Reproducibility of skin prick testing with allergen extracts from different manufacturers

Allergen extracts for skin prick testing (SPT) are available from several manufacturers. Although these solutions are specified according to well-defined internal company standards, there is no generally accepted overall standardization. To assess the comparability of skin prick test solutions of various manufacturers, we compared extracts of nine different allergens from four companies by SPT in 29 children sensitive to one or more of the allergens, in a double blind fashion. RAST (Pharmacia) and EAST (Kallestad) were determined in simultaneous blood samples. Allergen extracts were also examined by rocket immunoelectrophoresis for their content of major allergens. Skin reactions, assessed by mean diameter of wheals, to identical allergen extracts varied significantly between the four vendors (P less than 0.05-0.001). Correlation between RAST and EAST was good for all allergens except birch pollen and mugwort. Content of the major allergen in corresponding extracts varied significantly between the different companies (less than 1%-2000%). These data underline the need for international reference extracts as intracompany standardization of test solutions alone is not enough to yield general reproducibility of skin prick test results.     

Food allergen avoidance – the patient's viewpoint

The profile of potentially fatal food allergies has altered in recent years. The vigilance required for allergen avoidance when shopping or eating out depends on information which is often hidden or misleading. Families with allergic children suffer social exclusion and stress, made worse by a serious shortage of specialist patient care. Those who die are usually teenagers and young adults who suffer from severe allergic asthma or anaphylaxis after eating away from the home. A recognised manufacturing standard would endorse businesses seeking to remove the risk of allergen cross-contamination, whilst the integration of allergy into training for caterers and environmental health professionals would influence and inform foodservice businesses.     

Regulatory frameworks for cell therapy products in Japan

This paper reviews regulatory frameworks for cell therapy products in Japan. Two procedures are used to investigate the use of new cell therapy products in Japan. One is to perform clinical trials in accordance with the provisions of the Pharmaceuticals Affairs Act (PAA); the other is to perform clinical research in accordance with the provisions of the Medical Practitioners Act. For full commercialization of medical products in Japan, we must consider the universal health care system. All medical products used to treat patients in the system must be approved, in accordance with the provisions of the PAA, as drugs or medical devices. Thus, researchers in academia who have developed new cell therapy products should consider performing clinical trials in accordance with the provisions of the PAA to test their products clinically. This article describes development and review processes for new drug/device applications in accordance with the provisions of the PAA and gives an example of clinical review of a cell therapy product by the Pharmaceuticals and Medical Devices Agency.     

Comparison of the biological activity of the most common sublingual allergen solutions made by two European manufacturers

BACKGROUND: The clinical efficacy of sublingual immunotherapy has been documented in numerous studies and meta-analyses and is argued to be a favored alternative to the subcutaneous route if allergic symptoms are treated with a high-dose therapy. What is still lacking is a 'conversion rate' between the biological activities of different allergen solutions to determine the one with the higher concentration. METHODS: A randomized, double-blind, parallel-group study was done with three groups sensitized to the allergens birch, grass or house dust mite via skin prick test. Staloral in the concentrations 10, 100 and 300 IR and SLITone in the concentration of 1,000 STU per milliliter were used for a computer-based comparison of the geometric mean wheal sizes of the different solutions. For each patient, individual regression curves led to the calculation of a mean corresponding IR value for the SLITone solution. RESULTS: A total of 47 patients took part in this clinical trial, most of whom were sensitized to more than one allergen. Values for birch (30 patients) showed that 1,000 STU corresponded to 77 IR, for grass (29 patients) 1,000 STU matched 78 IR and for house dust mite (30 patients) 1,000 STU matched 27 IR based on dose-response relationships. The Wilcoxon test showed that for all allergens the allergenic activity of the SLITone solution was significantly higher than the 10 IR solution and significantly lower than the 100- and 300-IR solutions. CONCLUSION: We established a conversion rate between the two leading sublingual allergen solutions on the European market to compare different units of measurement.     

Regulatory aspects of nigrostriatal dopaminergic neurons

Summary In the urethane-anesthetized rat, electrical stimulation (10 Hz, 30 s, 250 A) of the medial forebrain bundle (MFB), at 20-min intervals over an 8-h period, combined with intracerebral microdialysis in the striatum caused: an undiminished increase in the release of dopamine (DA) with each stimulation episode; a decreased efflux of 3,4-dihydroxyphenylacetic acid (DO-PAC) and 4-hydroxy-3-methoxyphenylacetic acid (HVA) after the first stimulation only; a delayed increased efflux of DOPAC with no change in HVA; and a poststimulation depression of firing of dopaminergic neurons in the substantia nigra (before, 3.1±0.7 Hz; after, 1.9±1.0 Hz; P<0.05). After the last stimulation episode, the release of DA declined to prestimulation values, while the increased efflux of DOPAC persisted for three more hours. After the infusion of tetrodotoxin (4.0×10^-7 M, 1.5 l, 1.0 l/min) into the MFB, the basal release of DA was reduced (P<0.05), while the efflux of DOPAC and HVA was increased (P<0.05). A model is proposed suggesting that: (1) during increased release of DA in the striatum, the metabolism of DA is decreased; (2) inhibition of nigrostriatal dopaminergic neurons is the usual cause of increased synthesis and metabolism of DA in the striatum; and (3) increased release of DA, and increased synthesis and metabolism of DA in the striatum are not causally linked and are noncoupled processes.     

Regulatory enablers and regulatory challenges for the development of tissue-engineered products in the EU

The EU Regulation on Advanced Therapy Medicinal Products (ATMP) bridges a regulatory gap and is expected to act as an enabler for the regenerative medicine sector in the EU by setting a centralised and harmonised regulatory framework for tissue-engineered products. Some of its key features are a workable and comprehensive scope, a new committee allowing for a pooling of expertise and tailored yet flexible requirements meant to keep pace with technology development. However, while providing a much needed regulatory framework, the new regulation still has potential shortfalls with regard to facilitating the research and commercialisation of tissue-engineered products in the future.     

Challenges in the implementation of EAACI guidelines on allergen immunotherapy: A global perspective on the regulation of allergen products

Regulatory approaches for allergen immunotherapy (AIT) products and the availability of high‐quality AIT products are inherently linked to each other. While allergen products are available in many countries across the globe, their regulation is very heterogeneous. First, we describe the regulatory systems applicable for AIT products in the European Union (EU) and in the United States (US). For Europe, a depiction of the different types of relevant procedures, as well as the committees involved, is provided and the fundamental role of national agencies of the EU member states in this complex and unique network is highlighted. Furthermore, the regulatory agencies from Australia, Canada, Japan, Russia, and Switzerland provided information on the system implemented in their countries for the regulation of allergen products. While AIT products are commonly classified as biological medicinal products, they are made available by varying types of procedures, most commonly either by obtaining a marketing authorization or by being distributed as named patient products. Exemptions from marketing authorizations in exceptional cases, as well as import of allergen products from other countries, are additional tools applied by countries to ensure availability of needed AIT products. Several challenges for AIT products are apparent from this analysis and will require further consideration.     

Regulatory role of DC‐derived osteopontin in systemic allergen sensitization

Osteopontin (OPN) is a secreted phosphoglycoprotein with a wide range of functions, and is involved in various pathophysiological conditions. However, the role of OPN in IgE and Th2‐associated allergic responses remains incompletely defined. The aim of this study was to elucidate the role of OPN in systemic allergen sensitization in mice. When compared with OPN^+/+ mice, significantly increased levels of OVA‐induced IgE were found in OPN^?/? mice. OPN^?/? DC demonstrated an increased capacity to enhance Th2 cytokine production in CD4⁺ T cells from sensitized OPN^+/+ mice. Furthermore, significantly reduced levels of IL‐12p70 expression were seen in LPS‐stimulated OPN^?/? DC as compared with the WT DC, and the reduction was reversible by the addition of recombinant OPN (rOPN). rOPN was able to suppress OVA‐induced IL‐13 production in the cultures of CD4 and OPN^?/? DC, but this inhibitory activity was neutralized by the addition of anti‐IL‐12 Ab. In addition, administration of rOPN in vivo suppressed OVA‐specific IgE production; however, this suppressive effect was abrogated in IL‐12‐deficient mice. These results indicate that DC‐derived OPN plays a regulatory role in the development of systemic allergen sensitization, which is mediated, at least in part, through the production of endogenous IL‐12.     

Biological equilibration of allergen preparations: methodological aspects and reproducibility

A method for biological equilibration (BE) of allergen reference preparations using the skin-prick test (SPT) method and histamine HCl 10 mg/ml as reference substance (reference method), was evaluated. The precision was low for weals less than 10 mm². The slope (log weal area/log concentration) of allergen and histamine did not vary significantly between investigators and allergens. The median slopes were 0.39 ( n = 384) and 0.34 ( n = 397), for allergen and histamine, respectively ( P < 0.01). The concentration of allergen eliciting a weal of the same size as that of histamine HCl 1 mg/ml (C_hl) in the median sensitive patient, 1000 Biological Units/ml (BU/ml), did not vary significantly between clinics/geographical regions (grasses, mites and moulds). As BE is repeatable between regions. BUs estimated by this method are generally valid. A high correlation ( r = 0.91, P < 0.001) was found between the median C_hl as estimated with histamine 1 and 10 mg/ml as reference substance, respectively. Thus, this reference method for BE is valid. The precision of the SPT method with histamine HCl 1 mg/ml is not as good as with 10 mg/ml, which is therefore recommended as the reference concentration.     

Hope for the clinical laboratory: from the viewpoint of the thyroidologist

We have tried to screen for hyperthyroidism by neural networks using routine test data (without hormonal data), and found that screening with a set of three parameters (alkaline phosphatase, creatinine, and total cholesterol) allowed for quite accurate screening. The trouble in this study was that the methods of measurement for blood chemistry have sometimes changed in our hospital and the reference ranges have changed accordingly. Therefore, the data obtained several years ago could not be used. There were also remarkable inter-laboratory differences in free thyroxine measurement. We hope that the standardization of clinical laboratory measurement will be achieved in nationwide in the near future.     

Tumor heterogeneity from the viewpoint of pathologists

Morphological and functional heterogeneity are found in tumors, with the latter reflecting the different levels of resistance against antitumor therapies. In a therapy-resistant subpopulation, the expression levels of differentiation markers decrease, and those of immature markers increase. In addition, this subpopulation expresses genes involved in drug metabolism, such as aldehyde dehydrogenase 1A1 (ALDH1A1). Because of their similarity to stem cells, cells in the latter therapy-resistant subpopulation are called cancer stem cells (CSCs). Like normal stem cells, CSCs were originally thought not to arise from non-CSCs, but this hierarchical model is too simple. It is now believed that CSCs are generated from non-CSCs. The plasticity of tumor phenotypes between CSCs and non-CSCs causes difficulty in completely curing tumors. In this review, focusing on ALDH1A1 as a marker for CSCs or immature tumor cells, the dynamics of ALDH1A1-expressing tumor cells and their regulatory mechanisms are described, and the plausible regulatory mechanisms of plasticity of ALDH1A1 expression phenotype are discussed. Genetic mutations are a significant factor for tumorigenesis, but non-mutational epigenetic reprogramming factors yielding tumor heterogeneity are also crucial in determining tumor characteristics. Factors influencing non-mutational epigenetic reprogramming in tumors are also discussed.     

Regulatory activity of human CD4 CD25 T cells depends on allergen concentration, type of allergen and atopy status of the donor

Regulatory CD4+ CD25+ FoxP3-positive T cells (Treg) are functional in most atopic patients with allergic rhinitis and are able to inhibit T helper type 1 (Th1) and Th2 cytokine production of CD4+ CD25- T cells. This study was designed to analyse the following additional aspects: influence of allergen concentration, influence of the type of allergen, and influence of the atopy status of the donor on the strength of the regulatory activity. CD4+ CD25- T cells from healthy non-atopic controls or from grass-pollen-allergic or wasp-venom-allergic donors were stimulated alone or in the presence of Treg with autologous mature monocyte-derived dendritic cells which were pulsed with different concentrations of the respective allergens. Treg from grass-pollen-allergic donors failed to inhibit proliferation but not cytokine production of CD4+ CD25- T cells at high antigen doses while Treg from non-atopic donors did not fail at these allergen concentrations. Proliferative responses and cytokine production of CD4+ CD25- T cells from most of the examined wasp-venom-allergic patients were not inhibited at any concentration of wasp venom. The use of wasp venom- or phospholipase A2-pulsed dendritic cells for stimulation of CD4+ CD25- T cells from donors who were not allergic to wasp stings only resulted in an inhibited proliferation and Th2 cytokine production by Treg at 10-fold lower than the optimal concentration, while interferon-gamma production was inhibited at all concentrations investigated. These data demonstrate that in allergic diseases the function of Treg is dependent on the concentration and the type of the respective allergen with different thresholds for individual allergens and patients.