Anti-CD20 mAb-Induced B Cell Apoptosis Generates T Cell Regulation of Experimental Myeloperoxidase ANCA-Associated Vasculitis

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.

Comparative pharmacoeconomic analysis of rituximab and traditional tacrolimus regimens in membranous nephropathy in China

Background: Rituximab (RTX) is a monoclonal antibody that selectively targets CD20 and is frequently used in the treatment of membranous nephropathy (MN). Analysis of the therapeutic efficacy and safety of RTX in treating MN in practice and a comparative pharmacoeconomic analysis of the RTX and traditional tacrolimus (TAC) regimens can provide valuable insights to aid decision-making by the government and relevant medical insurance departments. Methods: We conducted a statistical analysis of medical records from patients diagnosed with MN who underwent RTX treatment between 1 January 2019 and 1 January 2023. The TAC data were obtained from the clinical literature. The efficacy rates and incidence of adverse effects (AEs) were calculated to compare the efficacy and safety of RTX and TAC. Based on the patient's disease status, we developed a Markov model to compare the total cost, remission rate, and incremental cost-effectiveness ratio (ICER) of the two regimens. Both univariate and probability sensitivity analyses were performed to validate the stability of the developed model. Results: The RTX group enrolled 53 patients with MN, and the 12-month overall efficacy rate was not significantly different from that of the TAC group with 35 patients (86.79% vs. 71.4%, p = 0.0131); however, the relapse rate was significantly lower in the RTX group (3.77% vs. 22.8%, p = 0.016). The RTX group demonstrated no severe AEs (SAEs), while the TAC group demonstrated six cases of SAEs, including 4 cases of severe pneumonia, 1 case of lung abscess and 1 case of interstitial lung disease, accounting for 7.89% of traditional tacrolimus-treated patients. The baseline analysis results revealed that over a 5-year post-treatment period, RTX increased quality-adjusted life years (QALYs) by 0.058 and costs by ¥7,341. Assuming three times the 2022 domestic gross domestic product as the willingness-to-pay (WTP) threshold per QALY, the ICER of RTX compared to TAC was ¥124,631.14/QALY, which is less than the WTP threshold of ¥257,094/QALY, indicating that RTX treatment is approximately two times more cost-effective compared to TAC. Conclusion: The current analysis indicates that despite the expensive unit price of RTX, it remains a cost-effective treatment option for MN compared to TAC.

Animal models for anti-neutrophil cytoplasmic antibody-associated vasculitis: Are current models good enough?

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is a rare and severe systemic autoimmune disease characterized by pauci-immune necrotizing inflammation of small blood vessels. AAV involves multiple organ systems throughout the body. Our knowledge of the pathogenesis of AAV has increased considerably in recent years, involving cellular, molecular and genetic factors. Because of the controlled environment with no other confounding factors, animal models are beneficial for studying the mechanistic details of disease development and for providing novel therapeutic targets with fewer toxic side effects. However, the complexity and heterogeneity of AAV make it very difficult to establish a single animal model that can fully represent the entire clinical spectrum found in patients. The aim of this review is to overview the current status of animal models for AAV, outline the pros and cons of methods, and propose potential directions for future research.

Examining Myeloperoxidase (MPO) biomarker in the saliva of patients with Lactobacillus-associated caries in Hilla City

This study aimed to evaluate the levels of myeloperoxidase (MPO) biomarkers in the saliva of individuals with Lactobacillus spp.-related caries in Hilla City. A total of 115 samples were collected, including 90 (78.26%) from patients with severe dental caries and 25 (21.74%) from healthy subjects as a control group. The age range was between 20 and 45 years, with a mean age of 33.76±2.01 for patients with severe dental caries and 24.15±0.44 for healthy subjects. Female participants constituted the majority of the study sample, with 77 (85.5%) females and 13 (14.5%) males. Pathogenic bacteria were isolated and identified using gram staining, biochemical tests, and the VITEK 2 compact system. Of the 90 clinical samples, 65 (72.2%) showed positive bacterial culture, while 25 (27.7%) samples had no bacterial growth. Lactobacillus spp. accounted for 25/65 (38.4%) of the total isolates, making it the predominant etiological agent compared to other types of bacteria, constituting 40/65 (61.5%). There was a significant decrease (p≤0.05) in myeloperoxidase levels in patients with severe dental caries and positive Lactobacillus culture compared to the control group.

Research advances on targeted-Treg therapies on immune-mediated kidney diseases

The primary function of regulatory T cells (Tregs) is blocking the pathogenic immunological response mediated by autoreactive cells, establishing and maintaining immune homeostasis in tissues. Kidney diseases are often caused by Immune imbalance, including alloimmune graft damage after renal transplantation, direct immune-mediated kidney diseases like membranous nephropathy (MN) and anti-glomerular basement membrane (anti-GBM) glomerulonephritis, as well as indirect immune-mediated ones like Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAVs), IgA nephropathy (IgAN) and lupus nephritis (LN). Treg cells are deficient numerically and/or functionally in those kidney diseases. Targeted-Treg therapies, including adoptive Tregs transfer therapy and low-dose IL-2 therapy, have begun to thrive in treating autoimmune diseases in recent years. However, the clinical use of targeted Treg-therapies is rarely mentioned in those kidney diseases above except for kidney transplantation. This article mainly discusses the newest progressions of targeted-Treg therapies in those specific examples of immune-mediated kidney diseases. Meanwhile, we also reviewed the main factors that affect Treg development and differentiation, hoping to inspire new strategies to develop target Tregs-therapies. Lastly, we emphasize the significant impediments and prospects to the clinical translation of target-Treg therapy. We advocate for more preclinical and clinical studies on target Tregs-therapies to decipher Tregs in those diseases.

Regulatory T cells and systemic vasculitis

PURPOSE OF THE REVIEW

Emerging data suggest that regulatory T-cells (Treg) alterations play a major role in systemic vasculitis pathophysiology. We performed a systematic review of recent advances in the role of Treg and interleukin (IL)-10 in the pathogenesis and treatment of systemic vasculitis, including giant cell arteritis (GCA), Takayasu arteritis, Behçet's disease, antineutrophil cytoplasm antibodies (ANCA) associated vasculitis (AAV), and cryoglobulinemia associated vasculitis.

RECENT FINDINGS

Emerging data suggest that Treg deficiencies are disease-specific, affecting distinct pathways in distinct vasculitides. Decreased peripheral blood frequencies of Treg are described in all vasculitis when compared to healthy donors. Altered Treg functions are reported in GCA, Takayasu arteritis, AAV, and Behçet's disease with different mechanisms proposed. Treatment with biologics, and sometimes other immunosuppressants, may restore Treg frequencies and/or immune activity with significant differences in active disease or disease in remission in several systemic vasculitis. IL-10 is elevated in GCA, AAV, cryoglobulinemia associated vasculitis. In Behçet's disease, IL-10 is decreased in peripheral blood and elevated in saliva. In Takayasu arteritis, IL-10 levels were essentially elevated in patients' vessel wall. Several new therapeutic approaches targeting Treg and Il-10 (low dose IL-2, CAR Treg…) are developed to treat patients with systemic vasculitis.

SUMMARY

Treg and IL-10 play a central role in the regulation of inflammation in vasculitis and new targeting approaches are emerging.

The emerging role of regulatory cell-based therapy in autoimmune disease

Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

Old known and possible new biomarkers of ANCA-associated vasculitis

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders involving severe, systemic, small-vessel vasculitis with short- and long term serious and life-threating complications. Despite the simplification of treatment, fundamental aspects concerning assessment of its efficacy and its adaptation to encountered complications or to the relapsing/remitting/subclinical disease course remain still unknown. The pathogenesis of AAV is complex and unique, and despite the progress achieved in the last years, much has not to be learnt. Foremost, there is still no accurate marker enabling us to monitoring disease and guide therapy. Therefore, the disease management relays often on clinical judgment and follows a" trial and error approach". In the recent years, an increasing number of new molecules s have been explored and used for this purpose including genomics, B- and T-cell subpopulations, complement system factors, cytokines, metabolomics, biospectroscopy and components of our microbiome. The aim of this review is to discuss both the role of known historical and clinically established biomarkers of AAV, as well as to highlight potential new ones, which could be used for timely diagnosis and monitoring of this devastating disease, with the goal to improve the effectiveness and ameliorate the complications of its demanding therapy.

The frequency of Treg subsets distinguishes disease activity in ANCA vasculitis

Objectives

T regulatory cells (Tregs) are a heterogeneous group of immunoregulatory cells that dampen self-harming immune responses and prevent the development of autoimmune diseases. In anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis, Tregs possess diminished suppressive capacity, which has been attributed to the expression of a FOXP3 splice-variant lacking exon 2 in T cells (FOXP3Δ2 CD4+ T cells). However, the suppressive capacity of Tregs varies between subsets. We evaluated the frequency of Treg subsets in ANCA vasculitis as a potential explanation for diminished suppressive capacity.

Methods

We developed a custom mass cytometry panel and performed deep immune profiling of Tregs in healthy controls, patients with active disease and in remission. Using these data, we performed multidimensional reduction and discriminant analysis to identify associations between Treg subsets and disease activity.

Results

Total Tregs were expanded in ANCA vasculitis, which was associated with remission and the administration of rituximab and/or prednisone. The frequency of FOXP3Δ2 CD4+ T cells did not distinguish disease activity and this population had high expression levels of CD127 and lacked both CD25 and Helios, suggesting that they are not conventional Tregs. The frequency of CXCR3+, CD103+ and CCR7+ Tregs distinguished disease activity, and the combination of the frequency of these three Treg subsets segregated active patients from patients in remission and healthy controls. From these three subsets, the frequency of CXCR3+ Tregs distinguished patients with active disease with renal involvement.

Conclusion

Treg heterogeneity can discriminate disease activity and should be explored as a biomarker of disease activity in ANCA vasculitis.

Animal models of vasculitis

PURPOSE OF REVIEW

Vasculitis describes a wide spectrum of rare, inflammatory, multisystem disorders. These heterogenous diseases all have inflammation of blood vessels as a central feature. However, they differ in terms of their genetic and environmental risk factors, disease pathogenesis, clinical presentations and treatment strategies. Many animal models of vasculitis exist, each resembling a different human clinical phenotype. This review provides an overview of recently published findings from experimental animal models of vasculitis.

RECENT FINDINGS

Several new animal models have been described during the review period. New insights gleaned from existing animal models regarding cause, disease effector mechanisms and novel treatments identified in established animal models are discussed.

SUMMARY

Animal models continue to be an important tool for understanding disease pathogenesis, especially in rare and complex diseases such as vasculitis. They also provide an invaluable platform for development and preclinical testing of new treatments.

Avacopan for the treatment of ANCA-associated vasculitis

Introduction: Anti-neutrophil cytoplasm autoantibodies (ANCA)-associated vasculitides (AAVs) are a group of rare heterogeneous diseases characterized by blood vessel inflammation resulting in organ destruction and death. Although various treatment strategies have resulted in marked improvement in vasculitis-specific outcomes, many patients with AAV continue to suffer from complications related to the prolonged use of glucocorticoids (GC) such as infections, metabolic abnormalities, and increased cardiovascular morbidity. Recently, activation of the alternative complement pathway has been implicated in the augmentation of the damage caused by AAV via the complement C5a receptor (C5aR1, CD88). Specifically targeting this pathway may lead to improved outcomes in patients with AAV.Areas covered: In this article, we have summarized the rationale for targeting the complement pathway in AAV. The relevant pre-clinical, phase I, II and III findings with emphasis on the efficacy, and safety of avacopan, a new oral competitive inhibitor that interferes with the binding of C5a to C5aR1 (CD88), are reviewed.Expert opinion: These results are encouraging, may led to major changes in the treatment approach for AAV, and give rise to future studies utilizing complement inhibitors in AAV patients, and potentially in other immune mediated diseases.