Changes of T Help Cell 17 and Interleukin-17 in Children With Mycoplasma Pneumoniae Infection and Its Clinical Significance

Objective To study the change and clinical significances of helper T cell (Th) 17 and interleukin (IL)-17 in children with Mycoplasma pneumoniae (MP) infection. Methods A total of 32 children with MP pneumonia (MPP) were recruited in the Department of Pediatrics of Nantong People's Hospital from June 2009 to December 2010. They were selected into MPP group with the average age of (9.3±2.5) years old. They were further divided into MPP sub-group 1 (symptom of pneumonia, n=18) and MPP sub-group 2 (symptom with lesion of exo-lung, n=14). At the same time, a total of 26 health children who underwent physical examination were selected into control group. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Panzhihua Second People's Hospital. Informed consent was obtained from each participate. The peripheral blood mononuclear cells were isolated, then frequency of Th17 were determined by flow cytometry (FACS). Serum contents of IL-17 were detected by enzyme linked immunosorbent assay (ELISA). Results ① The frequencies of Th17 cells of MP infection children in MPP sub-group 1 and MPP sub-group 2 were obviously higher than those in control group [(2.05±0.65)% vs. (1.21±0.36)%, (2.98±0.72)% vs. (1.21±0.36)%, P<0.01], the frequency of Th17 cells of MPP sub-group 2 was higher than that in MPP sub-group 1[(2.98±0.72)% vs. (2.05±0.65)%, P<0.01]. ② The serum levels of IL-17 in MP infection group were higher than those in control group [(11.62±5.37) pg/mL vs. (6.45±1.62) pg/mL, (17.34±7.45) pg/mL vs. (6.45±1.62) pg/mL, P<0.01], MPP sub-group 2 was higher than that in MPP sub-group 1[(11.62±5.37) pg/mL vs. (17.34±7.45) pg/mL, P<0.01]. Conclusions Abnormal frequencies of Th17 and IL-17 levels play a key role in the pathogenic mechanism of MP infection in children. Key words: Mpcoplasma pneumoniae; T help cell 17; interleukin-17