Pulmonary function in children with homozygous alpha₁-protease inhibitor deficiency

Abstract

Alpha₁-protease inhibitor (alpha₁-PI) deficiency is a well-recognized cause of emphysema in adults; howerver, the natural history of this disorder in children is unclear. Because of the paucity of data in the paediatric age group, we performed whole body plethysmography, spirometry, and diffusing capacity, in a cohort of 17 homozygous (PiZZ phenotype) children (9 females, 8 males; mean age ± SEM 13.4±0.9, range 7–18 years) and in 17 normal school-children (13.5±0.9, 7–18 years), using a matched-pair design. Blood was drawn for determination of serum alpha₁-PI levels, PI phenotype, and standard biochemical tests of liver function. Among the PiZZ subjects, 12 were detected during diagnostic workup of prolonged neonatal icterus, and 5 by routine testing in paediatric patients. None had chronic respiratory symptoms except for an 18-year-old PiZZ girl with a history of recent onset of exertional dyspnoea. All were non-smokers. The Wilcoxon test was used for statistical analysis. As expected, serum alpha₁-PI levels were lower in the PiZZ group (16% of the control value). A few patients had slight elevations of their liver enzymes. As for the pulmonary function parameters, differences between groups were not significant. Individual data showed no consistent abnormality in lung function except for signs of mild expiratory obstructive airway disease with hyperinflation (elevated TGV/TLC ratio) in the only symptomatic 18-year-old subject (0.63, control subject 0.49). This was unresponsive to bronchodilators. For her, augmentation therapy with intravenous infusions of alpha₁-PI may be considered.