Given the dysfunction of B cells, XLA patients are susceptible to recurrent bacterial infections and show more severe clinical manifestations.37 For example, several case reports have focused on XLA combined with invasive Klebsiella pneumoniae polyarticular septic arthritis and Campylobacter jejuni systemic infections.38, 39 Thus, the functions of Btk in a variety of bacterial infections should be determined. The gene discussed is BTK; the disease is bacterial infectious disease.