PD-L1 (SP142) expression in neoplastic cells predicts a poor prognosis for patients with intravascular large B-cell...

Intravascular large B-cell lymphoma (IVLBCL) is a rare form of diffuse large B-cell lymphoma (DLBCL) arising in extranodal sites. PD-L1 expression of tumor cells has been reported in IVLBCL cells, but its clinicopathological relevance remains to be elucidated.

This study was aimed to reveal the characteristics of PD-L1⁺ IVLBCL.

Neoplastic PD-L1 expression was examined in 34 cases of IVLBCL and clinicopathological characteristics between patients with PD-L1⁺ and PD-L1^- IVLBCL were compared. We assessed PD-L1 expression with SP142 antibody. Twelve (35%) of 34 cases showed positivity for PD-L1. The PD-L1⁺ group had significantly lower survival rates compared to the PD-L1^- group. The PD-L1⁺ IVLBCL group also had a significantly lower age distribution and a lower frequency of patients older than 60 years compared to the PD-L1^- group. Very recently, we speculate that there is possible link between PD-L1⁺ IVLBCL and PD-L1⁺ extranodal DLBCL-NOS (eDLBCL) because features of the two groups showed overlapping. Therefore, we compared the clinicopathological characteristics of the PD-L1⁺ IVLBCL and PD-L1⁺ eDLBCL. There were no significant differences in clinicopathological parameters and prognosis.

The worse prognosis of the PD-L1⁺ group might be caused by immune evasion mechanisms, which are linked to PD-L1 expression. Therefore, PD-L1⁺ IVLBCL cases might be regarded as good candidates for targeted immunotherapy. We also highlighted the overlapping features of PD-L1⁺ IVLBCL and PD-L1⁺ eDLBCL. This result suggests that they should be regarded as one entity, immune evasion-related extranodal large B-cell lymphoma.