Oligoclonal Expansion of CD8 + CD57 + T Cells With Restricted T-Cell Receptor β Chain Variability After Bone Marrow Transplantation

Abstract

AbstractA major expansion of CD8 + 57+ lymphocytes expressing an α-β T-cell receptor (TCR) is frequent after bone marrow transplantation (BMT). We examined the clonality of the TCR β gene repertoire in these expanded CD8 + 57+ cells after allogeneic or autologous BMT. We performed a polymerase chain reaction (PCR) analysis of the Vβ chain usage in CD8 + 57 + cells purified from nine BMT recipients with a series of oligonucleotides specific for 20 Vβ gene families. PCR products from selected TCR β gene rearrangements were sequenced. The CD8 + 57+ cells from eight of nine patients used a restricted set of Vβ families, with a marked predominance of two to three Vβ gene families per patient, whereas the control autologous CD57 ~ subset expressed the whole 20 Vβ families. A direct sequencing analysis confirmed the Vβ16 and Vβ17 clonality in six patients, showing a striking homology in the CDR3 sequences of the Vβ16 products. The CD8 + 57+ cells, but not the CD57−cells, displayed an oligoclonal pattern of TCR rearrangements as shown by PCR analysis of TCR7 gene rearrangements. Such an oligoclonal expansion of CD8 + 57 + cells, using a restricted set of the Vβ gene families, may result from a specific TCR stimulation of a limited number of T-cell clones in BMT recipients.