SummaryBackgroundSmall studies suggest peanut oral immunotherapy (OIT) might be effective in the treatment of peanut allergy. We aimed to establish the efficacy of OIT for the desensitisation of children with allergy to peanuts.MethodsWe did a randomised controlled crossover trial to compare the efficacy of active OIT (using characterised peanut flour; protein doses of 2–800 mg/day) with control (peanut avoidance, the present standard of care) at the NIHR/Wellcome Trust Cambridge Clinical Research Facility (Cambridge, UK). Randomisation (1:1) was by use of an audited online system; group allocation was not masked. Eligible participants were aged 7–16 years with an immediate hypersensitivity reaction after peanut ingestion, positive skin prick test to peanuts, and positive by double-blind placebo-controlled food challenge (DBPCFC). We excluded participants if they had a major chronic illness, if the care provider or a present household member had suspected or diagnosed allergy to peanuts, or if there was an unwillingness or inability to comply with study procedures. Our primary outcome was desensitisation, defined as negative peanut challenge (1400 mg protein in DBPCFC) at 6 months (first phase). Control participants underwent OIT during the second phase, with subsequent DBPCFC. Immunological parameters and disease-specific quality-of-life scores were measured. Analysis was by intention to treat. Fisher's exact test was used to compare the proportion of those with desensitisation to peanut after 6 months between the active and control group at the end of the first phase. This trial is registered with Current Controlled Trials, number ISRCTN62416244.FindingsThe primary outcome, desensitisation, was recorded for 62% (24 of 39 participants; 95% CI 45–78) in the active group and none of the control group after the first phase (0 of 46; 95% CI 0–9; p<0·001). 84% (95% CI 70–93) of the active group tolerated daily ingestion of 800 mg protein (equivalent to roughly five peanuts). Median increase in peanut threshold after OIT was 1345 mg (range 45–1400; p<0·001) or 25·5 times (range 1·82–280; p<0·001). After the second phase, 54% (95% CI 35–72) tolerated 1400 mg challenge (equivalent to roughly ten peanuts) and 91% (79–98) tolerated daily ingestion of 800 mg protein. Quality-of-life scores improved (decreased) after OIT (median change −1·61; p<0·001). Side-effects were mild in most participants. Gastrointestinal symptoms were, collectively, most common (31 participants with nausea, 31 with vomiting, and one with diarrhoea), then oral pruritus after 6·3% of doses (76 participants) and wheeze after 0·41% of doses (21 participants). Intramuscular adrenaline was used after 0·01% of doses (one participant).InterpretationOIT successfully induced desensitisation in most children within the study population with peanut allergy of any severity, with a clinically meaningful increase in peanut threshold. Quality of life improved after intervention and there was a good safety profile. Immunological changes corresponded with clinical d...

Heterozygous germ-line mutations in the bone morphogenetic protein type-II receptor (BMPR-II) gene underlie heritable pulmonary arterial hypertension (HPAH). Although inflammation promotes PAH, the mechanisms by which inflammation and BMPR-II dysfunction conspire to cause disease remain unknown. Here we identify that tumour necrosis factor-α (TNFα) selectively reduces BMPR-II transcription and mediates post-translational BMPR-II cleavage via the sheddases, ADAM10 and ADAM17 in pulmonary artery smooth muscle cells (PASMCs). TNFα-mediated suppression of BMPR-II subverts BMP signalling, leading to BMP6-mediated PASMC proliferation via preferential activation of an ALK2/ACTR-IIA signalling axis. Furthermore, TNFα, via SRC family kinases, increases pro-proliferative NOTCH2 signalling in HPAH PASMCs with reduced BMPR-II expression. We confirm this signalling switch in rodent models of PAH and demonstrate that anti-TNFα immunotherapy reverses disease progression, restoring normal BMP/NOTCH signalling. Collectively, these findings identify mechanisms by which BMP and TNFα signalling contribute to disease, and suggest a tractable approach for therapeutic intervention in PAH.

We demonstrated a substantial increase in dose threshold after OIT in all subjects, including the subject with proven anaphylaxis. OIT was well tolerated and conferred protection against at least 10 peanuts, more than is likely to be encountered during accidental ingestion.

We used a novel protocol using gradual updosing, and higher maintenance dose resulting in a better outcome compared with rush protocols. There was a 1000-fold increase in the amount of peanut tolerated with a good safety profile. No serious adverse events occurred. Most subjects tolerated five peanuts and all were protected against amounts likely during accidental ingestion. New information is provided on 'extrinsic factors', updosing method and factors associated with success (trial registration http://ClinicalTrials.gov- ID number NCT01259804).

This study shows that immunotherapy shifted cytokine responses to allergen from a TH-2 to a TH-1 dominant pattern, suggesting direct effects on T cells. How these cytokine changes relate to clinical desensitization is not clear. In the longer term they would result in an isotype switch from IgE to IgG. Early changes in cytokine or chemokine production might downregulate mast cell or basophil reactivity and explain the rapid desensitization in rush VIT.

One hundred and eighty-one open egg challenges were performed in 95 children whose median age of allergy onset was 12 months. Fifty-three of 95 (56%) had at least one annual repeat challenge. Pre-study historical reactions occurred to baked egg in five (5%), lightly cooked in 58 (61%) and uncooked in nine (9%); respiratory reactions occurred in 11 (12%) and seven (7%) had anaphylaxis; adrenaline was used during five reactions. There were 77 well-cooked and 104 uncooked egg challenges. Tolerance was gained twice as rapidly to well-cooked than uncooked egg (median 5.6 vs. 10.3 years; P<0.0001) and continued to 13 years; hazard ratio 2.23 (95% confidence interval 1.6-3.9). Nearly 1/3 had resolved allergy to well-cooked egg at 3 years and 2/3 at 6 years. Of 28/77 (37%) positive well-cooked egg challenges, 65% had cutaneous symptoms, 68% gastrointestinal and 39% rhinitis, with no other respiratory reactions. Adrenaline was not required. CONCLUSIONS AND CLINICAL RELEVANCE RESOLUTION: of egg allergy takes place over many years, with children outgrowing allergy to well-cooked egg approximately twice as quickly as they outgrow allergy to uncooked egg. There were no severe reactions to well-cooked egg challenge, and adrenaline was not required. Our data support initiation of home reintroduction of well-cooked egg from 2 to 3 years of age in children with previous mild reactions and no asthma. Resolution continues to occur in older children, so that despite an earlier positive challenge, attempts at reintroduction should be continued.

Neutrophil apoptosis represents a major mechanism involved in the resolution of acute inflammation. In contrast to the effect of hypoxia observed in many other cell types, oxygen deprivation, as we have shown, causes a profound but reversible delay in the rate of constitutive apoptosis in human neutrophils when aged in vitro. This effect was mimicked by exposing cells to 2 structurally unrelated ironchelating agents, desferrioxamine (DFO) and hydroxypyridines (CP-94), and it appeared specific for hypoxia in that no modulation of apoptosis was observed with mitochondrial electron transport inhibitors, glucose deprivation, or heat shock. The involvement of chelatable iron in the oxygen-sensing mechanism was confirmed by the abolition of the DFO and CP-94 survival effect by Fe 2؉ ions. Although hypoxia inducible factor-1␣ (HIF-1␣) mRNA was identified in freshly isolated neutrophils, HIF-1␣ protein was only detected in neutrophils incubated under hypoxic conditions or in the presence of DFO. Moreover, studies with cyclohexamide demonstrated that the survival effect of hypoxia was fully dependent on continuing protein synthesis. These results indicate that the neutrophil has a ferroprotein oxygen-sensing mechanism identical to that for erythropoietin regulation and results in HIF-1␣ up-regulation and profound but reversible inhibition of neutrophil apoptosis. This finding may have important implications for the resolution of granulocytic inflammation at sites of low-oxygen tension. IntroductionNeutrophils are key effector cells of the innate immune system and play a vital role in host defense against gram-negative bacteria. However, excessive or sustained activation of these cells can result in significant tissue damage, with injury resulting from the release of histotoxic granule contents, reactive-oxygen intermediates, and other proinflammatory mediators. 1 Persistent accumulation of primed and activated neutrophils is a cardinal feature of a number of lung diseases, including acute lung injury, bronchiectasis, and chronic obstructive airways disease, and it is associated with disease progression and destruction of lung tissue. 2 Similarly, in myocardial infarction, neutrophils have been implicated in extending the area of primary myocardial injury by releasing protease-rich granule contents into adjacent viable tissue, 3 and, in rheumatoid arthritis, neutrophil-derived reactive-oxygen species and granule enzymes have been demonstrated in synovial fluid and again implicated in disease pathogenesis. 4,5 Understanding the mechanisms that modulate neutrophil influx, activation, and longevity is therefore of major pathophysiologic importance to a number of organ systems. The latter 2 events are regulated in large part by the capacity of senescent neutrophils to undergo spontaneous apoptosis, which leads to inhibition of secretory function and to prompt ingestion and removal by inflammatory macrophages. 6,7 Apoptosis is a constitutive event in neutrophils and is proposed to be a major mechanism underlying the resolutio...

The capacity of cytokines to modulate neutrophil apoptosis is thought to be a major factor influencing the resolution of granulocytic inflammation. We have previously shown that the late survival effect of TNF‐α  in human neutrophils involves activation of both NF‐κB and phosphoinositide 3‐kinase (PI3‐kinase) pathways. In this study, we address how these pathways integrate to prevent cell death. In human neutrophils, TNF‐α  (200 U/ml) induced rapid IκB‐α  degradation, NF‐κB activation and IL‐8 release (31.8±5.4 pg/105 cells/2 h), whereas GM‐CSF (10 ng/ml) stimulated an equivalent IL‐8 release (26.5±4.5 pg/105 cells/2 h) without enhanced IκB‐α  degradation or NF‐κB activation compared to control. Importantly, inhibition of PI3‐kinase did not modify TNF‐α ‐induced IκB‐α  degradation, yet fully inhibited the survival effect of both cytokines. Inhibition of IκB‐α  phosphorylation, PI3‐kinase or ERK1/2 activation blocked IL‐8 release by both cytokines. Blocking IL‐8 activity by inhibiting its synthesis or by using a neutralizing antibody enhanced the early pro‐apoptotic effectof TNF‐α  and inhibited its late survival effect without affecting GM‐CSF‐induced survival. These data suggest that cross‐talk between NF‐κB and PI3‐kinase pathways in TNF‐α ‐stimulated neutrophils results from NF‐κB/ERK1/2‐dependent IL‐8 production which acts in an autocrine manner to drive PI3‐kinase‐dependent survival. In contrast, GM‐CSF‐mediated survival does not involve NF‐κB activation or IL‐8 release.