T-cell repertoire complexity after allogeneic bone marrow transplantation

We analyzed the T-cell repertoire in patients transplanted with bone marrow from an HLA identical sibling by determining the TCR diversity through V beta-CDR3-size spectratyping with V beta/C beta- and V beta/J beta-specific primers. Using the V beta/C beta primers, we observed limited TCR diversity only in recipients of a T-cell-depleted graft, whereas the TCR diversity of patients transplanted with an unmanipulated graft seemed to be indistinguishable from the one of a normal individual. However, with V beta/J beta-specific primers, increase of the resolution by approximately 10-fold also allowed the detection of imbalances in the TCR repertoire of recipients of an unmanipulated graft. This demonstrates that when high numbers of T cells are cotransfused with marrow, the TCR repertoire is more complete but still not as complete as in normal individuals, thereby emphasizing the important role of coinfused mature T cells in the restoration of the T-cell compartment after bone marrow transplantation.