This issue of the Journal of Human Immunity features a study (https://doi.org/10.70962/jhi.20250227) reporting the long-awaited first case of autosomal recessive human CTLA-4 deficiency. Here, the features of this patient are compared and contrasted to those in CTLA-4 haploinsufficient patients, patients treated with CTLA-4 inhibitors, and Ctla4−/− mice.
Helen C. Su (Wed,) studied this question.