Immune parameters at late follow-up, between 5 and 32 years after HSCT. (A) CD4⁺ T-cell counts in the different subsets. (B) CD8⁺ T-cell counts in the different subsets. (C) CD4⁺ TREC numbers. ○ denotes healthy control subjects; •, patients with SCID at long-term follow-up with poor long-term reconstitution of the naive CD4⁺ T-cell population; and, patients with SCID at long-term follow-up with good long-term reconstitution of the naive CD4⁺ T-cell population.