RESUMEN
Objective To investigate the triggering receptor expressed on myeloid cells-1(TREM-1) of cord blood leukocytes in neonates and the transcription level of mRNA, and analyze its promoting function of inflammatory cytokine secretion. Methods During the period from September 2013 to March 2014, cord blood was collected from 20 term neonates at the time of birth, and peripheral blood was collected from 20 healthy adults. The expression of TREM-1 and TREM-1 mRNA on leukocytes was observed using flow cytometry and real-time reverse transeription-polymerase chain reaction, respectively. After the whole cord blood was stimulated by lipopolysaccharide (LPS) or LP17 plus LPS, the contents of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), IL-8 and soluble TREM-1 (sTREM-1) in the supernatant were analyzed by enzyme linked immunosorbent assay. The statistical significance was determined using the one-way ANOVA test, t test, q test and Pearson correlation coefficient. Results The mean fluorescence intensity of TREM-1 on leukocytes of newborns was not different compared with healthy adults (P>0.05), while the percentage of TREM-1 positive on polymorphonuclear cells was lower than that of healthy adults [(82.3±7.1)% vs (98.6±4.8)%, P<0.05]. The level of TREM-1 mRNA in newborns was lower than in healthy adults (1.16±0.13 vs 1.63±0.24, t=7.714, P<0.01). The LPS treatment significantly increased sTREM-1 in newborn whole blood compared with the control treatment [(156.7±36.3) vs (34.6±6.1) pg/ml, t=13.623, P<0.01]. The concentration of IL-6, TNF-αand IL-8 decreased significantly when TREM-1 was blocked by LP17. In addition, the concentration of sTREM-1 showed a positive correlation with the levels of TNF-α(r=0.519, P<0.05), IL-6 (r=0.507, P<0.05) and IL-8 (r=0.538, P<0.05). Conclusions Healthy newborns exhibit expression of TREM-1 on monocytes similar to healthy adults, and most PMNs express TREM-1 at the newborn stage. Blocking the TREM-1 signal transduction pathway may reduce inflammatory responses of neonate leukocytes.