Interaction of group-specific component (vitamin D-binding protein) with immobilized Cibacron blue F3-GA

Group-specific component (vitamin D-binding protein) was purified to homogeneity from human plasma by a three-step procedure involving pseudo-ligand affinity chromatography on immobilized Cibacron blue F3-GA followed by gel filtration and ion-exchange chromatography. Upon pseudo-ligand chromatography, Gc globulin was separated into two peaks. The first, which represented approx. 4% of the total Gc globulin, was eluted together with other alpha-globulins of similar Mr and/or pI, and the second (96% of Gc globulin) was clearly retarded. Collection of the latter provided a fraction 10-fold enriched in Gc globulin, with yields higher than 90%. Incubation of plasma with trace amounts of radioactively-labeled 25-OH vitamin D3 showed that the radioactivity coeluted with the first peak. In addition, after saturation with 25-OH vitamin D3, all the Gc globulin was eluted in the first peak. This indicates that the two peaks correspond to the holo and the apo forms of the protein, respectively, and suggests that either the interaction of the apo form with the Cibacron blue dye involves the binding site for vitamin D metabolites, or that the holo-protein undergoes a conformational change as a consequence of formation of the complex

Dépistage du déficit en alpha1-antitrypsine sur sang capillaire recueilli sur papier-filtre : bilan des 20 premiers mois

International audienceIntroduction. - Alpha1-antitrypsin deficiency is a predisposing factor for pulmonary disease and under-diagnosis is a significant problem. The results of a targeted screening in patients with respiratory symptoms possibly indicative of severe deficiency are reported here.Methods. - Data were collected from March 2016 to October 2017 on patients who had a capillary blood sample collected during a consultation with a pulmonologist and sent to the laboratory for processing to determine alpha1-antitrypsin concentration, phenotype and possibly genotype.Results. - In 20 months, 3728 test kits were requested by 566 pulmonologists and 718 (19 %) specimens sent: among these, 708 were analyzable and 613 were accompanied by clinical information. Of the 708 samples, 70 % had no phenotype associated with quantitative alpha1-antitrypsin deficiency, 7 % had a phenotype associated with a severe deficiency and 23 % had a phenotype associated with an intermediate deficiency. One hundred and eight patients carried at least one Pl*Z allele which is considered to be a risk factor for liver disease.Conclusions. - The results of this targeted screening program for alpha1-antitrypsin deficiency using a dried capillary blood sample reflect improvement in early diagnosis of this deficiency in lung disease with good adherence of the pulmonologists to this awareness campaign

Cohorte DEFI-ALPHA et projet hospitalier de recherche clinique POLYGEN DEFI-ALPHA. Étude des facteurs cliniques, biologiques et génétiques associés à l’apparition et à l’évolution de complications hépatiques chez les enfants présentant un déficit en alpha-1 antitrypsine

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Assessment of liver fibrosis by transient elastography (Fibroscan((R))) in patients with A1AT deficiency

BACKGROUND: Alpha-1-antitrypsin deficiency (A1ATD) is a common genetic condition which predisposes to emphysema and liver disorders. It is estimated that 10-15% of homozygous individuals for the Z allele (PiZZ) may develop liver fibrosis. The optimal modalities to detect liver disease in PiZZ adult patients need to be defined. The aim of this prospective study was to perform a systematic non-invasive evaluation of the liver fibrosis by elastometry using Fibroscan((R)) in a cohort of A1ATD patients with emphysema. METHODS: Patients followed in our respiratory unit were enrolled in this prospective study and underwent on the same day a physical examination, a biochemical profiling, an abdominal ultrasound (US) and a Fibroscan((R)). RESULTS: Twenty-nine PiZZ adults (19 male) were included. Median age was 50.4 yrs (21.5-67.2). Median serum A1AT level was 0.20 g/L (0.15-0.33). Liver Function Tests (LFT) were not normal in 2 patients and US was abnormal in 6 patients. Two patients had both abdnormal LFT and US. Fibroscan((R)) was technically feasible in 28/29 (97%) patients. Median liver stiffness was 4.5 kPa (2.8-32.8), and was \\textgreater 7.2 kPa in 5/28 (18%) and \\textgreater 14 kPa in 2/28 (7%) patients. Liver stiffness was increased in 2/2 (100%) patients with abnormal LFT and US, in 1/4 (25%) with abnormal LFT or US and in 2/22 (10%) patients with normal LFT and US. CONCLUSIONS: Fibroscan((R)) is an easy and repeatable tool which can be used in PiZZ patients to screen for the presence of significant liver fibrosis and to identify patients at higher risk to develop liver complications in the future and who may benefit from a closer surveillance

Potential anti-leukemic activity of iron chelation after allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia

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