Exhaled nitric oxide in patients with PiZZ Phenotype-related alpha 1-anti-trypsin deficiency

There is no report of exhaled NO (eNO) in subjects with different phenotype s of alpha (1)-anti-trypsin (AAT) deficiency. Exhaled nitric oxide was evaluated by means of single-breath chemiluminesce nce analysis (fractional exhaled concentration at the plateau level [p1FE(N o)]) in 40 patients with AAT deficiency. Patients were divided according to the protease inhibitor (Pi) phenotype: PiMZ/MS, n = 25; PiSZ n = 6; PiZZ, n = 9. Nineteen healthy subjects served as controls. Levels of eNO in PiZZ patients were also compared with those of subjects, without AAT deficiency (PiMM), matched for diagnosis, sex, age, smoking habit and forced expirator y volume in 1 sec (FEV1). In AAT deficiency subjects airway hyper-responsiv eness to methacholine (PD20 FEV1) was also assessed. p1FE(No) was significantly lower in the PiZZ group (4.5 +/- 1.4 ppb) than i n matched PiMM subjects (8.2 +/- 3.8 ppb), in healthy controls (9.3 +/- 2.8 ppb) and in patients of other phenotypes. Dynamic lung volumes and DLCO we re significantly lower in PiZZ than in other AAT-deficient patients. Bronch ial hyper-responsiveness was not different among AAT phenotypes. These results suggest that eNO may be significantly reduced in PiZZ as comp ared to healthy control subjects and to AAT subjects with other phenotypes, independent of the level of airway obstruction. Whether, at least potentia lly, eNO may be considered as an early marker of lung involvement in AAT de ficiency must be confirmed with studies on larger number of subjects.