P1254: RESPONSE TO DA-EPOCH-R IN PATIENTS WITH HIGH GRADE B CELL LYMPHOMA IS ASSOCIATED WITH A REDUCTION OF PD1 POSITIVE EXHAUSTED CD8 T CELLS - V. de Jonge; C. Duetz; W. Bruins; E. van Werkhoven; M. Nijland; K. de Heer; M. van der Poel; Y. Sandberg; C. Klerk; D. de Jong; J. Zijlstra; M. J. Kersten; et al. (HemaSphere, 2022)