Immune Escape Mechanisms in Intravascular Large B-Cell Lymphoma: A Molecular Cytogenetic and Immunohistochemical Study. Issue 4 (1st November 2021)

• Record Type: Journal Article
• Authors: Patel, Nisha; Slack, Graham W; Bodo, Juraj; Ben-Neriah, Susana; Villa, Diego; Durkin, Lisa; Socha, Daniel; Steidl, Christian; Hsi, Eric D
• Is Part Of: American journal of clinical pathology. Volume 157:Issue 4(2022)
• Page Start: 578
• Page End: 585
• Publication Date: 2021-11-01
• Subjects: Intravascular B-cell lymphoma -- Programmed cell death ligand 1 (PD-L1) -- MHC protein expression -- Immunohistochemistry (IHC); Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqab154
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Objectives: Intravascular large B-cell lymphomas (IVLBCLs) are rare extranodal LBCLs in which relapse is relatively frequent. We sought to further characterize potential immune escape mechanisms in IVLBCLs that newer therapies can exploit. Methods: A series of 33 IVLBCLs were evaluated for programmed cell death ligand 1 (PD-L1) and PD-L2 expression by immunohistochemistry (IHC), chromosomal alterations (CAs) in the PDL1/PDL2 locus by fluorescence in situ hybridization, and loss of major histocompatibility complex (MHC) class I and II expression by IHC. Results: Cases were subclassified as classical (n = 22) or hemophagocytic syndrome (HPS)–associated (n = 11) variants. A total of 12 cases (39%; n = 12/31) expressed PD-L1 and/or PD-L2. CAs were seen in 7 cases (7/29 [24%]) and included gains, amplifications, and rearrangements. CAs in classical variant cases (24%; n = 5/21) included gains (n =1), gains with concurrent rearrangements (n = 2), and amplifications (n = 2). The 2 HPS-associated variant cases with CAs (25%; n = 2/8) both showed amplification, including 1 case with a concurrent rearrangement. A majority of cases with CAs (71%; n = 5/7) were PD-L1/PD-L2 IHC positive. Among PD-L1/PD-L2 IHC–positive cases, 45% harbored a CA. Loss of MHC class I and/or class II was seen in 27% (n = 9/33) of cases. Conclusions: Altogether, our data show that 65% (n = 20/31) of IVLBCLs may exploit immune evasion strategies through PD-L1/PD-L2 expression or downregulation of MHC proteins.