Long-Term Treatment With Selective PI3Kδ Inhibitor Leniolisib in Adults With Activated PI3Kδ Syndrome

Activated phosphoinositide 3-kinase delta syndrome (APDS) is an inborn error of immunity that manifests as immune deficiency and dysregulation; symptoms include frequent infections and lymphoproliferation. In our dose-finding and phase 3 placebo-controlled trials, treatment with the selective PI3Kδ inhibitor leniolisib reduced lymphoproliferation and normalized lymphocyte subsets. Here, we present 6 years of follow-up from the 6 adult patients in the original dose-finding trial receiving leniolisib. We used data from the ongoing open-label extension study, which was supplemented at later time points by investigators, including health-related quality of life assessed through a clinician-reported questionnaire. We observed improvements in health-related quality of life: 5/6 patients experienced an increase in physical capabilities and socialization and a decrease in prescribed medications. Immune subsets improved in all patients: mean transitional B-cell levels decreased from 38.17% to 2.47% and the CD4:CD8 T-cell ratio normalized to 1.11. Manifestations seen before and within the first year of leniolisib exposure, such as infections and gastrointestinal conditions, attenuated following year 2 with few new conditions emerging out to year 6. Thrombocytopenia or lymphopenia remained present in half of patients at year 6. Of 83 adverse events through year 5, 90.36% were grade 1; none were grade 4-5 nor deemed leniolisib-related. Collectively, we saw an enhancement in health-related quality of life as well as durable changes in lymphocyte subsets and clinical manifestations, further supporting the use of leniolisib as a long-term therapeutic option for the treatment of APDS. (Funded by Novartis Pharmaceuticals Corporation and Pharming Group NV; ClinicalTrials.gov identifier: NCT02859727.).

Genotype, oxidase status, and preceding infection or autoinflammation do not affect allogeneic HCT outcomes for CGD

Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by life-threatening infections and inflammatory conditions. Hematopoietic cell transplantation (HCT) is the definitive treatment for CGD, but questions remain regarding patient selection and impact of active disease on transplant outcomes. We performed a multi-institutional retrospective and prospective study of 391 patients with CGD treated either conventionally (non-HCT) enrolled from 2004 to 2018 or with HCT from 1996 to 2018. Median follow-up after HCT was 3.7 years with a 3-year overall survival of 82% and event-free survival of 69%. In a multivariate analysis, a Lansky/Karnofsky score <90 and use of HLA-mismatched donors negatively affected survival. Age, genotype, and oxidase status did not affect outcomes. Before HCT, patients had higher infection density, higher frequency of noninfectious lung and liver diseases, and more steroid use than conventionally treated patients; however, these issues did not adversely affect HCT survival. Presence of pre-HCT inflammatory conditions was associated with chronic graft-versus-host disease. Graft failure or receipt of a second HCT occurred in 17.6% of the patients and was associated with melphalan-based conditioning and/or early mixed chimerism. At 3 to 5 years after HCT, patients had improved growth and nutrition, resolved infections and inflammatory disease, and lower rates of antimicrobial prophylaxis or corticosteroid use compared with both their baseline and those of conventionally treated patients. HCT leads to durable resolution of CGD symptoms and lowers the burden of the disease. Patients with active infection or inflammation are candidates for transplants; HCT should be considered before the development of comorbidities that could affect performance status. This trial was registered at www.clinicaltrials.gov as #NCT02082353.

Inborn Errors of Immunity

Inborn errors of immunity occur in 1 in 1000 to 1 in 5000 individuals and are characterized by immune deficiency and immune dysregulation. The primary care provider (PCP) should be familiar with key features of these diagnoses including recurrent and/or severe infections, hyperinflammation, malignancy, and autoimmunity and have a low threshold to refer for evaluation. The PCP can begin a laboratory evaluation before referral by sending a complete blood count (CBC) with differential, antibody levels, vaccine titers, and possibly other tests. Management approaches vary from antibiotic prophylaxis to hematopoietic stem cell transplantation depending on the specific diagnosis.

A granular view of X-linked chronic granulomatous disease exploiting single-cell transcriptomics

X-linked chronic granulomatous disease (X-CGD) is a rare monogenetic immunodeficiency primarily affecting phagocytes. Precipitated by mutations in the CYBB gene, patients exhibit a compromised oxidative burst, leading to recurrent infections which can be life-threatening. Curiously, autoimmune manifestations are also common in patients and carriers. Here, exploiting the cell type-specific nature of this disorder, we characterize X-CGD on a transcriptional level using single-cell sequencing. Peripheral blood from 14 X-CGD probands and 10 carriers signed onto IRB approved protocol NCT00404560, as well as from 15 controls was sampled, and PBMCs and isolated monocytes were subjected to single-cell sequencing. Probands exhibited a strong differential expression signal relative to controls. This was composed of not only genes previously described to be up-regulated in X-CGD such as IFI27, and indeed an autoimmunity-associated broader type I interferon response, but also previously undescribed genes involved in monocyte function (ARG1), antimicrobial proteins (CAMP, SLPI), and inflammasome components (AIM2). Surprisingly, expression variability was not greater in carriers relative to probands or controls, indicating a lack of cell autonomous effects from the deletion of CYBB. Interestingly, aggregate expression of differentially expressed genes in the probands was able to classify carriers from sex-matched controls with high accuracy (AUROC = 0.92), indicating the presence of an X-CGD-specific gene signature. This gene signature was also strongly co-expressed across 17 chordate species, pointing towards the disruption of ancestral pathways important in antimicrobial immunity in X-CGD probands and carriers.

This work was partially supported by a Swiss National Science Foundation fellowship to S.M. 

139 Absence of Coding in an Outpatient Paediatric Orthopaedic Department – Where Does the Money Go?

Aim

Paediatric orthopaedics conditions are often managed in the outpatient department (OPD) setting. Due to the lack of official coding for these minor procedures in our OPD, the hospital receives neither financial benefit nor evidence for a formal auditing process. With the Paediatric Get It Right First Time (GIRFT) report underway, we have looked at building a coding pathway for paediatric interventions in our OPD.

Method

The number of paediatric orthopaedic interventions were collated and grouped in a 6-month period, and a clinical outcome form was created accordingly. After consulting with the coding department, a cost analysis of prospective earnings was conducted, as well as comparisons to current standard tariff rates for OPD attendance.

Results

From January 2021 to June 2021, 100 interventions were performed in our OPD with the breakdown of: 21 clubfoot serial casting, 70 serial casting for pathology such as tip toe walkers, 6 Botox injections in spastic contracture limbs and 3 Pavlik harnesses for developmental dysplasia of the hip. With the assistance of coding department, a new paediatric procedural coding form was created with 14 relevant interventions listed. A loss of £6110 was calculated due to tariff rates being solely attendance based compared to interventional based.

Conclusions

Paediatric orthopaedic OPD should have clinical coding outcomes in place for each intervention that is performed to ensure that the hospital trust receives appropriate financial commission as well as ensure a formal audit trial can be produced.

Trends in Pediatric Primary Immunodeficiency: Incidence, Utilization, Transplantation, and Mortality

BACKGROUND

Primary immunodeficiency disorders (PIDDs) describe a myriad of diseases caused by inherited defects within the immune system. As the number of identified genetic defects associated with PIDDs increases, understanding the incidence and outcomes of PIDD patients becomes imperative.

OBJECTIVE

To characterize the frequency of new diagnoses, patterns of health care utilization, rates of hematopoietic stem cell transplantation (HSCT), and mortality in pediatric patients with PIDDs.

METHODS

A retrospective cohort analysis of the Pediatric Health Information System database from 2004 to 2018 for pediatric inpatients with an International Classification of Diseases, Ninth and 10th Revisions (ICD-9/ICD-10). code associated with PIDD.

RESULTS

A total of 17,234 patients with a PIDD were hospitalized from 2004 to 2018. There were 2.8 new PIDD diagnoses and 6.3 PIDD hospitalizations per 1,000 discharges; these metrics were unchanged during the study period. The number of new diagnoses for B-cell and antibody defects significantly increased over time. The number of new PIDD diagnoses significantly increased in adolescents or adults and decreased in infants. T-cell disorders had the highest number of intensive care unit admissions. There were 747 PIDD patients who underwent HSCT; complications of HSCT significantly decreased over time. Mortality rates significantly decreased in all PIDD patients and in patients receiving HSCT.

CONCLUSIONS

The total hospitalizations and incidence of PIDDs within the hospitalized pediatric population were unchanged. There were significant changes in the class of PIDD diagnosed, the age at diagnosis, and health care utilization metrics. Mortality significantly decreased over time within the PIDD cohort.

A Toolkit and Framework for Optimal Laboratory Evaluation of Individuals with Suspected Primary Immunodeficiency

Knowledge related to the biology of inborn errors of immunity and associated laboratory testing methods continues to expand at a tremendous rate. Despite this, many patients with inborn errors of immunity suffer for prolonged periods of time before identification of their underlying condition, thereby delaying appropriate care. Understanding that test selection and optimal evaluation for patients with recurrent infections or unusual patterns of inflammation can be unclear, we present a document that distills relevant clinical features of immunologic disease due to inborn errors of immunity and related appropriate and available test options. This document is intended to serve the practicing clinical immunologist and, in turn, patients by describing best available test options for initial and expanded immunologic evaluations across the disease spectrum. Our goal is to demystify the process of evaluating patients with suspected immune dysfunction and to enable more rapid and accurate diagnosis of such individuals.

Correction: Chronic Granulomatous Disease-Associated IBD Resolves and Does Not Adversely Impact Survival Following Allogeneic HCT

The original version of this article unfortunately contained the missing author, Caridad Martinez. The authors would like to correct the list. We apologize for any inconvenience that this may have caused. The correct author list is shown above.

Infections in Infants with SCID: Isolation, Infection Screening, and Prophylaxis in PIDTC Centers

PURPOSE

The Primary Immune Deficiency Treatment Consortium (PIDTC) enrolled children with severe combined immunodeficiency (SCID) in a prospective natural history study of hematopoietic stem cell transplant (HSCT) outcomes over the last decade. Despite newborn screening (NBS) for SCID, infections occurred prior to HSCT. This study's objectives were to define the types and timing of infection prior to HSCT in patients diagnosed via NBS or by family history (FH) and to understand the breadth of strategies employed at PIDTC centers for infection prevention.

METHODS

We analyzed retrospective data on infections and pre-transplant management in patients with SCID diagnosed by NBS and/or FH and treated with HSCT between 2010 and 2014. PIDTC centers were surveyed in 2018 to understand their practices and protocols for pre-HSCT management.

RESULTS

Infections were more common in patients diagnosed via NBS (55%) versus those diagnosed via FH (19%) (p = 0.012). Outpatient versus inpatient management did not impact infections (47% vs 35%, respectively; p = 0.423). There was no consensus among PIDTC survey respondents as to the best setting (inpatient vs outpatient) for pre-HSCT management. While isolation practices varied, immunoglobulin replacement and antimicrobial prophylaxis were more uniformly implemented.

CONCLUSION

Infants with SCID diagnosed due to FH had lower rates of infection and proceeded to HSCT more quickly than did those diagnosed via NBS. Pre-HSCT management practices were highly variable between centers, although uses of prophylaxis and immunoglobulin support were more consistent. This study demonstrates a critical need for development of evidence-based guidelines for the pre-HSCT management of infants with SCID following an abnormal NBS.

TRIAL REGISTRATION

NCT01186913.

Effect of isoflurane on myocardial ischemia-reperfusion injury through the p38 MAPK signaling pathway

OBJECTIVE

To investigate the effect of isoflurane on myocardial ischemia-reperfusion injury through the p38 mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS

A total of 36 specific-pathogen-free (SPF) Sprague-Dawley rats were randomly divided into sham group (n=12), model group (n=12) and isoflurane group (n=12). In model group and isoflurane group, the myocardial ischemia-reperfusion injury model was established via the ligation of left anterior descending coronary artery (ischemia for 30 min and reperfusion for 3 h). In sham group, the left anterior descending coronary artery was not ligated, but the chest was opened and threaded using the same method. After ischemia, the rats in isoflurane group were inhaled with isoflurane. The cardiac function of rats in each group was detected before ischemia (T0) and once every 2 h after reperfusion (T1-T4) for a total of 5 times, and the cardiac function indexes included ejection fraction (EF), fractional shortening (FS), left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP). After the rats were executed, the myocardial infarction tissues were taken for hematoxylin-eosin (HE) staining and 2,3,5-triphenyltetrazolium chloride (TTC) staining to observe the morphological changes in tissues and the degrees of myocardial ischemia and infarction. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in myocardial cells in the infarction site in each group were detected using the MDA and SOD kits. Moreover, the expression levels of related proteins in the p38 MAPK signaling pathway in myocardial cells in the infarction site were detected via Western blotting.

RESULTS

In model group, the cardiac function was significantly damaged (p<0.01), there was significant pathological damage in the myocardium, the area of myocardial infarction was significantly increased (p<0.01), the MDA content was significantly increased (p<0.01), the SOD activity declined obviously (p<0.01), and the expression levels of p-p38 and p-tau protein were significantly increased (p<0.01) compared with those in control group. After intervention with isoflurane, the cardiac function of rats was significantly improved (p<0.01), the pathological damage in myocardial tissues was alleviated, the area of myocardial infarction was reduced (p<0.01), the MDA content declined (p<0.01), the SOD activity was increased (p<0.01), and the expression levels of p-p38 and p-tau protein were decreased (p<0.01).

CONCLUSIONS

Isoflurane can, through inhibiting the p38 MAPK signaling pathway, effectively protect the cardiac function of rats from myocardial ischemia-reperfusion injury, reduce the area of myocardial infarction, alleviate the pathological damage in myocardial cells and reduce the oxidative stress response.

Excellent outcomes following hematopoietic cell transplantation for Wiskott-Aldrich syndrome: a PIDTC report

Wiskott-Aldrich syndrome (WAS) is an X-linked disease caused by mutations in the WAS gene, leading to thrombocytopenia, eczema, recurrent infections, autoimmune disease, and malignancy. Hematopoietic cell transplantation (HCT) is the primary curative approach, with the goal of correcting the underlying immunodeficiency and thrombocytopenia. HCT outcomes have improved over time, particularly for patients with HLA-matched sibling and unrelated donors. We report the outcomes of 129 patients with WAS who underwent HCT at 29 Primary Immune Deficiency Treatment Consortium centers from 2005 through 2015. Median age at HCT was 1.2 years. Most patients (65%) received myeloablative busulfan-based conditioning. With a median follow-up of 4.5 years, the 5-year overall survival (OS) was 91%. Superior 5-year OS was observed in patients <5 vs ≥5 years of age at the time of HCT (94% vs 66%; overall P = .0008). OS was excellent regardless of donor type, even in cord blood recipients (90%). Conditioning intensity did not affect OS, but was associated with donor T-cell and myeloid engraftment after HCT. Specifically, patients who received fludarabine/melphalan-based reduced-intensity regimens were more likely to have donor myeloid chimerism <50% early after HCT. In addition, higher platelet counts were observed among recipients who achieved full (>95%) vs low-level (5%-49%) donor myeloid engraftment. In summary, HCT outcomes for WAS have improved since 2005, compared with prior reports. HCT at a younger age continues to be associated with superior outcomes supporting the recommendation for early HCT. High-level donor myeloid engraftment is important for platelet reconstitution after either myeloablative or busulfan-containing reduced intensity conditioning. (This trial was registered at www.clinicaltrials.gov as #NCT02064933.).

Hematopoietic Cell Transplantation in Patients With Primary Immune Regulatory Disorders (PIRD): A Primary Immune Deficiency Treatment Consortium (PIDTC) Survey

Primary Immune Regulatory Disorders (PIRD) are an expanding group of diseases caused by gene defects in several different immune pathways, such as regulatory T cell function. Patients with PIRD develop clinical manifestations associated with diminished and exaggerated immune responses. Management of these patients is complicated; oftentimes immunosuppressive therapies are insufficient, and patients may require hematopoietic cell transplant (HCT) for treatment. Analysis of HCT data in PIRD patients have previously focused on a single gene defect. This study surveyed transplanted patients with a phenotypic clinical picture consistent with PIRD treated in 33 Primary Immune Deficiency Treatment Consortium centers and European centers. Our data showed that PIRD patients often had immunodeficient and autoimmune features affecting multiple organ systems. Transplantation resulted in resolution of disease manifestations in more than half of the patients with an overall 5-years survival of 67%. This study, the first to encompass disorders across the PIRD spectrum, highlights the need for further research in PIRD management.

104 Oral Sodium Bicarbonate Therapy for Older Patients with Chronic Kidney Disease and Low-Grade Acidosis: The BiCARB Randomised Controlled Trial

Background

Oral sodium bicarbonate is often used to treat metabolic acidosis in older people with advanced chronic kidney disease, but evidence is lacking on whether this provides a net gain in health or quality of life.

Methods

We conducted a multicentre, parallel group, double-blind, placebo-controlled randomised trial. Adults aged 60 years and over with category 4 or 5 chronic kidney disease, not on dialysis, with serum bicarbonate concentrations &lt;22 mmol/L were recruited from 27 UK centres. Participants were randomised 1:1 to oral sodium bicarbonate or matching placebo. The primary outcome was the between-group difference in the Short Physical Performance Battery at 12 months, adjusted for baseline. Other key outcome measures included generic and disease-specific health-related quality of life, anthropometry, physical performance, renal function, adverse events including commencement of renal replacement therapy, and health economic analysis.

Results

We randomised 300 participants, mean age 74 years; 86 (29%) were female. Mean baseline estimated GFR was 19 ml/min/1.73m2. Study medication adherence was 73% in both groups. No significant treatment effect was evident for the primary outcome of the between-group difference in the Short Physical Performance Battery at 12 months (-0.4 points; 95% CI -0.9 to 0.1, p=0.15). No significant treatment benefit was seen for any of the secondary outcomes. Adverse events were more frequent in the bicarbonate arm (457 versus 400). Time to commencing renal replacement therapy was similar in both groups (HR 1.22, 95% CI 0.74 to 2.02, p=0.43). Health economic analysis showed lower quality of life and higher costs in the bicarbonate arm at one year (£1234 vs £807); placebo dominated bicarbonate under all sensitivity analyses for incremental cost-effectiveness.

Conclusions

Oral sodium bicarbonate did not improve a wide range of health measures in this trial, and is unlikely to be cost-effective for use in the UK NHS in this patient group.

Reticular Dysgenesis and Mitochondriopathy Induced by Adenylate Kinase 2 Deficiency with Atypical Presentation

Reticular dysgenesis is an autosomal recessive form of severe combined immunodeficiency (SCID) that usually manifests in newborns. It is a unique example of an immune deficiency that is linked to dysfunctional mitochondrial energy metabolism and caused by adenylate kinase 2 (AK2) deficiency. It is characterized by an early differentiation arrest in the myeloid lineage, impaired lymphoid maturation, and sensorineural hearing loss. In this study, a novel AK2 homozygous mutation, c.622 T > C [p.Ser208Pro], was identified in an Old Order Amish patient through whole exome sequencing. Functional studies showed that the patient’s cells have no detectable AK2 protein, as well as low oxygen consumption rate (OCR), extracellular acidification rate (ECAR) and proton production rate (PPR). An increased production of reactive oxygen species, mitochondrial membrane permeability, and mitochondrial mass, and decreased ATP production, were also observed. The results confirm the pathogenicity of the AK2 mutation and demonstrate that reticular dysgenesis should be considered in Amish individuals presenting with immune deficiency. We also describe other pathophysiological aspects of AK2 deficiency not previously reported.

Effect of Epicutaneous Immunotherapy vs Placebo on Reaction to Peanut Protein Ingestion Among Children With Peanut Allergy: The PEPITES Randomized Clinical Trial

IMPORTANCE

There are currently no approved treatments for peanut allergy.

OBJECTIVE

To assess the efficacy and adverse events of epicutaneous immunotherapy with a peanut patch among peanut-allergic children.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, placebo-controlled trial conducted at 31 sites in 5 countries between January 8, 2016, and August 18, 2017. Participants included peanut-allergic children (aged 4-11 years [n = 356] without a history of a severe anaphylactic reaction) developing objective symptoms during a double-blind, placebo-controlled food challenge at an eliciting dose of 300 mg or less of peanut protein.

INTERVENTIONS

Daily treatment with peanut patch containing either 250 μg of peanut protein (n = 238) or placebo (n = 118) for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was the percentage difference in responders between the peanut patch and placebo patch based on eliciting dose (highest dose at which objective signs/symptoms of an immediate hypersensitivity reaction developed) determined by food challenges at baseline and month 12. Participants with baseline eliciting dose of 10 mg or less were responders if the posttreatment eliciting dose was 300 mg or more; participants with baseline eliciting dose greater than 10 to 300 mg were responders if the posttreatment eliciting dose was 1000 mg or more. A threshold of 15% or more on the lower bound of a 95% CI around responder rate difference was prespecified to determine a positive trial result. Adverse event evaluation included collection of treatment-emergent adverse events (TEAEs).

RESULTS

Among 356 participants randomized (median age, 7 years; 61.2% male), 89.9% completed the trial; the mean treatment adherence was 98.5%. The responder rate was 35.3% with peanut-patch treatment vs 13.6% with placebo (difference, 21.7% [95% CI, 12.4%-29.8%; P < .001]). The prespecified lower bound of the CI threshold was not met. TEAEs, primarily patch application site reactions, occurred in 95.4% and 89% of active and placebo groups, respectively. The all-causes rate of discontinuation was 10.5% in the peanut-patch group vs 9.3% in the placebo group.

CONCLUSIONS AND RELEVANCE

Among peanut-allergic children aged 4 to 11 years, the percentage difference in responders at 12 months with the 250-μg peanut-patch therapy vs placebo was 21.7% and was statistically significant, but did not meet the prespecified lower bound of the confidence interval criterion for a positive trial result. The clinical relevance of not meeting this lower bound of the confidence interval with respect to the treatment of peanut-allergic children with epicutaneous immunotherapy remains to be determined.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02636699.

Ecthyma gangrenosum without bacteraemia: evidence in favour of a broader definition

Ecthyma gangrenosum (EG) is often defined as a cutaneous manifestation of Pseudomonas aeruginosa septicaemia, typically secondary to neutropenia. There is increasing recognition that a broader definition is warranted, as numerous causative organisms and predisposing conditions have been reported. We describe two cases of EG that occurred without bacteraemia. In this atypical subset of cases, the skin is thought to represent the primary inoculation site from which haematogenous spread can occur. The first case occurred in the context of human immunodeficiency virus (HIV) infection, a rarely reported association. The evidence base guiding clinicians on management of EG is very limited, particularly in relation to patients with HIV, in whom recurrence risk may be higher than normal. Recurrent EG is described in our second case, in an individual with Good syndrome, a rare association of thymoma and immunodeficiency.

Beyond DNA: An Integrated and Functional Approach for Classifying Germline Variants in Breast Cancer Genes

Genetic testing for hereditary breast cancer is an integral part of individualized care in the new era of precision medicine. The accuracy of an assay is reliant on not only the technology and bioinformatics analysis utilized but also the experience and infrastructure required to correctly classify genetic variants as disease-causing. Interpreting the clinical significance of germline variants identified by hereditary cancer testing is complex and has a significant impact on the management of patients who are at increased cancer risk. In this review we give an overview of our clinical laboratory's integrated approach to variant assessment. We discuss some of the nuances that should be considered in the assessment of genomic variants. In addition, we highlight lines of evidence such as functional assays and structural analysis that can be useful in the assessment of rare and complex variants.

Desensitization regimens for drug allergy: state of the art in the 21st century

Adverse reactions to drugs are increasingly being recognized as important contributions to disease in their own right as well as impediments to the best treatment of various conditions, including infectious, autoimmune, and neoplastic maladies. Rapid drug desensitization (RDD) is an effective mechanism for safely administering important medications while minimizing or entirely circumventing such adverse reactions in sensitized patients. We reviewed the literature on RDD in the last 10 years, including our experience from the Brigham and Women's Hospital Desensitization Program with hundreds of patients desensitized to a broad variety of drugs. RDD in our programme has been uniformly successful in patients with hypersensitivity reactions to antibiotics, chemotherapeutics, and monoclonal antibodies. Any reactions that occur during desensitization are generally much less severe than the initial hypersensitivity reaction to the drug, and patients have received the full dose of the desired medication 99.9% of the time out of (796) desensitizations. To date, there have been no fatalities. RDD is a safe and highly effective method for treating sensitized patients with the optimal pharmacologic agents. Its use should be expanded, but because patient safety is paramount, protocols must be created, reviewed, and overseen by allergist-immunologists with special training and experience in modern techniques of desensitization.

Melanoma sentinel node biopsy and prediction models for relapse and overall survival

BACKGROUND

To optimise predictive models for sentinal node biopsy (SNB) positivity, relapse and survival, using clinico-pathological characteristics and osteopontin gene expression in primary melanomas.

METHODS

A comparison of the clinico-pathological characteristics of SNB positive and negative cases was carried out in 561 melanoma patients. In 199 patients, gene expression in formalin-fixed primary tumours was studied using Illumina's DASL assay. A cross validation approach was used to test prognostic predictive models and receiver operating characteristic curves were produced.

RESULTS

Independent predictors of SNB positivity were Breslow thickness, mitotic count and tumour site. Osteopontin expression best predicted SNB positivity (P=2.4 × 10⁻⁷), remaining significant in multivariable analysis. Osteopontin expression, combined with thickness, mitotic count and site, gave the best area under the curve (AUC) to predict SNB positivity (72.6%). Independent predictors of relapse-free survival were SNB status, thickness, site, ulceration and vessel invasion, whereas only SNB status and thickness predicted overall survival. Using clinico-pathological features (thickness, mitotic count, ulceration, vessel invasion, site, age and sex) gave a better AUC to predict relapse (71.0%) and survival (70.0%) than SNB status alone (57.0, 55.0%). In patients with gene expression data, the SNB status combined with the clinico-pathological features produced the best prediction of relapse (72.7%) and survival (69.0%), which was not increased further with osteopontin expression (72.7, 68.0%).

CONCLUSION

Use of these models should be tested in other data sets in order to improve predictive and prognostic data for patients.

Cellular senescence in naevi and immortalisation in melanoma: a role for p16?

Cellular senescence, the irreversible proliferative arrest seen in somatic cells after a limited number of divisions, is considered a crucial barrier to cancer, but direct evidence for this in vivo was lacking until recently. The best-known form of human cell senescence is attributed to telomere shortening and a DNA-damage response through p53 and p21. There is also a more rapid form of senescence, dependent on the p16-retinoblastoma pathway. p16 (CDKN2A) is a known melanoma susceptibility gene. Here, we use retrovirally mediated gene transfer to confirm that the normal form of senescence in cultured human melanocytes involves p16, since disruption of the p16/retinoblastoma pathway is required as well as telomerase activation for immortalisation. Expression (immunostaining) patterns of senescence mediators and markers in melanocytic lesions provide strong evidence that cell senescence occurs in benign melanocytic naevi (moles) in vivo and does not involve p53 or p21 upregulation, although p16 is widely expressed. In comparison, dysplastic naevi and early (radial growth-phase, RGP) melanomas show less p16 and some p53 and p21 immunostaining. All RGP melanomas expressed p21, suggesting areas of p53-mediated senescence, while most areas of advanced (vertical growth-phase) melanomas lacked both p16 and p21, implying escape from both forms of senescence (immortalisation). Moreover, nuclear p16 but not p21 expression can be induced in human melanocytes by oncogenic BRAF, as found in around 80% of naevi. We conclude that cell senescence can form a barrier to melanoma development. This also provides a potential explanation of why p16 is a melanoma suppressor gene.

Persistent nodules at injection sites (aluminium granuloma) -- clinicopathological study of 14 cases with a diverse range of histological reaction patterns

AIMS

To assess and document the spectrum of histological appearances of persistent swellings which occur at injection sites following vaccination or allergen desensitization.

METHODS AND RESULTS

Fourteen cases were studied. Four overlapping histological reaction patterns were evident. Ten cases showed at least focal fibrosis, fat necrosis and a mixed inflammatory cell infiltrate mainly in the subcutis, giving rise to the features of a non-specific septal and lobular panniculitis. The appearance of three cases, in addition to the non-specific panniculitis pattern, also included prominent lymphoid follicles with germinal centres and a prominent perifollicular infiltrate resembling a lymphoma (pseudolymphoma pattern). A single case mimicked lupus profundus, with a perivascular and periadnexal infiltrate in the dermis and hyaline fat necrosis. Three cases showed a predominantly palisaded histiocytic infiltrate surrounding eosinophilic necrobiosis, in a pattern closely resembling deep granuloma annulare or rheumatoid nodule. The remaining case partly showed this appearance, but in combination with panniculitis, thus demonstrating an overlap of patterns. A common feature in all 14 cases was the focal presence of histiocytes with abundant violaceous granular cytoplasm. These were shown to contain aluminium on energy dispersive X-ray microanalysis.

CONCLUSION

Persistent swellings at injections sites show a variety of overlapping patterns, which mimic other conditions. Identification of characteristic histiocytes with violaceous granular cytoplasm is the key distinctive feature allowing the correct diagnosis to be reached.

Comprehensive FDTD modelling of photonic crystal waveguide components

Planar photonic crystal waveguide structures have been modelled using the finite-difference-time-domain method and perfectly matched layers have been employed as boundary conditions. Comprehensive numerical calculations have been performed and compared to experimentally obtained transmission spectra for various photonic crystal waveguides. It is found that within the experimental fabrication tolerances the calculations correctly predict the measured transmission levels and other major transmission features.

Efficient propagation of TM polarized light in photonic crystal components exhibiting band gaps for TE polarized light

We have investigated the properties of TM polarized light in planar photonic crystal waveguide structures, which exhibit photonic band gaps for TE polarized light. Straight and bent photonic crystal waveguides and couplers have been fabricated in silicon-on-insulator material and modelled using a 3D finite-difference-time-domain method. The simulated spectra are in excellent agreement with the experimental results, which show a propagation loss as low as 2.5+/-4 dB/mm around 1525 nm and bend losses at 2.9+/-0.2 dB for TM polarized light. We demonstrate a high coupling for TM polarized light in a simple photonic crystal coupler with a size of ~ 20 m x 20 m. These promising features may open for the realization of ultra-compact photonic crystal components, which are easily integrated in optical communication networks.