McQuillan Karen, Gargoum Fatma, Murphy Mark P, McElvaney Oliver J, McElvaney Noel G, Reeves Emer P
Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin, Ireland.
Front Pharmacol. 2020 Jul 17;11:1098. doi: 10.3389/fphar.2020.01098. eCollection 2020.
In people with cystic fibrosis (PWCF), inflammation with concurrent infection occurs from a young age and significantly influences lung disease progression. Studies indicate that neutrophils are important effector cells in the pathogenesis of CF and in the development of anti-neutrophil cytoplasmic autoantibodies (ANCA). ANCA specific for bactericidal permeability increasing protein (BPI-ANCA) are detected in people with CF, and correlate with infection with . The aim of this study was to determine the signaling mechanism leading to increased BPI release by CF neutrophils, while identifying IgG class BPI-ANCA in CF airways samples as the cause for impaired antimicrobial activity of BPI against Plasma and/or bronchoalveolar lavage fluid (BAL) was collected from PWCF (n = 40), CF receiving ivacaftor therapy (n = 10), non-CF patient cohorts (n = 7) and healthy controls (n = 38). Plasma and BAL BPI and BPI-ANCA were measured by ELISA and GTP-bound Rac2 detected using an assay. The antibacterial effect of all treatments tested was determined by colony forming units enumeration. Levels of BPI are significantly increased in plasma (p = 0.007) and BALF (p < 0.0001) of PWCF. The signaling mechanism leading to increased degranulation and exocytosis of BPI by CF neutrophils (p = 0.02) involved enhancement of Rac2 GTP-loading (p = 0.03). The full-length BPI protein was detectable in all CF BAL samples and patients displayed ANCA with BPI specificity. IgG class autoantibodies were purified from CF BAL complexed to BPI (n=5), with IgG autoantibody cross-linking of antigen preventing BPI induced killing (p < 0.0001). Results indicate that the immune-mediated diminished antimicrobial defense, attributed to anti-BPI-IgG, necessitates the formation of a drug/immune complex intermediate that can maintain cytotoxic effects of BPI towards Gram-negative pathogens, with the potential to transform the current treatment of CF airways disease.
在囊性纤维化患者（PWCF）中，炎症并发感染在年轻时就会发生，并显著影响肺部疾病的进展。研究表明，中性粒细胞是囊性纤维化发病机制以及抗中性粒细胞胞浆自身抗体（ANCA）形成过程中的重要效应细胞。在囊性纤维化患者中可检测到针对杀菌通透性增加蛋白的ANCA（BPI-ANCA），且其与 感染相关。本研究的目的是确定导致囊性纤维化中性粒细胞释放BPI增加的信号传导机制，同时确定囊性纤维化气道样本中的IgG类BPI-ANCA是BPI对 抗菌活性受损的原因。从PWCF（n = 40）、接受依伐卡托治疗的囊性纤维化患者（n = 10）、非囊性纤维化患者队列（n = 7）和健康对照者（n = 38）中采集血浆和/或支气管肺泡灌洗液（BAL）。通过ELISA法检测血浆和BAL中的BPI和BPI-ANCA，并使用 检测法检测结合GTP的Rac2。通过菌落形成单位计数来确定所有测试治疗的抗菌效果。PWCF患者血浆（p = 0.007）和BALF（p < 0.0001）中BPI水平显著升高。导致囊性纤维化中性粒细胞BPI脱颗粒和胞吐增加的信号传导机制（p = 0.02）涉及Rac2 GTP负载增强（p = 0.03）。在所有囊性纤维化BAL样本中均可检测到全长BPI蛋白，且患者表现出具有BPI特异性的ANCA。从与BPI复合的囊性纤维化BAL中纯化出IgG类自身抗体（n = 5），抗原的IgG自身抗体交联可阻止BPI诱导的 杀伤（p < 0.0001）。结果表明，归因于抗BPI-IgG的免疫介导的抗菌防御减弱需要形成一种药物/免疫复合物中间体，该中间体可维持BPI对革兰氏阴性病原体的细胞毒性作用，有可能改变目前对囊性纤维化气道疾病的治疗方法。
