Detection of α1-antitrypsin deficiency in children with lung diseases

Serum protein electrophoresis, quantitative determination of a1-antitrypsin concentration, and a1-antitrypsin phenotyping and genotyping were used to evaluate a diagnostic approach in the laboratory detection of a1-antitrypsin deficiency in 181 school children (aged 6-14 years) with inflammatory lung diseases (asthma in 76, pneumonia in 84, recurrent pneumonia in 11, and lung tuberculosis in ten children). The a1-globulin fraction of 2.3% on serum protein electrophoresis was used as a cut-off value for subsequent detection of a1-antitrypsin deficiency. The proteinase inhibitor MZ phenotype/genotype was confirmed in 2.76% of the children with a serum concentration of a1-antitrypsin < 2.0 g/L and relative proportion of serum protein a1 fraction Ł 2.3%. In children with lung diseases, the relative a1-globulin fraction of Ł 2.3% on serum protein electrophoresis points to the need for additional laboratory testing (a1-antitrypsin concentration, phenotyping/genotyping) to verify or reject the diagnosis of a1-antitrypsin deficiency.