Another significant group of patients requiring immunoglobulin replacement are patients with combined immunodeficiency, such as patients with what can be considered as “hyper IgE syndromes” (DOCK8 deficiency, STAT3 deficiency, IL6 receptor deficiency), hyper IgM syndrome, ataxia telangiectasia patients, and “leaky SCIDs” such as hypomorphic presentations of artemis, as well as others [2,3,4,5,6]. Here, STAT3 is linked to ataxia telangiectasia.