Bradley W. Richmond

Oral antimycobacterial therapy in chronic cutaneous sarcoidosis: a randomized, single-masked, placebo-controlled study.

IMPORTANCE Sarcoidosis is a chronic granulomatous disease for which there are limited therapeutic options. This is the first randomized, placebo-controlled study to demonstrate that antimycobacterial therapy reduces lesion diameter and disease severity among patients with chronic cutaneous sarcoidosis. OBJECTIVE To evaluate the safety and efficacy of once-daily antimycobacterial therapy on the resolution of chronic cutaneous sarcoidosis lesions. DESIGN AND PARTICIPANTS A randomized, placebo-controlled, single-masked trial on 30 patients with symptomatic chronic cutaneous sarcoidosis lesions deemed to require therapeutic intervention. SETTING A tertiary referral dermatology center in Nashville, Tennessee. INTERVENTIONS Participants were randomized to receive either the oral concomitant levofloxacin, ethambutol, azithromycin, and rifampin (CLEAR) regimen or a comparative placebo regimen for 8 weeks with a 180-day follow-up. MAIN OUTCOMES AND MEASURES Participants were monitored for absolute change in lesion diameter and decrease in granuloma burden, if present, on completion of therapy. OBSERVATIONS In the intention-to-treat analysis, the CLEAR-treated group had a mean (SD) decrease in lesion diameter of -8.4 (14.0) mm compared with an increase of 0.07 (3.2) mm in the placebo-treated group (P = .05). The CLEAR group had a significant reduction in granuloma burden and experienced a mean (SD) decline of -2.9 (2.5) mm in lesion severity compared with a decline of -0.6 (2.1) mm in the placebo group (P = .02). CONCLUSIONS AND RELEVANCE Antimycobacterial therapy may result in significant reductions in chronic cutaneous sarcoidosis lesion diameter compared with placebo. These observed reductions, associated with a clinically significant improvement in symptoms, were present at the 180-day follow-up period. Transcriptome analysis of sarcoidosis CD4+ T cells revealed reversal of pathways associated with disease severity and enhanced T-cell function following T-cell receptor stimulation. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01074554.

Reversal of Global CD4+ Subset Dysfunction Is Associated with Spontaneous Clinical Resolution of Pulmonary Sarcoidosis

Sarcoidosis pathogenesis is characterized by peripheral anergy and an exaggerated, pulmonary CD4+ Th1 response. In this study, we demonstrate that CD4+ anergic responses to polyclonal TCR stimulation are present peripherally and within the lungs of sarcoid patients. Consistent with prior observations, spontaneous release of IL-2 was noted in sarcoidosis bronchoalveolar lavage CD4+ T cells. However, in contrast to spontaneous hyperactive responses reported previously, the cells displayed anergic responses to polyclonal TCR stimulation. The anergic responses correlated with diminished expression of the Src kinase Lck, protein kinase C-θ, and NF-κB, key mediators of IL-2 transcription. Although T regulatory (Treg) cells were increased in sarcoid patients, Treg depletion from the CD4+ T cell population of sarcoidosis patients did not rescue IL-2 and IFN-γ production, whereas restoration of the IL-2 signaling cascade, via protein kinase C-θ overexpression, did. Furthermore, sarcoidosis Treg cells displayed poor suppressive capacity indicating that T cell dysfunction was a global CD4+ manifestation. Analyses of patients with spontaneous clinical resolution revealed that restoration of CD4+ Th1 and Treg cell function was associated with resolution. Conversely, disease progression exhibited decreased Th1 cytokine secretion and proliferative capacity, and reduced Lck expression. These findings implicate normalized CD4+ T cell function as a potential therapeutic target for sarcoidosis resolution.

Sarcoidosis Th17 Cells are ESAT-6 Antigen Specific but Demonstrate Reduced IFN-γ Expression

RationaleSarcoidosis is a granulomatous disease of unknown etiology. Many patients with sarcoidosis demonstrate antigen-specific immunity to mycobacterial virulence factors. Th-17 cells are crucial to the immune response in granulomatous inflammation, and have recently been shown to be present in greater numbers in the peripheral blood and bronchoalveolar lavage (BAL) fluid (BALF) of sarcoidosis patients than healthy controls. It is unclear whether Th-17 cells in sarcoidosis are specific for mycobacterial antigens, or whether they have similar functionality to control Th-17 cells.MethodsFlow cytometry was used to determine the numbers of Th-17 cells present in the peripheral blood and BALF of patients with sarcoidosis, the percentage of Th-17 cells that were specific to the mycobacterial virulence factor ESAT-6, and as well as to assess IFN-γ expression in Th-17 cells following polyclonal stimulation.ResultsPatients with sarcoidosis had greater numbers of Th-17 cells in the peripheral blood and BALF than controls and produced significantly more extracellular IL-17A (p = 0.03 and p = 0.02, respectively). ESAT-6 specific Th-17 cells were present in both peripheral blood and BALF of sarcoidosis patients (p < 0.001 and p = 0.03, respectively). After polyclonal stimulation, Th-17 cells from sarcoidosis patients produced less IFN-γ than healthy controls.ConclusionsPatients with sarcoidosis have mycobacterial antigen-specific Th-17 cells peripherally and in sites of active sarcoidosis involvement. Despite the Th1 immunophenotype of sarcoidosis immunology, the Th-17 cells have reduced IFN-γ expression, compared to healthy controls. This reduction in immunity may contribute to sarcoidosis pathogenesis.

Airway bacteria drive a progressive COPD-like phenotype in mice with polymeric immunoglobulin receptor deficiency

Mechanisms driving persistent airway inflammation in chronic obstructive pulmonary disease (COPD) are incompletely understood. As secretory immunoglobulin A (SIgA) deficiency in small airways has been reported in COPD patients, we hypothesized that immunobarrier dysfunction resulting from reduced SIgA contributes to chronic airway inflammation and disease progression. Here we show that polymeric immunoglobulin receptor-deficient (pIgR−/−) mice, which lack SIgA, spontaneously develop COPD-like pathology as they age. Progressive airway wall remodelling and emphysema in pIgR−/− mice are associated with an altered lung microbiome, bacterial invasion of the airway epithelium, NF-κB activation, leukocyte infiltration and increased expression of matrix metalloproteinase-12 and neutrophil elastase. Re-derivation of pIgR−/− mice in germ-free conditions or treatment with the anti-inflammatory phosphodiesterase-4 inhibitor roflumilast prevents COPD-like lung inflammation and remodelling. These findings show that pIgR/SIgA deficiency in the airways leads to persistent activation of innate immune responses to resident lung microbiota, driving progressive small airway remodelling and emphysema.

Randomized Trial of Video Laryngoscopy for Endotracheal Intubation of Critically Ill Adults.

Objective:To evaluate the effect of video laryngoscopy on the rate of endotracheal intubation on first laryngoscopy attempt among critically ill adults. Design:A randomized, parallel-group, pragmatic trial of video compared with direct laryngoscopy for 150 adults undergoing endotracheal intubation by Pulmonary and Critical Care Medicine fellows. Setting:Medical ICU in a tertiary, academic medical center. Patients:Critically ill patients 18 years old or older. Interventions:Patients were randomized 1:1 to video or direct laryngoscopy for the first attempt at endotracheal intubation. Measurements and Main Results:Patients assigned to video (n = 74) and direct (n = 76) laryngoscopy were similar at baseline. Despite better glottic visualization with video laryngoscopy, there was no difference in the primary outcome of intubation on the first laryngoscopy attempt (video 68.9% vs direct 65.8%; p = 0.68) in unadjusted analyses or after adjustment for the operator’s previous experience with the assigned device (odds ratio for video laryngoscopy on intubation on first attempt 2.02; 95% CI, 0.82–5.02, p = 0.12). Secondary outcomes of time to intubation, lowest arterial oxygen saturation, complications, and in-hospital mortality were not different between video and direct laryngoscopy. Conclusions:In critically ill adults undergoing endotracheal intubation, video laryngoscopy improves glottic visualization but does not appear to increase procedural success or decrease complications.

Vitamin D, innate immunity, and sarcoidosis granulomatous inflammation: insights from mycobacterial research.

Purpose of review Recent discoveries cast doubt on granuloma formation solely as a protective mechanism, and highlight the importance of innate immunity of the host response to pathogenic mycobacteria. Here, we briefly review evidence that mycobacterial antigens are involved in sarcoidosis pathogenesis, and explore how defects in innate immunity might contribute to the disease. Recent findings Patients with sarcoidosis demonstrate antigen-specific immune responses against mycobacterial virulence factors systemically and at sites of active involvement. Recent studies have shown the vitamin D-regulated, antimicrobial peptide cathelicidin to be important to the immune response against pathogenic mycobacteria. Given mounting evidence that mycobacterial antigens are involved in sarcoidosis pathogenesis, cathelicidin could play a role in sarcoidosis pathogenesis. Summary Granuloma formation is not an inevitable consequence of infection with mycobacteria. Little is known about why some individuals overcome infection by mycobacteria, whereas others develop chronic infection with granuloma formation. Here, we propose that granuloma formation might result from defects in innate immunity that prevent successful eradication of the inciting agent. Given that mycobacterial antigens have been shown to contribute to sarcoidosis pathogenesis, further research should investigate whether defects in the innate immune response to mycobacterial antigens contribute to this enigmatic disease.

p52 Overexpression Increases Epithelial Apoptosis, Enhances Lung Injury, and Reduces Survival after Lipopolysaccharide Treatment

Although numerous studies have demonstrated a critical role for canonical NF-κB signaling in inflammation and disease, the function of the noncanonical NF-κB pathway remains ill-defined. In lung tissue from patients with acute respiratory distress syndrome, we identified increased expression of the noncanonical pathway component p100/p52. To investigate the effects of p52 expression in vivo, we generated a novel transgenic mouse model with inducible expression of p52 in Clara cell secretory protein–expressing airway epithelial cells. Although p52 overexpression alone did not cause significant inflammation, p52 overexpression caused increased lung inflammation, injury, and mortality following intratracheal delivery of Escherichia coli LPS. No differences in cytokine/chemokine expression were measured between p52-overexpressing mice and controls, but increased apoptosis of Clara cell secretory protein–positive airway epithelial cells was observed in transgenic mice after LPS stimulation. In vitro studies in lung epithelial cells showed that p52 overexpression reduced cell survival and increased the expression of several proapoptotic genes during cellular stress. Collectively, these studies demonstrate a novel role for p52 in cell survival/apoptosis of airway epithelial cells and implicate noncanonical NF-κB signaling in the pathogenesis of acute respiratory distress syndrome.

Secretory IgA Deficiency in Individual Small Airways Is Associated with Persistent Inflammation and Remodeling

Rationale: Maintenance of a surface immune barrier is important for homeostasis in organs with mucosal surfaces that interface with the external environment; however, the role of the mucosal immune system in chronic lung diseases is incompletely understood. Objectives: We examined the relationship between secretory IgA (SIgA) on the mucosal surface of small airways and parameters of inflammation and airway wall remodeling in chronic obstructive pulmonary disease (COPD). Methods: We studied 1,104 small airways (<2 mm in diameter) from 50 former smokers with COPD and 39 control subjects. Small airways were identified on serial tissue sections and examined for epithelial morphology, SIgA, bacterial DNA, nuclear factor‐&kgr;B activation, neutrophil and macrophage infiltration, and airway wall thickness. Measurements and Main Results: Morphometric evaluation of small airways revealed increased mean airway wall thickness and inflammatory cell counts in lungs from patients with COPD compared with control subjects, whereas SIgA level on the mucosal surface was decreased. However, when small airways were classified as SIgA intact or SIgA deficient, we found that pathologic changes were localized almost exclusively to SIgA‐deficient airways, regardless of study group. SIgA‐deficient airways were characterized by (1) abnormal epithelial morphology, (2) invasion of bacteria across the apical epithelial barrier, (3) nuclear factor‐&kgr;B activation, (4) accumulation of macrophages and neutrophils, and (5) fibrotic remodeling of the airway wall. Conclusions: Our findings support the concept that localized, acquired SIgA deficiency in individual small airways of patients with COPD allows colonizing bacteria to cross the epithelial barrier and drive persistent inflammation and airway wall remodeling, even after smoking cessation.

Bacterial-derived Neutrophilic Inflammation Drives Lung Remodeling in a Mouse Model of Chronic Obstructive Pulmonary Disease

Abstract Loss of secretory IgA is common in the small airways of patients with chronic obstructive pulmonary disease and may contribute to disease pathogenesis. Using mice that lack secretory IgA in the airways due to genetic deficiency of polymeric Ig receptor (pIgR−/− mice), we investigated the role of neutrophils in driving the fibrotic small airway wall remodeling and emphysema that develops spontaneously in these mice. By flow cytometry, we found an increase in the percentage of neutrophils among CD45+ cells in the lungs, as well as an increase in total neutrophils, in pIgR−/− mice compared with wild‐type controls. This increase in neutrophils in pIgR−/− mice was associated with elastin degradation in the alveolar compartment and around small airways, along with increased collagen deposition in small airway walls. Neutrophil depletion using anti‐Ly6G antibodies or treatment with broad‐spectrum antibiotics inhibited development of both emphysema and small airway remodeling, suggesting that airway bacteria provide the stimulus for deleterious neutrophilic inflammation in this model. Exogenous bacterial challenge using lysates prepared from pathogenic and nonpathogenic bacteria worsened neutrophilic inflammation and lung remodeling in pIgR−/− mice. This phenotype was abrogated by antiinflammatory therapy with roflumilast. Together, these studies support the concept that disruption of the mucosal immune barrier in small airways contributes to chronic obstructive pulmonary disease progression by allowing bacteria to stimulate chronic neutrophilic inflammation, which, in turn, drives progressive airway wall fibrosis and emphysematous changes in the lung parenchyma.

Lung Dendritic Cells Drive NK Cytotoxicity in Chronic Obstructive Pulmonary Disease via IL-15Rα

Rationale: Lung natural killer cells (NKs) kill a greater percentage of autologous lung parenchymal cells in chronic obstructive pulmonary disease (COPD) than in nonobstructed smokers. To become cytotoxic, NKs require priming, typically by dendritic cells (DCs), but whether priming occurs in the lungs in COPD is unknown. Methods: We used lung tissue and in some cases peripheral blood from patients undergoing clinically indicated resections to determine in vitro killing of CD326+ lung epithelial cells by isolated lung CD56+ NKs. We also measured the cytotoxicity of unprimed blood NKs after preincubation with lung DCs. To investigate mechanisms of DC‐mediated priming, we used murine models of COPD induced by cigarette smoke (CS) exposure or by polymeric immunoglobulin receptor (pIgR) deficiency, and blocked IL‐15R&agr; (IL‐15 receptor &agr; subunit) trans‐presentation by genetic and antibody approaches. Results: Human lung NKs killed isolated autologous lung epithelial cells; cytotoxicity was increased (P = 0.0001) in COPD, relative to smokers without obstruction. Similarly, increased lung NK cytotoxicity compared with control subjects was observed in CS‐exposed mice and pIgR−/− mice. Blood NKs both from smokers without obstruction and subjects with COPD showed minimal epithelial cell killing, but in COPD, preincubation with lung DCs increased cytotoxicity. NKs were primed by CS‐exposed murine DCs in vitro and in vivo. Inhibiting IL‐15R&agr; trans‐presentation eliminated NK priming both by murine CS‐exposed DCs and by lung DCs from subjects with COPD. Conclusions: Heightened NK cytotoxicity against lung epithelial cells in COPD results primarily from lung DC‐mediated priming via IL‐15 trans‐presentation on IL‐15R&agr;. Future studies are required to test whether increased NK cytotoxicity contributes to COPD pathogenesis.