The influence of programmed cell death ligand 2 (PD-L2) expression on survival outcome and tumor microenvironment in...

The frequency and significance of programmed cell death ligand (PD-L) 2 expression in diffuse large B cell lymphoma (DLBCL) remain undefined. We described the expression pattern of PD-L/PD-1 in 88 DLBCL patients using immunohistochemistry. The association between PD-L expression and clinical characteristics/outcomes were analyzed. PD-L1 and PD-L2 were expressed in 14.8% and 68.2% of DLBCL patients with median positivity on tumor cells of 100% and 90%, respectively. PD-1 on tumor-infiltrating lymphocytes (TILs) was expressed in 12.5% of patients. Interestingly, 45.5% of patients had PD-L2 expressing TILs which were significantly associated with bulky disease (p = .046) and elevated lactate dehydrogenase (p = .048). PD-L1 and/or PD-L2 expression on lymphoma cells was associated with inferior progression-free survival (Hazard ratio [HR] 2.20; 95% Confidence Interval [CI] 1.004-4.84, p = .049) and overall survival (HR 2.27; 95%CI 1.03-4.98, p = .042), using multivariate analysis. In summary, PD-L2 expression on DLBCL is common and, together with PD-L1, were related to poor outcomes.