The importance of EN ISO 15189 accreditation of allergen-specific IgE determination for reliable in vitro allergy diagnosis.

BACKGROUND: Allergen-specific serum immunoglobulin E detection and quantification have become an important step in allergy diagnosis and follow-up. In line with the current trend of laboratory test accreditation to international standards, we set out to design and assess an accreditation procedure for allergen-specific serum IgE. METHODS: Method validation according to the accreditation procedure under the EN ISO 15189 standard was carried out for allergen-specific immunoglobulin E determination using the fluoroimmunoenzymatic method ImmunoCAP(®) (ThermoFisher). Data were produced by 25 hospital laboratories in France. A total of 29 allergen specificities including mixes, extracts, and molecular allergens were assayed. Allergen-specific serum immunoglobulin E concentrations ranged from 0.1 to 100 kUA /l. RESULTS: Repeatability, reproducibility, and accuracy results fulfilled method validation criteria for automated laboratory tests and proved similar irrespective of the allergen specificity, allergen-specific serum immunoglobulin E concentration, or individual laboratory. CONCLUSION: Allergen-specific serum immunoglobulin E determination with the fluoroimmunoenzymatic method ImmunoCAP(®) is a highly repeatable, reproducible, and accurate method which may be considered as a single analyte assay in view of the EN ISO 15189 accreditation procedure.

[Serological diagnosis of celiac disease]. / Diagnostic sérologique de la maladie cœliaque.

Screening studies using high-sensitivity and specificity markers indicate a prevalence of celiac disease of up to 1% in European and North-American populations. Celiac disease is a frequent condition that has become an important public health issue. Yet the majority of cases remain undiagnosed due to the polymorphism of its clinical manifestations. The new insight in the pathogenesis of celiac disease has lead to the development of new diagnostic tools. Early screening of symptomatic patients and pre-identified at-risk groups significantly improves the quality of life while reducing morbidity and mortality. However, prophylactic benefits of early diagnosis by assessing the general population have not been shown in any study. French and Northern American scientific societies have introduced serological testing in their newly revised strategies to diagnose celiac disease. Older markers judged insufficiently accurate like anti-gliadin and anti-reticulin antibodies have recently been withdrawn from the list of reimbursed medical expenses in France. Anti-endomysium and tissue transglutaminase IgA antibodies have proven to be at this day the most sensitive and specific markers for the diagnosis and follow-up of patients on gluten-free diet, at the exception of IgA-deficient patients. Assays testing for IgG antibodies are recommended upon IgA-deficiency. Although very accurate, a better standardisation of current assays may enable serological testing to replace in a near future histological confirmation brought by small bowel biopsies which remains today the gold standard test to diagnose celiac disease. Indeed, serological testing represents and attractive alternative as it is less invasive, less expansive, laboursaving and more objective in interpretation.

[Atopic dermatitis aggravates the allergic airways inflammation in acute viral bronchiolitis]. / La dermatite atopique aggrave l'inflammation allergique dans la bronchiolite aiguë virale.

INTRODUCTION: Exhaled nitric oxide (FeNO) is a putative non-invasive marker of eosinophilic airway inflammation with a good predictive value for allergic asthma in preschool children. The aim of the present study was to compare FeNO after acute viral bronchiolitis (AVB) in children aged less than 2 years without atopic dermatitis (AD) vs those with atopic dermatitis, as well as children with AD without any history of AVB. METHODS: Forty-two children (mean age +/- SD: 12.3 +/- 5.2 months; range 5.0-23.5; sex-ratio M: F=1.3: 1) were included in this prospective study, > 8 wks after an episode of AVB. The patients' atopic status was assessed both by clinical phenotype and IgE- mediated response to inhaled and/or food allergens. FeNO (ppb) was measured off-line by the chemoluminescence method on samples obtained from gas collected in a balloon during tidal breathing. RESULTS: There was a significant difference between the AVB/AD (23.4 +/- 14.3 ppb, n=15) vs the AVB without AD group (13.5 +/- 10. 1 ppb, n=13) or the AD without AVB group (11.0 +/- 8.3 ppb, n=14). Maternal feeding for more than 2 months decreased FeNO by 50%. CONCLUSION: Atopic children below 2 years with AD produce more NO after AVB than non-atopic children or atopic children without any history of AVB. Maternal feeding decreases FeNO.

Successful autologous transplantation with peripheral blood hemopoietic cells in a patient with acute leukemia.

One patient with acute nonlymphocytic leukemia (ANLL) in remission was given intensive chemotherapy (DAT regimen) as late intensification treatment. Seven leukaphereses were performed during the period of marrow recovery following aplasia induced by the DAT regimen. High numbers of nucleated cells (7.8 X 10(8)/kg) and granulocyte-macrophage precursors (9.5 X 10(4)/kg) were collected and then cryopreserved and stored in liquid nitrogen. When he relapsed, the patient was treated with etoposide (600 mg/m2), cyclophosphamide (120 mg/kg), and total body irradiation (1000 rad), followed by the transfusion of thawed autologous leukocytes. The time to reach 0.5 X 10(9) granulocytes/liter and 50 X 10(9) platelets/liter was 16 and 35 days, respectively. This observation demonstrates that circulating hemopoietic stem cells are capable of complete hemopoietic reconstitution after marrow-ablative therapy with supralethal doses of chemoradiotherapy.

Collection of peripheral blood stem cells in multiple myeloma following single high-dose cyclophosphamide with and without recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF).

High-dose cyclophosphamide (HD-CY; 7 g/m2) was administered to patients suffering from high risk multiple myeloma (MM). The safety of this procedure, the recirculation and collection of peripheral blood stem cells (PBSC) and the effect of rhGM-CSF and HD-CY were studied. Group I patients (n = 21) were treated with HD-CY alone. Group II patients (n = 10) received 5 micrograms/kg/day rhGM-CSF iv after HD-CY. Neutropenia was shorter in group II (p = 0.01). In group II, the number of circulating colony forming units (CFU-GM) after 14 days was correlated with the number of circulating CFU-GM after 7 days (r = 0.85, p < 0.0001) and with the number of CD34+ cells (r = 0.839, p = 0.01). The total number of mononuclear cells (MNC) and CFU-GM collected per patient was two and seven-fold higher, respectively, in group II (p = 0.01 and p = 0.03). Recovered MNC and CFU-GM were 1.7 and 7-fold higher, respectively, in group II (p = 0.01 and p = 0.004). Our data show that HD-CY is an efficient means of collecting functional PBSC in MM. We suggest that rhGM-CSF is able to further enhance this yield in MM.

[Circulating hematopoietic cells. Results of 6 autologous grafts]. / Cellules hématopoïétiques circulantes. Résultats de 6 greffes autologues.

Six patients with acute non-lymphocytic leukemia underwent autologous transplantation of circulating stem cells collected during remission. They were given cyclophosphamide (120 mg/kg) and total body irradiation (1,000-1,200 rads) (five patients) or busulfan (16 mg/kg) and melphalan (140 mg/m2) before the transfusion of 6.7 X 10(8) nucleated cells/kg corresponding to 19.7 X 10(4) CFU-GM/kg. Granulopoietic engraftment was observed in every case and was influenced by the number of CFU-GM injected. Megakaryocytic recovery was obtained in four cases.

Oat sensitization in children with atopic dermatitis: prevalence, risks and associated factors.

BACKGROUND: Topical treatments of atopic dermatitis (AD) may be responsible for cutaneous allergies. Percutaneous sensitization to oat used in emollients/moisturizers has already been reported. Our objectives were to measure the prevalence of oat sensitization in AD children, to assess its relevance, and to look at related parameters. METHODS: We recruited prospectively children with AD referred for allergy testing between June 2001 and December 2004. Atopy patch tests (APT) and skin prick tests (SPT) to oat proteins (1%, 3% and 5%) and to the European standard series were performed followed by oral food challenge (OFC) and repeated open application test (ROAT) in the oat-sensitized group. RESULTS: About 302 children were enrolled. Oat APT and SPT were positive in 14.6% and 19.2% of cases, respectively. Children under 2 years of age were more likely to have positive APT. In oat-sensitized children, OFC and ROAT were positive in 15.6% (five of 32) and 28% (seven of 25) of cases, respectively. Thirty-two percentage of oat cream users had oat-positive atopy patch test (APT) vs 0% in the nonusers group. CONCLUSIONS: Oat sensitization in AD children seen for allergy testing is higher than expected. It may be the result of repeated applications of cosmetics with oats on a predisposed impaired epidermal barrier. We suggest avoiding topical-containing oat proteins in infants with AD.

[Collection and freezing of blood stem cells in acute nonlymphoblastic leukemia]. / Collection et congélation des cellules souches sanguines au cours des leucémies aiguës non lymphoblastiques.

Blood-derived hemopoietic stem cells were collected using a continuous (10 patients) or a semi-continuous flow separator (2 patients) in some patients with acute non-lymphocytic leukemia. For ten out of those patients, five to seven leukaphereses were performed during a short period (median = 11 days) of marrow recovery following severe aplasia induced by an intensive chemotherapy. The mean number of CFU-GM cells collected per leukapheresis and per patient respectively was 6.7 X 10(4)/kg and 38.5 X 10(4)/kg. This latter number was similar to that obtained during a marrow harvest performed for a bone marrow transplantation, suggesting that high numbers of hemopoietic stem cells can be collected from the peripheral blood in leukemic patients and used for autologous transplantation.