Clinical significance of serum Toll-like receptor 4/Myeloid differentiation factor 88 and D-dimer level detection in children with serious Mycoplasma pneumoniae pneumonia

Abstract

Objective To explore the clinical significance of serum Toll-like receptor 4(TLR4)/Myeloid differentiation factor 88(MyD88) and D-dimer level detection in children with serious Mycoplasma pneumoniae pneumonia(MPP). Methods Ninety cases of MPP hospitalized children from June 2015 to December 2016 at Affiliated Hospital of Xuzhou Medical College were divided into serious MPP group (42 cases) and mild MPP group (48 cases) according to the severity of their illness.The level of serum D-dimer was detected by immune turbidimetry, and the expressions of TLR4, MyD88 and nuclear factor-κB(NF-κB) were detected by Western blot. Results (1)The level of D-dimer [(1 850.12±153.50) μg/L vs.(297.36±27.42) μg/L], white blood counts (WBC)[(11.52±0.38)×109/L vs.(7.98±0.62)×109/L], neutrophile granulocyte ratio (N)(0.87±0.01 vs.0.55±0.01), C-reactive protein (CRP)[(64.59±7.93) mg/L vs.(19.79±6.38) mg/L], as well as erythrocyte sedimentation rate (ESR)[(52.13±1.8) mm/1 h vs.(22.78±1.43) mm/1 h]in the serious MPP group were higher than those in the mild MPP group, and the differences were statistically significant (t=6.511, 3.342, 2.891, 8.075, 7.922, all P<0.05). (2)The expression of TLR4 (1.53±0.12 vs. 0.45±0.07), MyD88 (1.28±0.10 vs. 0.37±0.12) and NF-κB (1.49±0.16 vs. 0.53±0.10) in the serious MPP group were higher than those in the mild MPP group, and the differences were statistically significant (t=3.511, 7.614, 8.122, all P<0.05). (3)The D-dimer levels, TLR4, MyD88 and NF-κB of the cases who had the image feature of lung patchy shadow (46 cases), atelectasis (17 cases) and pleural effusion (29 cases), were obviously higher than those who had not, and the differences were statistically significant(all P<0.05). (4)The plasma D-dimer level[(2 984.19±138.43) μg/L vs.(640.48±78.89) μg/L]and expressions of TLR4(2.53±0.41 vs. 0.92±0.17), MyD88(2.18±0.12 vs. 0.57±0.06), NF-κB(2.47±0.16 vs. 0.89±0.15) in the cases with extrapulmonary complications (13 cases) were higher than those without extrapulmonary complications, and the differences were statistically significant (all P<0.01). Conclusion The expre-ssion of TLR4/MyD88 increased in consistent with the up-regulation of D-dimer level in children with serious MPP, which indicated that the TLR4/MyD88 signaling pathway may participate in the formation of hypercoagulable state of children with serious MPP. Key words: Mycoplasma pneumoniae pneumonia; D-dimer; Toll-like receptor 4; Myeloid differentiation factor 88