CD4+ T cells have a key instructive role in educating dendritic cells in allergy.

BACKGROUND: Dendritic cells (DCs) are central in allergy as regulators of the Th1/Th2 balance. We have recently demonstrated a unique transcriptional profile of DCs in patients with ongoing allergy compared with healthy subjects and shown that crosstalk between DCs and memory T cells affects the transcriptional profile of T cells. However, the transcriptional profile of DCs educated by T cells in allergy is unknown. METHODS: In the present study, we have examined the transcriptional profiles of DCs after stimulation with grass pollen allergens, Phleum pratense and coculture with autologous CD4+ memory T cells using high-density microarray. Protein analysis was performed using flow cytometry and recombinant antibody protein microarrays. Patients with allergic rhinitis and healthy subjects were compared. RESULTS: The results reveal a distinct T-cell-induced DC profile in atopic individuals. Accordingly, about 170 genes were upregulated and 40 genes downregulated. For example, the chemokine receptor CXCR4 and the tumor necrosis factor receptor CD30 were upregulated in DCs derived from atopic donors, and this could also be verified at the protein level. CONCLUSION: We conclude that crosstalk between CD4+ memory T cells and autologous DCs induces transcriptional reprogramming in DCs. This finding suggests that T cells have a key instructive role in educating DCs in Th2-type responses.

Effects of intranasal TNFalpha on granulocyte recruitment and activity in healthy subjects and patients with allergic rhinitis.

BACKGROUND: TNFalpha may contribute to the pathophysiology of airway inflammation. For example, we have recently shown that nasal administration of TNFalpha produces late phase co-appearance of granulocyte and plasma exudation markers on the mucosal surface. The objective of the present study was to examine indices of granulocyte presence and activity in response to intranasal TNFalpha challenge. METHODS: Healthy subjects and patients with allergic rhinitis (examined out of season) were subjected to nasal challenge with TNFalpha (10 microg) in a sham-controlled and crossover design. Nasal lavages were carried out prior to and 24 hours post challenge. Nasal biopsies were obtained post challenge. Nasal lavage fluid levels of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were analyzed as indices of neutrophil and eosinophil activity. Moreover, IL-8 and alpha2-macroglobulin were analyzed as markers of pro-inflammatory cytokine production and plasma exudation. Nasal biopsy numbers of neutrophils and eosinophils were monitored. RESULTS: Nasal lavage fluid levels of MPO recorded 24 hours post TNFalpha challenge were increased in healthy subjects (p = 0.0081) and in patients with allergic rhinitis (p = 0.0081) (c.f. sham challenge). Similarly, alpha2-macroglobulin was increased in healthy subjects (p = 0.014) and in patients with allergic rhinitis (p = 0.0034). Lavage fluid levels of ECP and IL-8 were not affected by TNFalpha challenge. TNFalpha increased the numbers of subepithelial neutrophils (p = 0.0021), but not the numbers of eosinophils. CONCLUSION: TNFalpha produces a nasal inflammatory response in humans that is characterised by late phase (i.e., 24 hours post challenge) neutrophil activity and plasma exudation.

The human IgE-encoding transcriptome to assess antibody repertoires and repertoire evolution.

Upon encounter with antigen, the B lymphocyte population responds by producing a diverse set of antigen-specific antibodies of various isotypes. The vast size of the responding populations makes it very difficult to study clonal evolution and repertoire composition occurring during these processes in humans. Here, we have explored an approach utilizing the H-EPSILON-encoding transcriptome to investigate aspects of repertoire diversity during the season of antigen exposure. We show through sequencing of randomly picked transcripts that the sizes of patients' repertoires are relatively small. This specific aspect of the transcriptome allows us to construct evolutionary trees pinpointing features of somatic hypermutation as it occurs in humans. Despite the small size of the repertoires, they are highly diverse with respect to VDJ gene usage, suggesting that the H-EPSILON-encoding transcriptome is a faithful mimic of other class-switched isotypes. Importantly, it is possible to use antibody library and selection technologies to define the specificity of clonotypes identified by random sequencing. The small size of the H-EPSILON-encoding transcriptome of peripheral blood B cells, the simple identification of clonally related sets of genes in this population, and the power of library and selection technologies ensure that this approach will allow us to investigate antibody evolution in human B lymphocytes of known specificity. As H-EPSILON repertoires show many of the hallmarks of repertoires encoding other isotypes, we suggest that studies of this type will have an impact on our understanding of human antibody evolution even beyond that occurring in the IgE-producing B cell population.

Antagonism of the prostaglandin D2 receptor CRTH2 attenuates asthma pathology in mouse eosinophilic airway inflammation.

BACKGROUND: Mast cell-derived prostaglandin D2 (PGD2), may contribute to eosinophilic inflammation and mucus production in allergic asthma. Chemoattractant receptor homologous molecule expressed on TH2 cells (CRTH2), a high affinity receptor for prostaglandin D2, mediates trafficking of TH2-cells, mast cells, and eosinophils to inflammatory sites, and has recently attracted interest as target for treatment of allergic airway diseases. The present study involving mice explores the specificity of CRTH2 antagonism of TM30089, which is structurally closely related to the dual TP/CRTH2 antagonist ramatroban, and compares the ability of ramatroban and TM30089 to inhibit asthma-like pathology. METHODS: Affinity for and antagonistic potency of TM30089 on many mouse receptors including thromboxane A2 receptor mTP, CRTH2 receptor, and selected anaphylatoxin and chemokines receptors were determined in recombinant expression systems in vitro. In vivo effects of TM30089 and ramatroban on tissue eosinophilia and mucus cell histopathology were examined in a mouse asthma model. RESULTS: TM30089, displayed high selectivity for and antagonistic potency on mouse CRTH2 but lacked affinity to TP and many other receptors including the related anaphylatoxin C3a and C5a receptors, selected chemokine receptors and the cyclooxygenase isoforms 1 and 2 which are all recognized players in allergic diseases. Furthermore, TM30089 and ramatroban, the latter used as a reference herein, similarly inhibited asthma pathology in vivo by reducing peribronchial eosinophilia and mucus cell hyperplasia. CONCLUSION: This is the first report to demonstrate anti-allergic efficacy in vivo of a highly selective small molecule CRTH2 antagonist. Our data suggest that CRTH2 antagonism alone is effective in mouse allergic airway inflammation even to the extent that this mechanism can explain the efficacy of ramatroban.

Effects of TNFalpha on the human nasal mucosa in vivo.

BACKGROUND: TNFalpha is a cytokine that may contribute to the pathophysiology of airway inflammation. Inhalation of TNFalpha produces granulocyte recruitment and airway hyperresponsiveness in man. Anti-TNFalpha treatment may inhibit allergen-induced plasma exudation in guinea-pig airways. Increased nasal mucosal output of TNFalpha has been demonstrated in allergic rhinitis, but the effect of TNFalpha on the human nasal mucosa has not been examined in vivo. OBJECTIVE: To examine effects of topical TNFalpha on the human nasal mucosa in vivo. METHODS: In a dose-finding study, healthy subjects received intranasal TNFalpha (0-7.5 microg). Nasal lavages were carried out before as well as 10 min and 24 h post challenge and alpha(2)-macroglobulin was measured as an index of plasma exudation. In a second study, involving patients with allergic rhinitis examined out of season, a sham-controlled nasal challenge with TNFalpha (10 microg) was performed and followed 24 h later by an allergen challenge. Lavages were performed before the TNFalpha challenge, 24 h thereafter, and 10 min post allergen challenge. alpha(2)-Macroglobulin, eosinophil cationic protein (ECP), myeloperoxidase (MPO), and IL-8 were analyzed as indices of plasma exudation, eosinophil activity, neutrophil activity, and pro-inflammatory cytokine production, respectively. RESULTS: In the dose-finding study, TNFalpha produced significant increases in alpha(2)-macroglobulin 24h post challenge (p<0.01). In allergic rhinitis, 10 microg of TNFalpha also produced this effect (p<0.01) as well as increases in ECP and IL-8 (p<0.01). MPO was increased 24 h post challenge, but this change did not reach statistical significance. TNFalpha did not produce any acute effects and did not affect the responsiveness to allergen. CONCLUSION: The present study demonstrates that topical TNFalpha produces a human nasal inflammatory response. These data suggest a role of TNFalpha in nasal conditions characterized by mucosal inflammation.

A single-arm, open-label, phase 2 clinical trial evaluating disease response following treatment with BI-505, a human anti-intercellular adhesion molecule-1 monoclonal antibody, in patients with smoldering multiple myeloma.

BACKGROUND: Smoldering multiple myeloma (SMM) is an indolent disease stage, considered to represent the transition phase from the premalignant MGUS (Monoclonal Gammopathy of Undetermined Significance) state towards symptomatic multiple myeloma (MM). Even though this diagnosis provides an opportunity for early intervention, few treatment studies have been done and the current standard of care is observation until progression. BI-505, a monoclonal antibody directed against intercellular adhesion molecule 1 (ICAM-1) with promising anti-myeloma activity in preclinical trials, is a possible treatment approach for this patient category with potential to eliminate tumor cells with minimal long-term side effects. BI-505 was well tolerated in an earlier phase 1 trial. METHODS AND FINDINGS: In this phase 2 trial the effects of BI-505 in patients with SMM were studied. Four patients were enrolled and three of them completed the first cycle of treatment defined as 5 doses of BI-505, a total of 43 mg/kg BW, over a 7-week period. In the three evaluable patients, BI-505 showed a benign safety profile. None of the patients achieved a response as defined per protocol. EudraCT number: 2012-004884-29. CONCLUSIONS: The study was conducted to assess the efficacy, safety and pharmacodynamics of BI-505 in patients with SMM. BI-505 showed no clinically relevant efficacy on disease activity in these patients with SMM, even if well tolerated. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01838369.

A Phase I Dose-Escalation Study of Antibody BI-505 in Relapsed/Refractory Multiple Myeloma.

PURPOSE: This multicenter, first-in-human study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of BI-505, a human anti-ICAM-1 monoclonal antibody, in advanced relapsed/refractory multiple myeloma patients. EXPERIMENTAL DESIGN: BI-505 was given intravenously, every 2 weeks, at escalating doses from 0.0004 to 20 mg/kg, with extension of therapy until disease progression for responding or stable patients receiving 0.09 mg/kg or higher doses. RESULTS: A total of 35 patients were enrolled. The most common adverse events were fatigue, pyrexia, headache, and nausea. Adverse events were generally mild to moderate, and those attributed to study medication were mostly limited to the first dose and manageable with premedication and slower infusion. No maximum tolerated dose was identified. BI-505's half-life increased with dose while clearance decreased, suggesting target-mediated clearance. The ICAM-1 epitopes on patient bone marrow myeloma were completely saturated at 10 mg/kg doses. Using the International Myeloma Working Group criteria, 7 patients on extended therapy had stable disease for more than 2 months. CONCLUSIONS: BI-505 can be safely administered at doses that saturate myeloma cell ICAM-1 receptors in patients. This study was registered at www.clinicaltrials.gov (NCT01025206).

Splenic metabolic activity predicts risk of future cardiovascular events: demonstration of a cardiosplenic axis in humans.

OBJECTIVES: This study sought to determine whether splenic activation after acute coronary syndrome (ACS) is linked to leukocyte proinflammatory remodeling and whether splenic activity independently predicts the risk of cardiovascular disease (CVD) events. BACKGROUND: Pre-clinical data suggest the existence of a cardiosplenic axis, wherein activation of hematopoietic tissues (notably in the spleen) results in liberation of proinflammatory leukocytes and accelerated atherosclerotic inflammation. However, it is presently unknown whether a cardiosplenic axis exists in humans and whether splenic activation relates to CVD risk. METHODS: (18)F-fluorodeoxyglucose ((18)FDG)-positron emission tomography (PET) imaging was performed in 508 individuals across 2 studies. In the first study, we performed FDG-PET imaging in 22 patients with recent ACS and 22 control subjects. FDG uptake was measured in spleen and arterial wall, whereas proinflammatory gene expression of circulating leukocytes was assessed by quantitative real-time polymerase chain reaction. In a second study, we examined the relationship between splenic tissue FDG uptake with subsequent CVD events during follow-up (median 4 years) in 464 patients who previously had undergone FDG-PET imaging. RESULTS: Splenic activity increased after ACS and was significantly associated with multiple indices of inflammation: 1) up-regulated gene expression of proinflammatory leukocytes; 2) increased C-reactive protein; and 3) increased arterial wall inflammation (FDG uptake). Moreover, in the second study, splenic activity (greater than or equal to the median) was associated with an increased risk of CVD events (hazard ratio [HR]: 3.3; 95% confidence interval [CI]: 1.5 to 7.3; p = 0.003), which remained significant after adjustment for CVD risk factors (HR: 2.26; 95% CI: 1.01 to 5.06; p = 0.04) and for arterial FDG uptake (HR: 2.68; 95% CI: 1.5 to 7.4; p = 0.02). CONCLUSIONS: Our findings demonstrate increased splenic metabolic activity after ACS and its association with proinflammatory remodeling of circulating leukocytes. Moreover, we observed that metabolic activity of the spleen independently predicted risk of subsequent CVD events. Collectively, these findings provide evidence of a cardiosplenic axis in humans similar to that shown in pre-clinical studies.

NK cells and asthma.

NK cells have been associated with immune surveillance of tumor cells and defense mechanisms against various pathogens. However, by their capacity for immunoregulation NK cells may also play a role in determining the response to allergens. The novel possibility that NK cell activity may in part decide development of allergic airway inflammation and thus potentially be involved in the inception of asthma is discussed in this review article.

Eosinophil infiltration and activation at the gastric ulcer margin in rats.

BACKGROUND: Recruitment and activation of eosinophils have been studied intensely in asthma and other allergic diseases. Less is known about the infiltration and behaviour of eosinophils during gastric ulcer healing. AIM: To examine the tissue infiltration and activation of eosinophils in the ulcer margin at different time points after ulcer induction (days 1-15). METHODS: Eosinophil peroxidase (EPO) staining and transmission electron microscopy (TEM) were used to observe eosinophil infiltration and activation in rats with acetic-acid-induced ulcer in the oxyntic mucosa. The distribution of macrophages was evaluated by immunocytochemistry using the macrophage-specific antibodies ED1 and ED2. RESULTS: There was a prominent increase in eosinophils around the ulcer margin at day 1 after ulcer induction, which peaked at day 5. TEM revealed characteristic signs of eosinophil activation, including cytolysis and piecemeal degranulation. Eosinophil cytolysis was the major form of activation, seen most frequently at day 5. A few scattered apoptotic eosinophils could also be observed. In normal controls and sham-operated rats, activated eosinophils were detected rarely. The distribution pattern of infiltrated eosinophils closely resembled that of macrophages at the ulcer margin. However, in the central part of the granulation tissue (at day 5) only macrophages could be found. CONCLUSIONS: There is marked infiltration and signs of activation of eosinophils together with macrophages at the margin of newly formed ulcers.

Inhalation of LPS induces inflammatory airway responses mimicking characteristics of chronic obstructive pulmonary disease.

AIM: Inhalation of lipopolysaccharide (LPS) produces both systemic and pulmonary inflammatory responses. The aim of this study was to further characterize the response to LPS in order to develop a human model suitable for early testing of drug candidates developed for the treatment for chronic obstructive pulmonary disease (COPD). MATERIALS: Blood and induced sputum were obtained 4, 24 and 48 h following inhalation of saline and LPS (5 and 50 µg). Blood was analysed for C-reactive protein (CRP), α(1)-antitrypsin and neutrophils/leucocytes, and sputum was analysed for biomarkers of neutrophil inflammation and remodelling activities, i.e. neutrophil elastase (NE) protein/activity and α(1)-antitrypsin. Levels of tumour necrosis factor-α (TNFα) were measured in both blood and sputum. Urine was collected 0-24 and 24-48 h postchallenge, and desmosine, a biomarker of elastin degradation, was measured. RESULTS: Lipopolysaccharide inhalation induced dose-dependent flu-like symptoms and increases in plasma CRP and α(1)-antitrypsin as well as increases in blood neutrophil/leucocyte numbers. Furthermore, LPS produced increases in sputum TNFα and sputum NE activity. Urine levels of desmosine were unaffected by the LPS challenge. All subjects recovered 48 h postchallenge, and indices of inflammatory activity were significantly lower at this observation point cf 24 h postchallenge. CONCLUSION: Inhalation of LPS in healthy volunteers can be used as a safe and stable model of neutrophil inflammation. Blood/plasma and sputum indices can be employed to monitor the response to LPS. We suggest that this model may be used for initial human studies of novel COPD-active drugs.

Clinical efficacy and pharmacokinetic profiles of intranasal and oral cetirizine in a repeated allergen challenge model of allergic rhinitis.

BACKGROUND: Intranasal and oral antihistamines are effective in treating allergic rhinitis. Studies comparing these routes of administration of an antihistamine regarding efficacy and pharmacokinetic profile are lacking. OBJECTIVE: To compare topical and oral routes of administration of cetirizine regarding efficacy, plasma exudation, and systemic drug levels in a repeated allergen challenge model of allergic rhinitis. METHODS: Oral cetirizine dihydrochloride, 10 mg once daily, and topical cetirizine dinitrate in a dose corresponding to 4.4 mg of the dihydrochloride salt twice daily were given to grass pollen-sensitive individuals for 12 days in a double-blind, placebo-controlled, crossover design. Timothy grass pollen allergen challenges were given once daily for 7 days using a nasal spray device. Nasal symptoms and peak inspiratory flow were recorded in the morning, 10 minutes after allergen challenge, and in the evening. The pharmacokinetics of the treatments was monitored in 8 patients. The remaining 28 patients were challenged topically with histamine 12 and 24 hours after the final topical and oral cetirizine doses, respectively. Nasal lavage levels of alpha2-macroglobulin were determined to evaluate histamine-induced mucosal plasma exudation. RESULTS: During the last 3 days of the repeated allergen challenge model, chronic symptoms were established. Both treatments reduced symptoms 10 minutes after allergen challenge (P < .001 vs placebo). Neither treatment reduced morning and evening symptoms or nasal peak inspiratory flow. Topical, but not oral, cetirizine reduced histamine-induced plasma exudation (P < .01 vs placebo) when systemic drug levels were similar in the 2 treatment regimens. CONCLUSIONS: Topical and oral cetirizine reduced acute nasal symptoms produced by allergen challenges in patients with established chronic symptoms. There were also antihistaminic effects of topical cetirizine not related to systemic drug levels.

Onset of action of a topical antihistamine as assessed by histamine challenge-induced plasma exudation responses.

BACKGROUND: Although usually administered orally, antihistamines are available also for topical use in allergic rhinitis. Information on onset of action of these drugs is incomplete. OBJECTIVE: To examine onset of action of topical cetirizine-dinitrate on plasma exudation evoked by repeated nasal histamine challenges. METHODS: A liposome formulation of cetirizine-dinitrate (2.44 mg per nasal cavity) was delivered via a nasal spray device as 2 consecutive actuations per nasal cavity in a placebo-controlled design. The nasal mucosal surface was challenged and lavaged with a histamine solution (100 microg/mL) 5, 15, 25, and 55 minutes after each treatment. In addition, the mucosa was lavaged with saline before each treatment. The lavage fluid levels of alpha2-macroglobulin were measured as an index of mucosal exudation (luminal entry) of plasma. RESULTS: Histamine produced significant increases in nasal lavage fluid levels of alpha2-macroglobulin at all observation points (5 through 55 minutes after treatment). Nasal cetirizine-dinitrate significantly inhibited this response at 5 and 15 minutes after treatment. CONCLUSIONS: The effect of topical cetirizine-dinitrate, as established by histamine challenge-induced mucosal exudation of plasma, has an early onset (ie, within 5 to 10 minutes).

Genomic and functional delineation of dendritic cells and memory T cells derived from grass pollen-allergic patients and healthy individuals.

Dendritic cells (DCIs) possess a potent ability to modulate and activate specific T-cell responses to allergens, which play a pivotal role in allergic inflammation by secreting cytokines and other mediators. However, the molecular mechanisms by which allergen-challenged DCs regulate specific T-cell responses are still not well characterized. This study aims at elucidating the molecular mechanisms underlying the DC-T-cell interaction during an allergic immune response to grass pollen, using a genomic and functional approach. Transcriptional analysis was performed on grass allergen Phleum pratense-stimulated DCs and on autologous memory CD4(+) T cells co-cultured with allergen-challenged DCs from healthy and allergic donors. DCs from the allergic donors were potent inducers of T-cell proliferation and T(h)2 polarization, as demonstrated by high IL-4, IL-5 and IL-13, and low IFN-gamma production. A gradual up-regulation of activation markers on both DCs and T cells was evident during the co-culture period, demonstrating an educational element of the DC-T-cell interaction. The global transcriptional analysis revealed a differential gene regulation in DCs and T cells derived from allergic donors after stimulation with allergen, as compared with the healthy donors. Peripheral memory CD4(+) T cells from healthy and allergic donors also responded differently after stimulation with allergen-loaded DCs with respect to cytokine production, proliferation, surface marker expression and gene transcription. We found up-regulated genes involved in T(h)2 cell biology, such as genes important for homing, adhesion, signaling and transcription, in addition to genes previously not described in the context of allergy. The panel of differentially expressed genes in the allergic group will form the basis for an increased understanding of the molecular mechanisms in allergy.

Acute allergic responses induce a prompt luminal entry of airway tissue eosinophils.

Traditionally, traffic and activation of eosinophils in asthmatic airways are thought to take place during the late-phase allergic reaction. The present study tests the hypothesis that when eosinophils are present in the tissue before allergen exposure, as in chronically inflamed asthmatic airways, acute anaphylactic reactions initiate an eosinophil response. Using a guinea-pig allergic model, where eosinophilia is present at baseline conditions, the traffic of resident eosinophils was examined in vivo immediately after allergen challenge. By 2 min after challenge, eosinophils had moved up to apical epithelial positions. Within 10 min, a marked migration of eosinophils into the airway lumen was demonstrated. Along with the allergen-induced egression of eosinophils, acute luminal entry of plasma proteins and eotaxin occurred. Eosinophil egression was effectively inhibited by the antiexudative drug formoterol, whereas the proexudative drug bradykinin could in naive animals evoke a prompt luminal entry of eosinophils. In conclusion, the present study demonstrates that acute allergic reactions initiate a prompt transepithelial migration of resident eosinophils. Our data further suggest that this response in part is initiated by the plasma exudation response, which may alter the transepithelial gradient of eosinophil chemoattractants including eotaxin. We propose that prompt eosinophil response is a significant component of the acute phase of allergic reactions when occurring in airways where these cells are already present in the mucosa.

Neural expression and increased lavage fluid levels of secretoneurin in seasonal allergic rhinitis.

Secretoneurin is a neuropeptide potentially involved in migration of eosinophils, monocytes, and dendritic cells. Whether secretoneurin is present in the human airway mucosa and whether it is released at ongoing allergic airway inflammation is currently unknown. In patients with allergic rhinitis, we have explored the occurrence of secretoneurin in nasal mucosal biopsies and lavage fluids before and during natural allergen exposure. Immunohistochemical analysis revealed an abundance of nerves displaying secretoneurin immunoreactivity, which were distributed predominantly around blood vessels and submucosal glands. A majority of nerve fibers containing vesicular acetylcholine transporter, tyrosine hydroxylase, calcitonin gene-related peptide, and vasoactive intestinal peptide were also secretoneurin-immunoreactive, indicating a localization of secretoneurin in cholinergic, adrenergic, and sensory nerves. Lavage fluid levels of secretoneurin were increased at allergen exposure (p < 0.01-0.05). Levels of secretoneurin did not correlate with eosinophil cationic protein (rho = 0.1, p = 0.7). We conclude that secretoneurin has a widespread occurrence in nasal mucosal nerves of patients with seasonal allergic rhinitis and that increased nasal lavage fluid levels of secretoneurin may characterize ongoing allergen exposure. These data favor a role of secretoneurin in the local traffic of immune cells in human airway mucosa.