[Expression of PD-L1 and PD-1 in Pathological Tissue of Patients Newly Diagnosed with Diffuse Large B-Cell Lymphoma]

To investigate the expression of PD-L1 and PD-1 in pathological tissue of patients newly diagnosed with diffuse large B-cell lymphoma (DLBCL).

Data of DLBCL patients who visited the Department of Hematology, Peking University Third Hospital from May 2014 to March 2017 were collected, and a total of 21 patients with pathological tissue sections which were still available at the initial treatment were selected. The patients were divided into complete remission (CR) group and refractory relapse (RR) group according to clinical outcome. The expression and proportion of PD-1 and PD-L1 in pathological tissue sections were detected by multiplex fluorescence immunohistochemical staining, and the differences in the expression of different molecular markers in different clinical characteristics and different prognosis were compared using non-parametric test.

The ratio of PD-L1⁺ cells to PD-1⁺ cells (PD-L1⁺ : PD-1⁺) was 5.14±3.825 in increased lactate dehydrogenase (LDH) group, which was significantly higher than 0.76±0.563 in non-increased LDH group (P=0.001). The ratio of PD-L1⁺ : PD-1⁺ in increased Treg cells group was 1.41±1.454, which was lower than 6.42±4.426 in decreased Treg cells group (P=0.023).

The increased expression ratio of PD-L1 to PD-1 in pathological tissue sections of newly diagnosed DLBCL patients is associated with poor prognostic clinical characteristics.