Pulmonary function in children with homozygous alpha1-protease inhibitor deficiency.

UNLABELLED

Alpha1-protease inhibitor (alpha1-PI) deficiency is a well-recognized cause of emphysema in adults; however, 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 schoolchildren (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 infusion of alpha1-PI may be considered.

CONCLUSION

Our study confirms the absence of pulmonary function abnormalities in the vast majority of children with homozygous alpha1-PI deficiency. Serial measurements of lung function may help to distinguish those individuals who require treatment with alpha1-PI from those who do not.