Treatment with rituximab affects both the cellular and the humoral arm of the immune system in patients with SLE

Rituximab in the Treatment of Non-Infectious Uveitis: A Review

Non-infectious uveitis (NIU) is an immune-mediated disorder manifesting as ocular pain, redness, floaters, and photophobia, and is a leading cause of preventable blindness. Managing NIU presents considerable challenges due to the condition's resistance to high-dose corticosteroids and various immunotherapies. This review assesses the efficacy and safety of rituximab (RTX) in the treatment of NIU, based on individual case reports and small-scale studies. A cohort of 78 patients (20 males, 58 females), with a mean onset age of 32.3 years (range 8-72), was analyzed. Juvenile idiopathic arthritis (JIA) was the most frequently associated comorbidity, affecting 28 patients, while anterior uveitis was the predominant subtype, observed in 26 of 47 cases. Prior to RTX therapy, patients had been treated with an average of 1.7 conventional immunosuppressive agents (range 0-5) and 1.1 biologics (range 0-4). RTX was introduced following the failure of high-dose corticosteroids, immunosuppressive drugs, and biologics to control the uveitis. The median time from diagnosis to RTX initiation was 7.7 years (range 0.25-21). Post-RTX, 44.2% of patients experienced improvement in visual acuity, 79.5% achieved resolution of ocular inflammation, and 8.9% showed partial improvement. Additionally, 81.1% were able to reduce their corticosteroid dosage. Overall, 88.6% (69 out of 78) demonstrated a positive response to RTX treatment. These findings indicate that RTX may serve as an effective therapeutic option for NIU unresponsive to steroids and multiple immunotherapies. It may also warrant consideration as a potential first-line treatment in certain cases.

Dynamics of SARS-CoV-2 immunity after vaccination and breakthrough infection in rituximab-treated rheumatoid arthritis patients: a prospective cohort study

Background

SARS-CoV-2 vaccination in rheumatoid arthritis (RA) patients treated with B cell-depleting drugs induced limited seroconversion but robust cellular response. We aimed to document specific T and B cell immunity in response to vaccine booster doses and breakthrough infection (BTI).

Methods

We included 76 RA patients treated with rituximab who received up to four SARS-CoV-2 vaccine doses or three doses plus BTI, in addition to vaccinated healthy donors (HD) and control patients treated with tumor necrosis factor inhibitor (TNFi). We quantified anti-SARS-CoV-2 receptor-binding domain (RBD) Spike IgG, anti-nucleocapsid (NC) IgG, 92 circulating inflammatory proteins, Spike-binding B cells, and Spike-specific T cells along with comprehensive high-dimensional phenotyping and functional assays.

Findings

The time since the last rituximab infusion, persistent inflammation, and age were associated with the anti-SARS-CoV-2 RBD IgG seroconversion. The vaccine-elicited serological response was accompanied by an incomplete induction of peripheral Spike-specific memory B cells but occurred independently of T cell responses. Vaccine- and BTI-elicited cellular immunity was similar between RA and HD ex vivo in terms of frequency or phenotype of Spike-specific cytotoxic T cells and in vitro in terms of the functionality and differentiation profile of Spike-specific T cells.

Interpretation

SARS-CoV-2 vaccination in RA can induce persistent effector T-cell responses that are reactivated by BTI. Paused rituximab medication allowed serological responses after a booster dose (D4), especially in RA with lower inflammation, enabling efficient humoral and cellular immunity after BTI, and contributed overall to the development of potential durable immunity.

Targeting BMI-1 to deplete antibody-secreting cells in autoimmunity

Objectives

B cells drive the production of autoreactive antibody-secreting cells (ASCs) in autoimmune diseases such as Systemic Lupus Erythematosus (SLE) and Sjögren's syndrome, causing long-term organ damage. Current treatments for antibody-mediated autoimmune diseases target B cells or broadly suppress the immune system. However, pre-existing long-lived ASCs are often refractory to treatment, leaving a reservoir of autoreactive cells that continue to produce antibodies. Therefore, the development of novel treatment methods targeting ASCs is vital to improve patient outcomes. Our objective was to test whether targeting the epigenetic regulator BMI-1 could deplete ASCs in autoimmune conditions in vivo and in vitro.

Methods

Use of a BMI-1 inhibitor in both mouse and human autoimmune settings was investigated. Lyn -/- mice, a model of SLE, were treated with the BMI-1 small molecule inhibitor PTC-028, before assessment of ASCs, serum antibody and immune complexes. To examine human ASC survival, a novel human fibroblast-based assay was established, and the impact of PTC-028 on ASCs derived from Sjögren's syndrome patients was evaluated.

Results

BMI-1 inhibition significantly decreased splenic and bone marrow ASCs in Lyn -/- mice. The decline in ASCs was linked to aberrant cell cycle gene expression and led to a significant decrease in serum IgG3, immune complexes and anti-DNA IgG. PTC-028 was also efficacious in reducing ex vivo plasma cell survival from both Sjögren's syndrome patients and age-matched healthy donors.

Conclusion

These data provide evidence that inhibiting BMI-1 can deplete ASC in a variety of contexts and thus BMI-1 is a viable therapeutic target for antibody-mediated autoimmune diseases.

From systemic lupus erythematosus to lupus nephritis: The evolving road to targeted therapies

Systemic lupus erythematosus is a chronic autoimmune disease characterized by loss of tolerance against nuclear and cytoplasmic self-antigens, induction of immunity and tissue inflammation. Lupus nephritis (LN), the most important predictor of morbidity in SLE, develops in almost 30% of SLE patients at disease onset and in up to 50-60% within the first 10 years. Firstly, in this review, we put the pathogenic mechanisms of the disease into a conceptual frame, giving emphasis to the role of the innate immune system in this loss of self-tolerance and the induction of the adaptive immune response. In this aspect, many mechanisms have been described such as dysregulation and acceleration of cell-death pathways, an aberrant clearance and overload of immunogenic acid-nucleic-containing debris and IC, and the involvement of antigen-presenting cells and other innate immune cells in the induction of this adaptive immune response. This result in a clonal expansion of autoreactive lymphocytes with generation of effector T-cells, memory B-cells and plasma cells that produce autoantibodies that will cause kidney damage. Secondly, we review the immunological pathways of damage in the kidney parenchyma, initiated by autoantibody binding and immune complex deposition, and followed by complement-mediated microvascular injury, activation of kidney stromal cells and the recruitment of leukocytes. Finally, we summarize the rationale for the treatment of LN, from conventional to new targeted therapies, focusing on their systemic immunologic effects and the minimization of podocytary damage.

Expression patterns of T cells-specific long noncoding RNAs in systemic lupus erythematosus patients carrying HLA risk/nonrisk alleles

BACKGROUND

Long noncoding RNAs (LncRNAs) play key roles in the regulation of gene expression and subsequently in the pathogenesis of several autoimmune diseases. This study aimed to explore the peripheral expression levels of T-cells-specific LncRNAs and transcription factors in systemic lupus erythematosus (SLE) patients carrying either human leukocyte antigens (HLA) risk or non-risk alleles.

METHODS

Genotypes of HLA-DRB1 and HLA-DQB1 loci for 106 SLE patients were determined by PCR-SSP. In the next step, patients were stratified based on the presence of HLA-DRB1*03 and/or DRB1*16 allele groups (HLA risk alleles positive or HLA-RPos) or carrying other DRB1 allele groups (HLA-RNeg). Then, transcript levels of LncRNAs (IFNG-AS1, RMRP, Th2LCR, and DQ786243) and mRNAs for transcription factors (Foxp3, Gata3, and Tbx21) were measured using qRT-PCR and compared between two subgroups of patients.

RESULTS

Totally, 47 cases were classified as HLA-RPos and 59 cases as HLA-RNeg patients. The HLA-RPos patients showed decreased transcript levels of DQ786243 (p = .001) and elevated expression of IFNG-AS1 (p = .06) and T-bet mRNA (p = .03) compared to the HLA-RNeg group. We observed significantly lower expression of Th2LCR (p < .0001) and DQ786243 (p = .001) and higher expression of Tbx21 (p = .009) and Foxp3 (p = .02) in DR3-positive versus DR3-negative patients. Likewise, decreased transcript levels of DQ786243 (p = .02) and RMRP (p = .003) were observed in DR16-positive versus DR16-negative patients. ROC curve analysis revealed the potential of DQ786243 and RMRP as biomarkers in SLE disease based on the carriage of HLA risk alleles.

CONCLUSIONS

Our results indicate that the contribution of multiple T cell subsets in SLE disease progression as judged by expression analysis of LncRNAs and transcription factors can be inspired by the inheritance of HLA risk/nonrisk alleles is SLE patients.

Regulation of CD8 T cell by B-cells: A narrative review

Activation of CD4 T cells by B cells has been extensively studied, but B cell-regulated priming, proliferation, and survival of CD8 T cells remains controversial. B cells express high levels of MHC class I molecules and can potentially act as antigen-presenting cells (APCs) for CD8 T cells. Several in vivo studies in mice and humans demonstrate the role of B cells as modulators of CD8 T cell function in the context of viral infections, autoimmune diseases, cancer and allograft rejection. In addition, B-cell depletion therapies can lead to impaired CD8 T-cell responses. In this review, we attempt to answer 2 important questions: 1. the role of B cell antigen presentation and cytokine production in the regulation of CD8 T cell survival and cell fate determination, and 2. The role of B cells in the formation and maintenance of CD8 T cell memory.

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.

Advancing Biologic Therapy for Refractory Autoimmune Hepatitis

Biologic agents may satisfy an unmet clinical need for treatment of refractory autoimmune hepatitis. The goals of this review are to present the types and results of biologic therapy for refractory autoimmune hepatitis, indicate opportunities to improve and expand biologic treatment, and encourage comparative clinical trials. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Rituximab (monoclonal antibodies against CD20 on B cells), infliximab (monoclonal antibodies against tumor necrosis factor-alpha), low-dose recombinant interleukin 2 (regulatory T cell promoter), and belimumab (monoclonal antibodies against B cell activating factor) have induced laboratory improvement in small cohorts with refractory autoimmune hepatitis. Ianalumab (monoclonal antibodies against the receptor for B cell activating factor) is in clinical trial. These agents target critical pathogenic pathways, but they may also have serious side effects. Blockade of the B cell activating factor or its receptors may disrupt pivotal B and T cell responses, and recombinant interleukin 2 complexed with certain interleukin 2 antibodies may selectively expand the regulatory T cell population. A proliferation-inducing ligand that enhances T cell proliferation and survival is an unevaluated, potentially pivotal, therapeutic target. Fully human antibodies, expanded target options, improved targeting precision, more effective delivery systems, and biosimilar agents promise to improve efficacy, safety, and accessibility. In conclusion, biologic agents target key pathogenic pathways in autoimmune hepatitis, and early experiences in refractory disease encourage clarification of the preferred target, rigorous clinical trial, and comparative evaluations.

Off-Label Uses of Rituximab in Dermatology

Purpose of Review

Rituximab has transformed the treatment of B-cell malignancies and rheumatoid arthritis in the past 2 decades. More recently, this anti-CD20 monoclonal antibody has seen increasing usage in the field of dermatology. This review highlights the evidence supporting its use in several important dermatologic conditions.

Recent Findings

Key recent findings include the 2018 FDA approval of rituximab for the treatment of moderate-to-severe pemphigus.

Summary

Data from randomized controlled trials have demonstrated the efficacy of rituximab in pemphigus, ANCA-associated vasculitis, and cryoglobulinemic vasculitis. More limited data suggests its use in recalcitrant cases of diseases such as pemphigoid, epidermolysis bullosa acquisita, and dermatomyositis. There is scarce evidence and mixed results for rituximab when studied in cutaneous polyarteritis nodosa and cutaneous lupus erythematosus.

Combined therapy with CD4+ CD25highCD127- T regulatory cells and anti-CD20 antibody in recent-onset type 1 diabetes is superior to monotherapy: Randomized phase I/II trial

AIMS

Monotherapy with autologous expanded CD4⁺ CD25^high CD127^- T regulatory cells (Tregs) or rituximab has been documented to slow disease progression in patients with recent-onset type 1 diabetes mellitus (T1DM). Whether a combined therapy including both drugs would further benefit this patient population is unknown.

MATERIALS AND METHODS

We conducted a three-arms clinical trial to explore the efficacy and safety of the combined treatment with Tregs and rituximab in paediatric patients with T1DM. The patients were allocated to three groups: Tregs only (n = 13), Tregs + rituximab (n = 12) and control (n = 11). The key primary efficacy analyses were C-peptide levels (mixed meal tolerance test) and the proportion of patients in remission at 12 and 24 months.

RESULTS

At month 24, as compared with the control, both treatment groups remained superior in the area under the curve of C-peptide mixed meal tolerance test, whereas in the analysis of all visits only the combined therapy improved area under the curve at 12 and 24 months. The proportion of patients in remission was significantly higher in the combined group than in the control group at 3, 6, 9 and 21 months but not at 18 and 24 months. There was no significant difference between the Tregs only group and control group. Adverse events occurred in 80% patients, mostly in the combined group and Tregs only group. No adverse events led to the withdrawal of the intervention or death. All comparisons were performed with alpha level of 5%.

CONCLUSIONS

Over 2 years, combined therapy with Tregs and rituximab was consistently superior to monotherapy in delaying T1DM progression in terms of C-peptide levels and the maintenance of remission.

Antigen-Presenting B Cells Program the Efferent Lymph T Helper Cell Response

B cells interact with T follicular helper (Tfh) cells in germinal centers (GCs) to generate high-affinity antibodies. Much less is known about how cognate T–B-cell interactions influence Th cells that enter circulation and peripheral tissues. Therefore, we generated mice lacking MHC-II expressing B cells and, by thoracic duct cannulation, analyzed Th cells in the efferent lymph at defined intervals post-immunization. Focusing on gut-draining mesenteric lymph nodes (MLNs), we show that antigen-specific α₄β₇⁺ gut-homing effector Th cells enter the circulation prior to CXCR5⁺PD-1⁺ Tfh-like cells. B cells appear to have no or limited impact on the early generation and egress of gut-homing Th cells but are critical for the subsequent appearance of Tfh-like cells that peak in the lymph before GCs have developed. At this stage, antigen-presenting B cells also reduce the proportion of α₄β₇⁺ Th cells in the MLN and efferent lymph. Furthermore, cognate B-cell interaction drives a broad transcriptional program in Th cells, including IL-4 that is confined to the Tfh cell lineage. The IL-4-producing Tfh-like cells originate from Bcl6⁺ precursors in the LNs and have gut-homing capacity. Hence, B cells program the efferent lymph Th cell response within a limited window of time after antigenic challenge.

New Insights into the Treatment of Glomerular Diseases: When Mechanisms Become Vivid

Treatment for glomerular diseases has been extrapolated from the experience of other autoimmune disorders while the underlying pathogenic mechanisms were still not well understood. As the classification of glomerular diseases was based on patterns of juries instead of mechanisms, treatments were typically the art of try and error. With the advancement of molecular biology, the role of the immune agent in glomerular diseases is becoming more evident. The four-hit theory based on the discovery of gd-IgA1 gives a more transparent outline of the pathogenesis of IgA nephropathy (IgAN), and dysregulation of Treg plays a crucial role in the pathogenesis of minimal change disease (MCD). An epoch-making breakthrough is the discovery of PLA2R antibodies in the primary membranous nephropathy (pMN). This is the first biomarker applied for precision medicine in kidney disease. Understanding the immune system's role in glomerular diseases allows the use of various immunosuppressants or other novel treatments, such as complement inhibitors, to treat glomerular diseases more reasonable. In this era of advocating personalized medicine, it is inevitable to develop precision medicine with mechanism-based novel biomarkers and novel therapies in kidney disease.

B cell depletion treatment decreases Th17 cells in patients with rheumatoid arthritis

INTRODUCTION

We aimed to evaluate for any possible effects of treatment with rituximab (RTX) on the peripheral Th17 and Treg subpopulations in patients with rheumatoid arthritis (RA).

PATIENTS AND METHODS

We analyzed 16 patients with RA initiating RTX treatment, 11 patients with RA initiating abatacept treatment, 11 patients with RA treated with other medications, 8 patients with other autoimmune rheumatic diseases initiating RTX, and 14 healthy volunteers. Th17 cells (CD4⁺IL23R⁺IL17A⁺) and Treg cells (CD4⁺CD25^hiFoxP3⁺) were evaluated flow-cytometrically.

RESULTS

Th17 cells from patients treated with RTX decreased significantly at weeks 8 and 16 (mean ± SEΜ: 3.01% ± 0.54℅ CD4⁺ cells at week 0 vs. 1.53% ± 0.24℅ at week 8 vs 1.10% ± 0.20℅ at week 16, p = 0.0004). Reductions of Th17 cells were evident in clinical responders (DAS28 score ≤ 3.2), ACPA (+) and RF (-) patients; circulating Tregs remained stable. Th17 and Tregs were not affected by ABA treatment or by changes in disease activity. Tregs, but not Th17 cells, decreased following treatment with RTX in patients with other autoimmune diseases (0.75% ± 0.16% at week 0 vs. 0.43% ± 0.16% at week 8, p = 0.033).

CONCLUSION

RTX-induced B cell depletion results in a significant reduction of circulating Th17 cell percentages, whereas it has no effect on Tregs of patients with RA. This reduction of Th17 cells was evident particularly in responders to RTX treatment, ACPA+ and RF (-) patients with RA.

Clinical relevance of T follicular helper cells in systemic lupus erythematosus

INTRODUCTION

T helper cells regulate a variety of immune responses and are involved in the pathogenesis of infection, allergy and autoimmune diseases. T follicular helper (Tfh) cells, which induce B cell maturation, play an important role in the production of the extremely diverse autoantibodies found in systemic lupus erythematosus (SLE).

AREA COVERED

We provide an overview of the plasticity and diversity of Tfh cells in humans and their involvement in the pathology and pathogenesis of SLE. Our review outlines the potential of Tfh cells as a therapeutic target for SLE.

EXPERT OPINION

Tfh cells are involved in the pathogenesis of SLE based on their plasticity and diversity. Tfh cell differentiation and function are variably regulated by cytokines (IL-12, interferons, IL-2, etc), co-stimulatory molecules (ICOS, CD40L, OX40, etc), and intracellular signals (JAK-STAT, etc). Elucidation of the mechanisms underlying Tfh cell differentiation and function may lead to the development of new therapies for SLE.

B-cell Deficiency Attenuates Transplant Glomerulopathy in a Rat Model of Chronic Active Antibody-mediated Rejection

BACKGROUND

Transplant glomerulopathy (TG) is a pathological feature of chronic active antibody-mediated rejection (cAMR) and is associated with renal allograft failure. The specific role of B cells in the pathogenesis of TG is unclear.

METHODS

We used a minor mismatched rat kidney transplant model with B cell-deficient recipients, generated by clustered regularly interspaced short palindromic repeats/Cas9 technology, to investigate the impact of B-cell depletion on the pathogenesis of TG. We hypothesized that B-cell deficiency would prevent TG in the rat kidney transplant model of cAMR. Treatment groups included syngeneic, allogeneic, sensitized allogeneic, and B cell-deficient allogeneic transplant recipients.

RESULTS

B cell-deficient recipients demonstrated reduced TG lesions, decreased microvascular inflammation, reduced allograft infiltrating macrophages, and reduced interferon gamma transcripts within the allograft. Allograft transcript levels of interferon gamma, monocyte chemoattractant protein-1, and interleukin-1β correlated with numbers of intragraft macrophages. B cell-deficient recipients lacked circulating donor-specific antibodies and had an increased splenic regulatory T-cell population.

CONCLUSIONS

In this model of cAMR, B-cell depletion attenuated the development of TG with effects on T cell and innate immunity.

Anti-CD20 therapy corrects a CD8 regulatory T cell deficit in multiple sclerosis

OBJECTIVE

To determine the effect of long-term anti-CD20 B-cell-depleting treatment on regulatory T cell immune subsets that are subnormal in untreated MS patients.

METHODS

30 clinically stable MS patients, before and over 38 months of ocrelizumab treatment, were compared to 13 healthy controls, 29 therapy-naïve MS, 9 interferon-β-treated MS, 3 rituximab-treated MS, and 3 rituximab-treated patients with other autoimmune inflammatory diseases. CD8, CD28, CD4, and FOXP3 expression in peripheral blood mononuclear cells was quantitated with flow cytometry.

RESULTS

CD8⁺ CD28^- regulatory cells rose from one-third of healthy control levels before ocrelizumab treatment (2.68% vs 7.98%), normalized by 12 months (13.5%), and rose to 2.4-fold above healthy controls after 18 months of ocrelizumab therapy (19.0%). CD4⁺ FOXP3⁺ regulatory cells were lower in MS than in healthy controls (7.98%) and showed slight long-term decreases with ocrelizumab. CD8⁺ CD28^- and CD4⁺ FOXP3⁺ regulatory T cell percentages in IFN-β-treated MS patients were between those of untreated MS and healthy controls.

INTERPRETATION

Long-term treatment with ocrelizumab markedly enriches CD8⁺ CD28^- regulatory T cells and corrects the low levels seen in MS before treatment, while slightly decreasing CD4⁺ FOXP3+ regulatory T cells. Homeostatic enrichment of regulatory CD8 T cells provides a mechanism, in addition to B cell depletion, for the benefits of anti-CD20 treatment in MS.

A Retrospective Analysis of Rituximab Treatment for B Cell Depletion in Different Pediatric Indications

Background: Rituximab (RTX) is used in cancer therapy as well as in the treatment of autoimmune diseases and alloimmune responses after transplantation. It depletes the disease-causing B cells by binding to the CD (cluster of differentiation) 20 antigen. We evaluate different pediatric treatment protocols (via fixed treatment schedule, B cell- or symptom-controlled) and their therapeutic effects. Methods: Demographic information, clinical and laboratory characteristics, and special laboratory values such as immunoglobulin G (IgG), CD19 positive B cells and Epstein-Barr viral load were retrospectively analyzed in children treated with RTX between 2008 and 2016. Results: Seventy-six patients aged 1 to 19 (median 13) years were treated with 259 RTX infusions. The spectrum of diseases was very heterogeneous. RTX led to a complete depletion of the B cells. The reconstitution time varied between patients and was dependent on the application schedule (median 11.8 months). Fourteen out of 27 (52%) patients developed hypogammaglobulinaemia. The risk of IgG deficiency was 2.6 times higher in children under 4 years of age than in olderones. In the last group IgG deficiency developed in only 38% of the cases (n = 8). Recurrent and severe infections were observed each in 11/72 (15%) patients. Treatment-related reactions occurred in 24/76 (32%) cases; however, treatment had to be discontinued in only 1 case. In 16/25 (76%), the Epstein-Barr viral load dropped below the detection limit after the first RTX infusion. Conclusion: RTX is an effective and well-tolerated drug for the treatment of oncological diseases as well as autoimmune and alloimmune conditions in children. B cell depletion and reconstitution varies both intra- und interindividually, suggesting that symptom-oriented and B cell-controlled therapy may be favorable. Treatment-related reactions, IgG deficiency and infections must be taken into account.

COVID-19: Infection or Autoimmunity

The clinical and laboratory features of COVID-19 are reviewed with attention to the immunologic manifestations of the disease. Recent COVID-19 publications describe a variety of clinical presentations including an asymptomatic state, pneumonia, a hemophagocytic lymphohistiocytosis like syndrome, Multisystem Inflammatory Syndrome in Children (MIS-C) but, also called Pediatric Inflammatory Multisystem Syndrome-Toxic Shock (PIMS-TS), Kawasaki Disease, and myocarditis. A common theme amongst multiple reports suggests an overexuberant autoimmune component of the disease but a common pathophysiology to explain the variations in clinical presentation has been elusive. Review of the basic science of other viral induced autoimmune disorders may give clues as to why immunosuppressive and immunomodulating regimens now appear to have some efficacy in COVID-19. Review of the immunopathology also reveals other therapies that have yet to be explored. There is potential use of T cell depleting therapies and possibly anti-CD20 therapy for COVID-19 and clinical research using these medications is warranted.

Are lupus animal models useful for understanding and developing new therapies for human SLE?

Systemic lupus erythematosus is a systemic autoimmune disease driven by a complex combination of genetic, environmental, and other immunoregulatory factors. The development of targeted therapies is complicated by heterogeneous clinical manifestations, varying organ involvement, and toxicity. Despite advances in understanding the mechanisms contributing to SLE, only one biologic drug, belimumab, is FDA-approved. The identification and development of potential therapies have largely been driven by studies in lupus animal models. Therefore, direct comparison of both the therapeutic and immunological findings in human and murine SLE studies is critical and can reveal important insights into indeed how useful and relevant are murine studies in SLE drug development. Studies involving belimumab, mycophenolate mofetil, abatacept, rituximab, and anti-interferon strategies generally demonstrated analogous findings in the attenuation of SLE manifestations and modulation of select immune cell populations in human and murine SLE. While further basic and translational studies are needed to identify SLE patient subsets likely to respond to particular therapeutic modalities and in dissecting complex mechanisms, we believe that despite some inherent weaknesses SLE mouse models will continue to be integral in developing targeted SLE therapies.

B-cell oligoclonal expansions in renal tissue of patients with immune-mediated glomerular disease

B-cell clonal expansion has been sporadically described in the blood and/or renal tissue of patients with glomerulonephritides, albeit with unclear pathogenetic role. Herein, using spectratyping analysis, we observed oligoclonal intrarenal B-cell populations in 59% of glomerulonephritis patients with podocyte injury (6/7 with focal segmental glomerulosclerosis, 1/3 minimal change disease, 1/3 idiopathic membranous nephropathy, 3/4 IgA nephropathy, 2/5 membranous lupus nephritis), 20% of glomerulonephritis patients without podocyte involvement (4/13 with mesangial or proliferative lupus nephritis, 0/3 idiopathic membranoproliferative glomerulonephritis, 0/4 pauci-immune vasculitis) and 17% of control patients with renal cancer. In multivariate analysis, oligoclonal B-cells were associated with podocyte injury and the grade of glomerulosclerosis (both p = .009). B-cell oligoclonal expansions were not found in the paired peripheral blood samples. We postulate that B-cell expansion in the kidney results from local stimuli, including antigens expressed on podocytes. Further studies to unravel the role of oligoclonal B-cells in (auto)immune-mediated kidney disease are warranted.

Mechanistic Paradigms of Natural Plant Metabolites as Remedial Candidates for Systemic Lupus Erythromatosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder involving a dysregulated immune response which ultimately leads to multiple organ failure. Several immunological and cellular checkpoints are available as drug targets. However, the available chemosynthetic drugs such as non-steroidal anti-inflammatory drugs and corticosteroids provide limited therapy with extreme toxicities. Moreover, the disease heterogeneity in SLE is very difficult to manage by a single drug component. Hence, it is imperative to utilize the holistic capabilities of natural plant products as immunomodulators and intracellular signaling regulators, thereby providing an auxiliary option of treatment. Additionally, the herbal drugs also serve as symptomatic relief providers, thereby serving as a prophylactic remedy in case of cerebrovascular, hepatic, nephropathological, hematological, cardiopulmonary, mucocutaneous and musculoskeletal manifestations of SLE. The present review attempts to showcase the current state of knowledge regarding the utility of plant-derived phyto-metabolites with their probable mechanistic roles in treating SLE, by means of targeting the signaling cascade, proinflammatory cytokine production and B-T cell co-stimulation. It is hoped that further preclinical and clinical studies will be embarked upon in order to understand the underlying therapeutic and mechanistic aspects of these medicinal herbs.

Pathogenic memory plasma cells in autoimmunity

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Memory plasma cells are long-lived but require specialized niches for their survival.

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Memory plasma cells are refractory to conventional immunosuppression.

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Pathogenic memory plasma cells represent ‘roadblocks’ to response to conventional therapy.

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Strategies for (selective) targeting of memory plasma cells are in preclinical and clinical tests.

Role of anti-DNA auto-antibodies as biomarkers of response to treatment in systemic lupus erythematosus patients: hypes and hopes. Insights and implications from a comprehensive review of the literature

Introduction: Due to the polymorphic clinical presentations and manifestations of systemic lupus erythematosus (SLE), biomarkers with enough diagnostic and prognostic value are of paramount importance. Recently, anti-double stranded DNA (anti-dsDNA) auto-antibodies have been proposed to monitor the response to different therapies. It has also been suggested that they should be employed as entry markers in trial studies. However, their clinical use remains still debated and, sometimes, controversial, due to conflicting findings reported. Areas covered: Through an extensive literature review, we evaluated changes in anti-dsDNA auto-antibodies levels before and after the administration of the treatment (either biological or non-biological). Expert opinion: Anti-dsDNA auto-antibodies related findings are still difficult to compare mainly because of the different detecting methods employed, even though in most studies included in this review a consistent decreasing pattern after the treatment seems to emerge. Hence, if properly standardized, anti-dsDNA auto-antibody profile may be a reliable biomarker to monitor the effectiveness of biologics as well as of non-biological drugs, especially if grouped in composite outcomes scores, such as the 'Lupus Multivariable Outcome Score' (LUMOS) or measured with other biomarkers, such as anti-nucleosome auto-antibodies. We recommend the assessment of anti-dsDNA auto-antibodies levels in both daily practice and research settings.

Therapies for multiple sclerosis targeting B cells

Increasing evidence suggests that B cells contribute both to the regulation of normal autoimmunity and to the pathogenesis of immune mediated diseases, including multiple sclerosis (MS). B cells in MS are skewed toward a pro-inflammatory profile, and contribute to MS pathogenesis by antibody production, antigen presentation, T cells stimulation and activation, driving autoproliferation of brain-homing autoreactive CD4+ T cells, production of pro-inflammatory cytokines, and formation of ectopic meningeal germinal centers that drive cortical pathology and contribute to neurological disability. The recent interest in the key role of B cells in MS has been evoked by the profound anti-inflammatory effects of rituximab, a chimeric monoclonal antibody (mAb) targeting the B cell surface marker CD20, observed in relapsing-remitting MS. This has been reaffirmed by clinical trials with less immunogenic and more potent B cell-depleting mAbs targeting CD20 – ocrelizumab, ofatumumab and ublituximab. Ocrelizumab is also the first disease-modifying drug that has shown efficacy in primary-progressive MS, and is currently approved for both indications. Another promising approach is the inhibition of Bruton's tyrosine kinase, a key enzyme that mediates B cell activation and survival, by agents such as evobrutinib. On the other hand, targeting B cell cytokines with the fusion protein atacicept increased MS activity, highlighting the complex and not fully understood role of B cells and humoral immunity in MS. Finally, all other approved therapies for MS, some of which have been designed to target T cells, have some effects on the frequency, phenotype, or homing of B cells, which may contribute to their therapeutic activity.

Role of Multivalency and Antigenic Threshold in Generating Protective Antibody Responses

Vaccines play a vital role in protecting our communities against infectious disease. Unfortunately, some vaccines provide only partial protection or in some cases vaccine-mediated immunity may wane rapidly, resulting in either increased susceptibility to that disease or a requirement for more booster vaccinations in order to maintain immunity above a protective level. The durability of antibody responses after infection or vaccination appears to be intrinsically determined by the structural biology of the antigen, with multivalent protein antigens often providing more long-lived immunity than monovalent antigens. This forms the basis for the Imprinted Lifespan model describing the differential survival of long-lived plasma cell populations. There are, however, exceptions to this rule with examples of highly attenuated live virus vaccines that are rapidly cleared and elicit only short-lived immunity despite the expression of multivalent surface epitopes. These exceptions have led to the concept that multivalency alone may not reliably determine the duration of protective humoral immune responses unless a minimum number of long-lived plasma cells are generated by reaching an appropriate antigenic threshold of B cell stimulation. Examples of long-term and in some cases, potentially lifelong antibody responses following immunization against human papilloma virus (HPV), Japanese encephalitis virus (JEV), Hepatitis B virus (HBV), and Hepatitis A virus (HAV) provide several lessons in understanding durable serological memory in human subjects. Moreover, studies involving influenza vaccination provide the unique opportunity to compare the durability of hemagglutinin (HA)-specific antibody titers mounted in response to antigenically repetitive whole virus (i.e., multivalent HA), or detergent-disrupted “split” virus, in comparison to the long-term immune responses induced by natural influenza infection. Here, we discuss the underlying mechanisms that may be associated with the induction of protective immunity by long-lived plasma cells and their importance in future vaccine design.

Therapies for multiple sclerosis targeting B cells

Increasing evidence suggests that B cells contribute both to the regulation of normal autoimmunity and to the pathogenesis of immune mediated diseases, including multiple sclerosis (MS). B cells in MS are skewed toward a pro-inflammatory profile, and contribute to MS pathogenesis by antibody production, antigen presentation, T cells stimulation and activation, driving autoproliferation of brain-homing autoreactive CD4+ T cells, production of pro-inflammatory cytokines, and formation of ectopic meningeal germinal centers that drive cortical pathology and contribute to neurological disability. The recent interest in the key role of B cells in MS has been evoked by the profound anti-inflammatory effects of rituximab, a chimeric monoclonal antibody (mAb) targeting the B cell surface marker CD20, observed in relapsing-remitting MS. This has been reaffirmed by clinical trials with less immunogenic and more potent B cell-depleting mAbs targeting CD20 - ocrelizumab, ofatumumab and ublituximab. Ocrelizumab is also the first disease-modifying drug that has shown efficacy in primary-progressive MS, and is currently approved for both indications. Another promising approach is the inhibition of Bruton's tyrosine kinase, a key enzyme that mediates B cell activation and survival, by agents such as evobrutinib. On the other hand, targeting B cell cytokines with the fusion protein atacicept increased MS activity, highlighting the complex and not fully understood role of B cells and humoral immunity in MS. Finally, all other approved therapies for MS, some of which have been designed to target T cells, have some effects on the frequency, phenotype, or homing of B cells, which may contribute to their therapeutic activity.

Dampening of CD8+ T Cell Response by B Cell Depletion Therapy in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

To compare the effects of rituximab (RTX) and conventional immunosuppressants (CIs) on CD4+ T cells, Treg cells, and CD8+ T cells in antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

A thorough immunophenotype analysis of CD4+, Treg, and CD8+ cells from 51 patients with AAV was performed. The production of cytokines and chemokines by CD8+ T cells stimulated in vitro was assessed using a multiplex immunoassay. The impact of AAV B cells on CD8+ T cell response was assessed using autologous and heterologous cocultures.

RESULTS

CD4+ and Treg cell subsets were comparable among RTX-treated and CI-treated patients. In contrast, within the CD8+ T cell compartment, RTX, but not CIS, reduced CD45RA+CCR7- (TEMRA) cell frequency (from a median of 39% before RTX treatment to 10% after RTX treatment [P < 0.01]) and efficiently dampened cytokine/chemokine production (e.g., the median macrophage inflammatory protein 1α level was 815 pg/ml in patients treated with RTX versus 985 pg/ml in patients treated with CIs versus 970 pg/ml in those with active untreated AAV [P < 0.01]). CD8+ T cell subsets cocultured with autologous B cells produced more proinflammatory cytokines in AAV patients than in controls (e.g., for tumor necrosis factor-producing effector memory CD8+ T cells: 14% in AAV patients versus 9.2% in controls [P < 0.05]). In vitro disruption of AAV B cell-CD8+ T cell cross-talk reduced CD8+ T cell cytokine production, mirroring the reduced CD8+ response observed ex vivo after RTX treatment.

CONCLUSION

The disruption of a pathogenic B cell/CD8+ T cell axis may contribute to the efficacy of RTX in AAV. Further studies are needed to determine the value of CD8+ T cell immunomonitoring in B cell-targeted therapies.

B-Cell Therapies in Multiple Sclerosis

B cells play a vital function in multiple sclerosis (MS) pathogenesis through an array of effector functions. All currently approved MS disease-modifying therapies alter the frequency, phenotype, or homing of B cells in one way or another. The importance of this mechanism of action has been reinforced with the successful development and clinical testing of B-cell-depleting monoclonal antibodies that target the CD20 surface antigen. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, was approved by the Food and Drug Administration (FDA) in March 2017 after pivotal trials showed dramatic reductions in inflammatory disease activity in relapsing MS as well as lessening of disability progression in primary progressive MS. These and other clinical studies place B cells at the center of the inflammatory cascade in MS and provide a launching point for development of therapies that target selective pathogenic B-cell populations.

Lymphocytes as Biomarkers of Therapeutic Response in Rheumatic Autoimmune Diseases, Is It a Realistic Goal?

Many therapies are available for patients with rheumatoid arthritis (RA) while biological therapies have limited effects in patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS). In both cases, biomarkers predicting drug response would be very useful to guide clinicians in their choice. We performed a systematic review to evaluate the value of lymphocyte phenotyping as a marker of therapeutic response. Of the 1063 articles retrieved, 39 fulfilled inclusion criteria and were included in the present review (25 for RA, 10 for SLE, and 4 for pSS). Lymphocyte phenotyping was described as a biomarker of therapeutic response in many studies, but most results could not be confirmed by independent teams using multivariate analysis. The most consistent result might be the association between rituximab response and the levels of memory B cells before therapy, although some studies were controversial. Thus, lymphocyte phenotyping cannot yet be proposed as a biomarker of response in rheumatic autoimmune diseases. The lack of reproducibility between studies may be explained by technical issues influencing lymphocyte phenotyping so standardization procedures should be developed for future studies. The patients' characteristics vary between studies, and large population studies, including a wide range of patients' characteristics and biomarkers, are required to provide predictive models for clinical outcomes. The use of new flow cytometry techniques such as single-cell mass cytometry technology might also help finder reliable biomarkers in the future.

Peripheral CD4+ T-cell changes in connective tissue diseases

Connective tissue diseases (CTDs) are all characterized by changes in the adaptive immune system. In the last few decades several CD4 + T lymphocytes and their products have been associated with the development, progression, organ involvement, or therapeutic response of different CTDs. The T helper (Th) T-cell subsets are easy to measure in the peripheral blood, however changes are difficult to interpret. This review summarizes data about Th1/Th2/Th17 and regulatory T-cell (Treg) changes in the most common CTDs. Concordance and divergence of data might help in the better understanding of the common processes of these different systemic autoimmune disorders and might give future clues for differences in disease behavior and treatment response.

Immunological memories of the bone marrow

Memory for antigens once encountered is a hallmark of the immune system of vertebrates, providing us with an immunity adapted to pathogens of our environment. Despite its fundamental relevance, the cells and genes representing immunological memory are still poorly understood. Here we discuss the concept of a circulating, proliferating, and ubiquitous population of effector lymphocytes vs concepts of resting and dormant populations of dedicated memory lymphocytes, distinct from effector lymphocytes and residing in defined tissues, particularly in barrier tissues and in the bone marrow. The lifestyle of memory plasma cells of the bone marrow may serve as a paradigm, showing that persistence of memory lymphocytes is not defined by intrinsic "half-lives", but rather conditional on distinct survival signals provided by dedicated niches. These niches are organized by individual mesenchymal stromal cells. They define the capacity of immunological memory and regulate its homeostasis.

B cell-based therapies in CNS autoimmunity: differentiating CD19 and CD20 as therapeutic targets

Increasing recognition of the role of B cells in the adaptive immune response makes B cells an important therapeutic target in autoimmunity. Numerous current and developmental immunotherapies target B cells for elimination through recognition of cell-surface proteins expressed specifically on B cells, in particular CD19 and CD20. Similarities and differences in the function and expression of these two molecules predict some shared, and some distinct, pharmacological effects of agents targeting CD19 versus CD20, potentially leading to differences in the clinical safety and efficacy of such agents. Here, we review current knowledge of CD19 and CD20 function and biology, survey current and developmental therapies that target these molecules, and discuss potential differences in elimination of B cells by drugs that target CD19 versus CD20, with particular focus on the central nervous system autoimmune diseases multiple sclerosis and neuromyelitis optica. The principles and mechanisms herein discussed might also be relevant to a variety of other nervous system autoimmune disorders, including NMDA (N-methyl-D-aspartate) receptor encephalitis, transverse myelitis and myasthenia gravis.

Analysis of FOXP3+ regulatory T cell subpopulations in peripheral blood and tissue of patients with systemic lupus erythematosus

Regulatory T cells (Tregs) are critical mediators of immune tolerance, yet their involvement in the autoimmune disease systemic lupus erythematosus (SLE) is incompletely understood. We analyzed CD4⁺ T cell subpopulations with Treg-related phenotypes and their association with disease activity in peripheral blood (PB) and tissues of patients with SLE. In detail, we quantified subpopulations regarding CD25, FOXP3, CD62L, CCR6, CD27, CD45RA, and CD45RO expression in PB from 31 patients with SLE divided into two disease activity groups and 32 healthy controls using flow cytometry. CD4⁺ and FOXP3⁺ T cells in skin and kidney biopsies of patients with SLE were quantified by immunohistochemistry. CD4⁺CD25^+/++FOXP3⁺ and CD4⁺CD25⁺CD45RA^-/CD45RO⁺ T cell frequencies were significantly higher in PB from patients with active compared to inactive SLE. The fraction of CD4⁺CD25⁺⁺FOXP3⁺ Tregs and CD4⁺CD25⁺CD45RA⁺/CD45RO^- naïve Tregs was not significantly different between these groups. CD4⁺CD25⁺⁺ Tregs from active SLE patients comprised significantly less CD27⁺ cells and more CCR6⁺ cells compared to patients with inactive SLE. The percentage of CD4⁺FOXP3⁺ T cells among inflammatory infiltrates in skin and kidney biopsies of SLE patients was not different from other inflammatory skin/kidney diseases. In conclusion, although CD4⁺FOXP3⁺ T cell frequencies in the inflamed tissues of SLE patients were comparable to other inflammatory diseases, distinct T cell subpopulations appeared misbalanced in PB of patients with active SLE. Here, cells phenotypically resembling activated T cells, but not Tregs, were increased compared to patients with inactive SLE. Within Tregs of patients with active SLE, markers related to Treg function and homing were altered.

Acquired thrombotic thrombocytopenic purpura

The von Willebrand factor (VWF)-cleaving metalloprotease, ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 motifs-13) is the only known target of the dysregulated immune response in acquired TTP. Autoantibodies to ADAMTS13 either neutralize its activity or accelerate its clearance, thereby causing a severe deficiency of ADAMTS13 in plasma. As a consequence, size regulation of VWF is impaired and the persistence of ultra-large VWF (ULVWF) multimers facilitates micro vascular platelet aggregation causing microangiopathic haemolytic anaemia and ischaemic organ damage. Autoimmune TTP although a rare disease with an annual incidence of 1.72 cases has a mortality rate of 20% even with adequate therapy.

We describe the mechanisms involved in ADAMTS13 autoimmunity with a focus on the role of B- and T-cells in the pathogenesis of this disorder. We discuss the potential translation of recent experimental findings into future therapeutic concepts for the treatment of acquired TTP.

B-cell Therapy for Multiple Sclerosis: Entering an era

Monoclonal antibodies that target CD20 expressing B cells represent an important new treatment option for patients with multiple sclerosis (MS). B-cell-depleting therapy is highly effective against relapsing forms of the disease and is also the first treatment approach proven to protect against disability worsening in primary progressive MS. Moreover, evolving clinical experience with B-cell therapy, combined with a more sophisticated understanding of humoral immunity in preclinical models and in patients with MS, has led to major progress in deciphering the immune pathogenesis of MS. Here, we review the nuanced roles of B cells in MS autoimmunity, the clinical data supporting use of ocrelizumab and other anti-CD20 therapies in the treatment of MS, as well as safety and practical considerations for prescribing. Last, we summarize remaining unanswered questions regarding the proper role of anti-CD20 therapy in MS, its limitations, and the future landscape of B-cell-based approaches to treatment. Ann Neurol 2018;83:13-26.

Plasma cell survival in the absence of B cell memory

Pre-existing serum antibodies play an important role in vaccine-mediated protection against infection but the underlying mechanisms of immune memory are unclear. Clinical studies indicate that antigen-specific antibody responses can be maintained for many years, leading to theories that reactivation/differentiation of memory B cells into plasma cells is required to sustain long-term antibody production. Here, we present a decade-long study in which we demonstrate site-specific survival of bone marrow-derived plasma cells and durable antibody responses to multiple virus and vaccine antigens in rhesus macaques for years after sustained memory B cell depletion. Moreover, BrdU⁺ cells with plasma cell morphology can be detected for 10 years after vaccination/BrdU administration, indicating that plasma cells may persist for a prolonged period of time in the absence of cell division. On the basis of these results, long-lived plasma cells represent a key cell population responsible for long-term antibody production and serological memory.

The long-term maintenance of antibody-secreting plasma cells and the requirement for memory B cells are unclear. Here, the authors show that plasma cells and the antibodies secreted are long-lived and maintained over a decade in the absence of memory B cells in non-human primates.

Regulatory T Cells in SLE: Biology and Use in Treatment

T regulatory cells (Tregs) represent a phenotypically and functionally heterogeneous group of lymphocytes that exert immunosuppressive activities on effector immune responses. Tregs play a key role in maintaining immune tolerance and homeostasis through diverse mechanisms which involve interactions with components of both the innate and adaptive immune systems. As in many autoimmune diseases, Tregs have been proposed to play a relevant role in the pathogenesis of systemic lupus erythematosus (SLE), an autoimmune disease characterized by a progressive breakdown of tolerance to self-antigens and the presence of concomitant hyperactive immune responses. Here, we review how Tregs dysfunction in SLE has been manipulated experimentally and preclinically in the attempt to restore, at last in part, the immune disturbances in the disease.

Rituximab in Minimal Change Disease: Mechanisms of Action and Hypotheses for Future Studies

Treatment with rituximab, a monoclonal antibody against the B-lymphocyte surface protein CD20, leads to the depletion of B cells. Recently, rituximab was reported to effectively prevent relapses of glucocorticoid-dependent or frequently relapsing minimal change disease (MCD). MCD is thought to be T-cell mediated; how rituximab controls MCD is not understood. In this review, we summarize key clinical studies demonstrating the efficacy of rituximab in idiopathic nephrotic syndrome, mainly MCD. We then discuss immunological features of this disease and potential mechanisms of action of rituximab in its treatment based on what is known about the therapeutic action of rituximab in other immune-mediated disorders. We believe that studies aimed at understanding the mechanisms of action of rituximab in MCD will provide a novel approach to resolve the elusive immune pathophysiology of MCD.

Kinetic analysis of changes in T- and B-lymphocytes after anti-CD20 treatment in renal pathology

INTRODUCTION

The main objective of this study is to describe qualitatively and quantitatively the different immune lymphocyte phenotypes of patients with renal disease after treatment with anti-CD20.

MATERIAL AND METHODS

Two cohorts of transplanted and autoimmune kidney patients were compared: (1) Those who began treatment with Rituximab, matched (for sex, age and general clinical parameters) with (2) Non-treated control kidney patients. Different analyses were performed: (A) B-lymphocyte subpopulations; (B) T-cell subpopulations; (C) serum levels of BAFF, APRIL, Rituximab and anti-Rituximab; (D) rs396991 polymorphism of CD16a and at different time points for each type of analysis: (i) at baseline, (ii) day 15, (iii) at three and (iv) six months post-antiCD20.

RESULTS

(A) A depletion of all B cell subsets analysed was observed preferentially decreasing the CD40⁺memory B-cells, switched memory cells and plasmablasts. (B) A significant decreased percentage of CD4⁺T-lymphocytes was observed. A significant decrease of the percentage of memory T-cells and an increase in naïve T-cells was also observed. (C) A significant increase for APRIL was observed, as well as a positive correlation between the APRIL levels, and the differential of B-cells. (D) The presence of CD16a Valine-variant induced greater changes in the variations of total T-cell and T-naïve subpopulations.

CONCLUSION

Our results highlight that the treatment of renal disease with Rituximab affects T-cells, particularly naïve/memory balance, while APRIL could be also a secondary marker of this treatment. The sequential analysis of phenotypic alterations of B- and T-cells could help patient management, although further studies to identify periods of remission or clinical relapse are warranted.

Roles of Regulatory T and B Cells in IgG4-Related Disease

Immunoglobulin G4 (IgG4) -related disease (RD) is a newly recognized systemic disease. Although there are several forms of IgG4-RD reported under various names, depending on the target organ and characteristics, patients with IgG4-RD manifest several immunologic and histologic abnormalities including increased levels of serum IgG4 and storiform fibrosis with infiltration of lymphocytes and IgG4-positive plasmacytes in the involved organs. However, the pathophysiology remains unclear. Regulatory immune cells play an important role in several immune-related diseases. In particular, abnormalities in regulatory T cell (Treg) and regulatory B cell (Breg) numbers and function are implicated in several immune-related (include autoimmune) conditions, and their roles in IgG4-RD have recently begun to be investigated. We provide an overview of the research conducted to date on Tregs and Bregs in IgG4-RD. We highlight the basic functions of these cells, their changes in patients with various forms of IgG4-RD, and insight gained from animal models of the disease. Based on the evidence accumulated thus far, we proposed a hypothesis for the pathophysiological mechanism of IgG4-RD with respect to the roles regulatory immune cells, and highlight the questions and venues of research deserving of further attenuation, Over all, we demonstrate that Tregs and Bregs have a clear impact on IgG4-RD, and further exploration of this field is expected to lead to a better mechanistic understanding of the disease, hopefully resulting in the in the discovery of new therapeutic targets.

Impact of Immune-Modulatory Drugs on Regulatory T Cell

Immunosuppression strategies that selectively inhibit effector T cells while preserving and even enhancing CD4FOXP3 regulatory T cells (Treg) permit immune self-regulation and may allow minimization of immunosuppression and associated toxicities. Many immunosuppressive drugs were developed before the identity and function of Treg were appreciated. A good understanding of the interactions between Treg and immunosuppressive agents will be valuable to the effective design of more tolerable immunosuppression regimens. This review will discuss preclinical and clinical evidence regarding the influence of current and emerging immunosuppressive drugs on Treg homeostasis, stability, and function as a guideline for the selection and development of Treg-friendly immunosuppressive regimens.

T Lymphocyte Activation Markers as Predictors of Responsiveness to Rituximab among Patients with FSGS

BACKGROUND AND OBJECTIVES

Rituximab is used with variable success in difficult FSGS. Because B cell depletion significantly affects T cell function, we characterized T cell subsets in patients with FSGS to determine if an immunologic signature predictive of favorable response to rituximab could be identified.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty-two consecutive patients with FSGS (median age =14.4 years old; range =6.2-25.0 years old) and age of onset of nephrotic syndrome 1-18 years old receiving rituximab for clinical indications between October of 2009 and February of 2014 were studied. Indications for rituximab were lack of sustained remission despite calcineurin inhibitors (CNIs) and mycophenolate in steroid-resistant patients and lack of steroid-sparing effect with cyclophosphamide and CNI or CNI toxicity in steroid-dependent patients. Exclusion criteria were infantile onset, known genetic mutations, and secondary causes. Rituximab (375 mg/m(2)) was given fortnightly up to a maximum of four doses. Immunologic subset monitoring was performed at baseline and regular intervals until relapse. Median follow-up duration postrituximab was 26.7 months (range =6.5-66.5 months). Baseline immunologic subsets were examined for association with rituximab response defined as resolution of proteinuria with discontinuation of prednisolone and CNI 3 months postrituximab.

RESULTS

Twelve patients (54.5%) responded to rituximab. Mitogen-stimulated CD154(+)CD4(+)CD3(+) subset before rituximab was significantly lower in FSGS responders compared with nonresponders (54.9%±28.1% versus 78.9%±16.4%; P=0.03). IFN-γ(+)CD3(+) and IL-2(+)CD3(+) were similarly decreased in responders compared with nonresponders (0.6%±0.8% versus 7.5%±6.1%; P=0.003 and 0.2%±0.5% versus 4.0%±4.7%; P<0.01, respectively). Recovery of all three activation subsets occurred 6 months postrituximab treatment (CD154(+)CD4(+)CD3(+), 74.8%±17.2%; IFN-γ(+)CD3(+), 7.1%±7.7%; and IL-2(+)CD3(+), 7.9%±10.9%; P<0.01). Receiver-operating characteristic analysis using optimal cutoff values showed that activated CD154(+)CD4(+)CD3(+) <83.3% (area under the curve [AUC], 0.81; 95% confidence interval [95% CI], 0.61 to 1.00), IFN-γ(+)CD3(+)<2.5% (AUC, 0.90; 95% CI, 0.75 to 1.00), and IL-2(+)CD3(+)<0.3% (AUC, 0.78; 95% CI, 0.57 to 0.98) were good predictors of rituximab response.

CONCLUSIONS

We have identified prognostic markers that define a subset of patients with FSGS bearing an immunologic signature representing hyporesponsiveness to T cell stimulation and therefore, who respond better to rituximab.