Critical analysis of rituximab-induced serological changes in connective tissue diseases

CD19-targeting CAR T cells protect from ANCA-induced acute kidney injury

OBJECTIVES

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (AAV) are life-threatening systemic autoimmune diseases manifesting in the kidneys as necrotizing crescentic glomerulonephritis (NCGN). ANCA antigens are myeloperoxidase (MPO) or proteinase 3. Current treatments include steroids, cytotoxic drugs and B cell-depleting antibodies. The use of chimeric antigen receptor (CAR) T cells in autoimmune diseases is a promising new therapeutic approach. We tested the hypothesis that CAR T cells targeting CD19 deplete B cells, including MPO-ANCA-producing B cells, thereby protecting from ANCA-induced NCGN.

METHODS

We tested this hypothesis in a preclinical MPO-AAV mouse model. NCGN was established by immunisation of MPO-/- mice with murine MPO, followed by irradiation and transplantation with haematopoietic cells from wild-type mice alone or together with either CD19-targeting CAR T cells or control CAR T cells.

RESULTS

CD19 CAR T cells efficiently migrated to and persisted in bone marrow, spleen, peripheral blood and kidneys for up to 8 weeks. CD19 CAR T cells, but not control CAR T cells, depleted B cells and plasmablasts, enhanced the MPO-ANCA decline, and most importantly protected from NCGN.

CONCLUSION

Our proof-of-principle study may encourage further exploration of CAR T cells as a treatment for ANCA-vasculitis patients with the goal of drug-free remission.

A Review of the Various Roles and Participation Levels of B-Cells in Non-Infectious Uveitis

Non-infectious uveitis is an inflammatory disorder of the eye that accounts for severe visual loss without evident infectious agents. While T cells are supposed to dominate the induction of inflammation in non-infectious uveitis, the role of B cells in the pathogenesis of this disease is obscure. Therefore, this review aimed to discuss diverse B-cell participation in different non-infectious uveitides and their roles in the pathogenesis of this disease as well as the mechanism of action of rituximab. Increasing evidence from experimental models and human non-infectious uveitis has suggested the participation of B cells in non-infectious uveitis. The participation levels vary in different uveitides. Furthermore, B cells play multiple roles in the pathogenic mechanisms. B cells produce autoantibodies, regulate T cell responses via antibody-independent functions, and constitute ectopic lymphoid structures. Regulatory B cells perform pivotal anti-inflammatory functions in non-infectious uveitis. Rituximab may work by depleting pro-inflammatory B cells and restoring the quantity and function of regulatory B cells in this disease. Identifying the levels of B-cell participation and the associated roles is beneficial for optimizing therapy. Diversified experimental model choices and emerging tools and/or methods are conducive for future studies on this topic.

Anti-CD20 Agents for Multiple Sclerosis: Spotlight on Ocrelizumab and Ofatumumab

Until recently, in the pathogenesis of Multiple Sclerosis (MS), the contribution of B cells has been largely underestimated, and the disease was considered a T-cell-mediated disorder. However, newer evidence shows that B cells play a crucial role in the pathogenesis of MS via antigen-driven autoantibody responses and through the cross regulation of T-helper cells. As B cells express the surface molecule CD20 at all points of differentiation, it provides a specific target for monoclonal antibodies, and the development and clinical testing of anti-CD20 antibody treatments for MS have been successful. After some observations, some small clinical trials found positive effects for the first anti-CD20 therapeutic rituximab in MS; newer agents have been specifically evaluated, resulting in the development of ocrelizumab and ofatumumab. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, was approved in March 2017 by the Food and Drug Administration (FDA) and is also the first proven therapy to reduce disability progression in primary progressive MS. This is particularly significant considering that disease-modifying treatment options are few for both primary and secondary progressive MS. Ofatumumab, a fully human anti-CD20 monoclonal antibody, that binds a distinct epitope, has been further investigated in phase 3 trials for relapsing forms of MS. In this review, we discuss in detail these two anti-CD20 agents and their advent for treatment of MS.

[The role of laboratory biomarkers in monitoring of rituximab biosimilar therapy (Acellbia, "BIOCAD") in patients with rheumatoid arthritis]

AIM

to evaluate the role of laboratory biomarkers in monitoring effectiveness of rituximab (RTM) biosimilar therapy in a total dose of 1200 mg.

MATERIALS AND METHODS

20 patients (pts) with rheumatoid arthritis (RA) (18 woman, mean age 61.5(54-66.5) years, mean disease duration 39.5(20-84) months, mean DAS28 5.6(4.9-6.8)) received two intravenous RTM biosimilar infusions (600 mg №2) in combination with DMARDs and glucocorticoids. Laboratory biomarkers were assessed at baseline and weeks 12 and 24 after the first infusion of RTX.

RESULTS

RTM biosimilar induced decreases in DAS28, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) at week 12 and 24, p.

B cells in multiple sclerosis therapy-A comprehensive review

For decades, B cells were ignored in multiple sclerosis (MS) pathogenesis, and the disease was always regarded as a T cell-mediated disorder. Recent evidence shows that there is an antigen-driven B-cell response in the central nervous system of patients with MS, and memory B cells/plasma cells are detectable in MS lesions. The striking efficacy of B cell-depleting therapies in reducing the inflammatory activity of the disease highlights that B cells may play more pathogenetic roles than expected. B cells express several unique characteristic markers on their surface, for example, CD19, CD20 molecules, that provide selective targets for monoclonal antibodies. In this respect, several B cell-targeted therapies emerged, including anti-CD20 antibodies (rituximab, ocrelizumab, and ofatumumab), anti-CD19 antibody (inebilizumab), and agents targeting the BAFF/APRIL signaling pathway (atacicept, belimumab, and LY2127399). In this review, we discuss, in detail, the immunobiology of B cells and their protective and destructive roles in MS pathogenesis. In the second part, we list the completed and ongoing clinical trials investigating the safety and efficacy of B cell-related monoclonal antibodies in MS.

Signal peptide peptidase and SPP-like proteases - Possible therapeutic targets?

Signal peptide peptidase (SPP) and the four homologous SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 are GxGD-type intramembrane-cleaving proteases (I-CLIPs). In addition to divergent subcellular localisations, distinct differences in the mechanistic properties and substrate requirements of individual family members have been unravelled. SPP/SPPL proteases employ a catalytic mechanism related to that of the γ-secretase complex. Nevertheless, differential targeting of SPP/SPPL proteases and γ-secretase by inhibitors has been demonstrated. Furthermore, also within the SPP/SPPL family significant differences in the sensitivity to currently available inhibitory compounds have been reported. Though far from complete, our knowledge on pathophysiological functions of SPP/SPPL proteases, in particular based on studies in mice, has been significantly increased over the last years. Based on this, inhibition of distinct SPP/SPPL proteases has been proposed as a novel therapeutic concept e.g. for the treatment of autoimmunity and viral or protozoal infections, as we will discuss in this review. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.

Autoantibodies against complement components in systemic lupus erythematosus – role in the pathogenesis and clinical manifestations

Many complement structures and a number of additional factors, i.e. autoantibodies, receptors, hormones and cytokines, are implicated in the complex pathogenesis of systemic lupus erythematosus. Genetic defects in the complement as well as functional deficiency due to antibodies against its components lead to different pathological conditions, usually clinically presented. Among them hypocomplementemic urticarial vasculitis, different types of glomerulonephritis as dense deposit disease, IgA nephropathy, atypical haemolytic uremic syndrome and lupus nephritis are very common. These antibodies cause conformational changes leading to pathological activation or inhibition of complement with organ damage and/or limited capacity of the immune system to clear immune complexes and apoptotic debris. Finally, we summarize the role of complement antibodies in the pathogenesis of systemic lupus erythematosus and discuss the mechanism of some related clinical conditions such as infections, thyroiditis, thrombosis, acquired von Willebrand disease, etc.

Altered B cell signalling in autoimmunity

Recent work has provided new insights into how altered B cell-intrinsic signals - through the B cell receptor (BCR) and key co-receptors - function together to promote the pathogenesis of autoimmunity. These combined signals affect B cells at two distinct stages: first, in the selection of the naive repertoire; and second, during extrafollicular or germinal centre activation responses. Thus, dysregulated signalling can lead to both an altered naive BCR repertoire and the generation of autoantibody-producing B cells. Strikingly, high-affinity autoantibodies predate and predict disease in several autoimmune disorders, including type 1 diabetes and systemic lupus erythematosus. This Review summarizes how, rather than being a downstream consequence of autoreactive T cell activation, dysregulated B cell signalling can function as a primary driver of many human autoimmune diseases.

Theranostic of biopharmaceuticals

Monoclonal antibodies (mAbs) and fusion proteins with an Fc portion of immunoglobulin G (IgG) are emblematic of the remarkable expansion of biopharmaceuticals. Despite their biological origin, these products display an interindividual variability in their efficacy and/or side effects, which must be taken into consideration. Biological monitoring allowing for adapted prescription and dose adjustments may lead to therapeutic optimization and limitation of the high costs of these drugs. Herein, we review the biological theranostic of mAbs and Fc fusion proteins, including pre-treatment analyses, monitoring of efficacy, therapeutic drug monitoring, and monitoring of side effects. Supported by concrete evidence, a specific interest is given to individualised therapeutic monitoring that combines intention to treat, biomarkers of efficacy and adaptation of serum concentrations.

B-cell tolerance in transplantation: is repertoire remodeling the answer?

T lymphocytes are the primary targets of immunotherapy in clinical transplantation; however, B lymphocytes and their secreted alloantibodies are also highly detrimental to the allograft. Therefore, the achievement of sustained organ transplant survival will likely require the induction of B-lymphocyte tolerance. During development, acquisition of B-cell tolerance to self-antigens relies on clonal deletion in the early stages of B-cell compartment ontogeny. We contend that this mechanism should be recapitulated in the setting of alloantigens and organ transplantation to eliminate the alloreactive B-cell subset from the recipient. Clinically feasible targets of B-cell-directed immunotherapy, such as CD20 and B-lymphocyte stimulator (BLyS), should drive upcoming clinical trials aimed at remodeling the recipient B-cell repertoire.

B cells and antibodies in multiple sclerosis pathogenesis and therapy

B cells and antibodies account for the most prominent immunodiagnostic feature in patients with multiple sclerosis (MS), namely oligoclonal bands. Furthermore, evidence is accumulating that B cells and antibodies contribute to MS pathogenesis in at least a subset of patients. The CNS provides a B-cell-fostering environment that includes B-cell trophic factors such as BAFF (B-cell-activating factor of the TNF family), APRIL (a proliferation-inducing ligand), and the plasma-cell survival factor CXCL12. Owing to this environment, the CNS of patients with MS is not only the target of the immunopathological process, but also becomes the site of local antibody production. B cells can increase or dampen CNS inflammation, but their proinflammatory effects seem to be more prominent in most patients, as B-cell depletion is a promising therapeutic strategy. Other therapies not primarily designed to target B cells have numerous effects on the B-cell compartment. This Review summarizes key features of B-cell biology, the role of B cells and antibodies in CNS inflammation, and current attempts to identify the targets of pathogenic antibodies in MS. We also review the effects of approved and investigational interventions-including CD20-depleting antibodies, BAFF/APRIL-depleting agents, alemtuzumab, natalizumab, FTY720, IFN-β, glatiramer acetate, steroids and plasma exchange-on B-cell immunology.

Treatment of interstitial lung diseases associated with connective tissue diseases

A variety of interstitial lung diseases (ILDs) have been reported in association with connective tissue diseases (CTDs). ILD is commonly associated with multiple CTDs and accounts for significant morbidity and mortality in these conditions. In rheumatoid arthritis and systemic sclerosis, ILD commonly occurs in the course of these disorders (incidence: 20-44%). The pathological findings of ILDs are similar to those of idiopathic interstitial pneumonia. A wide variety of histopathologic features, such as various types of interstitial pneumonia and airway involvement, have been observed that are specific for ILDs in rheumatoid arthritis, and this high variety makes its pathology complicated. The diagnosis of ILD is generally based on clinical presentation, bronchioalveolar lavage fluid and high-resolution computed tomography, among others. The most important differential diagnosis is infection, especially pneumocystis pneumonia, and treatment-related toxic damage. The immunosuppressive agents most widely used for the treatment of ILDs are cyclophosphamide, azathioprine, mycophenolate mofetil and calcineurin inhibitors. Other therapeutic strategies are currently being extensively studied, such as antifibrotic agents, endothelin-1 receptor antagonists, tyrosine kinase inhibitors and newer biological agents. In this article, we describe novel therapies for ILDs associated with CTDs.

The CC homozygosis of the -174G>C IL-6 polymorphism predicts a lower efficacy of rituximab therapy in rheumatoid arthritis

Identification of genetic biomarkers of response to biologics in rheumatoid arthritis (RA) is a relevant issue. Being IL-6 a key cytokine for B cell survival, the interleukin-6 (IL-6) -174G>C and the IL-6 receptor (IL-6R) D358A gene polymorphisms were investigated in 158 RA patients treated with rituximab (RTX). One hundred and twenty-eight (81.0%) were RF positive and 126 (79.7%) were anti-CCP positive. Response to therapy was evaluated at the end of the sixth month after the first RTX infusion, by using both the EULAR and the ACR criteria. The possible relationship with IL-6 serum levels was also studied. By univariate analysis, lack of response by the EULAR criteria was more prevalent in RA patients with the IL-6 -174 CC genotypes (39.1%), than in the GC/GG patients (18.5%) (OR 2.83; 95%CI=1.10-7.27; p=0.031). A good response was noticed in only one patient (4.3%) with the IL-6 -174 CC genotype, while it was present in 24.4% of GG/GC cases (p=0.06). By stepwise multivariate analysis (including RA duration, baseline DAS28, baseline HAQ, RF status, anti-CCP status and IL-6 genotype as covariates), the IL-6 -174CC genotype was selected as an independent predictor of no response to RTX by both EULAR and ACR≥50 criteria, while the IL-6R polymorphism resulted as not associated. No definite association between gene polymorphisms and IL-6 serum levels was noticed. Present results suggest a possible role for IL-6 genotyping to better plan treatment with RTX in RA, and larger studies are worthwhile.

B-lymphocyte homeostasis and BLyS-directed immunotherapy in transplantation

Current strategies for immunotherapy after transplantation are primarily T-lymphocyte directed and effectively abrogate acute rejection. However, the reality of chronic allograft rejection attests to the fact that transplantation tolerance remains an elusive goal. Donor-specific antibodies are considered the primary cause of chronic rejection. When naive, alloreactive B-cells encounter alloantigen and are activated, a resilient "sensitized" state, characterized by the presence of high-affinity antibody, is established. Here, we will delineate findings that support transient B-lymphocyte depletion therapy at the time of transplantation to preempt sensitization by eliminating alloreactive specificities from the recipient B-cell pool (ie, "repertoire remodeling"). Recent advances in our understanding of B-lymphocyte homeostasis provide novel targets for immunomodulation in transplantation. Specifically, the tumor necrosis factor-related cytokine BLyS is the dominant survival factor for "tolerance-susceptible" transitional and "preimmune" mature follicular B-cells. The transitional phenotype is the intermediate through which all newly formed B-cells pass before maturing into the follicular subset, which is responsible for mounting an alloantigen-specific antibody response. Systemic BLyS levels dictate the stringency of negative selection during peripheral B-cell repertoire development. Thus, targeting BLyS will likely provide an opportunity for repertoire-directed therapy to eliminate alloreactive B-cell specificities in transplant recipients, a requirement for the achievement of humoral tolerance and prevention of chronic rejection. In this review, the fundamentals of preimmune B-cell selection, homeostasis, and activation will be described. Furthermore, new and current B-lymphocyte-directed therapy for antibody-mediated rejection and the highly sensitized state will be discussed. Overall, our objective is to propose a rational approach for induction of humoral transplantation tolerance by remodeling the primary B-cell repertoire of the allograft recipient.

The late news on baff in autoimmune diseases

The B cell-activating factor of the tumor-necrosis factor family (BAFF) plays a dominant role in the B cell homeostasis. By rescuing autoreactive B cells, excessive BAFF favors the development of autoimmune diseases. Given the numbers of variants of this B cell-specific cytokine, caution must be exercized when determining its serum level. Alternate splice isoforms, such as Δ3 BAFF and Δ4 BAFF, have been identified. They raise the possibility that their overproduction impact the synthesis of full-length BAFF.

Secondary tumours in Sjögren's syndrome

The frequent association of Sjögren's syndrome (SS) with non-Hodgkin's B cell lymphoma (NHL) provides an example of the interplay of systemic autoimmunity and lymphoproliferative diseases, and an opportunity to study the pathogenetic steps of lymphomagenesis. NHL develops in approximately 5% of SS patients. Parotidomegaly, lymphadenopathy, inflammatory neuropathy and vasculitis have been found to be predictive of the development of lymphoma. A subsequent NHL is also heralded by the appearance of cryoglobulinaemia and serum or urinary monoclonal proteins. The typical histological type of NHL in SS is a low-grade extranodal marginal zone B cell lymphoma. The authors discuss the proposed key immunopathologic steps of lymphomagenesis in SS in detail. Recent results indicating the pathogenetic role of ectopic germinal centre formation in the involved exocrine glands, the potential importance of an antigen-driven clonal proliferation of autoreactive B-lymphocytes, the proposed role of the B-lymphocyte activating factor (BAFF) and of further cytokines and, finally, the changes of the chemokine milieu at the site of lymphoma development are highlighted.