Representative examples of TCRBV CDR3 size distribution in 2 age-matched HSC recipients.

cDNA was amplified in PCR reactions primed by one BV subfamily and a BC-specific fluorescent primer. Patient no. 1 (age at transplantation, 17.7 years) was studied at 26 months after CBT, without episode of GVHD, had totally polyclonal BV families and a high TREC value (11 614/μg CD3⁺ DNA). Patient no. 2 (age at transplantation, 16.5 years), studied at 24 months after BMT, after an episode of acute GVHD, had several TCRBV disturbances (BV2, BV4, and BV9), an undetectable family (BV7), and a low TREC value (389/μg CD3⁺ DNA). Both patients were treated for acute lymphoblastic leukemia.