CTLA4 and Immunodeficiency: Various attempts to score the extent of immunodeficiency and dysregulation activity with one of the aims being to facilitate decisions to transplant have been and are being undertaken, e.g., within the retrospective IPEX study (8), the prospective study on profound combined immunodeficiencies (PCID) (50), and ongoing studies on CTLA-4 and LRBA deficiency (unpublished data).