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Mycobacterium abscessus is a nontuberculous mycobacterium emerging as a significant pathogen for individuals with chronic lung disease, including cystic fibrosis and chronic obstructive pulmonary disease. Current therapeutics have poor efficacy. New strategies of bacterial control based on host defenses are appealing, but anti-mycobacterial immune mechanisms are poorly understood and are complicated by the appearance of smooth and rough morphotypes with distinct host responses. We explored the role of the complement system in the clearance of M. abscessus morphotypes by neutrophils, an abundant cell in these infections. M. abscessus opsonized with plasma from healthy individuals promoted greater killing by neutrophils compared to opsonization in heat-inactivated plasma. Rough clinical isolates were more resistant to complement but were still efficiently killed. Complement C3 associated strongly with the smooth morphotype while mannose-binding lectin 2 was associated with the rough morphotype. M. abscessus killing was dependent on C3, but not on C1q or Factor B; furthermore, competition of mannose-binding lectin 2 binding with mannan or N-acetyl-glucosamine during opsonization did not inhibit killing. These data suggest that M. abscessus does not canonically activate complement through the classical, alternative, or lectin pathways. Complement-mediated killing was dependent on IgG and IgM for smooth and on IgG for rough M. abscessus. Both morphotypes were recognized by Complement Receptor 3 (CD11b), but not CR1 (CD35), and in a carbohydrate- and calcium-dependent manner. These data suggest the smooth-to-rough adaptation changes complement recognition of M. abscessus and that complement is an important factor for M. abscessus infection.
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OBJECTIVE: Although the majority of cases of cystic fibrosis (CF) are now diagnosed through newborn screening, there is still a need to standardize the diagnostic criteria for those diagnosed outside of the neonatal period. This is because newborn screening started relatively recently, it is not performed everywhere, and even for individuals who were screened, there is the possibility of a false negative. To limit irreversible organ pathology, a timely diagnosis of CF and institution of CF therapies can greatly benefit these patients. STUDY DESIGN: Experts on CF diagnosis were convened at the 2015 CF Foundation Diagnosis Consensus Conference. The participants reviewed and discussed published works and instructive cases of CF diagnosis in individuals presenting with signs, symptoms, or a family history of CF. Through a modified Delphi methodology, several consensus statements were agreed upon. These consensus statements were updates of prior CF diagnosis conferences and recommendations. RESULTS: CF diagnosis in individuals outside of newborn screening relies on the clinical evidence and on evidence of CF transmembrane conductance regulator (CFTR) dysfunction. Clinical evidence can include typical organ pathologies seen in CF such as bronchiectasis or pancreatic insufficiency but often represent a broad range of severity including mild cases. CFTR dysfunction can be demonstrated using sweat chloride testing, CFTR molecular genetic analysis, or CFTR physiologic tests. On the basis of the large number of patients with bona fide CF currently followed in registries with sweat chloride levels between 30 and 40 mmol/L, the threshold considered "intermediate" was lowered from 40 mmol/L in the prior diagnostic guidelines to 30 mmol/L. The CF diagnosis was also discussed in the context of CFTR-related disorders in which CFTR dysfunction may be present, but the individual does not meet criteria for CF. CONCLUSIONS: CF diagnosis remains a rare but important condition that can be diagnosed when characteristic clinical features are seen in an individual with demonstrated CFTR dysfunction.
Assuntos
Fibrose Cística/diagnóstico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Testes Genéticos , Humanos , Recém-Nascido , Mutação , Triagem Neonatal , Guias de Prática Clínica como AssuntoRESUMO
BACKGROUND: Patients with cystic fibrosis (CF) exhibit a wide range of disease severity, and can be broadly stratified into high-risk and low-risk groups based on cystic fibrosis transmembrane conductance regulator (CFTR) mutation class. Patients with a low-risk genotype are often diagnosed as adults, with milder disease and lower sweat chloride values. The aim of the current study was to better understand radiographic and clinical characteristics of sinus disease in adult CF patients within this risk category. METHODS: Adult CF patients were retrospectively compared to a control group of patients with chronic rhinosinusitis. CF diagnostic testing and pulmonary characteristics were compared between high-risk and low-risk CF groups, and sinus CT findings were compared among all 3 groups. RESULTS: When comparing CF cohorts (n = 25 and 30, respectively), earlier age at diagnosis (p < 0.001), higher sweat chloride values (p < 0.001), lower forced expiratory volume in 1 second (FEV1 ) values (p < 0.001), and a higher prevalence of pulmonary infection with Pseudomonas aeruginosa (p = 0.001) were found in the high-risk genotype group. A significantly increased incidence of sinus hypoplasia/aplasia and bony sclerosis was seen when comparing both CF groups to the control cohort (n = 30), as well as when comparing the high-risk and low-risk CF genotype cohorts. CONCLUSION: The current study describes clinicopathologic findings of sinus disease in adult CF patients in the context of genotype severity. Our data demonstrate that while patients within a low-risk genotype cohort have generally milder lung disease, they retain classic radiographic findings of CF sinus disease that can help raise the index of suspicion for undiagnosed CF.
Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Mutação/genética , Adulto , Estudos de Casos e Controles , Cloretos/metabolismo , Doença Crônica , Fibrose Cística/diagnóstico por imagem , Feminino , Volume Expiratório Forçado/fisiologia , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Seios Paranasais/anormalidades , Seios Paranasais/diagnóstico por imagem , Infecções por Pseudomonas/complicações , Pseudomonas aeruginosa , Estudos Retrospectivos , Rinite/diagnóstico por imagem , Fatores de Risco , Sinusite/diagnóstico por imagem , Suor/química , Tomografia Computadorizada por Raios XRESUMO
OBJECTIVES: Circulating levels of the proinflammatory mediator High Mobility Group Box Protein 1 (HMGB1) are increased in septic patients and may contribute to sepsis-induced organ dysfunction. Although HMGB1 has been shown to activate neutrophils from healthy volunteers, the responses of neutrophils from septic patients to HMGB1 have not been reported. In the present study we evaluated gene expression and activation of major intracellular signaling pathways in peripheral blood neutrophils obtained from patients with sepsis-induced acute lung injury after culture with HMGB1 or LPS. DESIGN: Ex-vivo study performed in neutrophils from patients with sepsis-induced acute lung injury. SETTING: Immunology and genetics laboratory at an academic medical center. PATIENTS AND PARTICIPANTS: Twenty-two adult patients with sepsis-induced acute lung injury. MEASUREMENTS AND RESULTS: Using gene arrays, distinct patterns of gene expression were found in neutrophils from septic patients after stimulation with HMGB1 or LPS. While more than three-quarters of the genes upregulated by HMGB1 in neutrophils from septic patients also demonstrated increased expression after culture with LPS, the majority of genes affected by LPS did not show altered expression in neutrophils stimulated with HMGB1. Culture of neutrophils with HMGB1 induced downregulation of its own expression, a finding not present after exposure to LPS. Although HMGB1 and LPS both increased nuclear translocation of NF-kappaB, the magnitude of this effect was greater in LPS stimulated neutrophils from patients with sepsis-induced acute lung injury. CONCLUSION: These findings demonstrate that the patterns of gene expression differ between neutrophils from septic patients stimulated with HMGB1 or LPS, and also that neutrophils from septic patients are not anergic but instead demonstrate intact activation of NF-kappaB after exposure to LPS or HMGB1.