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Systemic lupus erythematosus (SLE), the prototype of systemic autoimmune diseases is characterized by extreme heterogeneity with a variable clinical course. Renal involvement may be observed and affects the outcome. Hydroxychloroquine should be administered to every lupus patient irrespective of organ involvement. Conventional immunosuppressive therapy includes corticosteroids, methotrexate, cyclophosphamide, mycophenolate mofetil, azathioprine, cyclosporine and tacrolimus. However, despite conventional immunosuppressive treatment, flares occur and broad immunosuppression is accompanied by multiple side effects. Flare occurrence, target organ involvement, side effects of broad immunosuppression and increased knowledge of the pathogenetic mechanisms involved in SLE pathogenesis as well as the availability of biologic agents has led to the application of biologic agents in SLE management. Biologic agents targeting various pathogenetic paths have been applied. B cell targeting agents have been used successfully. Belimumab, a B cell targeting agent, has been approved for the treatment of SLE. Rituximab, an anti-CD20 targeting agent is also used in SLE. Anifrolumab, an interferon I receptor-targeting agent has beneficial effects on SLE. In conclusion, biologic treatment is applied in SLE and should be further evaluated with the aim of a good treatment response and a significant improvement in quality of life. [ABSTRACT FROM AUTHOR]

Objectives: To assess the efficacy of a method to circumvent CD20-positive antigen masking by rituximab for flow cytometry analysis of B-cell malignancies in hematology patients.Methods: Mononuclear cells (MNCs) from 10 healthy individuals and 5 untreated patients with B-cell malignancies were sensitized with rituximab. Patients' diagnoses included chronic lymphocytic leukemia, hairy cell leukemia, and follicular lymphoma. MNCs were isolated by gradient density centrifugation. An EDTA/glycine acid (EGA) elution method was used to dissociate CD20-rituximab complexes; afterwards, CD20-positive immunoreactivity was assessed by flow cytometry. A saturation curve was built based on serial dilutions of rituximab. Median fluorescent intensities of CD20-positive signals were obtained before sensitization with rituximab and after its elution with EGA.Results: CD20-positive signals were not detectable by flow cytometry after rituximab sensitization of B cells. CD20-sensitized vs CD20-unsensitized, CD20-sensitized vs CD20-eluted, and CD20-eluted vs CD20-negative control (NC) MNC populations exhibited statistical differences (P = .001), while CD20-sensitized vs CD20-NC populations did not (P = .499), confirming CD20 antigen masking by rituximab.Conclusions: Rituximab interfered with the flow cytometry protocol for CD20 determination on normal and neoplastic B cells. The EGA method efficiently eluted rituximab, allowing for accurate identification of CD20-positive B cells. [ABSTRACT FROM AUTHOR]

Objectives: Rituximab (RTX) is associated with variable adverse gastrointestinal (GI) events. However, the histologic correlate in affected patients is not well defined.Methods: Patients (n = 93) who had received RTX and undergone endoscopic biopsies were identified. CD20 and PAX5 immunostains were performed on biopsy specimens showing inflammatory pathology (group A, 36 patients) and 35 of 57 noninflammatory biopsies (group B) that were taken within 1 year from the last RTX infusion. Histologic findings were correlated with tissue B-cell depletion (CD20/PAX5-/-).Results: B cells were depleted in 12 (33%) of 36 group A biopsy specimens. After excluding biopsies taken more than 1 year from the last RTX infusion, the frequencies of tissue B-cell depletion were similar between group A (12/26; 46.2%) and group B (17/35; 48.6%) (P > .05). Also, the frequencies of inflammatory pathology were not statistically different whether B cells were depleted or not (P > .05). In group A with tissue B-cell depletion (n = 12), causality was indicated in two (17%) cases showing lymphocytic colitis pattern of injury (LCPI).Conclusions: In RTX-treated patients, tissue B-cell depletion does not appear to be the main cause of inflammatory pathology in the GI tract. A minor subset, however, develops histologic evidence of potential RTX-induced effect, notably in the form of LCPI. [ABSTRACT FROM AUTHOR]

CD20 is expressed in the B lymphocyte, and an effective target for the detection and treatment of B cell lymphomas. Therefore, CD20 has been studied as a therapeutic target of B cell lymphomas and autoimmune disorders. Specific anti-CD20 monoclonal antibodies (mAbs), such as rituximab, ofatumumab, veltuzumab, and ocaratuzumab, have been developed. Revealing the recognition mechanism of antigen by mAbs could contribute to understanding the function of mAbs and could be useful for the development of vaccine. Rituximab is a mouse-human chimeric anti-CD20 mAb, which was developed and approved for the treatment of the B cell malignancies. Hence, the binding epitope of rituximab for CD20 has been studied. Some reports show that 170-ANPS-173, especially Ala170 and Pro172 of CD20 are important for rituximab binding. However, only phage display results showed that 182-YCYSI-186 of CD20 is also important for rituximab binding to CD20. In this study, we tried to determine the binding epitope of rituximab for CD20 using histidine-tag insertion for epitope mapping (HisMAP) method. The results showed that two regions of CD20 (169-PANPSE-174 and 183-CYSIQ-187) are important for rituximab-binding for CD20. [ABSTRACT FROM AUTHOR]

Background: Although R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) remains the standard chemotherapy regimen for diffuse large B cell lymphoma (DLBCL) patients, not all patients are responsive to the scheme, and there is no effective method to predict treatment response. Methods: We utilized 5hmC-Seal to generate genome-wide 5hmC profiles in plasma cell-free DNA (cfDNA) from 86 DLBCL patients before they received R-CHOP chemotherapy. To investigate the correlation between 5hmC modifications and curative effectiveness, we separated patients into training (n = 56) and validation (n = 30) cohorts and developed a 5hmC-based logistic regression model from the training cohort to predict the treatment response in the validation cohort. Results: In this study, we identified thirteen 5hmC markers associated with treatment response. The prediction performance of the logistic regression model, achieving 0.82 sensitivity and 0.75 specificity (AUC = 0.78), was superior to existing clinical indicators, such as LDH and stage. Conclusions: Our findings suggest that the 5hmC modifications in cfDNA at the time before R-CHOP treatment are associated with treatment response and that 5hmC-Seal may potentially serve as a clinical-applicable, minimally invasive approach to predict R-CHOP treatment response for DLBCL patients. [ABSTRACT FROM AUTHOR]

Histologic transformation of indolent lymphomas account for 13% of I de novo i presentations of diffuse large B-cell lymphoma (DLBCL) [[1]]. 126 (84%) patients had follicular lymphoma [FL], 10 (7%) low grade B-cell lymphoma not otherwise specified [NOS], 10 (7%) marginal zone lymphoma, 3 (2%) mucosa-associated lymphoid tissue [MALT] lymphoma and 1 (1%) Waldenstrom's macroglobulinemia. A separate retrospective study in Japan identified 52 patients with untreated Tr-iNHL who received R-CHOP or R-CHOP-like induction therapy, of whom 15 patients received MR. [Extracted from the article]

Rituximab is popularly used in the treatment of B-cell lymphomas that bear CD20 antigen. Most of the adverse events (AEs) induced by rituximab are infusion-related symptoms. However, rituximab-induced acute thrombocytopenia (RIAT), which often develops within the 1–3 days after rituximab administration, is relatively unusual, severe, and usually self-recovering. Until now, most of the reports about RIAT were described as case reports and RIAT often occurred in patients with mantle cell lymphoma (MCL). Here, we report two patients who developed severe RIAT, one patient had a refractory and relapsed follicular lymphoma (FL), and the other patient was newly diagnosed with splenic marginal zone lymphoma (SMZL). RIAT is a rare, under-diagnosed but serious adverse event that should arouse attention to clinicians, and routine blood count monitoring should be considered after the administration of rituximab, especially for high-risk lymphoma patients or patient with splenomegaly. [ABSTRACT FROM AUTHOR]

Aim: A significant proportion of patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are either steroid dependent or steroid resistant, requiring long‐term calcineurin inhibitors (CNI) use. Rituximab has more favourable safety profile. The present study was undertaken to evaluate the efficacy and safety of rituximab in CNI‐dependent patients. Methods: This was a prospective observational study conducted from July 2014 to February 2018. Steroid‐dependent nephrotic syndrome or steroid‐resistant nephrotic syndrome (biopsy proven MCD/FSGS), who were CNI dependent were enrolled. Mean age at enrolment was 22.77 ± 7.45 years. All patients received rituximab at a dose of 375 mg/m2 at entry in the study. CD‐19 levels were monitored monthly and patients having CD‐19 levels >5/μL and/or > 1% received additional low‐dose (100 mg) of rituximab. Results: A total of 24 patients were followed up for 12 months. At the end of 6 and 12 months, 87.5% and 79.16% of the patients achieved remission, respectively. Eight (33.33%) patients developed relapse. The mean dose of rituximab in the first year was 791 mg. The average cost of rituximab in the first year was 487.17$. Rituximab was well‐tolerated, with mild infusion reactions, respiratory tract infection and oral candidiasis in 5 (20.83%), 5 (20.83%) and 1 (4.17%) patient, respectively. Conclusions: CD‐19 targeted rituximab is a safe and cost‐effective agent in remission maintenance in adults with CNI dependent. Over three‐fourths of the patients with CNI‐dependent podocytopathy maintain clinical remission with CD‐19 targeted rituximab therapy. SUMMARY AT A GLANCE: This paper shows that rituximab, a monoclonal antibody‐based therapy that depletes CD‐19 and CD‐20‐positive B cells, may be an alternative approach to maintain remission in calcineurin‐inhibitor dependent podocytopathies. [ABSTRACT FROM AUTHOR]

Hodgkin's Lymphoma (HL) is a tumor composed by non-malignant and malignant B-cells. Classical HL expresses antigens CD15+ and CD30+, just only about 20 to 40% of patients expresses still CD20 antigen. This antigen is a protein ligand free present on B lymphocytes cells and its function is not well known. Some studies suggest that expression of CD20 may have a major role on Hodgkin's disease physiopathology and may affect patients' prognostic to treatment, as well relapse and refractory. In past few years, development of monoclonal antibodies Anti-CD20 changed drastically the treatment for non- Hodgkin lymphomas in which CD20 is expressed. HL treatment is essentially composed of radiotherapy and chemotherapy; however monoclonal antibodies Anti-CD20 space is not well delimitated because of: lack of information about clinical outcome to neither anti-CD20 monotherapy nor combined drug therapy with classic regimen; lack of information about CD20 physiopathology mechanisms in B-cells tumors. The objective of this review is discussing about CD20 function on Hodgkin's lymphoma development, its influence on disease evolution and outcomes, as well its effects on therapeutics and patients' prognostic. [ABSTRACT FROM AUTHOR]

B cell depletion by rituximab treatment might be inefficient in patients suffering from nephrotic syndrome. Due to the impaired glomerular filtration barrier a significant portion of the therapeutic antibody might be lost into the urinary space. In order to determine the amount of rituximab in the urine of such patients, CD20 + Daudi cells were stained with the patients' urine followed by a fluorochrome-labeled secondary antibody. Mean fluorescence intensity of that way labeled Daudi cells was determined by flow cytometry. Control samples with defined rituximab concentrations were used to create standard curves. The analyses revealed that all nephelometric IgG + urine samples tested also manifested rituximab at concentrations between 100 and 46,707 μg/L. The flow cytometry-based approach is an easy and reliable method to assess rituximab in patients' urine samples for monitoring individual rituximab treatment courses in all patients co-presenting impaired renal filtration. Presence of such antibodies in the urine could be considered as criteria to modify the formulation or modality of rituximab delivery in order to prevent the loss of the therapeutic antibodies and thereby ensuring efficacy of the therapy. [ABSTRACT FROM AUTHOR]

The clinical success of anti-CD20 monoclonal antibody (mAb)-mediated B cell depletion therapy has contributed to the understanding of B cells as major players in several autoimmune diseases. The first therapeutic anti-CD20 mAb, rituximab, is a murine--human chimera to which many patients develop antibodies and/or experience infusion-related reactions. A second generation of anti-CD20 mAbs has been designed to be more effective, better tolerated, and of lower immunogenicity. These include the humanized versions: ocrelizumab, obinutuzumab, and veltuzumab, and the fully human, ofatumumab. We conducted a literature search of relevant randomized clinical trials in the PubMed database and ongoing trials in Clinicaltrials. gov. Most of these trials have evaluated intravenous ocrelizumab or subcutaneous ofatumumab in rheumatoid arthritis, multiple sclerosis, or systemic lupus erythematosus. Understanding how newer anti-CD20 mAbs compare with rituximab in terms of efficacy, safety, convenience, and cost is important for guiding future management of anti-CD20 mAb therapy in autoimmune diseases. [ABSTRACT FROM AUTHOR]

Background and Objectives: Rituximab is an anti-CD20 monoclonal antibody approved in the first-line treatment of patients with chronic lymphocytic leukemia (CLL). Rituximab pharmacokinetics shows a time dependency possibly related to changes in the target antigen amount over time. The purpose of this study was to quantify the influence of both CD20 antigenic mass and the FcγRIIIA genetic polymorphism on rituximab pharmacokinetics in CLL.Methods: Rituximab pharmacokinetics was described in 118 CLL patients using a semi-mechanistic model including a latent target antigen turnover, which allowed the estimation of rituximab target-mediated elimination in addition to the endogenous clearance.Results: Target-mediated elimination rate constant increased with the baseline CD20 count on circulating B cells (p = 0.00046) and in patients with the FCGR3A-158VV genotype (p = 0.0016). Physiologic elimination of antigen was lower in the Binet C disease stage (p = 0.00018). The effects of these covariates on rituximab concentrations were mainly visible at the beginning of treatment. Body surface area also increased central and peripheral volumes of distribution (p = 1.3 × 10-5 and 0.0015, respectively).Conclusions: A pharmacokinetic model including target-mediated elimination accurately described rituximab concentrations in CLL and showed that rituximab 'consumption' (target-mediated elimination) increases with increasing baseline antigen count on circulating B cells and in FCGR3A-158VV patients.Clinical Trial Registration: NCT01370772. [ABSTRACT FROM AUTHOR]

To date, several new anti-CD20 monoclonal antibodies (mAbs) have been developed for potential efficacies compared with familiar mAb rituximab. Despite the recent advances in development of anti-CD20 mAbs for the treatment of B cell malignancies, the efforts should be continued to develop novel antibodies with improved properties. However, the development of mAbs against CD20 as a multi-transmembrane protein is challenging due to the difficulty of providing a lipid environment that can maintain native epitopes. To overcome this limitation, we describe a simple and efficient DNA immunization strategy for the construction of a novel anti-CD20 mAb with improved anti-tumour properties. Using a DNA immunization strategy that includes intradermal (i.d.) immunization with naked plasmid DNA encoding the CD20 gene, we generated the hybridoma cell line D4, which secretes functional mAbs against an extracellular epitope of CD20. Immunocytochemistry analysis and a cell-based enzyme-linked immunosorbent assay using a Burkitt's lymphoma cell line showed that D4 mAbs are capable of binding to native extracellular epitopes of CD20. Moreover, the binding specificity of D4 mAbs was determined by western blot analysis. Cell proliferation was examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was detected by the annexin V/propidium iodide staining and dye exclusion assay. The results showed that D4 anti-CD20 mAbs produced by DNA immunization exhibit potent growth inhibitory activity and have superior direct B-cell cytotoxicity compared to rituximab. We propose that antibody-induced apoptosis is one of the mechanisms of cell growth inhibition. Taken together, the data reported here open the path to DNA-based immunization for generating pharmacologically active monoclonal antibodies against CD20. In addition, the data support future in vivo animal testing and subsequent procedures to produce a potential therapeutic mAb. [ABSTRACT FROM AUTHOR]

Purpose: Treatment of patients with diffuse large B cell lymphoma (DLBCL) includes rituximab, an anti-CD20 monoclonal antibody (mAb). Insufficient tumor targeting might cause therapy failure. Tumor uptake of 89Zirconium (89Zr)-mAb is a potential imaging biomarker for tumor targeting, since it depends on target antigen expression and accessibility. The aim of this pilot study was to describe the performance of 89Zr-labeled-rituximab-PET to assess CD20 targeting in patients with relapsed/refractory DLBCL. Methods: Six patients with biopsy-proven DLBCL were included. CD20 expression was assessed using immunohistochemistry (IHC). 74 MBq 89Zr-rituximab (10 mg) was administered after the therapeutic dose of rituximab. Immuno-PET scans on day 0, 3 and 6 post injection (D0, D3 and D6 respectively) were visually assessed and quantified for tumor uptake. Results: Tumor uptake of 89Zr-rituximab and CD20 expression were concordant in 5 patients: for one patient, both were negative, for the other four patients visible tumor uptake was concordant with CD20-positive biopsies. Intense tumor uptake of 89Zr-rituximab on PET (SUVpeak = 12.8) corresponded with uniformly positive CD20 expression on IHC in one patient. Moderate tumor uptake of 89Zr-rituximab (range SUVpeak = 3.2–5.4) corresponded with positive CD20 expression on IHC in three patients. In one patient tumor uptake of 89Zr-rituximab was observed (SUVpeak = 3.8), while the biopsy was CD20-negative. Conclusions: This study suggests a positive correlation between tumor uptake of 89Zr-rituximab and CD20 expression in tumor biopsies, but further studies are needed to confirm this. This result supports the potential of 89Zr-rituximab-PET as an imaging biomarker for CD20 targeting. For clinical application of 89Zr-rituximab-PET to guide individualized treatment, further studies are required to assess whether tumor targeting is related to clinical benefit of rituximab treatment in individual patients. [ABSTRACT FROM AUTHOR]

B cells have emerged as effective targets for therapeutic intervention in autoimmunities in which the ultimate effectors are antibodies, as well as those in which T cells are primary drivers of inflammation. Proof of this principle has come primarily from studies of the efficacy of Rituximab, an anti-CD20 mAb that depletes B cells, in various autoimmune settings. These successes have inspired efforts to develop more effective anti-CD20s tailored for specific needs, as well as biologicals and small molecules that suppress B cell function without the risks inherent in B cell depletion. Here we review the current status of B cell-targeted therapies for autoimmunity. [ABSTRACT FROM AUTHOR]

In Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE), B-cell depletion therapy using rituximab results in variable clinical responses between individuals, which likely relates to variable B-cell depletion in the presence of immune defects. Outcomes in clinical trials with other type I anti-CD20 mAbs, ocrelizumab and ofatumumab, are comparable to rituximab. A mechanistically different type II mAb, obinutuzumab (OBZ), with greater capacity for B-cell depletion, has recently entered clinical trials in SLE. Here we consider whether type II anti-CD20 mAbs will provide mechanistic advantages to overcome the disease-related immune defects in autoimmune diseases such as SLE. [ABSTRACT FROM AUTHOR]

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with a complex pathogenesis, which includes both antibody- and T-cell-mediated effector mechanisms. Rituximab (an anti-human CD20 monoclonal antibody [mAb]) is one of the treatments for ITP and is known to deplete B cells but may also work by affecting the T-cell compartments. Here, we investigated the outcome of B-cell depletion (Bdep) therapy on CD8+ T-cell-mediated ITP using a murine model. CD61 knockout (KO) mice were immunized with CD61+ platelets, and T-cell-mediated ITP was initiated by transfer of their splenocytes into severe combined immunodeficiency (SCID) mice. The CD61 KO mice were administrated an anti-mouse CD20 mAb either before or after CD61+ platelet immunization. This resulted in efficient Bdep in vivo, accompanied by significant increases in splenic and lymph node CD4+ and CD8+ T cells and proportional increases of FOXP3+ in CD4+and CD8+ T cells. Moreover, Bdep therapy resulted in significantly decreased splenic CD8+ T-cell proliferation in vitro that could be rescued by interleukin-2. This correlated with normalization of in vivo platelet counts in the transferred SCID mice suggesting that anti-CD20 therapy significantly reduces the ability of CD8+ T cells to activate and mediate ITP. [ABSTRACT FROM AUTHOR]

Despite a significant improvement of thrombotic thrombocytopenic purpura (TTP) prognosis since the use of plasma exchange, morbidity and mortality remained significant because of poor response to standard treatment or exacerbations and relapses. Rituximab, a chimeric monoclonal antibody directed against the B-lymphocyte CD20 antigen, has shown a particular interest in this indication. Recent studies also reported strong evidence for its efficiency in the prevention of relapses. This review addresses these recent progresses and still opened questions in this topic: should rituximab be proposed in all patients at the acute phase? Should all patients benefit from a preemptive treatment? Is the infectious risk acceptable in this context? [ABSTRACT FROM AUTHOR]

Type I anti-CD20 mAb such as rituximab and ofatumumab engage with the inhibitory FcγR, FcγRIIb on the surface of B cells, resulting in immunoreceptor tyrosine-based inhibitory motif (ITIM) phosphorylation. Internalization of the CD20• mAb • FcγRIIb complex follows, the rate of which correlates with FcγRIIb expression. In contrast, although type II anti-CD20 mAbsuch as tositumomab and obinutuzumab also interact with and activate FcγRIIb, this interaction fails to augment the rate of CD20 • mAb internalization, raising the question of whether ITIM phosphorylation plays any role in this process. We have assessed the molecular requirements for the internalization process and demonstrate that in contrast to internalization of IgG immune complexes, FcγRIIb-augmented internalization of rituximab-ligated CD20 occurs independently of the FcγRIIb ITIM, indicating that signaling downstream of FcγRIIb is not required. In transfected cells, activatory FcγRI, FcγRIIa, and FcγRIIIa augmented internalization of rituximab-ligated CD20 in a similar manner. However, FcγRIIa mediated a slower rate of internalization than cells expressing equivalent levels of the highly homologous FcγRIIb. The difference was maintained in cells expressing FcγRIIa and FcγRIIb lacking cytoplasmic domains and in which the transmembrane domains had been exchanged. This difference may be due to increased degradation of FcγRIIa, which traffics to lysosomes independently of rituximab. We conclude that the cytoplasmic domain of FcγR is not required for promoting internalization of rituximab-ligated CD20. Instead, we propose that FcγR provides a structural role in augmenting endocytosis that differs from that employed during the endocytosis of immune complexes. [ABSTRACT FROM AUTHOR]

Rituximab is a monoclonal antibody which targets CD20 in B cells that is used for the treatment of CD20 positive oncologic and hematologic malignancies. Rituximab causes hypersensitivity reactions during infusions. The delay of treatment or loss of a highly efficient drug can be prevented by rapid drug desensitization method in patients who are allergic to rituximab. We report a low grade B cell non-Hodgkin lymphoma patient with rituximab hypersensitivity successfully treated with rapid drug desensitization. In experienced centers, drug desensitization is a novel modality to break through in case of hypersensitivity that should be considered. [ABSTRACT FROM AUTHOR]

Background: Present first-line therapy for diffuse large B-cell lymphoma, a subtype of non-Hodgkin lymphoma, is rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Ibrutinib, a novel oral Bruton's tyrosine kinase inhibitor, has shown single-drug activity in relapsed or refractory B-cell malignancies. We investigated the safety and efficacy of ibrutinib in combination with R-CHOP for patients with previously untreated CD20-positive B-cell non-Hodgkin lymphoma. Methods: In this phase 1b, open-label, non-randomised study, patients were recruited across six centres in the USA and France. Eligibility was age 18 years or older and treatment-naive histopathologically confirmed CD20-positive B-cell non-Hodgkin lymphoma. In the dose-escalation phase (part 1), patients with diffuse large B-cell lymphoma, mantle-cell lymphoma, or follicular lymphoma were enrolled. The primary objective was to determine a recommended phase 2 dose of ibrutinib with a standard R-CHOP regimen, by assessing safety in all patients who received treatment. Patients received ibrutinib 280 mg, 420 mg, or 560 mg per day in combination with a standard R-CHOP regimen every 21 days. Safety of the recommended phase 2 dose was then assessed in a dose-expansion population, which consisted of patients with newly diagnosed diffuse large B-cell lymphoma (part 2). Secondary objectives included assessments of the proportion of patients who had an overall response, pharmacokinetics, and pharmacodynamics. This trial is registered with ClinicalTrials.gov, number NCT01569750. Findings: From June 22, 2012, to March 25, 2013, 33 patients were enrolled (part 1: 17; part 2: 16) and 32 received ibrutinib plus R-CHOP treatment (one patient in the part 2 cohort withdrew). The maximum tolerated dose was not reached and the recommended phase 2 dose for ibrutinib was 560 mg per day. The most common grade 3 or greater adverse events included neutropenia (73% [24 of 33 patients]), thrombocytopenia (21% [seven patients]), and febrile neutropenia and anaemia (18% each [six patients]). The most frequently reported serious adverse events were febrile neutropenia (18% [six patients]) and hypotension (6% [two patients]). 30 (94%) of 32 patients who received one or more doses of combination treatment achieved an overall response. All 18 patients with diffuse large B-cell lymphoma who received the recommended phase 2 dose had an overall response. For those subtyped and treated at the recommended phase 2 dose, five (71%) of seven patients with the germinal centre B-cell-like subtype and two (100%) patients with the non-germinal centre B-cell-like subtype had a complete response. R-CHOP did not affect pharmacokinetics of ibrutinib, and ibrutinib did not alter the pharmacokinetics of vincristine. Pharmacodynamic data showed Bruton's tyrosine kinase was fully occupied (>90% occupancy) at the recommended phase 2 dose. Interpretation: Ibrutinib is well tolerated when added to R-CHOP, and could improve responses in patients with B-cell non-Hodgkin lymphoma, but our findings need confirmation in a phase 3 trial. Funding: Janssen. [ABSTRACT FROM AUTHOR]

Rituximab is an exciting monoclonal antibody drug approved for treating B-cell lymphomas and its target is the CD20 antigen which is expressed on the surface of B cells. In recent years, the variable efficacies of rituximab among different lymphoma patients have become an important clinical issue and urgently need to be solved for further development of antibodies with enhanced efficacies. In this work, atomic force microscopy (AFM) was used to investigate the nanoscale distribution of CD20 on the surface of tumour B cells from lymphoma patients to examine its potential role in the clinical therapeutic effects of rituximab. By performing ROR1 fluorescence labelling (ROR1 is a specific tumour cell surface marker) on the bone marrow cells prepared from B-cell lymphoma patients, the tumour B cells were recognized, and then AFM tips carrying rituximabs via polyethylene glycol crosslinkers were moved to the tumour cells to probe the specific CD20-rituximab interactions. By applying AFM single-molecule force spectroscopy (SMFS) at the local areas (500×500 nm2) on the surface of tumour B cells, the nanoscale distributions of CD20 on the surface of tumour B cells were mapped, visually showing that CD20 distributed heterogeneously on the cell surface. Bone marrow cell samples from three clinical B-cell lymphoma cases were collected to analyze the binding affinity and nanoscale distribution of CD20 on tumour cells. The experimental results showed that CD20 distribution on tumour cells were to some extent related to the clinical therapeutic outcomes while the CD20-rituximab binding forces did not have distinct effects to the clinical outcomes. These results can provide novel insights in understanding the rituximab's clinical efficacies from the nanoscale distribution of CD20 on the tumour cells at single-cell and single-molecule levels. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells mediate antilymphoma activity by spontaneous cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) when triggered by rituximab, an anti-CD20 monoclonal antibody (mAb) used to treat patients with B-cell lymphomas. The balance of inhibitory and activating signals determines the magnitude of the efficacy of NK cells by spontaneous cytotoxicity. Here, using a killer-cell immunoglobulin-like receptor (KIR) transgenic murine model, we show that blockade of the interface of inhibitory KIRs with major histocompatibility complex (MHC) class I antigens on lymphoma cells by anti-KIR antibodies prevents a tolerogenic interaction and augments NK-cell spontaneous cytotoxicity. In combination with anti-CD20 mAbs, anti-KIR treatment induces enhanced NK-cell-mediated, rituximab-dependent cytotoxicity against lymphoma in vitro and in vivo in KIR transgenic and syngeneic murine lymphoma models. These results support a therapeutic strategy of combination rituximab and KIR blockade through lirilumab, illustrating the potential efficacy of combining a tumor-targeting therapy with an NK-cell agonist, thus stimulating the postrituximab antilymphoma immune response. [ABSTRACT FROM AUTHOR]

Abstract: CD20, a membrane protein highly expressed on most B-cell lymphomas, is an effective target demonstrated in clinical practice for treating B-cell non-Hodgkin's lymphoma (NHL). Rituximab is a monoclonal antibody against CD20. In this work, we applied atomic force microscopy (AFM) to map the nanoscale distribution of CD20 molecules on the surface of cancer cells from clinical B-cell NHL patients under the assistance of ROR1 fluorescence recognition (ROR1 is a specific cell surface marker exclusively expressed on cancer cells). First, the ROR1 fluorescence labeling experiments showed that ROR1 was expressed on cancer cells from B-cell lymphoma patients, but not on normal cells from healthy volunteers. Next, under the guidance of ROR1 fluorescence, the rituximab-conjugated AFM tips were moved to cancer cells to image the cellular morphologies and detect the CD20-rituximab interactions on the cell surfaces. The distribution maps of CD20 on cancer cells were constructed by obtaining arrays of (16×16) force curves in local areas (500×500nm2) on the cell surfaces. The experimental results provide a new approach to directly investigate the nanoscale distribution of target protein on single clinical cancer cells. [Copyright &y& Elsevier]

Background: B-cell depletion therapy was demonstrated to be a valid and safe alternative as an adjuvant in oral-pharyngeal pemphigus vulgaris (OPV) patients. We aimed to assess its effects on anti-desmoglein (Dsg) 1 and 3 and leukocytes subsets profile in these patients' population. Methods and Materials: We evaluated the immunologic profile of 10 OPV patients treated with RTX as adjuvant by using the ELISA testing for anti-Dsg-1 and -3 titers and the immunophenotyping for B and T-cell lymphocyte subpopulations and compared them with the PDAI score for clinical remission. Results: A significant difference in medians between baseline, end of RTX therapy, and 6 months after RTX therapy was observed in Dsg-3 titer (p < 0.001), in the CD8 (p = 0.009), and CD20 counts (p < 0.001). Multiple comparisons after Bonferroni adjustment confirmed such significant differences mainly between baseline and the end of RTX therapy and baseline and 6 months after RTX therapy. Only the anti-Dsg-3 titer at the end of RTX therapy demonstrated a slight positive correlation with the PDAI score at baseline (p = 0.046, r = 0.652). Conclusions: B-cell depletion adjuvant therapy in OPV patients demonstrated a significant impact on anti-Dsg-3 titer and B and T-cell lymphocyte subpopulations profile. [ABSTRACT FROM AUTHOR]

A recent type 1 diabetes (T1D) clinical trial of rituximab (a B cell-depleting anti-CD20 antibody) achieved some therapeutic benefit in preserving C-peptide for a period of approximately nine months in patients with recently diagnosed diabetes. Our previous data in the NOD mouse demonstrated that co-administration of antigen (insulin) with anti-CD3 antibody (a T cell-directed immunomodulator) offers better protection than either entity alone, indicating that novel combination therapies that include a T1D-related autoantigen are possible. To accelerate the identification and development of novel combination therapies that can be advanced into the clinic, we have evaluated the combination of a mouse anti-CD20 antibody with either oral insulin or a proinsulin-expressing DNA vaccine. Anti-CD20 alone, given once or on 4 consecutive days, produced transient B cell depletion but did not prevent or reverse T1D in the NOD mouse. Oral insulin alone (twice weekly for 6 weeks) was also ineffective, while proinsulin DNA (weekly for up to 12 weeks) showed a trend toward modest efficacy. Combination of anti-CD20 with oral insulin was ineffective in reversing diabetes in NOD mice whose glycemia was controlled with SC insulin pellets; these experiments were performed in three independent labs. Combination of anti-CD20 with proinsulin DNA was also ineffective in diabetes reversal, but did show modest efficacy in diabetes prevention (p = 0.04). In the prevention studies, anti-CD20 plus proinsulin resulted in modest increases in Tregs in pancreatic lymph nodes and elevated levels of proinsulin-specific CD4+ T-cells that produced IL-4. Thus, combination therapy with anti-CD20 and either oral insulin or proinsulin does not protect hyperglycemic NOD mice, but the combination with proinsulin offers limited efficacy in T1D prevention, potentially by augmentation of proinsulin-specific IL-4 production. [ABSTRACT FROM AUTHOR]

Five per cent of patients with primary Sjogren's syndrome (pSS) develop malignant non-Hodgkin's lymphoma (NHL), usually of the mucosa-associated lymphoid tissue (MALT) and most frequently located in the major salivary glands. Rituximab (RTX), a chimeric monoclonal antibody against the CD20 molecule expressed on the surface of mature B cells that has been approved for the treatment of NHL, has been used to treat pSS-associated lymphoma. We have described two cases: one with MALT lymphoma in the parotid glands and the other with a rare thymus lymphoma accompanied by the rare complication of a bullous pneumopathy. Both were treated with RTX at haematological doses, which was unsuccessful in the patient with a salivary lymphoma; in the case of the patient with a thymus lymphoma, the mediastinum mass disappeared and did not relapse. Both patients experienced an improvement in the subjective symptoms of dryness, and their Schirmer's test and scialoscintigraphy results stabilised. The pulmonary bullae remained unchanged. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the effect of a low-dose rituximab (RIT) at <375 mg/m2 on B cells in the spleen and peripheral blood. Five renal transplant recipients received a single dose of RIT at 10, 15, 35, 150, or 300 mg/m2 3–13 days before transplantation. One patient who received the same immunosuppressive regimen except for RIT was also enrolled as a control. Splenectomy was performed at the time of transplantation in all patients. The B-cell count in the peripheral blood was analysed with a fluorescence-activated cell sorter using anti-CD19 antibodies, and the B cells in the spleen were analysed by immunohistochemistry using anti-CD20 and -CD79a antibodies. All but one dosage (10 mg/m2) of RIT completely eliminated B cells from the circulation within 30 days. Immunohistochemical examination of the spleen showed a marked reduction of B cells in the white pulps in all five recipients compared with that in the control patient. The observations in this study indicated that RIT has a potent effect of depleting B cells in the spleen and peripheral blood at low-doses of <375 mg/m2. [ABSTRACT FROM AUTHOR]

Rituximab (Rituxan®) is a human-mouse chimeric monoclonal antibody that targets the B-cellCD20antigen and causes rapid and specific B-cell depletion. Rituximab was approved in the United States in 1997 to treat low-grade or follicular, relapsed or refractory, CD20-positive B-cell non-Hodgkin's lymphoma (NHL). Since then, further clinical experience with rituximab has been incorporated into the prescribing information, which now stipulates an extended eight-week schedule, treatment of patients with refractory or relapsed bulky disease measuring >10 cm, and retreatment of patients who responded to rituximab previously. In 1998, the European Union approved rituximab (MabThera®) to treat stage III/IV, follicular, chemotherapy-resistant, or relapsed NHL. Recently, the European Union also approved the use of rituximab in combination with standard chemotherapy for aggressive NHL. Many clinical trials have evaluated rituximab, alone or with other therapies, in indolent and aggressive NHL as well as other B-cell lymphoproliferative disorders. New studies are evaluating rituximab's role in first-line therapy, maintenance therapy, and stem-cell transplantation procedures. The use of rituximab against autoimmune disorders, such as rheumatoid arthritis, immune thrombocytopenic purpura, autoimmune hemolytic anemia, systemic lupus erythematosus, and multiple sclerosis, is also under investigation. [ABSTRACT FROM AUTHOR]

• Rituximab can eliminate EBV for EBV-HLH with only B cells infected. • For EBV-HLH with B cells alone infected by EBV, HSCT may not be required. • Detection of EBV-infected lymphocyte subgroups can guide the treatment of EBV-HLH. Patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) have a poor prognosis. This study investigated the efficacy of rituximab-containing immuno-chemotherapy regimens for EBV-HLH. In this study, 15 patients were treated with rituximab-containing regimens. The treatment efficacy and adverse events were evaluated. In 10 patients, EBV DNA became negative after the first course of treatment. The lymphocyte types infected by EBV in the 10 patients were only infected with B cells and mainly infected with B cells. In the other 5 patients, the EBV DNA of peripheral blood mononuclear cells (PBMC) before and after treatment with the regimens had no statistical difference (P = 0.111). In addition, in these 5 patients, EBV mainly infected T and NK cells. Among the 5 patients without a significant decline in EBV DNA of PBMC, 2 patients received allogeneic hematopoietic stem cell transplantation and turned negative for EBV DNA. This study suggests that rituximab-containing regimens are effective therapy for EBV-HLH with only and mainly B lymphocytes infected by EBV, especially for eliminating EBV. [ABSTRACT FROM AUTHOR]

Rituximab is a monoclonal antibody directed specifically against the CD20 resulting in depletion of B lymphocytes. Rituximab is used in multiple autoimmune disorders across the medical specialties including multiple sclerosis, myesthenia grevis, rheumatoid arthritis and inflammatory bowel disease. In the field of endocrinology, rituximab is indicated specifically in resistant cases of Graves' opthalmopathy. We recently encountered a patient of multiple sclerosis, developing features of destructive thyroiditis after a course of rituximab and report the same here. [ABSTRACT FROM AUTHOR]

Rituximab is a chimeric monoclonal antibody directed against the CD20 antigen present on the surface of mature B cells. It has been widely used in the treatment of many dermatologic and rheumatologic conditions. The onset of psoriasis after rituximab therapy has not been reported in children. We report the first case of psoriasis after rituximab therapy in a 16-month-old boy with no other risk factors for developing psoriasis. [ABSTRACT FROM AUTHOR]

We report two cases of lymphomatoid papulosis ( LyP) occurring in conjunction with B-cell lymphoproliferative malignancies where the LyP was exacerbated during rituximab (anti- CD20 antibody)-based therapy. We postulate that the altered B-cell cytokine milieu acted to allow an exacerbation of the patient's concomitant T-cell disease and discuss the possible mechanisms by which this may have occurred. [ABSTRACT FROM AUTHOR]

Abstract: We measured anti-N-methyl-d-aspartate receptor (NMDAR) autoantibody levels and assessed B cell subsets using multicolor flow cytometry of peripheral blood mononuclear cells (PBMCs) from a recurrent anti-NMDAR encephalitis case to evaluate the effectiveness of rituximab treatment. Rituximab depleted CD20+ fractions of naïve and memory B cell subsets and reduced the number of CD20− plasmablasts. This study suggests that short-lived plasmablasts are removed by rituximab-induced depletion of the CD20+ B cell population. Increased numbers of plasmablasts in PBMCs may be a candidate predictive factor for unfavorable prognosis of anti-NMDAR encephalitis and an indication of when to commence second-line immunotherapy. [Copyright &y& Elsevier]

Background: Rituximab is a well-established component of treatment regimens for B-cell non-Hodgkin lymphoma. Rituximab binds the CD20 antigen on the surface of B lymphocytes, causing an enhanced clearance of malignant and benign B cells. Thus, rituximab leads to depletion of normal B lymphocytes as well, which can cause substantial immunodeficiency. Ibrutinib inhibits the Bruton tyrosine kinase and thereby B-cell activity. It is used for the treatment of different B-lymphocyte malignancies, such as mantle cell lymphoma. Recently, the combination of both drugs has been tested in various clinical scenarios.Case Presentation: We present a case of disseminated enterovirus infection resulting from combined rituximab and ibrutinib maintenance treatment in a 57-year-old Caucasian patient. with mantle cell lymphoma. Initially presenting with myositis symptoms, further diagnostic investigation revealed myocarditis, enteritis, myeloencephalitis, and hepatitis. These organ manifestations led to potentially life-threatening complications such as rhabdomyolysis, delirium, and heart rhythm disturbances. After treatment with high-dose intravenous immunoglobulins, virus clearance was achieved and organ functions could be restored.Conclusions: This case emphasizes the risk of combined therapy with rituximab/ibrutinib for severe immune-related side effects with the necessity of continuous patient monitoring. High-dose intravenous therapy should be considered as treatment for severe enterovirus infection. In severe enterovirus infections, we recommend subtyping for the development of efficient preventive and therapeutic strategies. [ABSTRACT FROM AUTHOR]

CD20 is a B-lymphocyte specific integral membrane protein, an activated-glycosylated phosphoprotein expressed on the surface of B-cells and a clinically validated target of monoclonal antibodies such as rituximab, ocrelizumab, ofatumumab and obinutuzumab in the treatment of all B cell lymphomas and leukemias as well as autoimmune diseases. Here, we report the extraction and purification of native CD20 from SUDHL4 and RAMOS cell lines. To improve the protein yield, we applied a calixarene-based detergent approach to solubilize, stabilize and purify native CD20 from HEK293 cells. Size Exclusion Chromatography (SEC) and Analytical Ultracentrifugation show that purified CD20 was non-aggregated and that CD20 oligomerization is concentration dependent. Negative stain electron microscopy and atomic force microscopy revealed homogenous populations of CD20. However, no defined structure could be observed. Interestingly, micellar solubilized and purified CD20 particles adopt uniformly confined nanodroplets which do not fuse and aggregate. Finally, purified CD20 could bind to rituximab and obinutuzumab as demonstrated by SEC, and Surface Plasmon Resonance (SPR). Specificity of binding was confirmed using CD20 antibody mutants to human B-cell lymphoma cells. The strategy described in this work will help investigate CD20 binding with newly developed antibodies and eventually help to optimize them. This approach may also be applicable to other challenging membrane proteins. [ABSTRACT FROM AUTHOR]

The article focuses on involvement of human neutrophils with chronic lymphocytic leukemia (CLL) B cells association with monoclonal antibodies of rituximab or obinutuzumab. Topics discussed include assessment of CD20 therapy involvement in leukemia therapy; monoclonal antibodies related to CD20 have an immune effector; and consideration of concerns for neutrophils over CD20 mediated immunotherapy.

The article assesses the effect of statin use on rituximab (RTX) treatment for pemphigus and pemphigoid disorders. The authors point out that B-cell depletion by RTX is dependent on the integrity of lipid rafts, which could be affected by decreased cholesterol synthesis. The data used by the researchers were obtained from patients at Sunnybrook Health Sciences Centre in Ontario. Noted is the effect of cholesterol levels on CD20 conformation.

We have identified a spliced mRNA transcript of CD20 (named D393-CD20) which was associated with resistance to RTX in primary B cell from patients with lymphoma and leukaemia. In the present work, we wished to investigate whether D393-CD20 variant was expressed by B cells from patients with pemphigus. Ten patients with bullous pemphigoid and twenty-five patients with pemphigus were included. All patients were responder to conventional immunosuppressive agents or rituximab ( n = 11). Efficacy of B-cell activation by pokeweed mitogen was assessed by CD86 expression using a FACS Canto II flow cytometer. mRNA CD20 expression study was then performed using RT-PCR assay allowing first to discriminate wild-type (wt)-CD20 and D393-CD20 transcript. Although wt-CD20 expression was always detected, we were unable to detect D393-CD20, even after B-cell activation or RTX treatment. Our results suggest that D393-CD20 transcript may be a molecular marker of B-cell malignancies rather than autoimmune disease like pemphigus. Further study of RTX non-responders or non-escaping PV patients is thus still required to appreciate whether D393-CD20 expression may be detected under the pressure of RTX therapy. [ABSTRACT FROM AUTHOR]

CD20 is an attractive therapeutic target given the success of its monoclonal antibody, Rituximab, in the treatment of B cell malignancies and B cell-mediated autoimmune diseases. Treatment with Rituximab causes a rapid depletion of B cells and decrease in disease symptoms. Despite the clinical efficiency of Rituximab, its mechanism of action is not completely understood. In the current study, we aimed at further investigating the Rituximab-induced cell death and the factors affecting such response. Our results indicate that Rituximab-induced cell death depends on the nature of cells and levels of CD20 expression on cell surface. Coexpression of CD20 with CD40, a member of the TNF receptor family that is known to be physically associated with CD20 on cell surface, enhances the apoptotic response induced by Rituximab. Inhibiting CD40 disulfide-bound homodimer formation, a process required for some CD40 signaling, further enhances Rituximab-induced cell death. Cell death induced by anti-CD40 mAb is also upregulated by the presence of CD20, suggesting a bidirectional influence of the CD20/CD40 association. Moreover, treating cells with both anti-CD20 and anti-CD40 antibodies improves the cell death response induced by a single agent treatment. These results highlight the role of the CD20/CD40 association in triggering B cell depletion and may pave the way for an alternative more efficient therapeutic strategy in treating B cell-mediated disorders. [ABSTRACT FROM PUBLISHER]

The CD20-specific monoclonal antibody rituximab (MabThera®, Rituxan®) is widely used as the backbone of treatment for patients with hematologic disorders. Intravenous administration of rituximab is associated with infusion times of 4–6 hours, and can be associated with infusion-related reactions. Subcutaneous administration of rituximab may reduce this and facilitate administration without infusion-related reactions. We sought to determine the feasibility of achieving equivalent efficacy (measured by endogenous B-cell depletion) and long-term durability of CD20 target coverage for subcutaneously administered rituximab compared with intravenous dosing. In these preclinical studies, male cynomolgus monkeys were treated with either intravenous rituximab or novel subcutaneous formulation of rituximab containing human recombinant DNA-derived hyaluronidase enzyme. Peripheral blood samples were analyzed for serum rituximab concentrations, peripheral B-cell depletion, and CD20 target coverage, including subset analysis according to CD21+ status. Distal lymph node B-cell depletion and CD20 target coverage were also measured. Initial peak serum concentrations of rituximab were significantly higher following intravenous administration than subcutaneous. However, the mean serum rituximab trough concentrations were comparable at 2 and 7 days post-first dose and 9 and 14 days post-second dose. Efficacy of B-cell depletion in both peripheral blood and distal lymph nodes was comparable for both methods. In lymph nodes, 9 days after the second dose with subcutaneous and intravenous rituximab, B-cell levels were decreased by 57% and 42% respectively. Similarly, levels of peripheral blood B cells were depleted by >94% for both subcutaneous and intravenous dosing at all time points. Long-term recovery of free unbound surface CD20 levels was similar, and the duration of B-cell depletion was equally sustained over 2 months for both methods. These results demonstrate that, despite initial peak serum drug level differences, subcutaneous rituximab has similar durability, pharmacodynamics, and efficacy compared with intravenous rituximab. [ABSTRACT FROM AUTHOR]

CD20 is a B cell surface marker that is expressed in various stages in B lymphocytes and certain lymphomas. Clinical administration of CD20 antibody, such as rituximab, is used widely to treat human B-cell lymphomas and other diseases. However, CD20 antibody failed to treat systemic lupus erythematosus (SLE or lupus). The reason for the failure is currently unknown. Type I interferons (IFN) are a major component for the host innate immunity, and a key pathogenic factor in lupus. We found that CD20 antibody potentiated human B cells for its production of IFNs in vitro. This function was specific to CD20-expressing cells and the potentiation function seems to be instant. In addition, ectopic expression of CD20 in non-B-lymphocytes increased the IFN promoter reporter activities. Because IFNs are a key pathogenic factor in lupus, our data suggest that, in the presence of virus infection, the CD20-antibody-mediated enhancement of IFN production might be related to its failure in lupus treatments. This work may provide new insights for CD20-Ab therapeutic applications. [ABSTRACT FROM AUTHOR]