Perceptions of autism spectrum disorder among the Swahili community on the Kenyan coast.

BACKGROUND: In high-income and Western societies there is great understanding and awareness of autism spectrum disorder (ASD); however, for many low-middle income countries, research and knowledge is notably lacking. In Africa, there is a growing prevalence of ASD due to increased diagnosis, yet it is still a poorly understood condition. AIMS: Emerging literature has emphasised how cultural and societal beliefs underpin the level of understanding of ASD, and which typically results in lack of awareness and acceptance. As such it is important to investigate the cultural perceptions towards ASD within low-middle income communities of African culture, to further understand the challenges and barriers individuals with ASD face. The aim of the current study was to probe participants from the Swahili community, on the coast of Kenya, of their cultural views towards ASD. METHOD: Semi-structured interviews were conducted with seven participants, and the data analysed using thematic analysis. RESULTS: Three key themes developed from the data; stigma, lack of awareness, and Government responsibility. CONCLUSION: Cultural perceptions negatively impacted awareness and are exacerbated by lack of directive from the Government in providing appropriate diagnostic and educational support.

Pay for performance and hip fracture outcomes: an interrupted time series and difference-in-differences analysis in England and Scotland.

AIMS: Hip fractures are associated with high morbidity, mortality, and costs. One strategy for improving outcomes is to incentivize hospitals to provide better quality of care. We aimed to determine whether a pay-for-performance initiative affected hip fracture outcomes in England by using Scotland, which did not participate in the scheme, as a control. MATERIALS AND METHODS: We undertook an interrupted time series study with data from all patients aged more than 60 years with a hip fracture in England (2000 to 2018) using the Hospital Episode Statistics Admitted Patient Care (HES APC) data set linked to national death registrations. Difference-in-differences (DID) analysis incorporating equivalent data from the Scottish Morbidity Record was used to control for secular trends. The outcomes were 30-day and 365-day mortality, 30-day re-admission, time to operation, and acute length of stay. RESULTS: There were 1 037 860 patients with a hip fracture in England and 116 594 in Scotland. Both 30-day (DID -1.7%; 95% confidence interval (CI) -2.0 to -1.2) and 365-day (-1.9%; 95% CI -2.5 to -1.3) mortality fell in England post-intervention when compared with outcomes in Scotland. There were 7600 fewer deaths between 2010 and 2016 that could be attributed to interventions driven by pay-for-performance. A pre-existing annual trend towards increased 30-day re-admissions in England was halted post-intervention. Significant reductions were observed in the time to operation and length of stay. CONCLUSION: This study provides evidence that a pay-for-performance programme improved the outcomes after a hip fracture in England. Cite this article: Bone Joint J 2019;101-B:1015-1023.

Validation of a prospective cohort study of older adults with hip fractures.

AIMS: This study sought to determine the proportion of older adults with hip fractures captured by a multicentre prospective cohort, the World Hip Trauma Evaluation (WHiTE), whether there was evidence of selection bias during WHiTE recruitment, and the extent to which the WHiTE cohort is representative of the broader population of older adults with hip fractures. PATIENTS AND METHODS: The characteristics of patients recruited into the WHiTE cohort study were compared with those treated at WHiTE hospitals during the same timeframe and submitted to the National Hip Fracture Database (NHFD). RESULTS: Patients recruited to WHiTE were more likely to be admitted from their own home (83.5% vs 80.2%; p < 0.001) and to have a higher median Abbreviated Mental Test Score (AMTS) (9 (interquartile range (IQR) 6 to 10) vs 9 (IQR 5 to 10); p < 0.001) than those who were not recruited. In terms of WHiTE cohort generalizability, participating hospitals included a greater proportion of Major Trauma Centres (47.8% vs 7.8%) and large hospitals (997 (IQR 873 to 1290) vs 707 (459 to 903) beds) with high-volume Emergency Departments (median annual attendances of 43 981 (IQR 37 147 to 54 385) vs 35 964 (IQR 26 229 to 50 551)). However, there were few differences in baseline characteristics between patients in the WHiTE cohort and those recorded in the NHFD. CONCLUSION: There is evidence of a weak selection bias towards recruiting fitter patients within the WHiTE cohort, which will help to put into context the findings of future studies. We conclude that the patients within the WHiTE cohort are representative of the national population of older adults with hip fractures throughout England, Wales, and Northern Ireland. Cite this article: Bone Joint J 2019;101-B:708-714.

Temporal trends and survivorship of total hip arthroplasty in very young patients: a study using the National Joint Registry data set.

AIMS: The aim of this study was to describe temporal trends and survivorship of total hip arthroplasty (THA) in very young patients, aged ≤ 20 years. PATIENTS AND METHODS: A descriptive observational study was undertaken using data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man between April 2003 and March 2017. All patients aged ≤ 20 years at the time of THA were included and the primary outcome was revision surgery. Descriptive statistics were used to summarize the data and Kaplan-Meier estimates calculated for the cumulative implant survival. RESULTS: A total of 769 THAs were performed in 703 patients. The median follow-up was 5.1 years (interquartile range (IQR) 2.6 to 7.8). Eight patients died and 35 THAs were revised. The use of metal-on-metal (MoM) bearings and resurfacing procedures declined after 2008. The most frequently recorded indications for revision were loosening (20%) and infection (20%), although the absolute risk of these events occurring was low (0.9%). Factors associated with lower implant survival were MoM and metal-on-polyethylene (MoP) bearings and resurfacing arthroplasty ( vs ceramic-on-polyethylene (CoP) and ceramic-on-ceramic (CoC) bearings, p = 0.002), and operations performed by surgeons who undertook few THAs in this age group as recorded in the NJR ( vs those with five or more recorded operations, p = 0.030). Kaplan-Meier estimates showed 96% (95% confidence interval (CI) 94% to 98%) survivorship of implants at five years. CONCLUSION: Within the NJR, the overall survival for very young patients undergoing THA exceeded 96% during the first five postoperative years. In the absence of studies that can better account for differences in the characteristics of the patients, surgeons should consider the association between early revision and the type of implant, the number of THAs performed in these patients, and the bearing surface when performing THA in very young patients. Cite this article: Bone Joint J 2018;100-B:1320-9.

Identification of alpha-gal sensitivity in patients with a diagnosis of idiopathic anaphylaxis.

IgE antibodies (Ab) specific to galactose-α-1,3-galactose (alpha-gal) are responsible for a delayed form of anaphylaxis that occurs 3-6 hours after red meat ingestion. In a unique prospective study of seventy participants referred with a diagnosis of idiopathic anaphylaxis (IA), six (9%) were found to have IgE to alpha-gal. Upon institution of a diet free of red meat, all patients had no further episodes of anaphylaxis. Two of these individuals had indolent systemic mastocytosis (ISM). Those with ISM had more severe clinical reactions but lower specific IgE to alpha-gal and higher serum tryptase levels, reflective of the mast cell burden. The identification of alpha-gal syndrome in patients with IA supports the need for routine screening for this sensitivity as a cause of anaphylaxis, where reactions to alpha-gal are delayed and thus may be overlooked.

Proposed diagnostic criteria and classification of basophilic leukemias and related disorders.

Basophils form a distinct cell lineage within the hematopoietic cell family. In various myeloid neoplasms, including chronic myeloid leukemia, basophilia is frequently seen. Acute and chronic basophilic leukemias, albeit rare, have also been described. However, no generally accepted criteria and classification of basophilic leukemias have been presented to date. To address this unmet need, a series of Working Conferences and other meetings were organized between March 2015 and March 2016. The current article provides a summary of consensus statements from these meetings, together with proposed criteria to delineate acute basophilic leukemia (ABL) from chronic basophilic leukemia (CBL) and primary forms of the disease where no preceding myeloid malignancy is detected, from the more common 'secondary' variants. Moreover, the term hyperbasophilia (HB) is proposed for cases with a persistent peripheral basophil count ⩾1000 per µl of blood. This condition, HB, is highly indicative of the presence of an underlying myeloid neoplasm. Therefore, HB is an important checkpoint in the diagnostic algorithm and requires a detailed hematologic investigation. In these patients, an underlying myeloid malignancy is often found and is then labeled with the appendix -baso, whereas primary cases of ABL or CBL are very rare. The criteria and classification proposed in this article should facilitate the diagnosis and management of patients with unexplained basophilia and basophil neoplasms in routine practice, and in clinical studies.

Regionalisation of trauma care in England.

AIMS: We aimed to determine whether there is evidence of improved patient outcomes in Major Trauma Centres following the regionalisation of trauma care in England. PATIENTS AND METHODS: An observational study was undertaken using the Trauma Audit and Research Network (TARN), Hospital Episode Statistics (HES) and national death registrations. The outcome measures were indicators of the quality of trauma care, such as treatment by a senior doctor and clinical outcomes, such as mortality in hospital. RESULTS AND CONCLUSION: A total of 20 181 major trauma cases were reported to TARN during the study period, which was 270 days before and after each hospital became a Major Trauma Centre. Following regionalisation of trauma services, all indicators of the quality of care improved, fewer patients required secondary transfer between hospitals and a greater proportion were discharged with a Glasgow Outcome Score of "good recovery". In this early post-implementation analysis, there were a number of apparent process improvements (e.g. time to CT) but no differences in either crude or adjusted mortality. The overall number of deaths following trauma in England did not change following the national reconfiguration of trauma services. Evidence from other countries that have regionalised trauma services suggests that further benefits may become apparent after a period of maturing of the trauma system. Cite this article: Bone Joint J 2016;98-B:1253-61.

Seasonality and nitrogen supply modify carbon partitioning in understory vegetation of a boreal coniferous forest.

Given the strong coupling between the carbon (C) and nitrogen (N) cycles, there is substantial interest in understanding how N availability affects C cycling in terrestrial ecosystems, especially in ecosystems limited by N. However, most studies in temperate and boreal forests have focused on the effects of N addition on tree growth. By comparison, less is known about the effects of N availability on the cycling of C in understory vegetation despite some evidence that dwarf shrubs, mosses, and lichens play an important role in the forest C balance. In this study, we used an in situ 13CO2 pulse-labeling technique to examine the short-term dynamics of C partitioning in understory vegetation in three boreal Pinus sylvestris forest stands exposed to different rates of N addition: a low and high N addition that receive annual additions of NH4NO3 of 20 and 100 kg N/ha, respectively, and this is a typo. It should be an unfertilized control. Labeling was conducted at two distinct periods (early vs. late growing season), which provided a seasonal picture of how N addition affects C dynamics in understory vegetation. In contrast to what has been found in trees, there was no obvious trend in belowground C partitioning in ericaceous plants in response to N additions or seasonality. Increasing N addition led to a greater percentage of 13C being incorporated into ericaceous leaves with a high turnover, whereas high rates of N addition strongly reduced the incorporation of 13C into less degradable moss tissues. Addition of N also resulted in a greater percentage of the 13C label being respired back to the atmosphere and an overall reduction in total understory carbon use efficiency. Taken together, our results suggest a faster cycling of C in understory vegetation with increasing N additions; yet the magnitude of this general response was strongly dependent on the amount of N added and varied seasonally. These results provide some of the first in situ C and N partitioning estimates for plants growing under the complex web of resource limitations in the boreal understory.

Quality of care for patients with a fracture of the hip in major trauma centres: a national observational study.

AIMS: In this study, we aimed to determine whether designation as a major trauma centre (MTC) affects the quality of care for patients with a fracture of the hip. PATIENTS AND METHODS: All patients in the United Kingdom National Hip Fracture Database, between April 2010 and December 2013, were included. The indicators of quality that were recorded included the time to arrival on an orthopaedic ward, to review by a geriatrician, and to operation. The clinical outcomes were the development of a pressure sore, discharge home, length of stay, in-hospital mortality, and re-operation within 30 days. RESULTS: There were 289 466 patients, 49 350 (17%) of whom were treated in hospitals that are now MTCs. Using multivariable logistic and generalised linear regression models, there were no significant differences in any of the indicators of the quality of care or clinical outcomes between MTCs, hospitals awaiting MTC designation and non-MTC hospitals. CONCLUSION: These findings suggest that the regionalisation of major trauma in England did not improve or compromise the overall care of elderly patients with a fracture of the hip. TAKE HOME MESSAGE: There is no evidence that reconfiguring major trauma services in England disrupted the treatment of older adults with a fracture of the hip.

Development and validation of the mastocytosis quality of life questionnaire: MC-QoL.

BACKGROUND: Mastocytosis is a heterogeneous disease characterized by a clonal expansion of mast cells in various organs. The vast majority of patients affected suffer from signs and symptoms caused by mediator release from mast cells. Although the disease burden is high, there is currently no specific instrument to measure health-related quality of life (HRQoL) impairment in patients with mastocytosis. OBJECTIVE: The aim of this study was to develop and validate a disease-specific tool to assess HRQoL impairment in patients with cutaneous and indolent systemic mastocytosis, the Mastocytosis Quality of Life Questionnaire (MC-QoL). METHODS: Sixty-two potential MC-QoL items were developed in a combined approach consisting of semi-structured patient interviews, expert input and literature research. Item selection was performed by impact analysis with 76 patients and a final review for face validity. The resulting MC-QoL was tested for validity, reliability and influence factors. In parallel, an US American-English version of the MC-QoL was developed. RESULTS: A total of 158 patients (41 CM, 41 MIS and 76 ISM) took part in the MC-QoL validation study. The final 27-item questionnaire was found to have a four-domain structure ('symptoms', 'emotions', 'social life/functioning' and 'skin'), a valid total score and an excellent test-retest reliability. Multiple regression analysis revealed disease duration, but not age, gender or skin involvement to be a significant determinant of HRQoL impairment in mastocytosis. CONCLUSIONS: The MC-QoL is the first disease-specific HRQoL questionnaire for adult patients with cutaneous and indolent systemic mastocytosis. This short, validated and reliable instrument will serve as a valuable tool in future clinical studies and in routine patient care.

Prophylactic antibiotics in open distal phalanx fractures: systematic review and meta-analysis.

A systematic review was conducted on 30 December 2014 to determine whether prophylactic antibiotics reduce the risk of superficial infection and osteomyelitis following open distal phalanx fractures. Four randomized controlled trials (353 fractures) were suitable for meta-analysis. There was no statistically significant difference between rates of superficial infection in the two groups. This finding persisted when only the two most recent and highest quality trials were included. There were no reported cases of osteomyelitis in the pooled dataset, despite patients with 164 fractures not receiving antibiotics. These results fail to show any effect of prophylactic antibiotics on the rate of superficial infections following open distal phalanx fractures. The focus of treatment should be on prompt irrigation and debridement rather than administration of prophylactic antibiotics.

Death from drought in tropical forests is triggered by hydraulics not carbon starvation.

Drought threatens tropical rainforests over seasonal to decadal timescales, but the drivers of tree mortality following drought remain poorly understood. It has been suggested that reduced availability of non-structural carbohydrates (NSC) critically increases mortality risk through insufficient carbon supply to metabolism ('carbon starvation'). However, little is known about how NSC stores are affected by drought, especially over the long term, and whether they are more important than hydraulic processes in determining drought-induced mortality. Using data from the world's longest-running experimental drought study in tropical rainforest (in the Brazilian Amazon), we test whether carbon starvation or deterioration of the water-conducting pathways from soil to leaf trigger tree mortality. Biomass loss from mortality in the experimentally droughted forest increased substantially after >10 years of reduced soil moisture availability. The mortality signal was dominated by the death of large trees, which were at a much greater risk of hydraulic deterioration than smaller trees. However, we find no evidence that the droughted trees suffered carbon starvation, as their NSC concentrations were similar to those of non-droughted trees, and growth rates did not decline in either living or dying trees. Our results indicate that hydraulics, rather than carbon starvation, triggers tree death from drought in tropical rainforest.

Prophylactic antibiotics in elective hip and knee arthroplasty: an analysis of organisms reported to cause infections and National survey of clinical practice.

OBJECTIVES: We wanted to investigate regional variations in the organisms reported to be causing peri-prosthetic infections and to report on prophylaxis regimens currently in use across England. METHODS: Analysis of data routinely collected by Public Health England's (PHE) national surgical site infection database on elective primary hip and knee arthroplasty procedures between April 2010 and March 2013 to investigate regional variations in causative organisms. A separate national survey of 145 hospital Trusts (groups of hospitals under local management) in England routinely performing primary hip and/or knee arthroplasty was carried out by standard email questionnaire. RESULTS: Analysis of 189 858 elective primary hip and knee arthroplasty procedures and 1116 surgical site infections found statistically significant variations for some causative organism between regions. There was a 100% response rate to the prophylaxis questionnaire that showed substantial variation between individual trust guidelines. A number of regimens currently in use are inconsistent with the best available evidence. CONCLUSIONS: The approach towards antibiotic prophylaxis in elective arthroplasty nationwide reveals substantial variation without clear justification. Only seven causative organisms are responsible for 89% of infections affecting primary hip and knee arthroplasty, which cannot justify such widespread variation between prophylactic antibiotic policies. Cite this article: Bone Joint Res 2015;4:181-189.

Drought impact on forest carbon dynamics and fluxes in Amazonia.

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.

KIT mutation analysis in mast cell neoplasms: recommendations of the European Competence Network on Mastocytosis.

Although acquired mutations in KIT are commonly detected in various categories of mastocytosis, the methodologies applied to detect and quantify the mutant type and allele burden in various cells and tissues are poorly defined. We here propose a consensus on methodologies used to detect KIT mutations in patients with mastocytosis at diagnosis and during follow-up with sufficient precision and sensitivity in daily practice. In addition, we provide recommendations for sampling and storage of diagnostic material as well as a robust diagnostic algorithm. Using highly sensitive assays, KIT D816V can be detected in peripheral blood leukocytes from most patients with systemic mastocytosis (SM) that is a major step forward in screening and SM diagnosis. In addition, the KIT D816V allele burden can be followed quantitatively during the natural course or during therapy. Our recommendations should greatly facilitate diagnostic and follow-up investigations in SM in daily practice as well as in clinical trials. In addition, the new tools and algorithms proposed should lead to a more effective screen, early diagnosis of SM and help to avoid unnecessary referrals.

Effect of regional trauma centralization on volume, injury severity and outcomes of injured patients admitted to trauma centres.

BACKGROUND: Centralization of complex healthcare services into specialist high-volume centres is believed to improve outcomes. For injured patients, few studies have evaluated the centralization of major trauma services. The aim of this study was to evaluate how a regional trauma network affected trends in admissions, case mix, and outcomes of injured patients. METHODS: A retrospective before-after study was undertaken of severely injured patients attending four hospitals that became major trauma centres (MTCs) in March 2012. Consecutive patients with major trauma were identified from a national registry and divided into two groups according to injury before or after the launch of a new trauma network. The two cohorts were compared for differences in case mix, demand on hospital resources, and outcomes. RESULTS: Patient volume increased from 442 to 1326 (200 per cent), operations from 349 to 1231 (253 per cent), critical care bed-days from 1100 to 3704 (237 per cent), and total hospital bed-days from 7910 to 22,772 (188 per cent). Patient age increased on MTC designation from 45.0 years before March 2012 to 48.2 years afterwards (P = 0.021), as did the proportion of penetrating injuries (1.8 versus 4.1 per cent; P = 0.025). Injury severity fell as measured by median Injury Severity Score (16 versus 14) and Revised Trauma Score (4.1 versus 7.8). Fewer patients required secondary transfer to a MTC from peripheral hospitals (19.9 versus 16.1 per cent; P = 0.100). There were no significant differences in total duration of hospital stay, critical care requirements or mortality. However, there was a significant increase, from 55.5 to 62.3 per cent (P < 0.001), in the proportion of patients coded as having a 'good recovery' at discharge after institution of the trauma network. CONCLUSION: MTC designation leads to an increased case volume with considerable implications for operating theatre capacity and bed occupancy. Although no mortality benefit was demonstrated within 6 months of establishing this trauma network, early detectable advantages included improved functional outcome at discharge.

Proposed diagnostic algorithm for patients with suspected mastocytosis: a proposal of the European Competence Network on Mastocytosis.

Mastocytosis is an emerging differential diagnosis in patients with more or less specific mediator-related symptoms. In some of these patients, typical skin lesions are found and the diagnosis of mastocytosis can be established. In other cases, however, skin lesions are absent, which represents a diagnostic challenge. In the light of this unmet need, we developed a diagnostic algorithm for patients with suspected mastocytosis. In adult patients with typical lesions of mastocytosis in the skin, a bone marrow (BM) biopsy should be considered, regardless of the basal serum tryptase concentration. In adults without skin lesions who suffer from mediator-related or other typical symptoms, the basal tryptase level is an important parameter. In those with a slightly increased tryptase level, additional investigations, including a sensitive KIT mutation analysis of blood leucocytes or measurement of urinary histamine metabolites, may be helpful. In adult patients in whom (i) KIT D816V is detected and/or (ii) the basal serum tryptase level is clearly increased (>25-30 ng/ml) and/or (iii) other clinical or laboratory features suggest the presence of 'occult' mastocytosis or another haematologic neoplasm, a BM investigation is recommended. In the absence of KIT D816V and other signs or symptoms of mastocytosis or another haematopoietic disease, no BM investigation is required, but the clinical course and tryptase levels are monitored in the follow-up. In paediatric patients, a BM investigation is usually not required, even if the tryptase level is increased. Although validation is required, it can be expected that the algorithm proposed herein will facilitate the management of patients with suspected mastocytosis and help avoid unnecessary referrals and investigations.

Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal.

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. In a subset of patients, circulating MCs are detectable. A major differential diagnosis to MCL is myelomastocytic leukemia (MML). Although criteria for both MCL and MML have been published, several questions remain concerning terminologies and subvariants. To discuss open issues, the EU/US-consensus group and the European Competence Network on Mastocytosis (ECNM) launched a series of meetings and workshops in 2011-2013. Resulting discussions and outcomes are provided in this article. The group recommends that MML be recognized as a distinct condition defined by mastocytic differentiation in advanced myeloid neoplasms without evidence of SM. The group also proposes that MCL be divided into acute MCL and chronic MCL, based on the presence or absence of C-Findings. In addition, a primary (de novo) form of MCL should be separated from secondary MCL that typically develops in the presence of a known antecedent MC neoplasm, usually aggressive SM (ASM) or MC sarcoma. For MCL, an imminent prephase is also proposed. This prephase represents ASM with rapid progression and 5%-19% MCs in BM smears, which is generally accepted to be of prognostic significance. We recommend that this condition be termed ASM in transformation to MCL (ASM-t). The refined classification of MCL fits within and extends the current WHO classification; and should improve prognostication and patient selection in practice as well as in clinical trials.

Targeting the KIT activating switch control pocket: a novel mechanism to inhibit neoplastic mast cell proliferation and mast cell activation.

Activating mutations in the receptor tyrosine kinase KIT, most notably KIT D816V, are commonly observed in patients with systemic mastocytosis. Thus, inhibition of KIT has been a major focus for treatment of this disorder. Here we investigated a novel approach to such inhibition. Utilizing rational drug design, we targeted the switch pocket (SP) of KIT, which regulates its catalytic conformation. Two SP inhibitors thus identified, DP-2976 and DP-4851, were examined for effects on neoplastic mast cell proliferation and mast cell activation. Autophosphorylation of both wild-type and, where also examined, KIT D816V activation was blocked by these compounds in transfected 293T cells, HMC 1.1 and 1.2 human mast cell lines, and in CD34(+)-derived human mast cells activated by stem cell factor (SCF). Both inhibitors induced apoptosis in the neoplastic mast cell lines and reduced survival of primary bone marrow mast cells from patients with mastocytosis. Moreover, the SP inhibitors more selectively blocked SCF potentiation of FcɛRI-mediated degranulation. Overall, SP inhibitors represent an innovative mechanism of KIT inhibition whose dual suppression of KIT D816V neoplastic mast cell proliferation and SCF-enhanced mast cell activation may provide significant therapeutic benefits.

Bone marrow stromal cells inhibit mast cell function via a COX2-dependent mechanism.

BACKGROUND: Mast cells (MCs) have a central role in the induction of allergic inflammation, such as seen in asthma, and contribute to the severity of certain autoimmune diseases, such as rheumatoid arthritis. The MC thus represents an important inflammatory cell, and one which has resisted therapeutic attempts to alter its role in disease. OBJECTIVE: Because bone marrow-derived stromal cells (BMSC, also known as mesenchymal stem cells or MSCs) have been reported to alter allergic inflammation in vivo, we chose to study the interaction between mouse BMSC and mouse bone marrow-derived MCs. METHODS: MC degranulation, cytokine production and chemotaxis were evaluated in vitro following co-culture with BMSCs either in cell contact or a transwell. In addition, MC degranulation was assessed in vivo following administration of BMSCs in a model of passive cutaneous anaphylaxis and a peritoneal degranulation assay. Mechanisms of MC suppression by BMSCs were determined through use of inhibitors or antibodies to COX1, COX2, nitric oxide, indoleamine 2, 3-dioxygenase, EP1-4 receptors, TGF-ß and IL-10. Lastly, we utilized either BMSCs or MCs deficient in COX1, COX2 or EP1-4 receptors to confirm the mechanisms of inhibition of MC function by BMSCs. RESULTS: We discovered that BMSCs will effectively suppress specific MC functions in vitro as well as in vivo. When MCs are cocultured with BMSCs to allow cell-to-cell contact, BMSCs suppressed MC degranulation, pro-inflammatory cytokine production, chemokinesis and chemotaxis. Similarly, MC degranulation within mouse skin or the peritoneal cavity was suppressed following in vivo administration of BMSCs. Further, we found that these inhibitory effects were dependent on up-regulation of COX2 in BMSCs; and were facilitated through the activation of EP4 receptors on MCs. CONCLUSION AND CLINICAL RELEVANCE: These observations support the concept that BMSCs have the ability to suppress MC activation and therefore could be the basis for a novel cell based therapeutic approach in the treatment of MC driven inflammatory diseases.