Elevated sputum interleukin-5 and submucosal eosinophilia in obese individuals with severe asthma.

RATIONALE: The relationship between airway inflammation and obesity in severe asthma is poorly understood. OBJECTIVES: We sought to determine the relationship between sputum mediator profiles and the distribution of eosinophilic inflammation and obesity in people with severe asthma. METHODS: Clinical parameters and eight mediators in sputum were assessed in 131 subjects with severe asthma from a single center categorized into lean, overweight, and obese groups defined by their body mass index. In an independent group of people with severe asthma (n = 45) and healthy control subjects (n = 19) eosinophilic inflammation was enumerated in bronchial submucosa, blood, and sputum and related to their body mass index. MEASUREMENTS AND MAIN RESULTS: Sputum IL-5 geometric mean (95% confidence interval) (pg/ml) was elevated in the obese (1.8 [1.2-2.6]) compared with overweight (1.1 [0.8-1.3]; P = 0.025) and lean (0.9 [0.6-1.2]; P = 0.018) subjects with asthma and was correlated with body mass index (r = 0.29; P < 0.001). There was no relationship among body mass index, the sputum cell count, or other sputum mediators. In the bronchoscopy group the submucosal eosinophil number in the subjects with asthma was correlated with body mass index (Spearman rank correlation, rs = 0.38; P = 0.013) and the median (interquartile range) number of submucosal eosinophils was increased in obese (19.4 [11.8-31.2]) (cells per square millimeter) versus lean subjects (8.2 [5.4-14.6]) (P = 0.006). There was no significant association between sputum or peripheral blood eosinophil counts and body mass index. CONCLUSIONS: Sputum IL-5 and submucosal eosinophils, but not sputum eosinophils, are elevated in obese people with severe asthma. Whether specific antieosinophilic therapy is beneficial, or improved diet and lifestyle in obese asthma has antiinflammatory effects beyond weight reduction, requires further study.

Evaluation of anti-TGF-beta2 antibody as a new postoperative anti-scarring agent in glaucoma surgery.

PURPOSE: Postoperative subconjunctival wound healing remains the commonest cause of late bleb failure after glaucoma filtration surgery. This study was undertaken to investigate whether the human monoclonal antibody that neutralizes transforming growth factor-beta2 (CAT-152; lerdelimumab) could be used as a postoperative agent to prevent scarring after glaucoma surgery and compared it with 5-fluorouracil (5-FU), to benchmark its potential clinical benefit. METHODS: In a randomized, controlled, masked-observer study, after modified glaucoma surgery, 48 rabbits were randomly allocated to receive a postoperative course of seven subconjunctival injections of CAT-152 (1 mg/mL), 5-FU (50 mg/mL), or no treatment. Bleb characteristics, the presence of subconjunctival drainage, and local reaction to treatment were assessed. Animals were killed on days 10, 21, and 30. Immunohistochemistry, histologic staining and electron microscopy were performed to demonstrate the mechanism of CAT-152-mediated effects on the extracellular matrix. RESULTS: CAT-152 significantly improved surgical outcome (log rank test, P < 0.001) and reduced subconjunctival collagen deposition (P < 0.01) compared with 5-FU and control. Median bleb survival was increased in the CAT-152 group (23.5 days) compared with the 5-FU (20 days) and control (16 days) treatment groups. CAT-152 treatment improved bleb morphology (P < 0.05) and was well tolerated. 5-FU prolonged the duration of corneal epitheliopathy (P < 0.01). CONCLUSIONS: Postoperative administration of CAT-152 significantly improved surgical outcome, reduced subconjunctival scarring, and minimized the risk of corneal side effects compared with the anti-scarring agent 5-FU. These findings suggest that CAT-152 may offer therapeutic benefit as a postoperative agent to prevent subconjunctival scarring after glaucoma filtration surgery.

A novel IgE-neutralizing antibody for the treatment of severe uncontrolled asthma.

The critical role played by IgE in allergic asthma is well-documented and clinically precedented, but some patients in whom IgE neutralization may still offer clinical benefit are excluded from treatment with the existing anti-IgE therapy, omalizumab, due to high total IgE levels or body mass. In this study, we sought to generate a novel high affinity anti-IgE antibody (MEDI4212) with potential to treat a broad severe asthma patient population. Analysis of body mass, total and allergen-specific IgE levels in a cohort of severe asthmatics was used to support the rationale for development of a high affinity IgE-targeted antibody therapeutic. Phage display technology was used to generate a human IgG1 lead antibody, MEDI4212, which was characterized in vitro using binding, signaling and functional assay systems. Protein crystallography was used to determine the details of the interaction between MEDI4212 and IgE. MEDI4212 bound human IgE with an affinity of 1.95 pM and was shown to target critical residues in the IgE Cε3 domain critical for interaction with FcεRI. MEDI4212 potently inhibited responses through FcεRI and also prevented the binding of IgE to CD23. When used ex vivo at identical concentration, MEDI4212 depleted free-IgE from human sera to levels ~1 log lower than omalizumab. Our results thus indicate that MEDI4212 is a novel, high affinity antibody that binds specifically to IgE and prevents IgE binding to its receptors. MEDI4212 effectively depleted free-IgE from human sera ex vivo to a level (1 IU/mL) anticipated to provide optimal IgE suppression in severe asthma patients.

Expression of the T helper 17-associated cytokines IL-17A and IL-17F in asthma and COPD.

BACKGROUND: Asthma and COPD are characterized by airway dysfunction and inflammation. Neutrophilic airway inflammation is a common feature of COPD and is recognized in asthma, particularly in severe disease. The T helper (Th) 17 cytokines IL-17A and IL-17F have been implicated in the development of neutrophilic airway inflammation, but their expression in asthma and COPD is uncertain. METHODS: We assessed IL-17A and IL-17F expression in the bronchial submucosa from 30 subjects with asthma, 10 ex-smokers with mild to moderate COPD, and 27 nonsmoking and 14 smoking control subjects. Sputum IL-17 concentration was measured in 165 subjects with asthma and 27 with COPD. RESULTS: The median (interquartile range) IL-17A cells/mm² submucosa was increased in mild to moderate asthma (2.1 [2.4]) compared with healthy control subjects (0.4 [2.8]) but not in severe asthma (P = .04). In COPD, IL-17A(+) cells/mm² submucosa were increased (0.5 [3.7]) compared with nonsmoking control subjects (0 [0]) but not compared with smoking control subjects (P = .046). IL-17F(+) cells/mm² submucosa were increased in severe asthma (2.7 [3.6]) and mild to moderate asthma (1.6 [1.0]) compared with healthy controls subjects (0.7 [1.4]) (P = .001) but was not increased in subjects with COPD. IL-17A and IL-17F were not associated with increased neutrophilic inflammation, but IL-17F was correlated with the submucosal eosinophil count (rs = 0.5, P = .005). The sputum IL-17 concentration in COPD was increased compared with asthma (2 [0-7] pg/mL vs 0 [0-2] pg/mL, P < .0001) and was correlated with post-bronchodilator FEV1% predicted (r = -0.5, P = .008) and FEV(1)/FVC (r = -0.4, P = .04). CONCLUSIONS: Our findings support a potential role for the Th17 cytokines IL-17A and IL-17F in asthma and COPD, but do not demonstrate a relationship with neutrophilic inflammation.

Short-term exposure to transforming growth factor beta induces long-term fibrotic responses.

Transforming growth factor beta (TGFbeta), a potent inducer of cell transdifferentiation, is heavily implicated in fibrotic disorders. Following cataract surgery, aberrant cell growth across the collagenous matrix of the lens capsule leads to fibrosis, and in turn secondary visual loss, known as posterior capsule opacification (PCO). These modifications are associated with transdifferentiated cells. Following surgery, protein levels in the eye transiently increase, lasting a matter of days whereas PCO takes much longer to reach clinical significance. In the present study, a human lens culture model was employed to show that a relatively brief 2-day exposure to TGFbeta gives rise to persistent, long-term signalling events resulting 28 days later in matrix contraction and transdifferentiation. These events can be suppressed by application of the human monoclonal anti-TGFbeta2 antibody CAT-152 either simultaneously or after TGFbeta2 exposure. Radiolabel binding studies revealed the lens capsule serves as a store for TGFbeta2. Importantly, similar binding studies showed that the capsule could also serve as a reservoir for CAT-152. The data reveal the longevity of TGFbeta2 action through matrix association, but also demonstrate how early application of a TGFbeta2 antibody can overcome the detrimental TGFbeta actions leading to potential inhibition of PCO development and other fibrotic disorders.

Measurement of eotaxin (CCL11) in induced sputum supernatants: validation and detection in asthma.

BACKGROUND: Induced sputum is widely used in asthma research; however, for many mediators, the detection methods have not been validated. OBJECTIVE: We sought to optimize the method of detection of eotaxin, an important chemokine acting through the CCR3 receptor on eosinophils, basophils, and T(H)2 cells. METHODS: Induced sputum from normal and asthmatic subjects was processed with dithioerythritol (DTE) or PBS; recovery of eotaxin was assessed by means of ELISA before and after spiking with recombinant eotaxin. Furthermore, the effects of removing DTE by means of ultrafiltration or the addition of protease inhibitors and high-speed centrifugation on endogenous levels and spiking recovery of eotaxin were assessed. RESULTS: Endogenous eotaxin was undetectable in DTE-processed samples, with a mean of only 30% (SD, 13%) spike recovery. DTE had no effect on the immunoassay capture antibody but dramatically reduced the detection of recombinant eotaxin. Removal of DTE from sputum before immunoassay did not improve detection, although it restored the recovery of a subsequent eotaxin spike. In contrast, PBS-processed sputum resulted in an eotaxin spike recovery of 101% (SD, 20%). Addition of protease inhibitors or high-speed centrifugation had no effect on eotaxin detection. By using this optimized protocol, eotaxin levels in PBS-processed sputum samples were found to be significantly increased in asthmatic sputum (P<.05). CONCLUSION: Measurement of eotaxin by means of immunoassay is adversely affected by DTE, possibly through irreversible denaturation of epitopes, which makes eotaxin undetectable by using the immunoassay antibody. Sputum samples should be processed into PBS for assessment of eotaxin, which is present at increased levels in asthmatic sputum.

Contribution of eotaxin-1 to eosinophil chemotactic activity of moderate and severe asthmatic sputum.

The CC chemokine eotaxin-1 (CCL11) is chemotactic for eosinophils, basophils, and type 2 helper T cells and may play a role in allergic inflammation. We investigated its contribution as an eosinophil chemoattractant in asthmatic airway secretions (sampled as induced sputum), which possess chemotactic activity for eosinophils and T cells. Sputum samples collected from healthy subjects and subjects with mild, stable-moderate, unstable-moderate, and severe asthma were processed with phosphate-buffered saline and assayed for eotaxin by ELISA and for eosinophil chemotactic activity by fluorescence-based chemotaxis assay. The contribution of eotaxin to chemotactic activity was studied by using a high-affinity neutralizing human anti-eotaxin antibody, CAT-213. Sputum eotaxin concentration was significantly raised in moderate and severe asthma (p < 0.05 versus healthy control subjects) but not in mild asthma. Chemotactic activity was significantly increased in all asthmatic groups relative to healthy subjects (p < 0.05) and was significantly inhibited by CAT-213 (100 nM) in subjects with moderate and severe asthma, with median inhibition of 52% (p < 0.05), 78% (p < 0.0001), and 86% (p < 0.0001), respectively, in samples representing stable-moderate, unstable-moderate, and severe asthma. Eotaxin contributed to the eosinophil chemotactic activity of sputum from subjects with more severe forms of asthma but not mild asthma, suggesting that its contribution is more important in more severe disease. This activity is inhibited significantly by CAT-213.