BCR and mature T-cell and NK-cell non-Hodgkin lymphoma: Since enrichment of EBV-positive B lymphocytes in the tumor microenvironment is characteristic of AITLs (45, 46, 90), we hypothesized that T-cell receptor (TCR) and B-cell receptor (BCR) repertoire diversity would vary across PTCL subtypes, with greater BCR diversity in AITLs due to polyclonal EBV-mediated B-cell expansion.