BTK and infection: The reason for the discrepancies in the in vivo phenotypes is not known and might be related to differences in the purity of the genetic C57BL/6 background or the sex of the Btk-null mice (we used male mice for in vivo experiments, while the sex has not been specified by Bao et al.), the Lm strains (the strain EGD was used for in vivo infections in our study, while the Lm strain has not been specified in the other study) and burdens (106 in our study versus 2×106 in the other study) used for infection, differences in the microbiota, or to other unknown factors.