Similar to our study, Barbosa et al. reported increased percentages of CD16-positive monocytes in CVID but not in X-linked agammaglobulinemia patients, suggesting that this finding might not be due to high levels of LPS, but rather to T and B cell aberrancies, which are common in patients with CVID [4]. Here, FCGR3A is linked to isolated agammaglobulinemia.