Combined 4-1BB and ICOS co-stimulation improves anti-tumor efficacy and persistence of dual anti-CD19/CD20 chimeric antigen receptor T cells

Chimeric antigen receptor (CAR) T-cell therapy is a promising therapeutic strategy against lymphoma. However, post-treatment relapses due to antigen loss remain a challenge. Here the authors designed a novel bicistronic CAR construct and tested its functions in vitro and in vivo. The CAR construct consisted of individual anti-CD19 and anti-CD20 single-chain fragment variables equipped with ICOS-CD3ζ and 4-1BB-CD3ζ intracellular domains, respectively. The CD19 and CD20 bicistronic CAR T cells exhibited tumor lytic capacities equivalent to corresponding monospecific CAR T cells. Moreover, when stimulated with CD19 and CD20 simultaneously, the bicistronic CAR T cells showed prolonged persistence and enhanced cytokine generation compared with single stimulations. Interestingly, the authors found that the 4-1BB signal was predominant in the signaling profiles of ICOS and 4-1BB doubly activated CAR T cells. In vivo study using a CD19/CD20 double-positive tumor model revealed that the bicistronic CAR T cells were more efficient than monospecific CD19 CAR T cells in eradicating tumors and prolonging mouse survival. The authors' novel bicistronic CD19/CD20 CAR T cells demonstrate improved anti-tumor efficacy in response to dual antigen stimulations. These data provide optimism that this novel bicistronic CAR construct can improve treatment outcomes in patients with relapsed/refractory B cell malignancy.

B cell depletion changes the immune cell profile in multiple sclerosis patients: One-year report

B cell depletion therapy has been shown to be beneficial in multiple sclerosis (MS). However, the mechanism by which B cell depletion mediates its beneficial effects in MS is still unclear. To better understand how B cell depletion may benefit patients with a disease previously thought to be primarily mediated by CD4 T cells, immune profiles were monitored in 48 patients in a phase II trial of ublituximab, a glycoengineered CD20 monoclonal antibody, at 18 time points over a year. As we previously described there was a significant shift in the percentages of T cells, NK cells, and myeloid cells following the initial dose of ublituximab, but this shift normalized within a week and these populations remained stable for the duration of the study. However, T cell subsets changed with an increase in the percentage of naïve CD4 and CD8 T cells and a decline in memory T cells. Importantly, the percentage of Th1 and CD4⁺GM-CSF⁺ T cells decreased, while the percentage of Tregs continued to increase over the year. Ublituximab not only depleted CD20⁺ B cells, but also CD20⁺ T cells. The favorable changes in the T cell subsets may contribute to the beneficial effects of B cell depletion therapy.

Prognostic Relevance of the Relative Presence of CD4, CD8 and CD20 Expressing Tumor Infiltrating Lymphocytes in Operable Non-small Cell Lung Cancer Patients

BACKGROUND/AIM

Non-small cell lung cancer (NSCLC) is one of the most lethal tumors. Given the failure of conventional therapeutic strategies, immunotherapy has emerged as a promising treatment modality that may improve the survival of patients with operable and advanced disease.

PATIENTS AND METHODS

We examined the relative presence of CD20+ B-cells, CD8+ cytotoxic, and CD4+ helper/regulatory T-cells in the tumor-infiltrating lymphocyte (TIL)-population in a series of surgically-treated NSCLCs, and assessed their role as prognostic indicators after surgery.

RESULTS

A high percent of CD4+ and CD8+ TILs in the tumor stroma was linked with poor (p=0.003) and good prognosis (p=0.01), respectively. High CD4/CD8 ratio defined a significantly worst prognosis [median survival 22 months vs. undefined, p=0.0002, hazard ratio (HR) 0.3 vs. 3.0]. Statistically significant results were also noted when the analysis was focused on the invading tumor front. In a multivariate model, the CD4/CD8-ratio assessed in the tumor stroma and the stage of disease were independent prognostic variables (p=0.0001, HR=4.1 and p=0.001, HR=1.5, respectively).

CONCLUSION

The balance between CD4+ and CD8+ lymphocytes infiltrating the tumor stroma is a crucial factor defining anti-tumor immune surveillance, has strong prognostic value, and may be tested as a predictive biomarker for immunotherapy in operable NSCLC.

[Clinical analysis of 11 cases of CD20 positive extranodal NK/T cell lymphoma]

Objective:To explore the clinical features and prognosis of CD20-positive extranodal NK/T cell lymphoma. Methods:To analyze the clinical characteristics and prognosis of 11 ENKTL patients admitted to this hospital. Results:Among the 11 patients, 6 cases with elevated LDH, 6 cases of anemia, and 8 cases with Ki-67≥50%. Two cases survived; 1 case lost contact; 8 cases died, and the average survival time of 8 cases was 22.5 months. Conclusion:The diagnosis of CD20 positive ENKTL is difficult, which requires a combination pathomorphology, immunohistochemistry, EBER and gene rearrangement detection and improve the understanding of the disease.Early diagnosis and active treatment is important.

CD20 as a gatekeeper of the resting state of human B cells

Worldwide about one million patients are given anti-CD20 antibodies such as rituximab (RTX) for the treatment of B cell-associated diseases. Despite the success of this first therapeutic antibody, little is known about the function of its target. The role of CD20 only becomes clear in the context of the nanoscale compartmentalization of the B lymphocyte membrane. We found that CD20 is an organizer of the IgD-class nanocluster on the B cell membrane. The loss of CD20 on human B cells results in a dissolution of the IgD-class nanocluster and a transient B cell activation inducing a B cell-to-PC differentiation. Thus, CD20 is an essential gatekeeper of a membrane nanodomain and the resting state of naive B cells.

CD20 is a B cell-specific membrane protein and represents an attractive target for therapeutic antibodies. Despite widespread usage of anti-CD20 antibodies for B cell depletion therapies, the biological function of their target remains unclear. Here, we demonstrate that CD20 controls the nanoscale organization of receptors on the surface of resting B lymphocytes. CRISPR/Cas9-mediated ablation of CD20 in resting B cells resulted in relocalization and interaction of the IgM-class B cell antigen receptor with the coreceptor CD19. This receptor rearrangement led to a transient activation of B cells, accompanied by the internalization of many B cell surface marker proteins. Reexpression of CD20 restored the expression of the B cell surface proteins and the resting state of Ramos B cells. Similarly, treatment of Ramos or naive human B cells with the anti-CD20 antibody rituximab induced nanoscale receptor rearrangements and transient B cell activation in vitro and in vivo. A departure from the resting B cell state followed by the loss of B cell identity of CD20-deficient Ramos B cells was accompanied by a PAX5 to BLIMP-1 transcriptional switch, metabolic reprogramming toward oxidative phosphorylation, and a shift toward plasma cell development. Thus, anti-CD20 engagement or the loss of CD20 disrupts membrane organization, profoundly altering the fate of human B cells.

Pulmonary arterial hypertension (PAH) from autopsy study: T-cells, B-cells and mastocytes detection as morphological evidence of immunologically mediated pathogenesis

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by severe vascular remodelling, resulting in increased pulmonary vascular resistance with cardiac hypertrophy and heart failure. However, the diagnosis of PAH is often inaccurate. Many cases of PAH are incorrectly diagnosed or missed, and they are often associated with death. The aim of this study was to verify the morphological and histological criteria of fatal cases of PAH and evaluate the lymphocytic populations associated to lesions with reactive neo-angiogenesis.

METHODS

Pulmonary lung sections from 10 cases of sudden unexpected death (SUD) in the absence of previously diagnosed diseases and in an apparent state of well-being, with final histological post autopsy diagnosis of PAH were collected. The pathological findings were compared using ten controls from non-pathological lung from deaths from other causes. The autopsies included 4 males (40%) and 6 females (60%) with an average age of 52.1 ± 10.1 years. Sections stained with hematoxylin and eosin (H&E) were revised for a morphological diagnosis. Subsequently, serial sections were performed and stained with immunohistochemistry for anti-CD20 (B-lymphocytes), anti-CD3 (T-lymphocytes), anti-CD4 (T-helper lumphocytes), anti-CD8 (T-cytotoxic lymphocytes) and anti-CD117/C-Kit (mast cells/MCs) to detect inflammatory infiltrate and different ratios of cell-type. Statistical analysis was conducted using a paired t-test looking at 100 cells in 3 different tissue samples representative of vascular lesion and 3 different random normal lung parenchyma fields without lesion (from 10 normal control lungs), to identify specific lymphocyte subpopulations in inflammatory infiltrates.

RESULTS

There was a significant percentage increase of CD20 (p < 0.001), CD8 (p = 0.002), CD4 (p < 0.001), and CD117/C-Kit positive (C-Kit+; p < 0.001) cells mainly detected around wall vessels; while increased MCs positivity and C-Kit+ were observed especially in alveolar septa. In addition, reactive angiomatosis was observed.

CONCLUSIONS

The inflammatory infiltrate should be included for a correct diagnosis of PAH besides the vascular remodelling. The inflammatory infiltrate seems to be implicated as a main factor in the pathogenesis. This finding is important to rule out secondary pulmonary hypertension, to identify SUDs of unknown causes and to add new elements to the literature that can explain the immunologically related pathogenesis of PAH.

Novel chimerized IgA CD20 antibodies: Improving neutrophil activation against CD20-positive malignancies

Current combination therapies elicit high response rates in B cell malignancies, often using CD20 antibodies as the backbone of therapy. However, many patients eventually relapse or develop progressive disease. Therefore, novel CD20 antibodies combining multiple effector mechanisms were generated. To study whether neutrophil-mediated destruction of B cell malignancies can be added to the arsenal of effector mechanisms, we chimerized a panel of five previously described murine CD20 antibodies to the human IgG1, IgA1 and IgA2 isotype. Of this panel, we assessed in vitro antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and direct cell death induction capacity and studied the efficacy in two different in vivo mouse models. IgA antibodies outperformed IgG1 antibodies in neutrophil-mediated killing in vitro, both against CD20-expressing cell lines and primary patient material. In these assays, we observed loss of CD19 with both IgA and IgG antibodies. Therefore, we established a novel method to improve the assessment of B-cell depletion by CD20 antibodies by including CD24 as a stable cell marker. Subsequently, we demonstrated that only IgA antibodies were able to reduce B cell numbers in this context. Additionally, IgA antibodies showed efficacy in both an intraperitoneal tumor model with EL4 cells expressing huCD20 and in an adoptive transfer model with huCD20-expressing B cells. Taken together, we show that IgA, like IgG, can induce ADCC and CDC, but additionally triggers neutrophils to kill (malignant) B cells. We conclude that antibodies of the IgA isotype offer an attractive repertoire of effector mechanisms for the treatment of CD20-expressing malignancies.

Bivalent binding on cells varies between anti-CD20 antibodies and is dose-dependent

Based on their mechanism of action, two types of anti-CD20 antibodies are distinguished: Type I, which efficiently mediate complement-dependent cytotoxicity, and Type II, which instead are more efficient in inducing direct cell death. Several molecular characteristics of these antibodies have been suggested to underlie these different biological functions, one of these being the manner of binding to CD20 expressed on malignant B cells. However, the exact binding model on cells is unclear. In this study, the binding mechanism of the Type I therapeutic antibodies rituximab (RTX) and ofatumumab (OFA) and the Type II antibody obinutuzumab (OBI) were established by real-time interaction analysis on live cells. It was found that the degree of bivalent stabilization differed for the antibodies: OFA was stabilized the most, followed by RTX and then OBI, which had the least amount of bivalent stabilization. Bivalency inversely correlated with binding dynamics for the antibodies, with OBI displaying the most dynamic binding pattern, followed by RTX and OFA. For RTX and OBI, bivalency and binding dynamics were concentration dependent; at higher concentrations the interactions were more dynamic, whereas the percentage of antibodies that bound bivalent was less, resulting in concentration-dependent apparent affinities. This was barely noticeable for OFA, as almost all molecules bound bivalently at the tested concentrations. We conclude that the degree of bivalent binding positively correlates with the complement recruiting capacity of the investigated CD20 antibodies.

The Immune Microenvironment of Chordomas: An Immunohistochemical Analysis

Simple Summary

Chordoma patients may be amenable to immunotherapy; however, the immune microenvironment of chordomas needs further investigation. We performed the immunohistochemical analysis of a chordoma series, showing that these tumors have a unique microenvironment characterized by the absence of PD-L1 tumor cell expression, but feature PD-L1+ immune cells playing a negative prognostic role.

Abstract

Chordomas are rare sarcomas that are usually treated by surgery and/or radiotherapy since these are chemo-resistant tumors, but immunotherapy could be a possible option for chordoma patients. However, few reports investigating the composition of the chordoma immune microenvironment exist. We immunohistochemically studied 81 chordomas regarding their immune microenvironment factors and compared them with clinicopathological data. Macrophages and CD4 cells were the most prominent inflammatory cell populations, followed by CD8 T cells, while CD20 B cells and high endothelial venules (MECA-79+) were less frequently found. PD-L1 (22C3) expression by inflammatory cells was found in 21 (26%) tumors and was associated with a larger tumor size. None of the cases showed the expression of PD-L1 by tumor cells. Survival analysis showed that younger patients had a better overall survival. Considering the immunohistochemical factors studied, higher CD8, the presence of PD-L1+ immune cells, and higher vascular density were adverse prognostic factors, but in multivariate analysis, only PD-L1+ immune cells retained prognostic significance. To conclude, chordoma tumor cells do not express PD-L1, but PD-L1+ immune cells seem to play a negative prognostic role, supporting the need for further studies in this field and the possible beneficial role of immunotherapy in these patients.

Short-Interval Sequential CAR-T Cell Infusion May Enhance Prior CAR-T Cell Expansion to Augment Anti-Lymphoma Response in B-NHL

Chimeric antigen receptor (CAR)-T cell therapy emerges as a new treatment for refractory or relapsed (r/r) B-cell non-Hodgkin lymphoma (B-NHL); however, the overall response rate (ORR) of which in the B-NHL patients is much lower compared to the patients with r/r B acute lymphoblastic leukemia (B-ALL). We previously confirmed that sequential infusions of CD20 and CD22 CAR-T cells significantly improved the prognosis of the B-NHL patients, while some advanced patients still progressed to death during these CAR-T cell treatments. In this study, we showed that timely sequential administration of the second CAR-T cells could enhance expansion of prior CAR-T cells with stronger tumor-killing capacity in vitro and in vivo. We further conducted compassionate treatments on two advanced B-NHL patients with short-interval sequential infusions of CD19/22/20 CAR-T cells. Disease progression was observed in both patients after primary CAR-T cell infusion but robust re-expansion of prior CAR-T cells and anti-tumor effects was induced by infusion of a secondary CAR-T cells. These results indicate sequential infusions of CAR-T cells with a short interval may improve therapeutic efficacy in the B-NHL patients by promoting expansion of prior CAR-T cells.

Approach to SARS-CoV-2 Vaccination in Patients With Multiple Sclerosis

For more than a year now, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been causing the coronavirus disease (COVID-19) pandemic with high mortality and detrimental effects on society, economy, and individual lives. Great hopes are being placed on vaccination as one of the most potent escape strategies from the pandemic and multiple vaccines are already in clinical use. However, there is still a lot of insecurity about the safety and efficacy of vaccines in patients with autoimmune diseases like multiple sclerosis (MS), especially under treatment with immunomodulatory or immunosuppressive drugs. We propose strategic approaches to SARS-CoV-2 vaccination management in MS patients and encourage fellow physicians to measure the immune response in their patients. Notably, both humoral and cellular responses should be considered since the immunological equivalent for protection from SARS-CoV-2 after infection or vaccination still remains undefined and will most likely involve antiviral cellular immunity. It is important to gain insights into the vaccine response of immunocompromised patients in order to be able to deduce sensible strategies for vaccination in the future.

CD32+CD4+ T Cells Sharing B Cell Properties Increase With Simian Immunodeficiency Virus Replication in Lymphoid Tissues

CD4 T cell responses constitute an important component of adaptive immunity and are critical regulators of anti-microbial protection. CD4⁺ T cells expressing CD32a have been identified as a target for HIV. CD32a is an Fcγ receptor known to be expressed on myeloid cells, granulocytes, B cells and NK cells. Little is known about the biology of CD32⁺CD4⁺ T cells. Our goal was to understand the dynamics of CD32⁺CD4⁺ T cells in tissues. We analyzed these cells in the blood, lymph nodes, spleen, ileum, jejunum and liver of two nonhuman primate models frequently used in biomedical research: African green monkeys (AGM) and macaques. We studied them in healthy animals and during viral (SIV) infection. We performed phenotypic and transcriptomic analysis at different stages of infection. In addition, we compared CD32+CD4+ T cells in tissues with well-controlled (spleen) and not efficiently controlled (jejunum) SIV replication in AGM. The CD32⁺CD4⁺ T cells more frequently expressed markers associated with T cell activation and HIV infection (CCR5, PD-1, CXCR5, CXCR3) and had higher levels of actively transcribed SIV RNA than CD32^-CD4⁺T cells. Furthermore, CD32⁺CD4⁺ T cells from lymphoid tissues strongly expressed B-cell-related transcriptomic signatures, and displayed B cell markers at the cell surface, including immunoglobulins CD32+CD4+ T cells were rare in healthy animals and blood but increased strongly in tissues with ongoing viral replication. CD32⁺CD4⁺ T cell levels in tissues correlated with viremia. Our results suggest that the tissue environment induced by SIV replication drives the accumulation of these unusual cells with enhanced susceptibility to viral infection.

Effect of Subcutaneous Anti-CD20 Antibody-Mediated B Cell Depletion on Susceptibility to Pneumocystis Infection in Mice

Anti-CD20 antibody therapy is used for both cancer and autoimmune disease but has been shown to be associated with Pneumocystis pneumonia in humans. This study shows that low-dose subcutaneous anti-CD20 can modulate B cell populations without grossly perturbing fungal immunity against Pneumocystis lung infection.

Prior work has shown that parenterally administered anti-CD20 (5D2) inhibits CD4⁺ T cell priming in response to challenge with Pneumocystis murina and predisposes to pneumonia. In this study, we investigated the effect of subcutaneous anti-CD20 antibody and Pneumocystis infection. In mice with primary infection, anti-CD20 antibody treatment depleted both CD19⁺ and CD27⁺ CD19⁺ cells but not T cells in the lung at days 14 and 28 after Pneumocystis inoculation. Although anti-CD20 antibody treatment impaired fungal clearance at day 14 postinfection, fungal burden in the lungs was substantially reduced at day 28 in both depleted and control mice in the low-dose group. Subcutaneous anti-CD20 antibody treatment did not alter antigen-specific serum immunoglobulin levels in mice compared with control mice, and there were no significant differences in the numbers of lung gamma interferon-positive (IFN-γ⁺) CD4⁺, interleukin 4-positive (IL-4⁺) CD4⁺, IL-5⁺ CD4⁺, and IL-17A⁺ CD4⁺ cells between depleted and control mice after infection. In mice with secondary infection, the lung fungal burden was comparable between depleted and control mice 14 days after reinfection. Low-dose subcutaneous anti-CD20 antibody treatment may delay fungal clearance, but it did not impair the ability of the host to clear Pneumocystis infection, irrespective of primary or secondary infection.

IMPORTANCE Anti-CD20 antibody therapy is used for both cancer and autoimmune disease but has been shown to be associated with Pneumocystis pneumonia in humans. This study shows that low-dose subcutaneous anti-CD20 can modulate B cell populations without grossly perturbing fungal immunity against Pneumocystis lung infection.

Efficacy Profile and Safety of Very Low-Dose Rituximab in Patients with Graves' Orbitopathy

Background: Rituximab (RTX), a chimeric human-murine anti-CD20 monoclonal antibody, has been used for treatment of active moderate-severe Graves' orbitopathy (GO) since 2004 as second-line therapy in patients unresponsive to intravenous steroids. We conducted an open-label prospective study (EUDRACT 2012-001980-53) in which patients were treated with a single infusion of only 100 mg RTX to analyze the efficacy and safety of this low dose. Methods: Seventeen patients, of whom nine had disease that was unresponsive to intravenous methylprednisolone and eight with newly diagnosed GO, were enrolled. Disease activity was assessed with the clinical activity score (CAS) and severity with a composite ophthalmic score. Long-term surgical treatment and quality of life were also assessed, as well as treatment-related adverse events. Results: Mean baseline CAS was 4.56 ± 0.96 and decreased to 1.25 ± 1.14 at 24 weeks (p = 0.001). Disease inactivation occurred within 24 weeks in >90% of patients and was unrelated to disease duration. Severity improved in about 60% of patients, with no relapses. All patients showed peripheral depletion of CD20⁺ and CD19⁺ cells at the end of RTX infusion (60 minutes). Two patients required surgical orbital decompression because of optic neuropathy (ON). Among adverse events observed, there was one patient who developed a cytokine release syndrome. Conclusions: A dose of 100 mg RTX is effective in patients with active moderate-severe GO. Low doses are better tolerated, expose patients to immune suppression for a shorter period of time, and are extremely cost effective, compared with higher doses. This dose, consistently with all other immunosuppressants, does not prevent the progression of GO to dysthyroid ON.

The Construction and Characterization of 1F5 Chimeric Anti-CD20 Monoclonal Antibodies: An Efficient Splicing by Overlap Extension-polymerase Chain Reaction Technique

Despite the unparalleled success of anti-CD20-targeted immunotherapy, the currently available mAbs are not sufficiently efficacious in the treatment of lymphoma. 1F5 is one of a panel of anti-CD20 mAbs that was used in the B-cell lymphoma serotherapy. Despite the efficacy of murine 1F5 mAbs in lymphoma patients, the 1F5 chimeric antibodies with human effector functionality are yet to be approved and widely used in the treatment of lymphoma. In this study, the conversion of 1F5 mAb from mouse IgG2a to human-mouse chimeric IgG1 was achieved and the chimeric antibody was partially characterized. We constructed the 1F5 chimeric mouse-human anti-CD20 antibody genes using an efficient Splicing by overlap extension-polymerase chain reaction (SOE-PCR) technique and cloned the chimeric heavy and light genes in pBudCE4.1mammalian expression vector, followed by purification of the expressed chimeric 1F5 mAbs using affinity chromatography. Our investigation also included the biological properties of purified chimeric antibodies. The generated 1F5 chimeric mAbs mediate complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) against Raji and Daudi Burkitt's lymphoma cell lines, which were comparable with rituximab and exhibit superior reduction in cell viability in vitro, compared to rituximab. The current study indicated that the generated chimeric 1F5 mAbs has potential CDC and ADCC activity which was comparable with rituximab whereas it exhibits a superior reduction in cell viability, compared to rituximab. Our work contributes to future studies involving in vivo biological functions and the application of the 1F5 chimeric antibody.

Hydrogen deuterium exchange mass spectrometry identifies the dominant paratope in CD20 antigen binding to the NCD1.2 monoclonal antibody

A comparative canine–human therapeutics model is being developed in B-cell lymphoma through the generation of a hybridoma cell that produces a murine monoclonal antibody specific for canine CD20. The hybridoma cell produces two light chains, light chain-3, and light chain-7. However, the contribution of either light chain to the authentic full-length hybridoma derived IgG is undefined. Mass spectrometry was used to identify only one of the two light chains, light chain-7, as predominating in the full-length IgG. Gene synthesis created a recombinant murine–canine chimeric monoclonal antibody expressing light chain-7 that reconstituted the IgG binding to CD20. Using light chain-7 as a reference sequence, hydrogen deuterium exchange mass spectrometry was used to identify the dominant CDR region implicated in CD20 antigen binding. Early in the deuteration reaction, the CD20 antigen suppressed deuteration at CDR3 (V_H). In later time points, deuterium suppression occurred at CDR2 (V_H) and CDR2 (V_L), with the maintenance of the CDR3 (V_H) interaction. These data suggest that CDR3 (V_H) functions as the dominant antigen docking motif and that antibody aggregation is induced at later time points after antigen binding. These approaches define a methodology for fine mapping of CDR contacts using nested enzymatic reactions and hydrogen deuterium exchange mass spectrometry. These data support the further development of an engineered, synthetic canine–murine monoclonal antibody, focused on CDR3 (V_H), for use as a canine lymphoma therapeutic that mimics the human–murine chimeric anti-CD20 antibody Rituximab.

A rapid multiple immunofluorescence method for the simultaneous detection of CD20 and CD3 in canine and feline cytological samples

CD20 and CD3 are considered reliable markers for B and T cells, respectively. This study aimed to develop a rapid multiple immunofluorescence (RMIF) method for the detection of CD20 and CD3 on a single cytology slide. Air-dried smears were prepared using samples collected from dogs (n=26) and cats (n=6). Immunosignal detection using the newly developed method required 60 min. Clear immunosignals for CD20 and CD3 were detected in 24 of 26 samples in dogs and in all 6 cats. As the RMIF (CD20/CD3) method can detect markers of both B and T cells simultaneously on a single cytology smear, it would be an efficient tool for the immunophenotyping of canine and feline lymphoma samples.

New Therapeutic Landscape in Neuromyelitis Optica

Purpose of review

This review discusses the current treatment trends and emerging therapeutic landscape for patients with neuromyelitis optica spectrum disorder (NMOSD).

Recent findings

Conventional immune suppressive therapies, such as B cell depletion, have been used for long-term treatment. However, the availability of recent FDA-approved and investigational drugs has made therapeutic choices for NMOSD more complex.

Summary

Recent randomized clinical trials have shown that eculizumab, inebilizumab, and satralizumab are efficacious therapies for AQP4 seropositive NMOSD. These therapies may not have the same benefit in patients with seronegative NMOSD, including MOG-associated disease, and further investigation is required in this population. Reliable biomarkers to guide therapy decisions are urgently needed. There is a plethora of promising investigational therapies currently in the pipeline with exciting and novel mechanisms of action.

Mucosa-associated lymphoid tissue lymphoma of the bladder: Case report

We report the cases of patient with primary mucosa-associated lymphoid tissue (MALT) lymphoma of the bladder who successfully treated with local radiation therapy after transurethral resection of the bladder tumor. She maintains good activity of daily living without relapse. We recommend this strategy for localized MALT lymphoma of the bladder, because it provide better quality of life for elderly patients.

Post-mortem diagnosis of intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a rare (<1%), typically aggressive extranodal variant of mature non-Hodgkin B-cell lymphoma. IVLBCL is characterized by malignant lymphoid cells lodged within blood vessels, particularly capillary channels. Herein, we present a case of a 50-year-old man with a history of myeloradiculitis (∼1 year) and paraparesis requiring hospitalization. During the course of his hospital stay, computed tomography (CT), magnetic resonance imaging, CT-positron emission tomography, and biopsy failed to establish a diagnosis. The patient died 2 months later from bilateral pneumonia. Postmortem examination was undertaken to determine the cause of death. Histologic sections of the patient’s brain, heart, lung, and liver showed aggregates of highly atypical cells bearing enlarged, pleomorphic, and hyperchromatic nuclei. Strong intravascular positivity for CD45 and CD20 markers indicated the cells were of B-cell origin, supporting a diagnosis of IVLBCL.

Prognostic value of tumor-infiltrating B lymphocytes and plasma cells in triple-negative breast cancer

Background

Recent investigations have demonstrated that the tumor microenvironment, including tumor-infiltrating lymphocytes (TILs), is an important factor in tumor growth and development. While the prognostic correlation of tumor-infiltrating T cells has been widely studied in breast cancer, that of tumor-infiltrating B cells and plasma cells has not received so much attention, especially in triple-negative breast cancer (TNBC).

Methods

We investigated 114 patients with TNBC who had surgery between 2006 and 2019 at Dokkyo Medical University Hospital. Intratumoral (i) TILs were considered to be lymphocytes within cancer cell nests and directly infiltrating tumor cells. Similarly, stromal (s) TILs were considered to be lymphocytes within the tumor stroma, but not directly infiltrating tumor cells. CD20 + , CD38 + and CD138 + staining was determined by estimating the number of positive B cells.

Results

sCD20 + TILs had prognostic significance for relapse-free survival (RFS) (p = 0.043) and overall survival (OS) (p = 0.027). The sCD38 + TILs were significantly related to favorable RFS (p = 0.042). iCD38, iCD138, and sCD138 was not significantly correlated with RFS (p = 0.065, p = 0.719, p = 0.074) or OS (p = 0.071, p = 0.689, p = 0.082).

Conclusions

The present study demonstrated that a high density of sCD20 + TILs was significantly related to favorable prognosis in both RFS and OS. Increased sCD38 + TILs in TNBC were correlated with a significantly favorable prognosis in RFS. These results indicate that TILs–B may have a profound influence on the clinical outcome of TNBC.

Immunotherapies Old and New: Hematopoietic Stem Cell Transplant, Chimeric Antigen Receptor T Cells, and Bispecific Antibodies for the Treatment of Relapsed/Refractory Diffuse Large B Cell Lymphoma

PURPOSE OF REVIEW

Diffuse large B cell lymphoma (DLBCL) is curable in a majority of patients; however, a significant portion of patients develop relapsed or refractory disease. High-dose chemotherapy followed by autologous stem cell transplant is the standard approach in appropriately selected patients. Many patients are not candidates for transplant and many who do receive autologous transplant relapse. Therapies which harness T cells including chimeric antigen receptor T cells (CAR-T) and bispecific antibodies are active in this chemotherapy-resistant population. We review the role of autologous and allogeneic stem cell transplant, CAR-T therapy, and bispecific antibodies in the treatment of relapsed or refractory DLBCL.

RECENT FINDINGS

Phase I studies of bispecific antibodies directed against CD20 × CD3 have shown activity in heavily pre-treated DLBCL including in patients who have progressed following autologous transplant and/or CAR-T therapy. Two CAR-T products have received regulatory approval in relapsed or refractory DLBCL, with other products in clinical trials. CAR-T treatment has resulted in durable remissions and trials are ongoing to determine if CAR-T should replace autologous transplant as second-line therapy for DLBCL. The development of multiple T cell-directed therapies for DLBCL offers new treatment options for chemotherapy-resistant disease. We discuss our approach to relapsed or refractory DLBCL patients and the open question of optimal sequencing of autologous transplant (a current standard treatment), CAR-T therapy (FDA approved), and bispecific antibodies (in clinical trials).

The Influence of B Cell Depletion Therapy on Naturally Acquired Immunity to Streptococcus pneumoniae

The anti-CD20 antibody Rituximab to deplete CD20+ B cells is an effective treatment for rheumatoid arthritis and B cell malignancies, but is associated with an increased incidence of respiratory infections. Using mouse models we have investigated the consequences of B cell depletion on natural and acquired humoral immunity to Streptococcus pneumoniae. B cell depletion of naïve C57Bl/6 mice reduced natural IgM recognition of S. pneumoniae, but did not increase susceptibility to S. pneumoniae pneumonia. ELISA and flow cytometry assays demonstrated significantly reduced IgG and IgM recognition of S. pneumoniae in sera from mice treated with B cell depletion prior to S. pneumoniae nasopharyngeal colonization compared to untreated mice. Colonization induced antibody responses to protein rather than capsular antigen, and when measured using a protein array B cell depletion prior to colonization reduced serum levels of IgG to several protein antigens. However, B cell depleted S. pneumoniae colonized mice were still partially protected against both lung infection and septicemia when challenged with S. pneumoniae after reconstitution of their B cells. These data indicate that although B cell depletion markedly impairs antibody recognition of S. pneumoniae in colonized mice, some protective immunity is maintained, perhaps mediated by cellular immunity.

Safety and efficacy of rituximab biosimilar (CT-P10) in systemic sclerosis: an Italian multicentre study

OBJECTIVES

Recent data have shown a significant efficacy of rituximab (RTX) in SSc. An RTX biosimilar (RTX-B) is a more affordable option. We assessed the safety and efficacy of an RTX-B (CT-P10) in SSc.

METHODS

SSc patients treated with RTX-B with at least 6 months of follow-up were retrospectively identified from six Italian referral centres. SSc patients naïve to RTX-B (RTX-Bn) or already treated with RTX originator and switched to an RTX-B (RTX-Bs) were evaluated. A comprehensive assessment of disease characteristics and organ involvement at baseline and after 6 months was obtained.

RESULTS

Thirty-three SSc patients were selected: 29 (87.9%) females, mean age 51.6 years (s.d. 14.2), mean disease duration 9.8 years (s.d. 8.1); 21 (64.5%) with dcSSc, 20 (60.1%) anti-topoisomerase I, 7 (21.2%) anti-RNA polymerase III and 6 (18.2%) anti-centromere positive. Seventeen (51.5%) were RTX-Bn and 16 were on RTX-Bs (48.5%). RTX was introduced because of skin progression in 18 patients (54.5%), interstitial lung disease (ILD) worsening in 11 (33.3%) and arthritis in 12 (36.4%). All patients were previously treated with immunosuppressants. At RTX-B introduction, 21 (63.6%) patients were on concomitant immunosuppressants: 15 (71.4%) on MMF and 6 (28.6%) on MTX. Twenty-three (69.7%) were on low-dose steroids. After 6 months, a significant reduction of the modified Rodnan skin score (mRSS), 28-joint DAS and CRP was observed (P = 0.002, 0.005 and 0.008, respectively); the mRSS significantly improved both in RTX-Bn (P < 0.024) and RTX-Bs patients (P < 0.031). No significant changes were observed for lung function tests, either in the entire cohort or in the subgroup of ILD patients. Only one RTX-Bs patient experienced transient neutropenia.

CONCLUSION

Our data suggest that RTX-B can represent a cheaper option in SSc patients, as it is effective in improving skin and joint involvement and in stabilizing lung function.

Tumor-Infiltrating CD20+ B Lymphocytes: Significance and Prognostic Implications in Oral Cancer Microenvironment

Simple Summary

The complex interplay between the different cellular components in the tumor microenvironment (TME) dynamically modulates the antitumor immune response. This study investigates the prognostic relevance of CD20⁺ tumor-infiltrating B lymphocytes in oral squamous cell carcinoma (OSCC), and also possible relationships with other immune subtypes and key players within the oral TME.

Abstract

Immunohistochemical analysis of stromal/tumoral CD20⁺ B lymphocytes was performed in 125 OSCC patients. Correlations with immune profiles CD4⁺, CD8⁺, and FOXP3⁺ tumor-infiltrating lymphocytes (TILs), tumoral PD-L1, and stem-related factors NANOG and SOX2 were assessed, and also associations with clinical data and patient survival. There was a strong positive correlation between the infiltration of CD20⁺ B lymphocytes and other immune profiles (i.e., CD4⁺, CD8⁺, and FOXP3⁺ TILs, and CD68⁺ and CD163⁺ macrophages) both in stroma and tumor nests. Strikingly, CD20⁺ TILs were inversely correlated with NANOG/SOX2 expression. Stromal CD20⁺ TILs were significantly associated with T classification and second primary tumors. A stratified survival analysis showed that tumoral CD20⁺ TILs were significantly associated with prognosis in male and younger patients, with tobacco or alcohol consumption, high tumoral CD8⁺ TILs, low tumoral infiltration by CD68⁺ macrophages, positive PD-L1 expression, and negative NANOG/SOX2. Multivariate Cox analysis further revealed clinical stage and tumoral CD20⁺ TILs independently associated with disease-specific survival (HR = 2.42, p = 0.003; and HR = 0.57, p = 0.04, respectively). In conclusion, high CD20⁺ TIL density emerges as an independent good prognostic factor in OSCC, suggesting a role in antitumor immunity. This study also uncovered an inverse correlation between CD20⁺ TILs and CSC marker expression.

Complement-Dependent Activity of CD20-Specific IgG Correlates With Bivalent Antigen Binding and C1q Binding Strength

Monoclonal antibodies directed against the CD20 surface antigen on B cells are widely used in the therapy of B cell malignancies. Upon administration, the antibodies bind to CD20 expressing B cells and induce their depletion via cell- and complement-dependent cytotoxicity or by induction of direct cell killing. The three antibodies currently most often used in the clinic are Rituximab (RTX), Ofatumumab (OFA) and Obinutuzumab (OBI). Even though these antibodies are all of the human IgG1 subclass, they have previously been described to vary considerably in the effector functions involved in therapeutic B cell depletion, especially in regards to complement activation. Whereas OFA is known to strongly induce complement-dependent cytotoxicity, OBI is described to be far less efficient. In contrast, the role of complement in RTX-induced B cell depletion is still under debate. Some of this dissent might come from the use of different in vitro systems for characterization of antibody effector functions. We therefore set out to systematically compare antibody as well as C1q binding and complement-activation by RTX, OFA and OBI on human B cell lines that differ in expression levels of CD20 and complement-regulatory proteins as well as human primary B cells. Applying real-time interaction analysis, we show that the overall strength of C1q binding to live target cells coated with antibodies positively correlated with the degree of bivalent binding for the antibodies to CD20. Kinetic analysis revealed that C1q exhibits two binding modes with distinct affinities and binding stabilities, with exact numbers varying both between antibodies and cell lines. Furthermore, complement-dependent cell killing by RTX and OBI was highly cell-line dependent, whereas the superior complement-dependent cytotoxicity by OFA was independent of the target B cells. All three antibodies were able to initiate deposition of C3b on the B cell surface, although to varying extent. This suggests that complement activation occurs but might not necessarily lead to induction of complement-dependent cytotoxicity. This activation could, however, initiate complement-dependent phagocytosis as an alternative mechanism of therapeutic B cell depletion.

Bcl-2 Enhances Chimeric Antigen Receptor T Cell Persistence by Reducing Activation-Induced Apoptosis

Simple Summary

Chimeric antigen receptor-modified T cells (CAR-T) have shown great success in the treatment of B-cell leukemia. However, their efficacy is compromised in B-cell-derived lymphoma and solid tumors. Optimization of CAR design to improve in vivo persistence is a focus of current CAR-T cell research. The aim of our study is to access the potential added value of integration of anti-apoptotic molecules for enhancing anti-tumor activity of CAR-T cells. We confirmed that integrating B cell lymphoma-2 (Bcl-2) into CAR-T cells improved the proliferation ability of CAR-T cells in vitro and in vivo, which led to enhanced anti-tumor activity and prolonged survival in a mouse xenograft lymphoma model. This work provides proof of concept evidence for a new strategy to optimize the function of CAR-T cells against lymphoma.

Abstract

Purpose: To evaluate the potential added value of integrating anti-apoptotic molecules for improving the anti-tumor activity of CAR-T cells. Methods: Four small molecules inhibiting apoptosis were tested for their ability to prevent activated induced CAR-T cell death. Five CD20-targeting, CD137 (4-1BB) and CD3ζ integrated CAR-T cells (20BBZ) with constitutively expressed anti-apoptotic genes were established, and we screened out the strongest proliferation enhancer: Bcl-2. The memory subtype and the exhaustion markers of CAR-T cells were analyzed. The anti-tumor activities of Bcl-2 integrating CAR-T cells (20BBZ-Bcl-2) were evaluated in vitro and in a mouse xenograft lymphoma model. Conclusion: The 20BBZ-Bcl-2 CAR-T cells showed improved proliferation ability compared to 20BBZ CAR-T cells in vitro. In addition, activation-induced apoptosis was reduced in the 20BBZ-Bcl-2 CAR-T cells. Consistent with the enhanced proliferation in vitro, 20BBZ-Bcl-2 CAR-T cells exhibited improved anti-tumor activity in a mouse xenograft lymphoma model.

Clinical and biological activity of rituximab in the treatment of pemphigus

B-cells are major effector cells in autoimmunity since they differentiate into plasmocytes that produce pathogenic auto-antibody such as anti-desmoglein antibodies in pemphigus patients. Major advances were obtained using whole B-cell depleting therapies including anti-CD20 antibodies in refractory pemphigus patients that lead to rituximab approval in pemphigus patients in EU and USA. This review summarizes the data supporting the efficacy of rituximab in pemphigus and provides an overview of the reported immunological changes underlying its therapeutic action. Short and long-term remission in pemphigus is explained by the removal of autoreactive B-cells involved in the production of pathogenic IgG auto-antibodies and by enhancement of the appearance of regulatory B-cells that could maintain long term immune tolerance.

Can rituximab be used in the treatment of pemphigus vulgaris during the COVID-19 pandemic?

Rituximab is a monoclonal antibody that targets CD20, a B‐lymphocyte antigen; that leads to a decline in the B‐cell counts for at least a year. The patients who have received rituximab treatment in the previous 5 years with the diagnosis of pemphigus group of diseases at Cerrahpaşa Medical Faculty were questioned for COVID‐19 infection. A total of 48 patients were included in this study; only one male patient had COVID‐19 infection which had a mild course. There is no significant difference in the total number of lymphocytes between patients who have received rituximab within the previous 5 years or last year. The number of lymphocytes is independent of the number of courses of rituximab treatment received. Therefore, we suggest that all pemphigus patients who have received rituximab treatment within the previous 5 years should be careful of the preventive measures against the COVID‐19 infection irrespective of the number of treatment courses or the number of years which has passed since the treatment. The disease course was mild in the only infected patient. Thus, rituximab may be used in the treatment of pemphigus vulgaris during the COVID‐19 pandemic if its use is necessary.

CD37 in B Cell Derived Tumors-More than Just a Docking Point for Monoclonal Antibodies

CD37 is a tetraspanin expressed prominently on the surface of B cells. It is an attractive molecular target exploited in the immunotherapy of B cell-derived lymphomas and leukemia. Currently, several monoclonal antibodies targeting CD37 as well as chimeric antigen receptor-based immunotherapies are being developed and investigated in clinical trials. Given the unique role of CD37 in the biology of B cells, it seems that CD37 constitutes more than a docking point for monoclonal antibodies, and targeting this molecule may provide additional benefit to relapsed or refractory patients. In this review, we aimed to provide an extensive overview of the function of CD37 in B cell malignancies, providing a comprehensive view of recent therapeutic advances targeting CD37 and delineating future perspectives.

Cerebrospinal fluid CD20 positive B-cell expansion in a case of anti-NMDAR encephalitis

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a potentially fatal autoimmune encephalitis with a strong B-cell response. We measured the proportion of CD20 positive and CD19 positive B-cells in the CSF from a case of severe anti-NMDAR encephalitis. The proportion of CD20 positive B-cells in the CSF was 15.0%, higher than CD19 positive B cells (10.1%), and higher than that seen in non-inflammatory neurological disorders (<1%). After the treatments of steroids, intravenous immunoglobulin and rituximab to eliminate B-cells, she recovered. These findings further support the use of rituximab that targets CD20 positive B-cells in anti-NMDAR encephalitis.

tANCHOR: a novel mammalian cell surface peptide display system

A novel tool for the presentation of peptides and small proteins on the surface of human cells has been developed. Our tANCHOR system utilizes tetraspanin anchors containing heterologous amino acid sequences inserted instead of the large extracellular loop. This technology allows a highly effective extracellular display of epitopes for antibody binding studies and many other potential applications.

MS4A1 expression and function in T cells in the colorectal cancer tumor microenvironment

The majority of human colorectal cancer remains resistant to immune checkpoint inhibitor (ICI) immunotherapy, but the underlying mechanism is incompletely understood. We report here that MS4A1, the gene encoding B cell surface marker CD20, is significantly downregulated in human colorectal carcinoma. Furthermore, MS4A1 expression level in colorectal carcinoma is positively correlated with patient survival. Analysis of scRNA-Seq dataset from public database revealed that MS4A1 is also expressed in subsets of T cells. A CD8⁺CD20⁺ subset of T cells exists in the neighboring non-neoplastic colon but disappears in tumor in human colorectal carcinoma. Furthermore, analysis of a published nivolumab treatment dataset indicated that nivolumab-bound T cells from human patients during anti-PD-1 immunotherapy exhibit significantly higher MS4A1 expression. Our findings indicate that CD8⁺CD20⁺ T subset functions in host cancer immunosurveillance and tumor microenvironment suppresses this T subset through a PD-L1-dependent mechanism.

Obinutuzumab-related adverse events: A systematic review and meta-analysis

Rituximab, the first anti-CD20 monoclonal antibody, has dramatically improved outcomes for patients with B-cell lymphoproliferative disorders. Obinutuzumab was developed to potentiate activity and overcome resistance to rituximab. Clinical data suggest that obinutuzumab is superior to rituximab in follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). Yet, it has increased toxicity. This systematic review and meta-analysis compiled all randomized controlled trials (RCTs) comparing obinutuzumab-based regimens with rituximab-based regimens to better assess their toxicity profile. Primary outcome was grade 3-4 infections; secondary outcomes included any adverse events (AE), grade 3-4 AE, drug discontinuation rate, and 3-years mortality. Relative risks (RRs) were estimated and pooled using a fixed-effect model, unless there was significant heterogeneity, in which case a random-effects model was used. Our comprehensive search yielded five RCTs conducted between 2009 and 2014, including 4247 patients. The trials included FL patients, CLL and diffuse large B cell lymphoma. Monoclonal antibodies were given with different chemotherapy regimens (in four trials) or as monotherapy (in one trial). The point estimate favored increase in both grade 3-4 infections rate (RR 1.17 [95% CI, 1.0-1.36]) and any AE rate (RR 1.05 [95% 1-1.1]) with obinutuzumab, although this was not statistically significant. There was a significantly increased rate of grade 3-4 AE (RR 1.15 [95% CI, 1.09-1.2]), as well as grade 3-4 toxicities including thrombocytopenia (RR 2.8 [95% CI, 1.92-4.06]), infusion related reactions (RR 2.8 [95% CI, 2.16-3.64]) and cardiac events (RR 1.65 [95% CI, 1.11-2.46]). There was no significant difference in grade 3-4 anemia and neutropenia nor in the 3-year mortality rate. The point estimate favored increase in discontinuation rate due to AE with obinutuzumab, although without statistical significance (RR 1.24 [95% CI, 1.0-1.54]). In conclusion, physicians need to weigh the clinical benefits of this agent against higher toxicity.

Impact of Rituximab on relapse rate and disability in an Ecuadorian cohort of patients with neuromyelitis optica spectrum disorders

BACKGROUND

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a severe inflammatory demyelinating disease of the central nervous system that often causes disability. Based on evidence from prospective and retrospective studies, Rituximab (RTX) has been used as the first-line of therapy in NMOSD. Nevertheless, evidence of the impact of RTX on relapse rate and disability in Ecuadorian patients with NMOSD is lacking.

OBJECTIVE

To evaluate the impact of RTX in an Ecuadorian cohort of patients with NMOSD.

MATERIALS AND METHODS

A retrospective study was conducted in a cohort of patients with NMOSD who received treatment with RTX in a third-level hospital in Quito, Ecuador. Digital medical records of NMOSD patients were reviewed to attain sociodemographic data, disease characteristics, and treatment with RTX. The annualized relapse rate ARR, as well as the degree of disability measured through the expanded disability scale (EDSS), was established before and after treatment.

RESULTS

Twenty-three patients with NMOSD treated with RTX were included, the mean age of onset of the disease was 37.2 years (range, 13-64.5). The average duration of disease was 8.5 years (range, 1.3-34.4). Positivity for antibodies against aquaporin-4 (AQP4-IgG) was identified in 78% of the patients. The mean duration of the treatment with RTX was 40 months (range, 12-61). After the RTX therapy, the number of relapses was reduced in 91% (21/23) of cases. The annualized relapsed rate (ARR) was reduced with RTX from 1.89 to 0.12 (p <0.001). The mean EDSS was also reduced from 4.8 to 3.9 (p = 0.014). In all patients, the mean EDSS was reduced or stabilized with RTX. Overall, the drug was well tolerated, the most frequent adverse events were infections which were present in 65.2% of cases.

CONCLUSIONS

Though with the limitations of and observational study, our data support RTX effectiveness and safety in an Ecuadorian cohort of patients with NMOSD.

Characterization of an interdigitating dendritic cell hyperplasia case in a lymph node of a control C57BL/6 mouse

Interdigitating dendritic cell (IDC) hyperplasia is considered a benign spontaneous condition occasionally observed in the lymph nodes of mice. It has been rarely reported and, to the best of our knowledge, it has never been characterized using immunohistochemistry. The present work describes a spontaneous IDC hyperplasia case in a lymph node of a 16-week-old control female C57BL/6 mouse. Microscopically, the lymph node architecture was completely effaced by the proliferation of eosinophilic spindle cells with an abundant pale cytoplasm forming trabecule admixed lymphocyte infiltrates. The spindle cell population was positive for F4/80, partially positive for S100 calcium-binding protein A4 (S100A4), slightly positive for E-cadherin, and negative for α-Smooth muscle actin (SMA) and cytokeratin. Lymphocytes were positive for CD3, CD4, CD20 and negative for CD8. Spindle cells were considered to be originated from the myeloid lineage, based on the immunohistochemistry (IHC) results, but their precise origin remains unclear (IDC or macrophages); even if macrophage origin is most likely based on F4/80 positivity, this remains to be further clarified using other markers.

4-1BB Signaling Boosts the Anti-Tumor Activity of CD28-Incorporated 2nd Generation Chimeric Antigen Receptor-Modified T Cells

While chimeric antigen receptor-modified T (CAR-T) cells have shown great success for the treatment of B cell leukemia, their efficacy appears to be compromised in B cell derived lymphoma and solid tumors. Optimization of the CAR design to improve persistence and cytotoxicity is a focus of the current CAR-T study. Herein, we established a novel CAR structure by adding a full length 4-1BB co-stimulatory receptor to a 28Z-based second generation CAR that targets CD20. Our data indicated that this new 2028Z-4-1BB CAR-T cell showed improved proliferation and cytotoxic ability. To further understand the mechanism of action, we found that constitutive 4-1BB sensing significantly reduced the apoptosis of CAR-T cells, enhanced proliferation, and increased NF-κB pathway activation. Consistent with the enhanced proliferation and cytotoxicity in vitro, this new structure of CAR-T cells exhibited robust persistence and anti-tumor activity in a mouse xenograft lymphoma model. This work provides evidence for a new strategy to optimize the function of CAR-T against lymphoma.

Tumour-Infiltrating Inflammatory Cells in Early Breast Cancer: An Underrated Prognostic and Predictive Factor?

The role of tumour-infiltrating inflammatory cells (TIICs) in the disease progression of hormone-receptor-positive breast cancer (HR+ BC) is largely unclear since it is generally regarded as the least immunogenic BC subtype. This study investigated the prognostic significance of CD1a+ dendritic cells, CD20+ B cells, CD45RO+ memory T cells and CD4+ T-helper cells in HR+ BC. One hundred and forty-six patients were treated for early stage, distant-metastases-free HR+ BC in an accelerated partial breast irradiation (APBI) phase II trial. Immunohistochemistry was used to double-stain two adjoining sets of tissue microarrays from pre-RT (radiotherapy) tumour resection samples for CD1a/CD20 and CD45RO/CD4. Cell densities of CD1a+, CD20+, CD45RO+ and CD4+ TIICs in the stromal and intraepithelial compartment were registered semiautomatically. High densities of CD20+ and CD4+ TIICs were strongly associated with reduced disease-free survival (DFS), while high stromal CD45RO+ TIIC densities were indicators of subsequent successful treatment. An immunoscore based on CD20+ and CD45RO+ TIIC densities identified three different risk groups (p < 0.001). Thus, contrary to current assumptions, intratumoural immune cell composition might be an important prognostic indicator and a possible contributing factor in the outcome of HR+ BC and should be the subject of further research. Specifically, B-cell infiltration entailed an increased relapse rate and could play an important role in disease progression.

COVID-19 vaccine-readiness for anti-CD20-depleting therapy in autoimmune diseases

Although most autoimmune diseases are considered to be CD4 T cell- or antibody-mediated, many respond to CD20-depleting antibodies that have limited influence on CD4 and plasma cells. This includes rituximab, oblinutuzumab and ofatumumab that are used in cancer, rheumatoid arthritis and off-label in a large number of other autoimmunities and ocrelizumab in multiple sclerosis. Recently, the COVID-19 pandemic created concerns about immunosuppression in autoimmunity, leading to cessation or a delay in immunotherapy treatments. However, based on the known and emerging biology of autoimmunity and COVID-19, it was hypothesised that while B cell depletion should not necessarily expose people to severe SARS-CoV-2-related issues, it may inhibit protective immunity following infection and vaccination. As such, drug-induced B cell subset inhibition, that controls at least some autoimmunities, would not influence innate and CD8 T cell responses, which are central to SARS-CoV-2 elimination, nor the hypercoagulation and innate inflammation causing severe morbidity. This is supported clinically, as the majority of SARS-CoV-2-infected, CD20-depleted people with autoimmunity have recovered. However, protective neutralizing antibody and vaccination responses are predicted to be blunted until naive B cells repopulate, based on B cell repopulation kinetics and vaccination responses, from published rituximab and unpublished ocrelizumab (NCT00676715, NCT02545868) trial data, shown here. This suggests that it may be possible to undertake dose interruption to maintain inflammatory disease control, while allowing effective vaccination against SARS-CoV-29, if and when an effective vaccine is available.

Combined Treatment with Polynucleotides and Hyaluronic Acid Improves Tissue Repair in Experimental Colitis

Inflammatory bowel diseases (IBDs) are chronic conditions that can benefit from the combined treatment of adenosine receptor agonists and hyaluronic acid (HA), which, binding the CD44, has pro-survival effects. Therefore, this study investigated the effects of a mixture of polynucleotides and HA in an experimental model of dinitrobenzenesulfonic acid (DNBS)-induced colitis. A group of 40 rats received a single intra-colonic instillation of DNBS, and after 6 h, animals were randomized to receive daily: (i) saline solution; (ii) polynucleotides (Poly; 8 mg/kg); (iii) polynucleotides (8 mg/kg) plus hyaluronic acid (HA; 15 mg/kg); and (iv) hyaluronic acid (HA; 15 mg/kg). Rats in the control group (n = 10) received saline solution only. Seven days after induction, animals receiving Poly plus HA showed reduced clinical signs, weight loss and colon shortening, ameliorated macroscopic and histological damage, and apoptosis. Moreover, the combined treatment reduced the positivity in the colonic infiltrate of CD3 positive T cells, CD20 positive B cells and CD44. Furthermore, Poly plus HA reduced colonic myeloperoxidase activity and malondialdehyde, indicating a dampening of the inflammatory infiltrate and oxidation products. Our research demonstrated that a combined treatment of polynucleotides with hyaluronic acid had a protective effect in a model of ulcerative colitis, suggesting that this association deserves further attention for the treatment of IBDs.

White matter lesions in multiple sclerosis are enriched for CD20dim CD8+ tissue-resident memory T cells

Brain CD8⁺ CD69⁺ tissue-resident memory T (T_RM ) cells comprise a CD20^dim subset, which is proportionally larger in CD103-negative T_RM cells. In multiple sclerosis (MS) lesions, CD20^dim T_RM -cell proportions are increased. CD20-expression is associated with higher levels of CXCR6, Ki-67, and granzyme B, supporting CD20^dim T_RM cells as a relevant subset in MS.

Immuno-Interface Score to Predict Outcome in Colorectal Cancer Independent of Microsatellite Instability Status

Simple Summary

For pathologists, how to precisely diagnose cancer from microscopy slides of tumor tissue samples so that each patient may receive the optimal treatment for his specific type of disease is a major task. Recent research based on digital pathology image analysis enables new approaches to assess tumor-host interaction at a microscopic level. The current study applies a novel spatial analysis method which computes Immunogradient indicators to estimate the migration of immune cells towards the tumor across the tumor/stroma interface. These indicators, computed for two types of immune cells (CD8 and CD20), proved to be independent prognostic factors in this study of 87 patients with colorectal cancer. The indicators were combined with infiltrative tumor growth pattern, assessed by a pathologist, into a new immuno-interface score which enabled prediction of the patient survival independent of other clinical, pathology and molecular characteristics of the tumor. The study demonstrates the value of computational pathology to advance the precision of clinical decision-making.

Abstract

Tumor-associated immune cells have been shown to predict patient outcome in colorectal (CRC) and other cancers. Spatial digital image analysis-based cell quantification increases the informative power delivered by tumor microenvironment features and leads to new prognostic scoring systems. In this study we evaluated the intratumoral density of immunohistochemically stained CD8, CD20 and CD68 cells in 87 cases of CRC (48 were microsatellite stable, MSS, and 39 had microsatellite instability, MSI) in both the intratumoral tumor tissue and within the tumor-stroma interface zone (IZ) which was extracted by a previously developed unbiased hexagonal grid analytics method. Indicators of immune-cell gradients across the extracted IZ were computed and explored along with absolute cell densities, clinicopathological and molecular data, including gene mutation (BRAF, KRAS, PIK3CA) and MSI status. Multiple regression modeling identified (p < 0.0001) three independent prognostic factors: CD8+ and CD20+ Immunogradient indicators, that reflect cell migration towards the tumor, were associated with improved patient survival, while the infiltrative tumor growth pattern was linked to worse patient outcome. These features were combined into CD8-CD20 Immunogradient and immuno-interface scores which outperformed both tumor-node-metastasis (TNM) staging and molecular characteristics, and importantly, revealed high prognostic value both in MSS and MSI CRCs.

Mechanism and Treatment of Rituximab Resistance in Diffuse Large Bcell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype B non-Hodgkin lymphoma in adults. After rituximab being introduced to treat DLBCL, the current first-line treatment is R-CHOP regimen. This regimen greatly improves patient's prognosis, however, relapsed or refractory cases are commonly seen, mainly due to the resistance to rituximab. Although a large number of experiments have been conducted to investigate rituximab resistance, the exac mechanisms and solutions are still unclear. This review mainly explores the possible mechanisms oft rituximab resistance and current new effective treatments for rituximab resistance in DLBCL.

High infiltration of CD20+ B lymphocytes in extranodal natural killer/T-cell lymphoma is associated with better prognosis

Immune cells have an uncertain function during the progression of extranodal natural killer/T-cell lymphoma (ENKTL). The present study determined the distribution, phenotype, and clinical significance of B lymphocytes in ENKTL. Immunohistochemistry indicated high infiltration of CD20⁺ B lymphocytes in the tumour tissues of 40% of the patients, and that a high infiltration correlated with better overall survival. Moreover, B lymphocytes had an active mature phenotype in situ and suppressed the proliferation of ENKTL cells in vitro. These results suggest that tumour infiltration of CD20⁺ B lymphocytes may be a new prognostic indicator for patients with ENKTL.

Treatment of hairy cell leukemia

INTRODUCTION

Purine analogs made dramatic improvements for patients with hairy cell leukemia (HCL), but patients often relapse, require multiple treatments, and may become refractory. Major developments in treatment of relapsed/refractory HCL occurred with discovery of disease biology. New agents increase the complexity of clinical decision-making.

AREAS COVERED

Anti-CD22 recombinant immunotoxin Moxetumomab Pasudotox (Moxe), CD20 Mabs rituximab and obinutuzumab, BRAF/MEK inhibitors vemurafenib and dabrafenib-trametinib, and Bruton's tyrosine kinase (BTK) inhibitor ibrutinib have been tested in HCL. All show efficacy but with different treatment durations and response rates, including for eradicating minimal residual disease (MRD). Side effects differ and must be considered when selecting treatment. Studies from PubMed indexed papers and abstracts presented at major international conferences are included.

EXPERT OPINION

Rituximab with either purine analog or BRAF-inhibitor achieves high rates of MRD-free complete remission (CR). Moxe achieves MRD-free CR without chemotherapy toxicities. Moxe should be considered prior to splenectomy or development of adenopathy. BRAF/MEK inhibition and ibrutinib are effective options but most patients remain MRD+, requiring indefinite treatment or rituximab to prevent relapse. Under investigation is MRD elimination with CD20 antibody combined with Moxe or BRAF inhibitor. High-risk diseases including HCL variant and IGHV4-34+ unmutated HCL require further investigation.

Bispecific Chimeric Antigen Receptor T Cell Therapy for B Cell Malignancies and Multiple Myeloma

Simple Summary

In relapsed, refractory B cell malignancies and multiple myeloma, chimeric antigen receptor (CAR) T cell therapy has represented a major scientific advancement with high response rates and durable responses for many. Nonetheless, target antigen downregulation in tumor cells can lead to poor responses and relapsed disease. Current FDA approved CAR T cell therapies only target a single B-cell specific cell marker. While effective, single targeted CAR T cell therapy can lead selective pressure against the target antigen leading to loss of expression and tumor cell escape. Simultaneous dual antigen targeting CAR therapy has been evaluated in multiple early phase clinical trials in response to these clinical challenges in hopes of improving response rates and preventing relapse. This article discusses the limitations of single targeted CAR T cell therapy, approaches to dual antigen targeting, and the results of early phase trials utilizing dual antigen targeting CAR T cell therapy.

Abstract

Chimeric antigen receptor (CAR) modified T cell therapy offers a targeted immunotherapeutic approach to patients with refractory hematological malignancies. This technology is most advanced in B cell malignancies and multiple myeloma and is rapidly evolving as more data become available regarding clinical efficacy and response durability. Despite excellent initial response rates with single antigen targeting CARs, failure to respond to therapy and relapse due to target antigen downregulation remain clinical challenges. To mitigate immunophenotypic selective pressures, simultaneous dual antigen targeting with bispecific CAR T cells or multiple administration of different populations of CAR T cells may prevent relapse by addressing one resistance mechanism attributed to antigenic loss. This article will review recently published data on the use of dual targeting with CAR T cells from early phase clinical trials aimed at treating B cell malignancies and multiple myeloma.