NOVEOS and ImmunoCAP Have Similar Performances for Diagnosing Food Allergies.

BACKGROUND: The clinical significance of newly available platforms for specific IgE measurement must be evaluated. However, data are lacking for NOVEOS (Hycor), especially for food allergens. OBJECTIVE: We compared the technical and clinical performance of two platforms (ImmunoCAP and NOVEOS) to measure specific IgE to 10 food allergens. METHODS: Sera from 289 clinically characterized patients were tested for IgE specific for six food allergen extracts (egg white, cow's milk, peanut, hazelnut, fish, and shrimp) and four molecular allergens (Gal d 1, Bos d 8, Ara h 2, and Cor a 14). Specific IgE measurements were carried out using ImmunoCAP and NOVEOS methods. Food allergy diagnoses were established according to international guidelines. RESULTS: A strong correlation (ρ > 0.9) was present between the two platforms whereas specific IgE concentrations measured with NOVEOS were consistently lower (mean, -15%) than with ImmunoCAP. NOVEOS and ImmunoCAP provided similar overall odds ratios and relative risks for food allergy diagnosis with both allergen extracts and molecular allergens. When all 10 allergens were considered, NOVEOS provided better receiver operating characteristic curves (P = .04). Finally, we found that the most discordant results were observed with hazelnut and peanut extracts and were related to cross-reactive carbohydrate determinants for these two with ImmunoCAP. CONCLUSIONS: Specific IgE determination by either ImmunoCAP or NOVEOS (odds ratios of allergy, 25.1 or 33.0, respectively) is highly informative regarding the risk of allergy in the selected population. The NOVEOS platform presents the advantage of being less affected by unwanted reactivity owing to carbohydrate determinant-specific IgE while requiring a 10-fold lower test sample volume.

The Prevalence Of Osteoporosis Is Low In Adult Cutaneous Mastocytosis Patients.

BACKGROUND: Systemic mastocytosis (SM) is a clonal disorder of mast cells (MCs) frequently associated with vertebral osteoporosis (OP) and subsequent vertebral fractures (VFs). The natural history of this OP remains unclear. Importantly, we do not know whether OP represents an early event triggered alongside MC abnormalities, and whether MC clonality is sufficient to trigger osteoporosis. OBJECTIVE: To describe OP in patients with medullar clonality in cutaneous mastocytosis (CM) and monoclonal mast cell activation syndrome (MMAS) and to compare their osteoporosis characteristics with those of nonadvanced SM patients (bone marrow mastocytosis and indolent systemic mastocytosis). METHODS: We retrospectively analyzed clinical, biological, and densitometric data of 27 CM, 13 MMAS, and 135 SM patients from the Mastocytosis Expert Center (CEREMAST) in Toulouse, France. RESULTS: The OP (respectively 3.7, 30.8, and 34.1%) and VFs (0.0%, 15.4%, and 20%) were less frequent in CM than in MMAS and SM, despite the presence of clonal MCs in the bone marrow. Most patients with OP and VFs in the non-SM groups had the usual risk factors for OP. Interestingly, the only non-SM patient with a typical SM-like OP had high bone marrow tryptase, developed bone marrow KIT mutation during follow-up, and had a family history of SM. Our data show that OP is not a common clinical finding in CM but is frequent in MMAS. When OP and VFs occur in CM and MMAS patients, they differ from the usual phenotype of SM bone fragility. CONCLUSIONS: Our findings suggest that, in most CM patients, the meaning and management of OP differs from that of OP in MMAS and nonadvanced SM. Prospective longitudinal studies and the validation of predictors are needed to identify CM and MMAS patients developing SM-related OP.

Monocytes are the main source of STING-mediated IFN-α production.

BACKGROUND: Type I interferon (IFN-I) production by plasmacytoid dendritic cells (pDCs) occurs during viral infection, in response to Toll-like receptor 7 (TLR7) stimulation and is more vigorous in females than in males. Whether this sex bias persists in ageing people is currently unknown. In this study, we investigated the effect of sex and aging on IFN-α production induced by PRR agonist ligands. METHODS: In a large cohort of individuals from 19 to 97 years old, we measured the production of IFN-α and inflammatory cytokines in whole-blood upon stimulation with either R-848, ODN M362 CpG-C, or cGAMP, which activate the TLR7/8, TLR9 or STING pathways, respectively. We further characterized the cellular sources of IFN-α. FINDINGS: We observed a female predominance in IFN-α production by pDCs in response to TLR7 or TLR9 ligands. The higher TLR7-driven IFN-α production in females was robustly maintained across ages, including the elderly. The sex-bias in TLR9-driven interferon production was lost after age 60, which correlated with the decline in circulating pDCs. By contrast, STING-driven IFN-α production was similar in both sexes, preserved with aging, and correlated with circulating monocyte numbers. Indeed, monocytes were the primary cellular source of IFN-α in response to cGAMP. INTERPRETATION: We show that the sex bias in the TLR7-induced IFN-I production is strongly maintained through ages, and identify monocytes as the main source of IFN-I production via STING pathway. FUNDING: This work was supported by grants from Région Occitanie/Pyrénées-Méditerranée (#12052910, Inspire Program #1901175), University Paul Sabatier, and the European Regional Development Fund (MP0022856).

[Performance criteria for the verification of IgE and tryptase assay methods: recommendations from the AllergoBioNet network]. / Critères de performance pour la vérification des méthodes de dosages des IgE et de la tryptase : recommandations du réseau AllergoBioNet.

Accreditation of an in vitro diagnostic assay according to the NF/EN/ISO 15189 standard requires to analyze its technical performance before implementation for routine use, and annually when reviewing effectiveness of quality controls. Performance is evaluated through repeatability, intermediate fidelity, accuracy and uncertainty of measurement. The coefficients of variation (CV) of the intra-assay and inter-assay precision tests must be compared with those of "peers" (results from laboratories employing the same method) and also with those obtained with "all methods", i.e., results from all laboratories performing the same assay, irrespective of the method. To our best knowledge, there is currently no French or international recommendation on what the acceptable limits of performance for specific IgE and tryptase assays should be. Therefore, the AllergoBioNet network of hospital allergy laboratories set out to characterize the performance of their current methods as a basis for the development of recommendations. The results provided by 24 centers were analyzed and led to consensus recommendations for specific IgE, total IgE and tryptase assays.

Pru p 7 sensitization is a predominant cause of severe, cypress pollen-associated peach allergy.

BACKGROUND: Peach is a common elicitor of food allergic reactions. Peach-induced immediate reactions may occur as benign pollen-food syndromes, usually due to birch pollen-related PR-10 cross-reactivity in temperate climates, and as potentially severe primary food allergies, predominantly related to nsLTP Pru p 3 in Mediterranean regions. The newly described peach allergen Pru p 7 has gained recent attention as a potential peach allergy severity marker. Sensitization to Pru p 7 and its allergenic homologues of the gibberellin-regulated protein family occurs in areas with high Cupressaceae tree pollen exposure. OBJECTIVE: We sought to investigate the distribution, clinical characteristics and molecular associations of Pru p 7 sensitization among subjects with suspected peach allergy in different regions of France. METHODS: Subjects with suspected peach allergy (n = 316) were included. Diagnostic work-up was performed according to current guidelines, including open food challenge when required. IgE antibody measurements and competition experiments were performed using the ImmunoCAP assay platform. RESULTS: Sensitization to Pru p 7 was present in 171 (54%) of all subjects in the study and in 123 of 198 (62%) diagnosed as peach allergic, more than half of whom were sensitized to no other peach allergen. Frequency and magnitude of Pru p 7 sensitization were associated with the presence of peach allergy, the clinical severity of peach-induced allergic reactions and the level of cypress pollen exposure. Cypress pollen extract completely outcompeted IgE binding to Pru p 7. Pru p 7 was extremely potent in basophil activation tests. CONCLUSION AND CLINICAL RELEVANCE: A subtype of Cupressaceae pollinosis, characterized by Pru p 7 sensitization, can be an underlying cause of severe peach allergy.

Hydroxychloroquine as a novel therapeutic approach in mast cell activation diseases.

There is no therapeutic agent approved in cutaneous mastocytosis and mast cell activation syndrome. We report the efficacy of hydroxychloroquine in four patients with cutaneous mastocytosis (n = 2) and mast cell activation syndrome (n = 2). We show that this molecule reduces the long-term survival of primary human mast cells, interferes with lysosome function and leads to the accumulation of non-functional tryptase in the mast cell granules. Furthermore, hydroxychloroquine decreases the production of pro-inflammatory mediators.

Distinct effect of age, sex, and CMV seropositivity on dendritic cells and monocytes in human blood.

We analyzed the impact of age, sex, and CMV on blood monocyte and dendritic cell (DC) subpopulations in 256 healthy individuals aged from 19 to 96 years. Flow cytometry was performed on whole blood within the 4 h following blood drawing. Myeloid (mDC) and plasmacytoid DC (pDC), classical, intermediate, and nonclassical monocytes were enumerated by means of TruCount tubes (BD Biosciences). We provided reference values for mDC, pDC and the three monocyte subpopulations. The numbers of classical, intermediate, and nonclassical monocytes slightly increased with age while the numbers of mDC and pDC did not vary significantly. The level of expression of CD64 and CD163 on monocytes significantly increased with age while HLA-DR expression did not vary significantly. More precisely, CD163 expression level on intermediate monocyte slightly increased with age in women only (Spearman P = 0.019) while CD64 expression increased on monocytes in CMV-positive individuals only. We observed that sex had almost no impact on the numbers of monocytes and DC and on their expression level of CD64 and HLA-DR. We observed a significant decrease in the numbers of pDC with age in CMV-positive individuals, but not in CMV negative individuals. This suggests that the lifelong subclinical infection by CMV could influence the number of circulating DC of lymphoid origin. In contrast, CMV serostatus had no significant impact on absolute numbers of mDC and monocytes.

Prevalence and risk factors for fragility fracture in systemic mastocytosis.

OBJECTIVES: Systemic mastocytosis (SM) is characterized by the accumulation of mast cells in tissues other than the skin. Bone involvement although frequent has not been thoroughly evaluated. Primary objective was to determine risk factors associated with fragility fractures (FF) in SM. Secondary objectives were to evaluate the ability of bone marrow tryptase (BMT) level to identify patients with FF, and to describe bone involvement in SM. METHODS: We analyzed retrospectively all consecutive patients seen in our expert center, with a diagnosis of SM according to the 2001 WHO criteria, and with complete bone assessment. We collected data about lifetime fractures, types of cutaneous manifestations, degranulation symptoms, blood and BMT levels, bone mineral density assessed by densitometry and KIT mutation. We performed a univariate analysis investigating the factors associated with FF and then a logistic multivariable regression analysis. We assessed the ability of bone marrow tryptase to identify patients with FF. RESULTS: Eighty-nine patients with SM were included. Thirty-six patients (40.4%) suffered from osteoporosis and twenty-five (28.1%) experienced lifetime FF. Univariate analysis identified age at diagnosis and disease onset, presence of telangiectasia macularis eruptiva perstans, digestive symptoms, mast cells activation symptoms, elevated BMT, low femoral and lumbar BMD, as associated with FF. Multivariate analysis identified elevated BMT, low femoral T score and older age at diagnosis as independently associated with FF. CONCLUSIONS: Low femoral T-score, BMT level, and older age at diagnosis are markers associated with FF in SM. BMT may represent an important biomarker to predict FF in SM patients.

Photo-induced graft-versus-host disease.

Overlap chronic graft-versus-host disease (GVHD) associates both features of acute and chronic GVHD. Trigger factors for chronic GVHD are unclear. We describe two patients who received allogenic haematopoietic stem-cell transplantation, and who later developed overlap chronic GVHD after sun exposure. Available data from in vivo investigations suggest ultraviolet B radiation (UVB) has a beneficial effect on acute and chronic GVHD. The role of sun irradiation as a trigger for isomorphic cutaneous GVHD has been rarely reported in the literature. Herein, we demonstrate for the first time, using repetitive broadband phototesting, that UVB triggers chronic GVHD.

Telangiectasia macularis eruptiva perstans (TMEP): A form of cutaneous mastocytosis with potential systemic involvement.

BACKGROUND: Telangiectasia macularis eruptiva perstans (TMEP) has not been fully characterized. OBJECTIVE: We sought to estimate the frequency and clinical characteristics of TMEP in a cohort of adult patients with cutaneous mastocytosis, and to assess the presence of systemic involvement. METHODS: We included all consecutive patients evaluated for cutaneous mastocytosis in 2 centers: the Mastocytosis Competence Center of the Midi-Pyrénées from May 2006 to December 2013, and the French Reference Center for Mastocytosis from January 2008 to September 2013. Skin phenotype, histopathology, presence of KIT mutation in the skin, and assessment of systemic involvement according to World Health Organization (WHO) criteria were prospectively investigated. RESULTS: Of 243 patients with cutaneous mastocytosis, 34 (14%) were given a diagnosis of TMEP. The diagnosis of systemic mastocytosis was established in 16 patients (47%) with TMEP. Three patients (9%) had aggressive systemic mastocytosis (C-findings according to WHO). In all, 32 patients (94%) exhibited at least 1 mast cell activation-related symptom. LIMITATIONS: Patient recruitment was undertaken at 2 referral centers with expertise in the diagnosis and treatment of mastocytosis so that the clinical findings and incidence of systemic involvement may be overestimated in comparison with the overall population of patients with TMEP. CONCLUSION: TMEP accounts for about 14% of patients with cutaneous mastocytosis. The disease manifests as mast cell activation symptoms in almost all patients and can be associated with systemic involvement in about 50% of cases.

Modulation of gene expression in CD4+ T lymphocytes following in vitro HIV infection: a comparison between human and chimpanzee.

Chimpanzees are susceptible to experimental infection by human deficiency virus (HIV)-1, but unlike humans, they exceptionally develop an immunodeficiency syndrome after HIV-1 inoculation. To explore the difference between human and chimpanzee, we analyzed the expression of 1547 genes of various functions in human or chimpanzee CD4+ lymphoblasts inoculated in vitro with HIV-1. We observed that, 1 day after HIV inoculation, fifty-eight genes were up-regulated in lymphoblasts of the three humans while their expression remained unchanged in lymphoblasts of the three chimpanzees. One gene is involved in adhesion of HIV (catenin-alpha), three in the immune response (semaphorin 4D, placental growth factor, IL-6), three in apoptosis (deleted in colorectal carcinoma, caspase 9 and FOXO1A). No difference between species was revealed for the expression of 373 genes related to glycosylation pathways. The in vitro human/chimpanzee comparison reveals new candidate genes up-regulated after inoculation with HIV-1 only in human lymphoblasts and which could be related to the higher sensitivity of human to HIV-induced AIDS.

[For an efficient and reasonable accreditation of allergen specific IgE]. / Pour une accréditation efficace et raisonnable du dosage des IgE spécifiques d'allergènes.

French medical laboratories must be accredited before November 2016 according to NF/EN/ISO 15189 standard. However, technical accreditation guidelines cannot be applied literally for the determination of specific IgE for several reasons: more than 600 allergen tests, lack of international gold standard, limited external quality controls. Furthermore, the technique for determination of specific IgE is CE DM-IVD marked, common to all specificities, automatised, standardized according to a single calibration curve. Thus, we propose an efficient but reasonable solution conform to the idea of the accreditation by validating the process. We recommend: a flexible extend type A; choice of only one representative allergen (Dermatophagoides pteronyssinus) for repeatability and precision (20 tests, 2 levels 0.5-1 and 8-12 kUA/L) performed on patients sera, reproducibility (30 consecutive determinations using an Internal Quality Control/IQC), accuracy (IQC and rare External Quality Controls) compared with peers. Sensitivity, specificity, dynamic range, detection threshold are determinated by the provider. Linearity may be checked if the laboratory practices sample dilution for values higher than the upper limit guaranteed by the provider. In the absence of international gold standard, the uncertainty is not measurable. In case of change of instrument, the results obtained by the systems must be compared through 35 tests of different specificities distributed across the range of calibration and including 5 values close to the detection limit. This methodology allows a scientifically effective verification, technically and financially reasonable, to ensure the excellence of the performance of the laboratory with regard to peers and users (allergologists and patients).

Study of cynomolgus monkey (Macaca fascicularis) Mhc DRB gene polymorphism in four populations.

The cynomolgus macaque (Macaca fascicularis) is currently used as an animal model in various fields of immunology especially in the development of innovative vaccines for the prevention and treatment of infectious diseases. The polymorphism of the major histocompatibility complex (MHC) influences the development of adaptive immune responses, and it is crucial to characterize the polymorphism of cynomolgus MHC genes. Among all macaque species, the cynomolgus macaque has the most diversified geographical area encompassing continental and insular populations. By the study of a large sample of animals from the Philippines (N = 359), we have characterized 20 DRB haplotypes. The DRB genotyping was performed by denaturing gradient gel electrophoresis (DGGE) sequencing of exon 2 and was confirmed by polymerase chain reaction-sequence-specific oligonucleotide. The DRB and DRA cDNA of 126 animals were characterized by cloning and sequencing. By means of DGGE sequencing, we characterized the polymorphism of genomic DRB exon 2 in three other cynomolgus macaque population samples (Java, Vietnam, and Mauritius), and we discuss about the origin of the founders of the Mauritian and the Filipino cynomolgus macaque populations.