T-bet suppresses proliferation of malignant B cells in chronic lymphocytic leukemia.

ABSTRACT: The T-box transcription factor T-bet is known as a master regulator of the T-cell response but its role in malignant B cells has not been sufficiently explored. Here, we conducted single-cell resolved multi-omics analyses of malignant B cells from patients with chronic lymphocytic leukemia (CLL) and studied a CLL mouse model with a genetic knockout of Tbx21. We found that T-bet acts as a tumor suppressor in malignant B cells by decreasing their proliferation rate. NF-κB activity, induced by inflammatory signals provided by the microenvironment, triggered T-bet expression, which affected promoter-proximal and distal chromatin coaccessibility and controlled a specific gene signature by mainly suppressing transcription. Gene set enrichment analysis identified a positive regulation of interferon signaling and negative control of proliferation by T-bet. In line, we showed that T-bet represses cell cycling and is associated with longer overall survival of patients with CLL. Our study uncovered a novel tumor suppressive role of T-bet in malignant B cells via its regulation of inflammatory processes and cell cycling, which has implications for the stratification and therapy of patients with CLL. Linking T-bet activity to inflammation explains the good prognostic role of genetic alterations in the inflammatory signaling pathways in CLL.

Autoantibody-Mediated Depletion of IL-1RA in Still's Disease and Potential Impact of IL-1 Targeting Therapies.

BACKGROUND: Adult-onset Still's disease (AOSD) and systemic juvenile idiopathic arthritis (sJIA) resemble a continuum of a rare, polygenic IL-1ß-driven disease of unknown etiology. OBJECTIVE: In the present study we sought to investigate a potential role of recently described autoantibodies neutralizing the interleukin-1(IL-1)-receptor antagonist (IL-1-Ra) in the pathogenesis of Still's disease. METHODS: Serum or plasma samples from Still's disease patients (AOSD, n = 23; sJIA, n = 40) and autoimmune and/or inflammatory disease controls (n = 478) were analyzed for autoantibodies against progranulin (PGRN), IL-1Ra, IL-18 binding protein (IL-18BP), and IL-36Ra, as well as circulating IL-1Ra and IL-36Ra levels by ELISA. Biochemical analyses of plasma IL-1Ra were performed by native Western blots and isoelectric focusing. Functional activity of the autoantibodies was examined by an in vitro IL-1ß-signaling reporter assay. RESULTS: Anti-IL-1-Ra IgG were identified in 7 (27%) out of 29 Still's disease patients, including 4/23 with AOSD and 3/6 with sJIA and coincided with a hyperphosphorylated isoform of endogenous IL-1Ra. Anti-IL-36Ra antibodies were found in 2 AOSD patients. No anti-PGRN or anti-IL-18BP antibodies were detected. Selective testing for anti-IL-1Ra antibodies in an independent cohort (sJIA, n = 34) identified 5 of 34 (14.7%) as seropositive. Collectively, 8/12 antibody-positive Still's disease patients were either new-onset active disease or unresponsive to IL-1 blocking drugs. Autoantibody-seropositivity associated with decreased IL-1Ra plasma/serum levels. Seropositive plasma impaired in vitro IL-1Ra bioactivity, which could be reversed by anakinra or canakinumab treatment. CONCLUSION: Autoantibodies neutralizing IL-1Ra may represent a novel patho-mechanism in a subgroup of Still's disease patients, which is sensitive to high-dose IL-1 blocking therapy.

Comparison of R-CHOP-14 and R-mini-CHOP in older adults with diffuse large B-cell lymphoma-A retrospective multicenter cohort study.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma entity, and its incidence increases with age. There is a paucity of data regarding use of biweekly R-CHOP (R-CHOP-14) in patients ≥80 years of age. We performed a retrospective cohort study of patients with DLBCL aged ≥80 years treated with R-CHOP-14 and R-miniCHOP in two academic tertiary centers in Germany between 01/01/2005 and 12/30/2019. Overall, 79 patients were included. Median age was 84 years (range 80-91). Despite higher CR rates with R-CHOP-14 (71.4% vs. 52.4%), no statistically significant difference could be found between patients treated with R-CHOP-14 and R-miniCHOP regarding overall survival (OS) (p = .88, HR 0.94, 95% CI = 0.47-1.90) and progression-free survival (PFS) (p = .26, HR 0.66, 95% CI = 0.32-1.36). At a median follow-up of 40 months, the 2-year OS rates were 56% with R-CHOP-14 and 53% with R-miniCHOP. Two-year PFS rates were 46% for R-CHOP-14 and 50% for R-mini-CHOP. Relative dose intensity of chemotherapy did not correlate with OS (p = .72). With the caveat of a retrospective cohort study, we conclude that lacking a difference in OS, R-miniCHOP should be preferred for most patients with untreated DLBCL aged ≥80 years.

Successful treatment of refractory donor-specific-human leukocyte antigen-antibody-induced primary graft-failure with daratumumab: A case report.

Donor-specific anti-human leukocyte antigen (HLA) antibodies represent a main cause of primary graft failure specifically in the setting of haploidentical stem cell transplantation. Newer therapy strategies including daratumumab could overcome some of these limitations. We describe the case of a patient with refractory acute myeloid leukemia. A haploidentical allogeneic stem cell transplantation was therefore initiated. HLA-antibodies testing revealed a high titer of donor-specific antibodies. First desensitization therapy failed, resulting in primary graft failure. A second desensitization regimen including plasmapheresis, intravenous gammaglobulins, and daratumumab resulted in good engraftment. Daratumumab is a promising and effective desensitization option in high-risk allo-sensitized patients undergoing haploidentical stem cell transplantation.

Hyper-N-glycosylated SEL1L3 as auto-antigenic B-cell receptor target of primary vitreoretinal lymphomas.

Primary vitreoretinal lymphoma (PVRL) is a rare subtype of DLBCL and can progress into primary central nervous system lymphoma (PCNSL). To investigate the role of chronic antigenic stimulation in PVRL, we cloned and expressed B-cell receptors (BCR) from PVRL patients and tested for binding against human auto-antigens. SEL1L3, a protein with multiple glycosylation sites, was identified as the BCR target in 3/20 PVRL cases. SEL1L3 induces proliferation and BCR pathway activation in aggressive lymphoma cell lines. Moreover, SEL1L3 conjugated to a toxin killed exclusively lymphoma cells with respective BCR-reactivity. Western Blot analysis indicates the occurrence of hyper-N-glycosylation of SEL1L3 at aa 527 in PVRL patients with SEL1L3-reactive BCRs. The BCR of a PVRL patient with serum antibodies against SEL1L3 was cloned from a vitreous body biopsy at diagnosis and of a systemic manifestation at relapse. VH4-04*07 was used in both lymphoma manifestations with highly conserved CDR3 regions. Both BCRs showed binding to SEL1L3, suggesting continued dependence of lymphoma cells on antigen stimulation. These results indicate an important role of antigenic stimulation by post-translationally modified auto-antigens in the genesis of PVRL. They also provide the basis for a new treatment approach targeting unique lymphoma BCRs with ultimate specificity.