CD58 Alterations Govern Antitumor Immune Responses by Inducing PDL1 and IDO in Diffuse Large B-Cell Lymphoma.

Recurrent abnormalities in immune surveillance-related genes affect the progression of diffuse large B-cell lymphoma (DLBCL) and modulate the response to therapeutic interventions. CD58 interacts with the CD2 receptor on T cells and NK cells and is recurrently mutated and deleted in DLBCL, suggesting that it may play a role in regulating antitumor immunity. In this study, we comprehensively analyzed the genomic characteristics of CD58 through targeted next-generation sequencing, RNA sequencing (RNA-seq), whole-exome sequencing, and single-cell RNA-seq in patients with newly diagnosed DLBCL. The CD58 mutation rate was 9.1%, and the copy number loss rate was 44.7% among all enrolled patients with DLBCL. Notably, CD58 genetic alterations, along with low CD58 expression, significantly correlated with reduced rates of response to R-CHOP therapy and inferior progression-free survival and overall survival. Single-cell RNA-seq revealed that CD58 expression in tumor cells was negatively correlated with CD8+ T-cell exhaustion/dysfunction status. Insufficient T-cell activation resulting from CD58 alterations could not be attributed solely to CD2 signaling. CD58 inhibited the activity of the JAK2/STAT1 pathway by activating the LYN/CD22/SH2 domain-containing phosphatase 1 (SHP1) axis, thereby limiting PDL1 and IDO expression. Elevated PDL1 and IDO expression in CD58-deficient DLBCL cells led to immune evasion and tumor-intrinsic resistance to chimeric antigen receptor T-cell therapy. Direct activation of CD58-CD2 costimulatory signaling in combination with anti-PDL1 blockade or IDO inhibitor sensitized CD58-deficient DLBCL to chimeric antigen receptor T-cell therapy. Collectively, this work identified the multiple roles of CD58 in regulating antitumor immune responses in DLBCL. Significance: Loss of CD58 mediates immune evasion and therapy resistance in diffuse large B-cell lymphoma by upregulating PDL1 and IDO through LYN/CD22/SHP1 signaling, providing potential targets and therapeutic strategies to improve patient treatment.