DLBCL and PBL display markedly different profiles of CD20, HLA-DR, and PRDM1/Blimp1 expression. Individual protein expression scores (a.u. indicates arbitrary units) using quantum dot IHC were calculated per marker, per case, as described in “Quantum dot fluorescent IHC” (possible range, 0-300). Line indicates median value. *P < .05. (A) CD20 expression is significantly lower in PBL compared to all 3 categories of DLBCL. (B) HLA-DR expression is significantly lower in PBL and MHCII (−) DLBCL compared to MHCII (+) or MHCII-puncture DLBCL. (C) PRDM1/Blimpl is significantly higher in PBL compared to all 3 categories of DLBCL. (D) Mean scores of CD20, HLA-DR, and PRDM1/Blimp1 in MHC II(+), MHC II-punctate, and MHC II(−) DLBCL and PBL.