Abstract
BACKGROUND: Tumour infiltrating lymphocyte (TIL) T-cell receptor (TCR) repertoire is prognostic in newly diagnosed diffuse large B-cell lymphoma (DLBCL), but evolution has not been evaluated at relapse. METHODS: We examined the TCR repertoire in nine paired DLBCL samples from diagnosis and relapse. RESULTS: We noted considerable differences, with dominant clones at diagnosis replaced at relapse by new clones that were absent or minor initially. There was low linearity between diagnostic and relapsed samples (r-values 0.01-0.316), with shared clones averaging 8.3% (range 0%-37%). Clonal diversity was reduced in relapsed samples, suggesting an increasingly defunct intratumoural immune response. CONCLUSION: T-cell diversity is reduced in relapsed/refractory DLBCL, which may have implications for immunotherapy usage.