Highly Altered Vβ Repertoire of T Cells Infiltrating Long-Term Rejected Kidney Allografts

Abstract

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 ± 10% of area infiltrate) may thus be instrumental in this phenomenom, which is likely to be dependant on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the Vβ chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR Vβ usage for the majority of Vβ families and also a very high percentage (55%) of Vβ families exhibiting common and oligoclonal Vβ-Cβ rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, Vβ8 and Vβ23 families exhibited common and oligoclonal Vβ-Jβ rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal Vβ8-Jβ1.4 rearrangement. Quantitative PCR showed that biased Vβ transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.