Profile of proinflammatory cytokines in children with Mycoplasma pneumoniae pneumonia

Background: To explore the profile and clinical significance of proinflammatory cytokines in serum and bronchoalveolar lavage fluid (BALF) of children with Mycoplasma pneumoniae pneumonia(MPP) and to elucidate the etiology and pathogenesis of severe MPP (SMPP). Methods: A cohort of 108 children with MPP was divided into SMPP (n=56) and non-severe MPP (NSMPP) (n=52). A total of 40 cases of hospitalized children, who underwent elective surgery, were selected as control group. The levels of proinflammatory cytokines in the serum and BALF were measured by ELISA(Enzyme-linked immunosorbent assay). Results: Compared to the control group, the MPP children showed that the levels of peripheral blood (PB) TNF-a, IFN-g, GM-CSF, IL-17, IL-18, IL-36a, sB7-H1, and sB7-H3 were much higher at the acute phase (P<0.05). Also, they were significantly higher in the SMPP group than that in the NSMPP group (P<0.05). Furthermore, in the SMPP group, the levels of TNF-a, IFN-g, GM-CSF, IL-1b, IL-2, IL-8, IL-36, MPO, MMP-9, NE, sB7-H3 in BALF were significantly higher at acute phase as compared to the control group (P<0.05). sB7-H3 was positively correlated with major proinflammatory cytokines in both PB and BALF specimens. The level of sB7-H3 in PB was >8000 pg/mL was an independent risk factor for SMPP. Conclusions: Excessive inflammation plays a critical role in the occurrence and development of MPP, especially SMPP, and sB7-H3 is an independent risk factor of SMPP.