Role of the Mycoplasma pneumoniae/Interleukin-8/Neutrophil Axis in the Pathogenesis of Pneumonia

Abstract

Neutrophil infiltration is the characteristic pathological feature of M. pneumoniae pneumonia (MPP). This study aimed to explore the associations among neutrophil activity, clinical presentation, and role of the M. pneumoniae/interleukin-8 (IL-8)/neutrophil axis in the pathogenesis of MPP. A total of 42 patients with MPP were prospectively enrolled in the study. Neutrophil activity, including matrix metalloproteinase-9 (MMP-9), myeloperoxidase (MPO), and neutrophil elastase (NE), were measured. Clinical information was collected for all patients and control group. In vitro, IL-8 production was measured at different time points after M. pneumoniae infection of bronchial epithelial cells, and neutrophil activity was analyzed after IL-8 stimulation. The percentage of neutrophil in the bronchoalveolar lavage fluid was higher in the group of patients with high levels of M. pneumoniae DNA than in those with low levels of M. pneumoniae DNA (P < 0.05). IL-8, MMP-9, and NE in patients with MPP significantly increased compared with controls and decreased after treatment (P < 0.05). MPO and MMP-9 were associated with duration of fever (r = 0.332, P < 0.05) and length of stay (r = 0.342, P < 0.05), respectively. In vitro, M. pneumoniae induced IL-8 production by bronchial epithelial cells in a time dependent manner. MPO, MMP-9 and NE production by neutrophils significantly increased compared with medium controls after IL-8 stimulation. In summary, the M. pneumoniae/IL-8/neutrophil axis likely plays a vital role in the pathogenesis of MPP.

Differences in inflammatory marker patterns for adult community‐acquired pneumonia patients induced by different pathogens

“…It may tell us that PDGF-BB has to be at an optimal concentration to have its effects on wound healing. 30,31 This may partly explain our results. IL-17A is regarded as pro-inflammatory cytokine and mainly expressed by Th17 cells.…”

“…Neutrophils are the main source of BPI and researches have demonstrated its vital role to protect the host against bacteria and MP infection. 30,31 This may partly explain our results.…”

Inflammatory Responses Regulating Alveolar Ion Transport during Pulmonary Infections

“…Interleukin-8 is a chemotactic factor that correlates with neutrophil accumulation in distal airspaces of patients with ARDS and is a predictor of mortality (48)(49)(50). IL-8 is secreted by bronchial epithelial cells and can be induced by Mycoplasma pneumoniae antigen or live M. pneumoniae (51) as well as by severe acute respiratory syndrome coronavirus spike protein or respiratory syncytial virus infection (52,53). The rate of AFC is impaired by high levels of IL-8 and is significantly lower in patients who have a pulmonary edema fluid concentration of IL-8 above 4,000 pg/ml (54).…”

Mpn491, a secreted nuclease ofMycoplasma pneumoniae, plays a critical role in evading killing by neutrophil extracellular traps

“…Among the cytokines, IL‐8 is a key mediator in the recruitment and activation of neutrophils. It has been shown that patients with M. pneumoniae pneumonia exhibit increased levels of IL‐8 in their bronchoalveolar lavage fluids (BALFs) as well as an increase of alveolar infiltration with neutrophils (Narita et al, ; Saraya et al, ; Chen et al, ).…”