Pulmonary Langerhans Cell Histiocytosis—Insight into the Incidence of Alfa-1-Antitrypsin Deficiency (A1ATD) Alleles

Introduction: The alpha-1 antitrypsin deficiency (A1ATD) is one of the three most common genetic disorders in Caucasians. It considerably increases the risk of progressive obstructive lung diseases, mostly chronic obstructive pulmonary disease. There is no data regarding the prevalence of main, clinically most important A1ATD alleles PI*Z and PI*S in patients with pulmonary Langerhans cell histiocytosis (PLCH). PLCH is not only strongly linked to the cigarette smoking, but is also characterised by polycystic lung lesions. The goal of the study was to assess the incidence of A1ATD alleles in patients with PLCH. Material and methods: Blood samples were collected from 34 adult patients (14 women and 20 men), with histologically confirmed PLCH. AAT serum concentration was assessed by nephelometry and PI-phenotype, identified by isoelectrofocusing. The PI*S and PI*Z alleles were confirmed by genotyping using real-time PCR. Results: Deficiency alleles PI*Z and PI*S were detected in 3 patients (one woman and 2 men), in 5.88% and 2.94%. The estimated incidence of deficiency alleles was 29.4/1000 (95% CI; 10–69.5) for PI*Z and 14.7/1000 (95%CI; 13.9–43.3) for PI*S. According to our previous reports, the expected prevalence of PI*Z and PI*S alleles in the general Polish population was 13.7/1000 (95% CI 5.8–21.5), and 7.6/1000 (95% CI 1.7–13.5) respectively. Conclusions: The incidence of main A1AT deficiency alleles in patients with PLCH seems higher than in the general Polish population. The study is ongoing.