Recovery of naive peripheral CD45RA⁺/CD62L⁺ T cells in long-term BMT patients. Peripheral CD4⁺ and CD8⁺ T cells from UPN 324 (30 years old) and his donor were examined by triple-color immunofluorescence at various time points after BMT. Values in brackets are numbers of CD45RA⁺/CD62L⁺ T cells per microliter of blood.