Clinicopathological analysis of neoplastic PD-L1-positive EBV+ diffuse large B cell lymphoma, not otherwise specified, in a Japanese cohort.

The programmed death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in the pathogenesis of Epstein-Barr virus-positive diffuse large B cell lymphoma, not otherwise specified (EBV+ DLBCL, NOS). Here, we describe PD-L1 expression by EBV+ DLBCL, NOS in order to evaluate its possible contribution to the pathogenesis of this tumor. The study included 57 cases of EBV+ DLBCL, NOS. The median patient age was 69 years and 95% (n = 54) were aged > 45. Extranodal lesions were present in 39 (69%) at initial diagnosis. PD-L1 expression (mAb SP142-positive staining) was present in more than 5% of tumor cells in only six cases (11%), in clear contrast to the 77% reported in cases aged under 45 years. Among the PD-L1+ cases, three were nodal lesions. All six PD-L1+ cases progressed in the 3 years after diagnosis and four of the six patients died of the disease within 2 years. PD-L1+ cases had significantly shorter PFS (P = 0.002) and relatively short OS (P = 0.26), compared with PD-L1- cases. EBV+ DLBCL, NOS in the elderly infrequently expressed PD-L1 and had poor prognosis. PD-L1 expression in EBV+ DLBCL, NOS of the elderly sheds light on the pathogenetic role of immune senescence.