STAT3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: However, a larger percentage (69% in our cohort vs. 40% in other cohorts) (21) had either CD4/CD8/CD19/NK cell lymphopenia, which may be attributable to polytherapy with multiple immunosuppressive agents—a finding consistent with that seen in other cases in the cohort with CTLA4 defect, IPEX syndrome, and STAT3 GOF.