“…1,2,3 It can be classified as primary, if it occurs in a previously healthy individual, or secondary, if there is an underlying or predisposing disorder, such as congenital lung disorders and immunodeficiencies. 1,2,4 A primary immunodeficiency (PID) screening (which included complete blood count and measurements of antibody production toward immunizations, serum immunoglobulin levels, total serum hemolytic complement assay and oxidative burst in neutrophils) was performed. IgA deficiency is the most common PID and often presents with recurrent sinopulmonary infections, but according to European Society for Immunodeficiencies (ESID) new criteria, diagnosis should only be considered at an age older than 4 years.…”