Pd-l1 gene alterations to identify a subset of diffuse large B cell lymphoma that harbor a T cell inflamed phenotype.

Abstract Programmed death-ligand 1 (PD-L1) expression on malignant cells is a dominant immune escape mechanism across a variety of human cancers. A unique genetic mechanism underlying PD-L1 upregulation has been uncovered in classical Hodgkin lymphoma (cHL), in which copy gains of the chromosomal region (9p24.1) containing the programmed death-1 (PD-1) ligands PD-L1 and PD-L2 are recurrently observed. While chromosome 9p24.1 copy-number alterations are ubiquitous in cHL, they also occur in diffuse large B-cell lymphoma (DLBCL), albeit with a lower incidence. Here, fluorescence in situ hybridization was used to identify DLBCLs harboring PD-L1 gene alterations, thereby enabling a characterization of the immunogenomic landscape of these lymphomas. Among 105 DLBCL cases analyzed, PD-L1 alterations were identified in 27%. PD-L1 alterations were highly enriched among non–germinal center DLBCLs and exhibited robust PD-L1 protein expression. These lymphomas were heavily infiltrated by clonally restricted T cells and frequently downregulated human leukocyte antigen expression. RNA sequencing of PD-L1–altered DLBCLs revealed upregulation of genes involved in negative T-cell regulation and NF-κB pathway activation, while whole-exome sequencing identified frequent mutations in genes involved in antigen presentation and T-cell costimulation. Many of these findings were validated in a large external data set. Interestingly, DLBCL patients with PD-L1 alterations had inferior progression-free survival following front-line chemoimmunotherapy; however, in the relapsed/refractory setting, PD-L1 alterations were associated with response to anti-PD-1 therapy. Collectively, our results indicate that PD-L1 alterations identify a unique biological subset of DLBCL in which an endogenous antilymphoma immune response has been activated, and that is associated with responsiveness to PD-1 blockade therapy.

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Abstract 699: Pd-l1 gene alterations identify a subset of diffuse large B cell lymphoma harboring a T cell inflamed phenotype

10.1158/1538-7445.am2018-699 ◽

2018 ◽

Author(s):

Justin Paul Kline ◽

James Godfrey ◽

Sravya Tumuluru ◽

Girish Venkataraman ◽

Riyue Bao ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Large B Cell Lymphoma ◽

Large B Cell ◽

Gene Alterations

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Use of immune repertoire sequencing to resolve discordant microscopic and immunochemical findings in a case of T cell-rich large B cell lymphoma in a young dog

BMC Veterinary Research ◽

10.1186/s12917-021-02783-3 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Gary Kwok Cheong Lee ◽

Dorothee Bienzle ◽

Stefan Matthias Keller ◽

Mei-Hua Hwang ◽

Nikos Darzentas ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Immune Repertoire ◽

Large B Cell Lymphoma ◽

Repertoire Sequencing ◽

Reactive Lymphocytes ◽

Large B Cell

Abstract Background Lymphocytic neoplasms with frequent reactive lymphocytes are uncommonly reported in dogs, and can pose a diagnostic challenge. Different diagnostic modalities such as cytology, flow cytometry, histopathology, immunohistochemistry, and clonality testing, are sometimes required for a diagnosis. This report illustrates the value of using a multi-modal diagnostic approach to decipher a complex lymphocytic tumor, and introduces immune repertoire sequencing as a diagnostic adjunct. Case presentation A 10-month-old Great Dane was referred for marked ascites. Cytologic analysis of abdominal fluid and hepatic aspirates revealed a mixed lymphocyte population including numerous large lymphocytes, yielding a diagnosis of lymphoma. Flow cytometrically, abdominal fluid lymphocytes were highly positive for CD4, CD5, CD18, CD45, and MHC II, consistent with T cell lymphoma. Due to a rapidly deteriorating clinical condition, the dog was euthanized. Post mortem histologic evaluation showed effacement of the liver by aggregates of B cells surrounded by T cells, suggestive of hepatic T cell-rich large B cell lymphoma. Immune repertoire sequencing confirmed the presence of clonal B cells in the liver but not the abdominal fluid, whereas reactive T cells with shared, polyclonal immune repertoires were found in both locations. Conclusions T cell-rich large B cell lymphoma is a rare neoplasm in dogs that may be challenging to diagnose and classify due to mixed lymphocyte populations. In this case, the results of histopathology, immunohistochemistry and immune repertoire sequencing were most consistent with a hepatic B cell neoplasm and reactive T cells exfoliating into the abdominal fluid. Immune repertoire sequencing was helpful in delineating neoplastic from reactive lymphocytes and characterizing repertoire overlap in both compartments. The potential pitfalls of equating atypical cytomorphology and monotypic marker expression in neoplasia are highlighted.

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