Cost-utility analysis of shockwave lithotripsy vs ureteroscopic stone treatment in adults.

OBJECTIVES: To assess the cost-effectiveness, resource use implications, quality-adjusted life-years (QALYs) and cost per QALY of care pathways starting with either extracorporeal shockwave lithotripsy (SWL) or with ureteroscopic retrieval (ureteroscopy [URS]) for the management of ureteric stones. PATIENTS AND METHODS: Data on quality of life and resource use for 613 patients, collected prospectively in the Therapeutic Interventions for Stones of the Ureter (TISU) randomized controlled trial (ISRCTN 92289221), were used to assess the cost-effectiveness of two care pathways, SWL and URS. A health provider (UK National Health Service) perspective was adopted to estimate the costs of the interventions and subsequent resource use. Quality-of-life data were calculated using a generic instrument, the EuroQol EQ-5D-3L. Results are expressed as incremental cost-effectiveness ratios and cost-effectiveness acceptability curves. RESULTS: The mean QALY difference (SWL vs URS) was -0.021 (95% confidence interval [CI] -0.033 to -0.010) and the mean cost difference was -£809 (95% CI -£1061 to -£551). The QALY difference translated into approximately 10 more healthy days over the 6-month period for the patients on the URS care pathway. The probabaility that SWL is cost-effective is 79% at a society's willingness to pay (WTP) threshold for 1 QALY of £30,000 and 98% at a WTP threshold of £20,000. CONCLUSION: The SWL pathway results in lower QALYs than URS but costs less. The incremental cost per QALY is £39 118 cost saving per QALY lost, with a 79% probability that SWL would be considered cost-effective at a WTP threshold for 1 QALY of £30 000 and 98% at a WTP threshold of £20 000. Decision-makers need to determine if costs saved justify the loss in QALYs.

Long-term oncological outcomes after haemorrhagic apoplexy in pituitary adenoma managed operatively and non-operatively.

INTRODUCTION: Depending on severity of presentation, pituitary apoplexy can be managed with acute surgery or non-operatively. We aim to assess long-term tumour control, visual and endocrinological outcomes following pituitary apoplexy with special emphasis on patients treated non-operatively. METHODS: Multicentre retrospective cohort study. All patients with symptomatic pituitary apoplexy were included. Patients were divided into 3 groups: group 1: surgery within 7 days; group 2: surgery 7 days-3 months; group 3: non-operative. Further intervention for oncological reasons during follow-up was the primary outcome. Secondary outcome measures included visual and endocrinological function at last follow-up. RESULTS: One hundred sixty patients were identified with mean follow-up of 48 months (n = 61 group 1; n = 34 group 2; n = 64 group 3). Factors influencing decision for surgical treatment included visual acuity loss (OR: 2.50; 95% CI: 1.02-6.10), oculomotor nerve palsy (OR: 2.80; 95% CI: 1.08-7.25) and compression of chiasm on imaging (OR: 9.50; 95% CI: 2.06-43.73). Treatment for tumour progression/recurrence was required in 17%, 37% and 24% in groups 1, 2 and 3, respectively (p = 0.07). Urgent surgery (OR: 0.16; 95% CI: 0.04-0.59) and tumour regression on follow-up (OR: 0.04; 95% CI: 0.04-0.36) were independently associated with long-term tumour control. Visual and endocrinological outcomes were comparable between groups. CONCLUSION: Urgent surgery is an independent predictor of long-term tumour control following pituitary apoplexy. However, 76% of patients who successfully complete 3 months of non-operative treatment may not require any intervention in the long term.

Prevalence of Frailty in Older Men and Women: Cross-Sectional Data from the Geelong Osteoporosis Study.

Few studies have investigated the prevalence of frailty in the Australian general population. This study determined the prevalence of frailty in a population-based sample of older adults and examined the relationship between frailty and comorbid conditions. Men (n = 347) and women (n = 360) aged ≥ 60 year from the Geelong Osteoporosis Study (GOS) were assessed between 2016-2019 and 2011-2014, respectively. Frailty was identified using a modified Fried frailty phenotype. Prevalence estimates were standardised to the 2011 Australian population. Kruskal-Wallis test and χ2 test were used to analyse data. For women, mean standardised prevalence estimates were 18.3% (14.1-22.5) for frail, 54.1% (47.3-60.8) pre-frail and 22.9% (18.9-26.8) robust. Corresponding estimates for men were 13.1% (9.8-16.3) frail, 47.8% (42.0-53.6) pre-frail and 27.3% (22.7-31.8) robust. Women who were frail were older, shorter, tended to have a higher body mass index (BMI) and used more medications compared to other groups. Compared to robust women, those who were frail were more likely to have cardio-metabolic (OR 3.5 (0.7-20.0)), pulmonary (OR 3.5 (1.5-8.4)) and musculoskeletal (OR 10.1 (2.1-48.0)) conditions. Frail men were older, had a higher BMI and were more likely to have musculoskeletal conditions (OR 5.8 (2.8-12.3)) and tended to be from a lower SES. No further associations were observed. This study reported the prevalence of frail and pre-frail individuals in a population-based sample of Australian men and women. Frailty was associated with musculoskeletal conditions for both men and women; however, associations with cardio-metabolic and pulmonary comorbidities were evident in women only.

Lymphocyte-independent pathways underlie the pathogenesis of murine cytomegalovirus-associated secondary haemophagocytic lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis (HLH) constitutes a spectrum of immunological disorders characterized by uncontrolled immune activation and key symptoms such as fever, splenomegaly, pancytopenia, haemophagocytosis, hyperferritinaemia and hepatitis. In genetic or primary HLH, hyperactivated CD8+ T cells are the main drivers of pathology. However, in acquired secondary HLH, the role of lymphocytes remains vague. In the present study the involvement of lymphocytes in the pathogenesis of a cytomegalovirus-induced model of secondary HLH was explored. We have previously reported CD8+ T cells to be redundant in this model, and therefore focused on CD4+ helper and regulatory T cells. CD4+ T cells were activated markedly and skewed towards a proinflammatory T helper type 1 transcription profile in mice displaying a severe and complete HLH phenotype. Counter to expectations, regulatory T cells were not reduced in numbers and were, in fact, more activated. Therapeutic strategies targeting CD25high hyperactivated T cells were ineffective to alleviate disease, indicating that T cell hyperactivation is not a pathogenic factor in cytomegalovirus-induced murine HLH. Moreover, even though T cells were essential in controlling viral proliferation, CD4+ T cells, in addition to CD8+ T cells, were dispensable in the development of the HLH-like syndrome. In fact, no T or B cells were required for induction and propagation of HLH disease, as evidenced by the occurrence of cytomegalovirus-associated HLH in severe combined immunodeficient (SCID) mice. These data suggest that lymphocyte-independent mechanisms can underlie virus-associated secondary HLH, accentuating a clear distinction with primary HLH.

Development of an international core outcome set for peripheral vascular malformations: the OVAMA project.

BACKGROUND: An important limitation in vascular malformation research is the heterogeneity in outcome measures used for the evaluation of treatment outcome. OBJECTIVES: To reach international consensus on a core outcome set (COS) for clinical research on peripheral vascular malformations: lymphatic (LM), venous (VM) and arteriovenous malformations (AVM). In this consensus study, we determined what domains should constitute the COS. METHODS: Thirty-six possibly relevant outcome domains were proposed to an international group of physicians, patients and the parents of patients. In a three-round e-Delphi process using online surveys, participants repeatedly rated the importance of these domains on a five-point Likert scale. Participants could also propose other relevant domains. This process was performed for LM, VM and AVM separately. Consensus was predefined as 80% agreement on the importance of a domain among both the physician group and the patient/parent group. Outcomes were then re-evaluated in an online consensus meeting. RESULTS: 167 physicians and 134 patients and parents of patients with LM (n = 50), VM (n = 71) and AVM (n = 29) participated in the study. After three rounds and a consensus meeting, consensus was reached for all three types of vascular malformations on the core domains of radiological assessment, physician-reported location-specific signs, patient-reported severity of symptoms, pain, quality of life, satisfaction and adverse events. Vascular malformation type-specific signs and symptoms were included for LM, VM and AVM, separately. CONCLUSIONS: Our recommendation is that therapeutic-efficacy studies on peripheral vascular malformations should measure at least these core outcome domains.

Redefining the structural motifs that determine RNA binding and RNA editing by pentatricopeptide repeat proteins in land plants.

The pentatricopeptide repeat (PPR) proteins form one of the largest protein families in land plants. They are characterised by tandem 30-40 amino acid motifs that form an extended binding surface capable of sequence-specific recognition of RNA strands. Almost all of them are post-translationally targeted to plastids and mitochondria, where they play important roles in post-transcriptional processes including splicing, RNA editing and the initiation of translation. A code describing how PPR proteins recognise their RNA targets promises to accelerate research on these proteins, but making use of this code requires accurate definition and annotation of all of the various nucleotide-binding motifs in each protein. We have used a structural modelling approach to define 10 different variants of the PPR motif found in plant proteins, in addition to the putative deaminase motif that is found at the C-terminus of many RNA-editing factors. We show that the super-helical RNA-binding surface of RNA-editing factors is potentially longer than previously recognised. We used the redefined motifs to develop accurate and consistent annotations of PPR sequences from 109 genomes. We report a high error rate in PPR gene models in many public plant proteomes, due to gene fusions and insertions of spurious introns. These consistently annotated datasets across a wide range of species are valuable resources for future comparative genomics studies, and an essential pre-requisite for accurate large-scale computational predictions of PPR targets. We have created a web portal (http://www.plantppr.com) that provides open access to these resources for the community.

An early innate response underlies severe influenza-induced exacerbations of asthma in a novel steroid-insensitive and anti-IL-5-responsive mouse model.

BACKGROUND: Acute worsening of asthma symptoms (exacerbation) is predominantly triggered by respiratory viruses, with influenza causing the most severe exacerbations. The lack of an adequate animal model hampers mechanistic insight and the development of new therapeutics. AIM: We developed and characterized a robust, consistent, and reproducible mouse model of severe exacerbation of chronic allergic asthma. METHODS: Chronic allergic airway inflammation was induced following a house dust mite (HDM) sensitization protocol. HDM-sensitized mice and controls were infected with influenza virus A/X31 H3N2 and either or not treated with inhaled fluticasone propionate (FP), systemic corticosteroids (Pred), or anti-IL-5. Mice were killed at different time points after infection: Cellular accumulation and cytokines levels in the airways, PenH as a measure of airway hyper-responsiveness (AHR), and lung histology and viral replication were assessed. RESULTS: Infection with low-dose A/X31 H3N2 led to prolonged deterioration of lung function, aggravated mucus production, peri-vascular, peri-bronchial, and allergic inflammation that was unresponsive to inhaled corticosteroids, but responsive to systemic corticosteroids. The exacerbation was preceded at 14 h after virus exposure by a marked innate, but no Th2 and Th1 response subsequently followed by enhanced numbers of eosinophils, neutrophils, dendritic, and T cells into the lung lumen, parenchyma, and draining lymph nodes in HDM-sensitized mice. Anti-IL-5 treatment attenuated eosinophils and prevented the X31-induced exacerbation. CONCLUSIONS: Together, these findings indicate that an early innate response that involves eosinophils underlies the exacerbation. This model recapitulates all major features of severe asthma exacerbations and can serve to discern driving mechanisms and promote the development of novel therapeutics.

Systematic characterization of novel lncRNAs responding to phosphate starvation in Arabidopsis thaliana.

BACKGROUND: Previously, several long non-coding RNAs (lncRNAs) were characterized as regulators in phosphate (Pi) starvation responses. However, systematic studies of novel lncRNAs involved in the Pi starvation signaling pathways have not been reported. RESULTS: Here, we used a genome-wide sequencing and bioinformatics approach to identify both poly(A) + and poly(A)- lncRNAs that responded to Pi starvation in Arabidopsis thaliana. We sequenced shoot and root transcriptomes of the Arabidopsis seedlings grown under Pi-sufficient and Pi-deficient conditions, and predicted 1212 novel lncRNAs, of which 78 were poly(A)- lncRNAs. By employing strand-specific RNA libraries, we discovered many novel antisense lncRNAs for the first time. We further defined 309 lncRNAs that were differentially expressed between P+ and P- conditions in either shoots or roots. Through Gene Ontology enrichment of the associated protein-coding genes (co-expressed or close on the genome), we found that many lncRNAs were adjacent or co-expressed with the genes involved in several Pi starvation related processes, including cell wall organization and photosynthesis. In total, we identified 104 potential lncRNA targets of PHR1, a key regulator for transcriptional response to Pi starvation. Moreover, we identified 16 candidate lncRNAs as potential targets of miR399, another key regulator of plant Pi homeostasis. CONCLUSIONS: Altogether, our data provide a rich resource of candidate lncRNAs involved in the Pi starvation regulatory network.

Cognate CD4 T-cell licensing of dendritic cells heralds anti-cytomegalovirus CD8 T-cell immunity after human allogeneic umbilical cord blood transplantation.

UNLABELLED: Reactivation of human cytomegalovirus (CMV) is hazardous to patients undergoing allogeneic cord blood transplantation (CBT), lowering survival rates by approximately 25%. While antiviral treatment ameliorates viremia, complete viral control requires CD8+ T-cell-driven immunity. Mouse studies suggest that cognate antigen-specific CD4+ T-cell licensing of dendritic cells (DCs) is required to generate effective CD8+ T-cell responses. For humans, this was not fully understood. We here show that CD4+ T cells are essential for licensing of human DCs to generate effector and memory CD8+ T-cell immunity against CMV in CBT patients. First, we show in CBT recipients that clonal expansion of CMV-pp65-specific CD4+ T cells precedes the rise in CMV-pp65-specific CD8+ T cells. Second, the elicitation of CMV-pp65-specific CD8+ T cells from rare naive precursors in cord blood requires DC licensing by cognate CMV-pp65-specific CD4+ T cells. Finally, also CD8+ T-cell memory responses require CD4+ T-cell-mediated licensing of DCs in our system, by secretion of gamma interferon (IFN-γ) by pp65-specific CD4+ T cells. Together, these data show that human DCs require licensing by cognate antigen-specific CD4+ T cells to elicit effective CD8+ T-cell-mediated immunity and fight off viral reactivation in CBT patients. IMPORTANCE: Survival rates after stem cell transplantation are lowered by 25% when patients undergo reactivation of cytomegalovirus (CMV) that they harbor. Immune protection against CMV is mostly executed by white blood cells called killer T cells. We here show that for generation of optimally protective killer T-cell responses that respond to CMV, the early elicitation of help from a second branch of CMV-directed T cells, called helper T cells, is required.

Human adipose tissue-derived mesenchymal stem cells abrogate plasmablast formation and induce regulatory B cells independently of T helper cells.

Mesenchymal or stromal stem cells (MSC) interact with cells of the immune system in multiple ways. Modulation of the immune system by MSC is believed to be a therapeutic option for autoimmune disease and transplant rejection. In recent years, B cells have moved into the focus of the attention as targets for the treatment of immune disorders. Current B-cell targeting treatment is based on the indiscriminate depletion of B cells. The aim of this study was to examine whether human adipose tissue-derived MSC (ASC) interact with B cells to affect their proliferation, differentiation, and immune function. ASC supported the survival of quiescent B cells predominantly via contact-dependent mechanisms. Coculture of B cells with activated T helper cells led to proliferation and differentiation of B cells into CD19(+) CD27(high) CD38(high) antibody-producing plasmablasts. ASC inhibited the proliferation of B cells and this effect was dependent on the presence of T cells. In contrast, ASC directly targeted B-cell differentiation, independently of T cells. In the presence of ASC, plasmablast formation was reduced and IL-10-producing CD19(+) CD24(high) CD38(high) B cells, known as regulatory B cells, were induced. These results demonstrate that ASC affect B cell biology in vitro, suggesting that they can be a tool for the modulation of the B-cell response in immune disease.

[Management of vascular anomalies in children]. / Prise en charge des anomalies vasculaires chez l'enfant.

Vascular anomalies, which are broadly identified as "angiomas", are rare entities and often unknown by the medical sphere. They are divided in two different categories which carry different prognosis and management: "vascular tumors" and "vascular malformations". Their precise identification is crucial and involves a good knowledge of the biological classification published by Mulliken and Glowacki and that has recently been updated by the International Society for the Study of Vascular Anomalies (ISSVA). Vascular tumors are benign, common, inborn or not and most of the time disappear with growth. Vascular malformations are always congenital and growth with the child. They can involve type of vessels solely or combined with others. A rheologic differentiation between slow and fast flow malformations is essential in order to characterize the seriousness of the lesion. Frequently, their diagnosis is clinically established and the anamnesis is conducted to answer three questions that are the time of revelation of the lesion ("When?"), its aspect ("What?") and its evolution ("How?"). Further investigations are usually not required but a non-invasive imaging technique such as Doppler ultrasound could be useful if a doubt exists. Surgery is not mandatory and must always be well thought because its consequences might be disastrous. It must be left to cosmetic sequelae of these lesions or to lesions that are totally resectable without causing any unacceptable deformation.

The effect of C1-inhibitor in a murine model of transfusion-related acute lung injury.

BACKGROUND AND OBJECTIVE: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Specific therapy is lacking. We assessed whether C1-inhibitor attenuates lung injury in a 'two-hit' TRALI model. METHODS: Mice were primed with lipopolysaccharide, subsequently TRALI was induced by MHC-I antibodies. In the intervention group, C1-inhibitor was infused concomitantly. Mice were supported with mechanical ventilation. After 2 h, mice were killed, lungs were removed and bronchoalveolar lavage fluid (BALF) was obtained. RESULTS: Injection of MHC-I antibodies induced TRALI, illustrated by an increase in wet-to-dry ratio of the lungs, in BALF protein levels and in lung injury scores. TRALI was further characterized by complement activation, demonstrated by increased BALF levels of C3a and C5a. Administration of C1-inhibitor resulted in increased pulmonary C1-inhibitor levels with high activity. C1-inhibitor reduced pulmonary levels of complement C3a associated with improved lung injury scores. However, levels of pro-inflammatory mediators were unaffected. CONCLUSION: In a murine model of TRALI, C1-inhibitor attenuated pulmonary levels of C3a associated with improved lung injury scores, but with persistent high levels of inflammatory cytokines.

CD25+ regulatory T cells transfer n-3 long chain polyunsaturated fatty acids-induced tolerance in mice allergic to cow's milk protein.

BACKGROUND: Recently, we have shown that dietary long-chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) largely prevent allergic sensitization in a murine model for cow's milk allergy. The aim of this study was to assess the contribution of regulatory T cells (Treg) in the prevention of food allergy by n-3 LCPUFA. METHODS: C3H/HeOuJ female donor mice were fed a control or fish oil diet before and during oral sensitization with cow's milk protein whey. Acute allergic skin response (ASR), anaphylaxis, body temperature, serum immunoglobulins, and mouse mast cell protease-1 (mmcp-1) were assessed. Splenocytes of sham- or whey-sensitized donor mice fed either control or fish oil diet were adoptively transferred to naïve recipient mice. Recipient mice received a whole splenocyte suspension, splenocytes ex vivo depleted of CD25+ cells, or MACS-isolated CD4+ CD25+ Treg. Recipient mice were sham- or whey-sensitized and fed control diet. RESULTS: The ASR as well as whey-specific IgE and whey-specific IgG1 levels were reduced in whey-sensitized donor mice fed the fish oil diet as compared to the control diet. Splenocytes of control-diet-fed whey-sensitized donors transferred immunologic memory. By contrast, splenocytes of fish-oil-fed whey-sensitized - but not sham-sensitized - donors transferred tolerance to recipients as shown by a reduction in ASR and serum mmcp-1, and depletion of CD25+ Treg abrogated this. Transfer of CD25+ Treg confirmed the involvement of Treg in the suppression of allergic sensitization. CONCLUSIONS: CD25+ Treg are crucial in whey allergy prevention by n-3 LCPUFA.

In vitro effects of rituximab on the proliferation, activation and differentiation of human B cells.

Rituximab is a chimeric anti-CD20 monoclonal antibody (mAb) used in B-cell malignancies, various autoimmune disorders and organ transplantation. Although administration of a single dose of rituximab results in full B-cell depletion in peripheral blood, there remains a residual B-cell population in secondary lymphoid organs. These nondepleted B cells might be altered by exposure to rituximab with subsequent immunomodulatory effects. Therefore, we analyzed in vitro the effects of rituximab on proliferation, activation and differentiation of CD19(+) B cells by means of carboxyfluorescein succinimidyl ester (CFSE)-based multiparameter flow cytometry. Rituximab inhibited the proliferation of CD27(-) naïve, but not of CD27(+) memory B cells. Interestingly, upon stimulation with anti-CD40 mAb and interleukin-21 in the presence of rituximab there was an enrichment of B cells that underwent only one or two cell divisions and displayed an activated naïve phenotype (CD27(-)IgD(+)CD38(-/+)). The potency of prestimulated B cells to induce T-cell proliferation was increased by exposure of the B cells to rituximab. Of note, after stimulation with rituximab-treated B cells, proliferated T cells displayed a more Th2-like phenotype. Overall, these results demonstrate that rituximab can affect human B-cell phenotype and function, resulting in an altered outcome of B-T cell interaction.

Contribution of regulatory T cells to alleviation of experimental allergic asthma after specific immunotherapy.

BACKGROUND: Allergen-specific immunotherapy (SIT) has been used since 1911, yet its mechanism of action remains to be elucidated. There is evidence indicating that CD4(+)FOXP3(+) regulatory T cells (Treg cells) are induced during SIT in allergic patients. However, the contribution of these cells to SIT has not been evaluated in vivo. OBJECTIVE: To evaluate the in vivo contribution of (i) CD4(+) CD25(+) T cells during SIT and of (ii) SIT-generated inducible FOXP3(+) Treg cells during allergen exposure to SIT-mediated suppression of asthmatic manifestations. METHODS: We used a mouse model of SIT based on the classical OVA-driven experimental asthma. Treg cells were quantified by flow cytometry 24 and 96 h post SIT treatment. We depleted CD4(+) CD25(+) T cells prior to SIT, and CD4(+)FOXP3(+) T cells prior to allergen challenges to study their contribution to the suppression of allergic manifestations by SIT treatment. RESULTS: Our data show that depletion of CD4(+)CD25(+) T cells at the time of SIT treatment reverses the suppression of airway hyperresponsiveness (AHR), but not of airway eosinophilia and specific IgE levels in serum. Interestingly, the number of CD4(+)CD25(+)FOXP3(+) T cells is transiently increased after SIT in the spleen and blood, suggesting the generation of inducible and presumably allergen-specific Treg cells during treatment. Depletion of CD4(+)FOXP3(+) Treg cells after SIT treatment partially reverses the SIT-induced suppression of airway eosinophilia, but not of AHR and serum levels of specific IgE. CONCLUSION AND CLINICAL RELEVANCE: We conclude that SIT-mediated tolerance induction towards AHR requires CD4(+)CD25(+) T cells at the time of allergen injections. In addition, SIT generates CD4(+)CD25(+)FOXP3(+) T cells that contribute to the suppression of airway eosinophilia upon allergen challenges. Therefore, enhancing Treg cell number or their activity during and after SIT could be of clinical relevance to improve the therapeutic effects of SIT.

House dust mite allergic airway inflammation facilitates neosensitization to inhaled allergen in mice.

BACKGROUND: The mechanism by which many monosensitized allergic individuals progress to polysensitization over time remains to be elucidated. Mouse models have contributed greatly to the understanding of sensitization to inhaled allergens in healthy airways but hardly any studies have addressed sensitization during established allergy. We hypothesized that an allergic inflammatory milieu might facilitate sensitization to inhaled allergens by the presence of mature dendritic cells (DCs) and IL-4. METHODS: Mice with house dust mite (HDM)-induced allergic airway inflammation received a single intratracheal dose of ovalbumin (OVA), 2 days after the last HDM exposure. Ten days later, sensitization was assessed by rechallenge with OVA. We evaluated the following factors for their importance in neosensitization: (1) maturation and recruitment of DCs to the airways, (2) dependency on DCs using CD11cDTR conditional knockout mice, (3) presence of ongoing airway inflammation by comparing sensitization at day 2 and day 14 after the last HDM exposure and (4) dependency on IL-4 by treatment with blocking antibodies. RESULTS: House dust mite -induced inflammation facilitated neosensitization to OVA. HDM-induced inflammation increased the number of airway DCs with a mature phenotype but a DC reduction of 93% did not inhibit sensitization. Neosensitization to OVA was dependent on ongoing inflammation and in particular on IL-4. CONCLUSIONS: These findings show that HDM-induced allergic airway inflammation facilitates neosensitization to a second inhaled allergen in an IL-4-dependent manner and provide insight into the underlying mechanism of the frequently observed progression to polysensitization in HDM-monosensitized individuals.

Lack of evidence of CD40 ligand involvement in transfusion-related acute lung injury.

Activated platelets have been implicated in playing a major role in transfusion-related acute lung injury (TRALI), as platelets can trigger neutrophils, resulting in vascular damage. We hypothesized that binding of platelet CD40 ligand (CD40L) to endothelial CD40 is essential in the onset of TRALI. Mice were challenged with monoclonal major histocompatibility complex (MHC)-1 antibody which induced TRALI, evidenced by pulmonary oedema, accompanied by significantly elevated bronchoalveolar fluid (BALF) levels of total protein and elevated plasma levels of keratinocyte-derived chemokine (KC) and macrophage inflammatory protein-2 (MIP-2) compared to infusion of isotype antibody (all Ps < 0·05). Treatment with ciglitazone, which inhibits platelet CD40L expression, had no effect on pulmonary and systemic inflammation compared to controls. In addition, treatment with anti-CD40L antibody, which antagonizes all CD40-CD40L interactions, also did not abrogate the TRALI reaction. Furthermore, levels of soluble CD40L were measured in a cohort of cardiac surgery patients, who were followed prospectively for the onset of TRALI after transfusion. Plasma levels of sCD40L at baseline and at time of developing TRALI did not differ between TRALI patients and controls (transfused cardiac surgery patients not developing acute lung injury) (275 ± 192 versus 258 ± 346 and 93 ± 82 versus 93 ± 123 pg/ml, respectively, not significant). In conclusion, these results do not support the idea that the CD40-CD40L interaction is involved in mediating TRALI.

CD4(+) CD25(+) T regulatory cells do not transfer oral tolerance to peanut allergens in a mouse model of peanut allergy.

BACKGROUND: Recent studies have implicated CD4(+) CD25(+) regulatory T cells (nTregs) in the maintenance of tolerance to oral antigens and in the regulation of the food allergic IgE response. OBJECTIVE: The objective was to assess if nTregs can transfer allergen-specific oral tolerance to naïve, non-TCR transgenic mice and regulate peanut extract (PE)-specific hypersensitivity responses. Additionally, the role of the regulatory cytokines IL-10 and TGF-ß in the modulation of peanut-allergic sensitization was studied. METHODS: CD25-enriched T cells from PE-tolerant mice were adoptively transferred to recipient mice, which were subsequently sensitized to PE. Depletion of CD25(+) cells and neutralization of IL-10 and TGF-ß were compared in a CH3/HeOuJ mouse model of peanut-allergic sensitization. RESULTS: Transfer of CD25(+) Tregs-enriched cell populations did not affect the PE-specific cytokine production or PE-specific antibody levels compared with control mice but interestingly resulted in a decrease of mast cell responsiveness. On the contrary, transfer of CD25(+) Tregs-depleted cells caused an increase in non-specific cytokine production, in the absence of changes in PE-specific responses. TGF-ß neutralization resulted even in a larger increase in spontaneous release of all cytokines measured (IL-4, IL-5, IL-10, IL-13, and IFN-γ), but surprisingly also to a higher PE-specific Th2-associated (IL-4, IL-5, IL-13) cytokine production compared with depletion of CD25 cells or neutralization of IL-10. Similarly, depletion of CD25 cells and TGF-ß neutralization but not of IL-10 neutralization lead to an increase in PE-specific antibody levels and elevated mast cell degranulation following a PE challenge. CONCLUSIONS AND CLINICAL RELEVANCE: We conclude that CD4(+) CD25(+) Tregs from non-transgenic-tolerant mice cannot transfer specific oral tolerance of exogenous antigens to naïve mice and are more involved in general immune suppressive mechanisms. However, we found evidence that TGF-ß secreting Tregs (Th3) may play an important role.

The role of intestinal dendritic cells subsets in the establishment of food allergy.

BACKGROUND: Food allergy affects approximately 6% of children and is the leading cause of hospitalization for anaphylactic reactions in westernized countries. Crucial in the establishment of allergy is the activation of dendritic cells (DC) leading to T helper 2-mediated responses. OBJECTIVE: We, therefore, investigated whether changes in DC subsets precede the establishment of food allergy, and which DC subsets have functional relevance during allergic sensitization in a mouse model. METHODS: Changes in DC populations in the intestine were analysed after exposure to cholera toxin alone and in combination with peanut extract (PE) as an allergen. To study the functional role of DC subsets in relation to food allergy, we used expansion of DC in vivo by treatment with Flt3L. RESULTS: Sensitization to PE in this mouse model was accompanied by a shift in DC subsets in intestinal tissues towards more CD11b(+) DC and less CD103(+) DC. No significant changes in the plasmacytoid DC (pDC) numbers were observed. Flt3L treatment, resulting in the expansion of all DC subtypes, inhibited allergic manifestations in our model, including Th2 cytokine production, PE-specific IgE and PE-induced mast cell degranulation. pDC depletion reversed Flt3L-induced inhibition of IgE responses and mast cell degranulation. conclusions and clinical relevance: The establishment of food allergy is accompanied by profound changes in DC subsets in the intestine towards more inflammatory CD11b(+) DC. In addition, expansion of DC numbers by Flt3L, in particular pDC, inhibits the establishment of allergic manifestations in the intestine. These findings are of relevance for understanding the role of DC subsets early during the process of allergic sensitization, and may lead to new therapeutic or prophylactic opportunities to prevent food allergy.

Regulation by intestinal γδ T cells during establishment of food allergic sensitization in mice.

BACKGROUND: Food allergy affects approximately 5% of children and is the leading cause of hospitalization for anaphylactic reactions in westernized countries. The mucosal adjuvant cholera toxin induces allergic sensitization to co-administered proteins in mice, while feeding the protein alone induces oral tolerance. Intestinal γδ T cells could be of importance in the induction of oral tolerance. This study aims to investigate whether γδ T cells have functional relevance in food allergic sensitization. METHODS: Changes in γδ T cells on days 1, 2, 3, and 7 after initiation of food allergy were evaluated using flowcytometry. Furthermore, the anti-γδ T-cell receptor (TCR) antibody UC7 was used to block the γδ TCR in mice in vivo, followed by sensitization to peanut. After 4 weeks, peanut-specific antibodies in serum and cytokine production in spleen were measured. RESULTS: Induction of food allergy resulted in a profound decrease in the percentage of γδ T cells in intestinal tissues and Peyer's Patches, but not in mesenteric lymph nodes or spleen. This decrease could be detected from days 1 to 2 after the initiation of food allergy and the number of γδ T cells returned to normal on day 7. Blockade of the γδ TCR resulted in elevated food allergic responses upon sensitization with peanut characterized by increased IgE and Th2 cytokine production in splenocytes. CONCLUSION: These results demonstrate a unique regulatory role of γδ T cells, suggesting that targeting γδ T cells in the intestine may contribute to strategies to prevent and possibly treat food allergy.