β in the serum and BALF samples were determined by enzyme-linked immunosorbent assay （ELISA）. Results The serum levels of TLR7， TLR9， MyD88， IFN-α and IFN-β in the SMPP and MPP groups were significantly higher than those in the control group， and the levels of all cytokines in the SMPP group were significantly higher compared with those in the MPP group （all P < 0.05）. The levels of TLR7， TLR9， MyD88， IFN-α and IFN-β in the BALF on the affected side were significantly higher than those on the contralateral side （all P < 0.01）. The area under the receiver operating characteristic curve （AUC） of serum TLR7 and MyD88 levels for predicting SMPP was 0.709 and 0.723. Conclusions Over-induced and generated TLR7， TLR9， IFN-α and IFN-β may be pathogenic factors for the incidence of SMPP and severe local lung tissue injury in children with SMPP. TLR7 and MyD88 can be used as predictors of SMPP to guide clinical treatment.

Keywords

• |children|severe mycoplasma pneumoniae pneumonia|toll-like receptor 7|toll-like receptor 9|interferon-α|interferon-β