Throughout this extended admission, he underwent comprehensive evaluations for primary immunodeficiencies, which included assessments of basic immunoglobulin levels and lymphocyte subsets. Agammaglobulinemia was established with absent peripheral B cells (CD19: 0.06%), therefore X-linked agammaglobulinemia (XLA) was regarded as the most probable diagnosis (Table 1). This evidence concerns the gene CD19 and Bruton-type agammaglobulinemia.