[Screening for alpha1-antitrypsin deficiency using dried blood spot: Assessment of the first 20 months]. / Dépistage du déficit en alpha1-antitrypsine sur sang capillaire recueilli sur papier-filtre : bilan des 20 premiers mois.

INTRODUCTION: 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 PI*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.

A preliminary assessment of alpha-1 antitrypsin S and Z deficiency allele frequencies in common variable immunodeficiency patients with and without bronchiectasis.

Common variable immunodeficiency (CVID) is the name given to a clinically heterogeneous group of hypogammaglobulinaemic immunodeficiency states. Bronchiectasis is a feature of this disease and is believed to be the result of recurrent bacterial infection affecting the respiratory tract. Bronchiectasis is also a feature associated with emphysematous changes of the lung in alpha-1 antitrypsin (AAT) deficiency, a serious and relatively common disease, affecting 1 : 2000 in the United Kingdom. This has been demonstrated to result from possession of deficiency alleles, the most clinically important alleles being PI*Z and PI*S. Isolated reports of families with antibody deficiency and AAT deficiency have been published but to date no study has been performed to specifically investigate if AAT deficiency is associated with the lung damage seen in CVID patients. We have developed a PCR genotyping assay that identifies S and Z deficiency alleles and we have used this assay in a preliminary study to investigate the occurrence of these deficiency alleles of AAT in 43 CVID patients. Results of this preliminary study suggest that CVID patients did not have an altered distribution of AAT genes when compared to 70 normal controls. Subgrouping of CVID patients into those with and without bronchiectasis demonstrated a Z allele frequency of 0.077 in those patients with bronchiectasis, which is higher than found in normal controls, namely 0.029 (P < 0.15). Due to the relatively small numbers studied, these results are inconclusive in determining whether AAT deficiency may exacerbate lung damage in some CVID patient, the data does however, indicate that a larger multi-centre study involving many more CVID patients may be useful.