Summary
Background
Allergen‐derived (T cell epitope) peptides may be safer for immunotherapy than native allergen, as they do not cross‐link immunoglobulin (Ig)E. However, HLA polymorphism results in ...multiple potential epitopes. Synthetic peptides of phospholipase (PL) A2 were selected for a peptide vaccine, on the basis of binding affinity for commonly expressed HLA‐DR molecules.
Objective
To evaluate treatment with an HLA‐DR‐based PLA2 peptide vaccine in subjects with mild honeybee allergy in an open, controlled study.
Methods
Twelve volunteers with allergy to bee venom received nine intradermal injections of PLA2 peptides, with six untreated subjects serving as controls. Outcome was assessed by the size of the late‐phase cutaneous reaction to allergen, peripheral blood mononuclear cell (PBMC) proliferation, cytokine release, and expression of genes associated with immune regulation.
Results
Subjects receiving peptides showed a decrease in the magnitude of the late‐phase cutaneous reaction to bee venom compared with controls (P=0.03). The proliferation of venom‐stimulated PBMCs decreased in treated subjects compared with controls (P=0.01). Peptide treatment reduced the production of IL‐13 by PLA2‐stimulated PBMCs (P<0.01) and IFN‐γ (P<0.01), and increased the production of IL‐10 (P=0.02). Transcription of the suppressor of cytokine signalling (Socs)3 gene was significantly increased following therapy. A transient, but modest, increase in allergen‐specific IgG was also observed.
Conclusion
HLA‐DR‐based T cell epitopes modify surrogate markers associated with successful immunotherapy and induction of immune regulation, supporting the concept that this form of treatment may be efficacious in human allergic disease.
In the present study, we show therapeutic amelioration of established ovalbumin (OVA)-induced allergic airway disease following house dust mite (HDM) peptide therapy. Mice were sensitized and ...challenged with OVA and HDM protein extract (Dermatophagoides species) to induce dual allergen sensitization and allergic airway disease. Treatment of allergic mice with peptides derived from the major allergen Der p 1 suppressed OVA-induced airway hyperresponsiveness, tissue eosinophilia, and goblet cell hyperplasia upon rechallenge with allergen. Peptide treatment also suppressed OVA-specific T-cell proliferation. Resolution of airway pathophysiology was associated with a reduction in recruitment, proliferation, and effector function of T(H)2 cells and decreased interleukin (IL)-17⁺ T cells. Furthermore, peptide immunotherapy induced the regulatory cytokine IL-10 and increased the proportion of Fox p3⁺ cells among those expressing IL-10. Tolerance to OVA was not associated with increased IL-35. In conclusion, our results provide in vivo evidence for the creation of a tolerogenic environment following HDM peptide immunotherapy, leading to the therapeutic amelioration of established OVA-induced allergic airway disease.
Recent experimental evidence suggests that calcium channel blockers (CCBs) may have anti-fibrotic effects on liver and pulmonary fibrosis. We aimed to investigate whether use of CCBs was associated ...with the skin fibrosis in patients with systemic sclerosis (SSc).
Based on the 5-year follow-up data from the Canadian Scleroderma Research Group registry, we used the generalised estimating equations (GEE) model to assess the relationship between use of CCBs and the primary outcome of skin fibrosis measured by the modified Rodnan skin score (mRSS). We also used GEE models to explore the associations between use of CCBs and risk of secondary outcomes including digital ulcers, pulmonary fibrosis, calcinosis, and scleroderma renal crisis.
There were 1547 patients (1330 females) with SSc included in this study. Their mean age was 55.5 years and there were 606 patients taking CCBs at baseline. No significant difference in mRSS between the use versus non-use of CCBs was found in the multivariable analysis: mean difference = -0.19 (95% confidence interval: -0.62, 0.23), p-value = 0.37. Use of CCBs was not significantly related to risk of secondary outcomes, with an odds ratio (OR) of 1.13 for digital ulcers, 0.94 for pulmonary fibrosis, 0.90 for calcinosis and 1.69 for scleroderma renal crisis, respectively.
No significant associations between use of CCBs and skin fibrosis, digital ulcers, pulmonary fibrosis, calcinosis and scleroderma renal crisis were found in patients with SSc. More evidence from other well-designed studies would be required to confirm these findings.
Background: The mechanisms of late asthmatic reactions provoked in atopic asthmatics by allergen‐derived T‐cell peptide epitopes remain unclear. Previous studies showed no changes in airway ...eosinophils or mast cell products after peptide challenge. In the present study our aim was to measure calcitonin gene‐related peptide (CGRP), neurokinin (NK)‐A, and substance P (SP) in bronchoalveolar lavage fluid and bronchial biopsies (BB) after inhalation of allergen‐derived T‐cell peptide epitopes since these neuropeptides (NP) had not previously been evaluated in this chronic asthma model.
Methods: Bronchoscopy, with BB and bronchoalveolar lavage (BAL), was performed in 24 cat‐allergic subjects 6 h after inhalation of Fel d 1‐derived peptides. Neuropeptides were measured in BAL by enzyme‐linked immunosorbent assay and CGRP expression in the airways was assessed by immunohistochemistry and confocal microscopy.
Results: Twelve subjects (termed ‘responders’) developed isolated late reactions. Calcitonin gene‐related peptide, but not NK‐A or SP, was significantly elevated in BAL in responders only. Biopsy studies showed that in virtually all responders peptide challenge induced marked increases in CGRP immunoreactivity in bronchial epithelial cells, infiltrating submucosal cells and in association with airway smooth muscle. Double immunostaining indicated that CGRP colocalized predominantly to CD3+/CD4+ and CD68+ submucosal inflammatory cells.
Conclusion: Calcitonin gene‐related peptide, a potent vasodilator, is markedly up‐regulated in the airways of atopic asthmatics during late‐phase reactions provoked by inhalation of allergen‐derived T‐cell peptides.
Background: We have previously described both modification of allergen immunotherapy using peptide fragments, and reduced regulation of allergen stimulated T cells by CD4+ CD25+ T cells from ...allergic donors when compared with nonallergic controls. It has been suggested that allergen immunotherapy induces regulatory T cell activity: we hypothesized that allergen peptide immunotherapy might increase suppressive activity of CD4+ CD25+ T cells.
Objective: To examine cat allergen‐stimulated CD4 T cell responses and their suppression by CD4+ CD25+ T cells before and after cat allergen peptide immunotherapy in a double‐blind placebo‐controlled study.
Methods: Peripheral blood was obtained and stored before and after peptide immunotherapy or placebo treatment. CD4+ and CD4+ CD25+ were then isolated by immunomagnetic beads and cultured with allergen in vitro.
Results: Comparing cells from blood taken before with that after peptide immunotherapy there was a significant reduction in both proliferation and IL‐13 production by allergen‐stimulated CD4+ T cells, whereas no change was seen after placebo. CD4+ CD25+ T cells suppressed both proliferation and IL‐13 production by CD4+ CD25− T cells before and after therapy but peptide therapy was not associated with any change in suppressive activity of these cells.
Conclusion: Allergen peptide immunotherapy alters T cell response to allergen through mechanisms other than changes in CD4+ CD25+ T cell suppression.
We recently demonstrated bronchial mucosal expression of IL-4 and IL-5 at the mRNA and protein level in both atopic and nonatopic (intrinsic) asthma. In this report, using double immunohistochemistry ...(IHC) and in situ hybridization (ISH), we show that 70% of IL-4 and IL-5 mRNA+ signals co-localized to CD3+ T cells, the majority (>70%) of which were CD4+, although CD8+ cells also expressed IL-4 and IL-5 mRNA. The remaining IL-4 and IL-5 mRNA signals co-localized to mast cells and eosinophils. The cellular distribution of these mRNA species did not differ between atopic and nonatopic asthmatics. In contrast, double IHC showed that IL-4 and IL-5 immunoreactivity was predominantly associated with eosinophils and mast cells, with few IL-5 or IL-4 immunoreactive CD3+ T cells detectable. However, total IL-4- or IL-5-positive cells detected by IHC were <40% of the total mRNA+ cells, raising the possibility that insufficient cytokine protein accumulated within T cells to enable detection by IHC. We conclude that: 1) in atopic and nonatopic asthma CD8+ T cells, in addition to CD4+ T cells, mast cells and eosinophils express mRNA for IL-4 and IL-5; 2) whereas IL-4 and IL-5 mRNA expression was associated mainly with T cells, immunoreactivity for the corresponding protein products was detectable predominantly in eosinophils and mast cells; and 3) this discrepancy may be partly attributable to the relative insensitivity of double IHC technique that does not allow detection of cytokine protein in T cells where, unlike eosinophils and mast cells, there is no facility for storage and concentration in granules.
Indirect allorecognition has been implicated in the mechanism of chronic rejection and alloantibody formation but precise definition of the epitopes involved has been limited. We have undertaken a ...detailed assessment of the antigenic properties of peptides derived from HLA‐A2. Candidate epitopes were identified in vitro by assessment of MHC class II binding. The immune response to these epitopes was determined in patients awaiting a renal transplant by the assessment of PBMC activation using γ‐interferon ELISPOT. Twenty‐two of fifty‐five patients responded to peptides from HLA‐A2 and this was associated with but not confined to those who had made antibody to HLA‐A2 (14/18). Nineteen of twenty‐two patients responded to peptides derived from the hypervariable α1 and α2 domains and 18/22 responded to peptides from the α3 and transmembrane domain, the sequences of which show little polymorphism. In six patients, the sequence of these peptides was identical to self, that is, the response was autoimmune. The finding of indirect epitopes derived from regions of MHC class I that exhibit little polymorphism provides a novel perspective on the immune response to alloantigen and has potential implications for the development of specific therapies.
This study of patients awaiting renal transplantation who express different patterns of antibody sensitization to HLA‐A2, demonstrates indirect allorecognition by T lymphocytes to epitopes derived not only from the highly polymorphic regions of HLA‐A2, but also to sequences shared by a range of different HLA.
Objectives:
Scleroderma renal crisis is a rare but serious complication affecting 2%–15% of patients with systemic sclerosis. Despite treatment with angiotensin-converting enzyme inhibitors, outcomes ...for scleroderma renal crisis patients are still poor. The cellular signaling mechanisms in scleroderma renal crisis are not yet known. Mammalian target of rapamycin, comprised of the subunits mTORC1 and mTORC2, has been shown to be activated in vascular lesions of renal transplant patients with anti-phospholipid antibody syndrome. Given the similarities between the pathophysiology of scleroderma renal crisis and anti-phospholipid antibody syndrome, we hypothesized that the mammalian target of rapamycin pathway would also be activated in the renal vasculature of patients with scleroderma renal crisis.
Methods:
We retrospectively analyzed renal biopsies of five patients with scleroderma renal crisis in the Canadian Scleroderma Research Group cohort. Immunostaining was performed using anti-P-S6RP antibodies to evaluate the phosphorylation of mTORC1, and anti-Rictor and anti-S473 to determine activation of mTORC2.
Results:
Four of the five patients showed mTORC1 activation in arteriolar endothelial cells, and three of the five patients showed mTORC1 activation in the arterial endothelial cells. Two of four samples showed Rictor expression in the arteriolar and arterial endothelial cells, showing mTORC2 activation. There was no expression of mTORC1 or mTORC2 in samples from two healthy controls.
Conclusion:
We demonstrate that both mTORC1 and mTORC2 are activated in renal biopsies with typical histologic features of scleroderma renal crisis. Dual mammalian target of rapamycin inhibitors are currently available and in development. These findings could inform further research into novel treatment targets for scleroderma renal crisis.
Objective
Dysbiosis of the infant gut microbiota may have long‐term health consequences. This study aimed to determine the impact of maternal intrapartum antibiotic prophylaxis (IAP) on infant gut ...microbiota, and to explore whether breastfeeding modifies these effects.
Design
Prospective pregnancy cohort of Canadian infants born in 2010–2012: the Canadian Healthy Infant Longitudinal Development (CHILD) Study.
Setting
General community.
Sample
Representative sub‐sample of 198 healthy term infants from the CHILD Study.
Methods
Maternal IAP exposures and birth method were documented from hospital records and breastfeeding was reported by mothers. Infant gut microbiota was characterised by Illumina 16S rRNA sequencing of faecal samples at 3 and 12 months.
Main outcome measures
Infant gut microbiota profiles.
Results
In this cohort, 21% of mothers received IAP for Group B Streptococcus prophylaxis or pre‐labour rupture of membranes; another 23% received IAP for elective or emergency caesarean section (CS). Infant gut microbiota community structures at 3 months differed significantly with all IAP exposures, and differences persisted to 12 months for infants delivered by emergency CS. Taxon‐specific composition also differed, with the genera Bacteroides and Parabacteroides under‐represented, and Enterococcus and Clostridium over‐represented at 3 months following maternal IAP. Microbiota differences were especially evident following IAP with emergency CS, with some changes (increased Clostridiales and decreased Bacteroidaceae) persisting to 12 months, particularly among non‐breastfed infants.
Conclusions
Intrapartum antibiotics in caesarean and vaginal delivery are associated with infant gut microbiota dysbiosis, and breastfeeding modifies some of these effects. Further research is warranted to explore the health consequences of these associations.
Tweetable
Maternal #antibiotics during childbirth alter the infant gut #microbiome.
Tweetable
Maternal #antibiotics during childbirth alter the infant gut #microbiome.
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