Expression and prognostic significance of the PD‐1/PD‐L1 pathway in AIDS‐related non‐Hodgkin lymphoma

Abstract

Abstract Objective Immune tolerance and evasion play a critical role in virus‐driven malignancies. However, the phenotype and clinical significance of programmed cell death 1 (PD‐1) and its ligands, PD‐L1 and PD‐L2, in aggressive acquired immunodeficiency syndrome (AIDS)‐related non‐Hodgkin lymphoma (AR‐NHL) remain poorly understood, particularly in the Epstein–Barr virus (EBV)‐positive subset. Methods We used in situ hybridization with EBV‐encoded RNA (EBER) to assess the EBV status. We performed immunohistochemistry and flow cytometry analysis to evaluate components of the PD‐1/PD‐L1/L2 pathway in a multi‐institutional cohort of 58 patients with AR‐NHL and compared EBV‐positive and EBV‐negative cases. Results The prevalence of EBV+ in AR‐NHL was 56.9% and was associated with a marked increase in the expression of PD‐1/PD‐L1/PD‐L2 in malignant cells. Patients with AR‐NHLs who tested positive for both EBER and PD‐1 exhibited lower survival rates compared to those negative for these markers (47.4% vs. 93.8%, p = 0.004). Similarly, patients positive for both EBER and PD‐L1 also demonstrated poorer survival (56.5% vs. 93.8%, p = 0.043). Importantly, PD‐1 tissue‐expression demonstrated independent prognostic significance for overall survival in multivariate analysis and was correlated to elevated levels of LDH (r = 0.313, p = 0.031), increased PD‐1+ Tregs (p = 0.006), and robust expression of EBER (r = 0.541, p < 0.001) and PD‐L1 (r = 0.354, p = 0.014) expression. Conclusions These data emphasize the importance of PD‐1‐mediated immune evasion in the complex landscape of immune oncology in AR‐NHL co‐infected with EBV, and contribute to the diagnostic classification and possible definition of immunotherapeutic strategies for this unique subgroup.

Keywords

• acquired immunodeficiency syndrome
• Epstein–Barr virus
• non‐Hodgkin lymphoma
• programmed cell death protein 1
• regulatory T cells