Immune Checkpoint Molecules in Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System

Sustained response following BTK inhibitors based treatment in HIV-related primary central nervous system lymphoma: case report

BACKGROUND

Despite increasing effort for treating primary central nervous system lymphoma (PCNSL), the prognosis of human immunodeficiency virus (HIV) -related PCNSL was still unsatisfactory. There is currently a lack of clinical evidence for the application of Bruton tyrosine kinase (BTK) inhibitor in HIV-related PCNSL. We reported two HIV-related PCNSL patients, who achieved sustained remission by application of BTK inhibitor based treatment. This protocol had not been previously reported for the treatment of HIV-related PCNSL.

CASE PRESENTATION

The two cases were characterized by the treatment choice of Bruton tyrosine kinase (BTK) inhibitor. Rituximab was not recommended for them due to their very low CD4+ T cell counts. They both took MTX as the first-line therapy and got a relief in initial phase. For the first case, ibrutinib was kept both in the first-line therapy and in the maintenance therapy. When the second case underwent a progressive disease, we continued to use orelabrutinib as one of the salvage treatment, in combination with programmed cell death-1 (PD-1) inhibitor plus lenalidomide. They both achieved a continuous response of up to 20 months without opportunistic infection.

CONCLUSIONS

This report highlights the safety and effectiveness of BTK inhibitors, as well as lenalidomide and PD-1 inhibitor in HIV-related PCNSL patients. Both the new therapeutic approaches and a multidisciplinary team authentically contributed to improved survival outcome among HIV-positive PCNSL patients.

Bruton's tyrosine kinase inhibitors in the treatment of primary central nervous system lymphoma: A mini-review

Primary central nervous system lymphoma (PCNSL) is a highly aggressive brain tumor with poor prognosis if no treatment. The activation of the NF-κB (nuclear factor kappa-B) is the oncogenic hallmark of PCNSL, and it was driven by B cell receptor (BCR) and Toll-like receptor (TLR) signaling pathways. The emergence of Bruton's tyrosine kinase inhibitors (BTKis) has brought the dawn of life to patients with PCNSL. This review summarizes the management of PCNSL with BTKis and potential molecular mechanisms of BTKi in the treatment of PCNSL. And the review will focus on the clinical applications of BTKi in the treatment of PCNSL including the efficacy and adverse events, the clinical trials currently being carried out, the underlying mechanisms of resistance to BTKi and possible solutions to drug resistance.

Molecular characteristics of immunocytes infiltration in primary central nervous system lymphoma

Background: Primary central nervous system lymphoma (PCNSL) is a rare B-cell lymphoma of central nervous system, which is often found in immunocompromised patients. The common clinical treatment of PCNSL is methotrexate (MTX) and whole brain radiation therapy. With the development of tumour immunology research, the tumour microenvironment of PCNSL is characterised by abnormal expression of different immune signature molecules and patients with PCNSL may benefit from tumour immunotherapy.

Methods: In our research, RNA-seq data from 82 PCNSL patients were collated by mining the microarray data from the GEO database. All samples were classified into three types related to tumour immune response by the Cibersort algorithm and consistent clustering. Differential analysis of genes was used to uncover 2 sets of differential genes associated with tumour immunity. The ICI scores of each sample were obtained by PCA algorithm, and the relationship between ICI scores and immune checkpoint expression, immunotherapy and drug sensitivity was investigated. Genes associated with ICI scores and their functional characteristics were investigated by WGCNA analysis and PPI analysis, based on the ICI scores of each sample.

Results: The tumour microenvironment in PCNSL has a greater relationship with the tumour immune response. ICI scores obtained from 375 differential genes were associated with multiple immune responses in PCNSL. PCNSL patients with higher ICI scores had a better tumour microenvironment and were sensitive to immunotherapy and some small molecule drug. This study also identified 64 genes associated with ICI scores, which may serve as important therapeutic and prognostic targets for PCNSL.

Conclusion: The presence of multiple immunosuppressive responses in the tumour microenvironment of PCNSL which suggested that improving the immune function of PCNSL patients through immunotherapy and targeted therapies can be an effective treatment for PCNSL. And the ICI score and associated genes may also provide a better predictor of the clinical use of immunotherapy.

PIM1 and CD79B Mutation Status Impacts the Outcome of Primary Diffuse Large B-Cell Lymphoma of the CNS

Primary diffuse large B cell lymphoma of the central nervous system (CNS DLBCL) is a rare malignancy with a distinct genetic profile. The clinicopathological significance of the mutation patterns remains unknown. Forty cases of primary CNS DLBCL were subjected to targeted exome sequencing covering 413 genes, including MYD88, CD79B and PIM1. Mutational analysis recognized two groups. The CDP (including CD79B and/or PIM1mutations) group was identified in 27 cases (67.5%), and the non-CDP (without CD79B and PIM1 mutations) group was identified in 13 cases 32.5%). The CDP group tended to occur in older patients (median age 57.0 vs. 48.4 years, p=0.015). Patients in the CDP group had a significantly longer 2-year overall survival (OS) (76% and 40%, p=0.0372) than those in the non-CDP group. Multivariate analysis revealed that age less than 60 years, no MYC and BCL2 double expression, and CDP group were three independent risk factors indicating favorable OS. PyClone analysis revealed the subcloning heterogeneity between the groups. In addition, transcriptional sequencing was successfully performed in 8 cases. A total of 131 genes were significantly differentially expressed between these two groups. The major categories of biological processes that were significantly altered between these two groups related to intracellular metabolism mechanisms. We developed a new molecular classification to divide CNS DLBCL into CDP and non-CDP groups based on CD79B and PIM1 mutational status. Patients with PIM1 and/or CD79B mutations had favorable long-term survival after high-dose methotrexate-based polychemotherapy.

Targeted Therapies and Immune Checkpoint Inhibitors in Primary CNS Lymphoma

This review article outlines the current development of emerging treatment strategies for primary central nervous system lymphoma, a rare brain tumor with, thus far, limited therapeutic options. Small molecule targeted tyrosine kinase inhibitors, immunomodulatory agents, and immune checkpoint inhibitors will be discussed. The mechanisms of action, results of completed clinical studies, ongoing clinical trials, and future perspectives are summarized. Among the most promising clinical developments in the field of CNS lymphomas is ibrutinib, an inhibitor of Bruton's tyrosine kinase, which relays activation of nuclear factor kappa B upon integration of constitutive B cell receptor and Toll-like receptor signals. Down-stream of nuclear factor kappa B, the thalidomide analogs lenalidomide and pomalidomide exert immunomodulatory functions and are currently explored against CNS lymphomas. Finally, immune checkpoint inhibitors, such as drugs targeting the PD-1 pathway, may become novel therapeutic options to unleash anti-tumor immunity in patients with primary CNS lymphoma.