Immune reconstitution by genotype. Patients with IL2RG, JAK3, and IL7R SCID mutations had significantly higher mean T-cell counts and percentages of naive T cells at 1 year post-HCT compared with RAG1/RAG2/Artemis or other mutations. (A) CD3, 2291 cells/μL vs 1646 cells/μL vs 982 cells/μL (P = .013). (B) CD4: 1366 cells/μL vs 826 cells/μL vs 754 cells/μL (P = .047). (C) CD8: 814 cells/μL vs 434 cells/μL vs 339 cells/μL (P = .007). (D) CD45RA: 30% vs 16% vs 12% (P = .031)