B cell biomarkers of rituximab responses in systemic lupus erythematosus

Disruption of memory B-cell trafficking by belimumab in patients with systemic lupus erythematosus

OBJECTIVES

Autoreactive memory B cells (MBCs) contribute to chronic and progressive courses in autoimmune diseases like SLE. The efficacy of belimumab (BEL), the first approved biologic treatment for SLE and LN, is generally attributed to depletion of activated naïve B cells and inhibition of B-cell activation. BEL's effect on MBCs is currently unexplained. We performed an in-depth cellular and transcriptomic analysis of BEL's impact on the blood MBC compartment in patients with SLE.

METHODS

A retrospective meta-analysis was conducted, pooling flow cytometry data from four randomized trials involving 1245 patients with SLE treated with intravenous BEL or placebo. Then, extensive MBC phenotyping was performed using high-sensitivity flow cytometry in patients with mild/moderate SLE and severe SLE/LN treated with subcutaneous BEL. Finally, transcriptomic characterization of surging MBCs was performed by single-cell RNA sequencing.

RESULTS

In BEL-treated patients, a significant increase in circulating MBCs, in a broad range of MBC subsets, was established at week 2, gradually returning to baseline by week 52. The increase was most prominent in patients with higher SLE disease activity, serologically active patients and patients aged ≤18 years. MBCs had a non-proliferating phenotype with a prominent decrease in activation status and downregulation of numerous migration genes.

CONCLUSION

Upon BEL initiation, an increase of MBCs was firmly established. In the small cohort investigated, circulating MBCs were de-activated, non-proliferative and demonstrated characteristics of disrupted lymphocyte trafficking, expanding on our understanding of the therapeutic mechanism of B-cell-activating factor inhibition by BEL.

TRIAL REGISTRATION

ClinicalTrials.gov, http://clinicaltrials.gov, NCT00071487, NCT00410384, NCT01632241, NCT01649765, NCT03312907, NCT03747159.

Sustained depression of B cell counts in lupus nephritis after treatment with rituximab and/or belimumab is associated with fewer disease flares

OBJECTIVE

To study the risk of lupus nephritis flare (LNF) or severe lupus flare (SLF) as a function of B cell count kinetics in lupus nephritis (LN) patients after they achieve at least a partial renal response (PRR) with induction treatment that includes rituximab (RTX) and/or belimumab (BLM).

METHODS

We performed a retrospective analysis of a cohort of 19 patients with severe LN that received a B cell agent (BCA), RTX and/or BLM, as part of an initial treatment regimen for an LN flare and had subsequent CD19+ B cell measurements in peripheral blood. We then characterized the follow-up periods, after B cell depressions occurred and PRR were achieved, by the corresponding trajectories of B cell counts (BCC). Time periods with sustained low BCC were type 1 (T1) episodes, while those with repletion of BCC>100 cells/μL were called type 2 (T2) episodes. Time periods with rapid BCC repletion, defined as >50 cells/μL in ≤6 months, were called T2b episodes. Corresponding C3, C4, and anti-dsDNA levels were recorded for each episode. The time from PRR until an event, either a LNF or SLF, or to censoring, either at the end of the study period or the end of available patient follow-up, was assessed for each episode type. Kaplan-Meier survival analysis was used to compare time to flare between T1 and T2 episodes.

RESULTS

There were 26 episodes of B cell depression. Seventeen (65%) were T1 and 9 (35%) were T2. Compared to T1 episodes, T2 episodes were 9.0 times more likely to result in flare over the follow-up period (hazard ratio (HR) = 9.0, 95% CI for HR = 2.2-36.7); this risk was even larger for T2b vs T1 episodes. Median BCC was 14 cells/μL in T1 and 160 cells/μL in T2 episodes. Both C3 and C4 levels significantly increased over the duration of the episode in T1 episodes only.

CONCLUSION

Sustained low BCC was associated with prolonged serologic and clinical response, whereas repletion, and particularly rapid repletion, of B cells after treatment with BCA was associated with subsequent disease flare.

Anti-B-Cell-Activating Factor (BAFF) Therapy: A Novel Addition to Autoimmune Disease Management and Potential for Immunomodulatory Therapy in Warm Autoimmune Hemolytic Anemia

Although rituximab is not specifically approved for the treatment of warm autoimmune hemolytic anemia (WAIHA), the First International Consensus Group recommends considering its use as part of the initial therapy for patients with severe disease and as a second-line therapy for primary WAIHA. Some patients do not respond to rituximab, and relapses are common. These relapses are associated with elevated B-cell-activating factor (BAFF) levels and the presence of quiescent long-lived plasma cells (LLPCs) in the spleen. A new group of immunomodulatory drugs, B-cell-activating factor inhibitors (BAFF-i), demonstrated efficacy in multiple autoimmune diseases and have the potential to improve WAIHA treatment outcomes by targeting B-cells and LLPCs. This article reviews the role of BAFF in autoimmune disorders and the currently available literature on the use of BAFF-directed therapies in various immunologic disorders, including WAIHA. Collectively, the clinical data thus far shows robust potential for targeting BAFF in WAIHA therapy.

European flow cytometry quality assurance guidelines for the diagnosis of primary immune deficiencies and assessment of immune reconstitution following B cell depletion therapies and transplantation

Over the last 15 years activity of diagnostic flow cytometry services have evolved from monitoring of CD4 T cell subsets in HIV-1 infection to screening for primary and secondary immune deficiencies syndromes and assessment of immune constitution following B cell depleting therapy and transplantation. Changes in laboratory activity in high income countries have been driven by initiation of anti-retroviral therapy (ART) in HIV-1 regardless of CD4 T cell counts, increasing recognition of primary immune deficiency syndromes and the wider application of B cell depleting therapy and transplantation in clinical practice. Laboratories should use their experience in standardization and quality assurance of CD4 T cell counting in HIV-1 infection to provide immune monitoring services to patients with primary and secondary immune deficiencies. Assessment of immune reconstitution post B cell depleting agents and transplantation can also draw on the expertise acquired by flow cytometry laboratories for detection of CD34 stem cell and assessment of MRD in hematological malignancies. This guideline provides recommendations for clinical laboratories on providing flow cytometry services in screening for immune deficiencies and its emerging role immune reconstitution after B cell targeting therapies and transplantation.

Combined rituximab and belimumab to treat recalcitrant epidermolysis bullosa aquisita associated with systemic lupus erythematosus

We report two cases of recalcitrant epidermolysis bullosa aquisita with associated systemic lupus erythematosus treated with combination rituximab and belimumab therapy. This resulted in the complete resolution of cutaneous lesions and a partial response of the mucosal lesions. These cases support the use of combined rituximab and belimumab for the treatment of recalcitrant immunobullous disease.

Disrupting B and T-cell collaboration in autoimmune disease: T-cell engagers versus CAR T-cell therapy?

B and T cells collaborate to drive autoimmune disease (AID). Historically, B- and T-cell (B-T cell) co-interaction was targeted through different pathways such as alemtuzumab, abatacept, and dapirolizumab with variable impact on B-cell depletion (BCD), whereas the majority of patients with AID including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and organ transplantation benefit from targeted BCD with anti-CD20 monoclonal antibodies such as rituximab, ocrelizumab, or ofatumumab. Refractory AID is a significant problem for patients with incomplete BCD with a greater frequency of IgD-CD27+ switched memory B cells, CD19+CD20- B cells, and plasma cells that are not directly targeted by anti-CD20 antibodies, whereas most lymphoid tissue plasma cells express CD19. Furthermore, B-T-cell collaboration is predominant in lymphoid tissues and at sites of inflammation such as the joint and kidney, where BCD may be inefficient, due to limited access to key effector cells. In the treatment of cancer, chimeric antigen receptor (CAR) T-cell therapy and T-cell engagers (TCE) that recruit T cells to induce B-cell cytotoxicity have delivered promising results for anti-CD19 CAR T-cell therapies, the CD19 TCE blinatumomab and CD20 TCE such as mosunetuzumab, glofitamab, or epcoritamab. Limited evidence suggests that anti-CD19 CAR T-cell therapy may be effective in managing refractory AID whereas we await evaluation of TCE for use in non-oncological indications. Therefore, here, we discuss the potential mechanistic advantages of novel therapies that rely on T cells as effector cells to disrupt B-T-cell collaboration toward overcoming rituximab-resistant AID.

B-cell depletion in autoimmune diseases

B cells have a pivotal function in the pathogenesis of autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. In autoimmune disease, B cells orchestrate antigen presentation, cytokine production and autoantibody production, the latter via their differentiation into antibody-secreting plasmablasts and plasma cells. This article addresses the current therapeutic strategies to deplete B cells in order to ameliorate or potentially even cure autoimmune disease. It addresses the main target antigens in the B-cell lineage that are used for therapeutic approaches. Furthermore, it summarises the current evidence for successful treatment of autoimmune disease with monoclonal antibodies targeting B cells and the limitations and challenges of these approaches. Finally, the concept of deep B-cell depletion and immunological reset by chimeric antigen receptor T cells is discussed, as well as the lessons from this approach for better understanding the role of B cells in autoimmune disease.

A Phase 1, randomized, double-blind, placebo-controlled, single- and multiple-dose escalation study to evaluate the safety and pharmacokinetics/pharmacodynamics of PF-06835375, a C-X-C chemokine receptor type 5 directed antibody, in patients with systemic lupus erythematosus or rheumatoid arthritis

BACKGROUND

The objective of this study was to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of PF‑06835375, a potent selective afucosyl immunoglobulin G1 antibody targeting C-X-C chemokine receptor type 5 (CXCR5) that potentially depletes B cells, follicular T helper (Tfh) cells, and circulating Tfh-like (cTfh) cells, in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

METHODS

This first-in-human, multicenter, double-blind, sponsor-open, placebo-controlled Phase 1 study recruited patients aged 18-70 years with SLE or RA. In Part A, patients received single doses of intravenous PF-06835375 (dose range: 0.03-6 mg) or placebo in six sequential single ascending dose (SAD) cohorts. In Part B, patients received repeat doses of subcutaneous PF-06835375 (dose range: 0.3-10 mg) or placebo on Days 1 and 29 in five multiple ascending dose (MAD) cohorts. Tetanus/Diphtheria (Td) and Meningococcal B (MenB/Trumenba™) vaccines were administered at Day 4 (Td and MenB) and Week 8 (MenB only) to assess PF-06835375 functional effects. Endpoints included treatment-emergent adverse events (TEAEs), pharmacokinetic parameters, pharmacodynamic effects on B and cTfh cells, and biomarker counts, vaccine response, and exploratory differential gene expression analysis. Safety, pharmacokinetic, and pharmacodynamic endpoints are summarized descriptively. The change from baseline of B and Tfh cell-specific genes over time was calculated using a prespecified mixed-effects model, with a false discovery rate < 0.05 considered statistically significant.

RESULTS

In total, 73 patients were treated (SAD cohorts: SLE, n = 17; RA, n = 14; MAD cohorts: SLE, n = 22; RA, n = 20). Mean age was 53.3 years. Sixty-two (84.9%) patients experienced TEAEs (placebo n = 17; PF-06835375 n = 45); most were mild or moderate. Three (9.7%) patients experienced serious adverse events. Mean t1/2 ranged from 3.4-121.4 h (SAD cohorts) and 162.0-234.0 h (MAD cohorts, Day 29). B and cTfh cell counts generally showed dose-dependent reductions across cohorts (range of mean maximum depletion: 67.3-99.3%/62.4-98.7% [SAD] and 91.1-99.6%/89.5-98.1% [MAD], respectively). B cell-related genes and pathways were significantly downregulated in patients treated with PF-06835375.

CONCLUSIONS

These data support further development of PF-06835375 to assess the clinical potential for B and Tfh cell depletion as a treatment for autoimmune diseases.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03334851.

Rituximab as an effective add-on maintenance therapy for disease activities in childhood-onset systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease that can result in high morbidity if not treated. This retrospective study aimed to evaluate the outcomes of rituximab treatment in a paediatric SLE cohort in Taiwan.

METHODS

The medical records of paediatric patients diagnosed with SLE at the National Taiwan University Hospital between January 1992 and August 2022 who received rituximab as maintenance therapy between January 2015 and August 2022 were retrospectively reviewed. To enhance our analysis, we included a contemporary comparison group, matching in case number and demographic characteristics. This study aimed to describe the indications, efficacy and safety of rituximab in the treatment of paediatric SLE and to analyse the factors associated with disease outcomes.

RESULTS

The study included 40 rituximab-treated patients with a median age of 14.3 years at the time of disease diagnosis. In the rituximab-treated cohort, the median score on the Systemic Lupus Erythematosus Disease Activity Index 2000 decreased from 8 before rituximab administration to 4 after 2 years. The levels of C3 and C4 increased and anti-double stranded DNA (anti-dsDNA) levels decreased significantly within 6 months. The equivalent oral prednisolone dose halved after 6 months. Finally, 8 (20%) patients achieved disease control and 35 (87.5%) patients had no flare-ups during the follow-up period (median, 2 years). Those patients who achieved disease control had a significantly shorter interval between diagnosis and rituximab administration. In terms of adverse effects, only one patient developed hypogammaglobulinaemia that required intravenous immunoglobulin (IVIG) replacement. Compared with the comparison group (n=53), the rituximab-treated cohort exhibited superior disease outcomes and a reduced incidence of flare-ups.

CONCLUSIONS

This study provides real-world data and illuminates rituximab's role in maintaining disease stability among patients with paediatric-onset SLE who are serologically active without major clinical deterioration. Most importantly, no mortality or development of end-stage renal disease was observed in the rituximab-treated cohort.

B cell subsets-related biomarkers and molecular pathways for systemic lupus erythematosus by transcriptomics analyses

BACKGROUND

Systemic lupus erythematosus (SLE), an autoimmune disease, is characterised by B-cell abnormalities and a loss of tolerance that can produce autoantibody. However, the imperative genes and molecular pathways involved in the change of B cell populations remain unclear.

METHODS

The expression of B cell subsets between SLE and healthy controls (HCs) was detected based on micro-array transcriptome data. The Weighted Gene Co-Expression Network Analysis (WGCNA) further revealed the co-expression modules of naïve and memory B cells. Whereafter, we performed the functional enrichment analysis, Protein-protein interaction (PPI) networks construction and feature selection to screen hub genes. Ultimately, we recruited SLE patients and HCs from the Second Hospital of Shanxi Medical University and further verified these genes in transcriptome sequencing samples.

RESULTS

Total of 1087 SLE patients and 86 HCs constituted in the study. Compared to HCs, the levels of peripheral naïve B cells of SLE patients decreased, while memory B cells increased. WGCNA identified two modules with the highest correlation for the subsequent analysis. The purple module was primarily in connection with naïve B cells, and the GO analysis indicated that these genes were mainly abundant in B cell activation. The blue module relevant to memory B cells was most significantly enriched in the "defence response to virus" correlation pathway. Then we screened six hub genes by PPI and feature selection. Finally, four biomarkers (IFI27, IFITM1, MX2, IRF7) were identified by transcriptome sequencing verification.

CONCLUSION

Our study identified hub genes and key pathways associated with the naïve and memory B cells respectively, which may offer novel insights into the behaviours of B cells and the pathogenesis of SLE.

The predictive and prognostic value of peripheral blood antigen-specific memory B cells in phospholipase A2 receptor-associated membranous nephropathy

Background

Phospholipase A2 receptor-associated membranous nephropathy (PLA2R-MN) is an anti-PLA2R antibody (PLA2R-Ab) mediated autoimmune kidney disease. Although antibody titer correlates closely with disease activity, whether it can provide longer-term predictions on disease course and progression is unclear. Rituximab, a B-cell depletion therapy, has become the first-line treatment option for PLA2R-MN; however, the response to Rituximab varies among patients.

Methods

We developed a flow cytometry-based test that detects and quantifies PLA2R antigen-specific memory B cells (PLA2R-MBCs) in peripheral blood, the primary source for PLA2R-Ab production upon disease relapse. We applied the test to 159 blood samples collected from 28 patients with PLA2R-MN (at diagnosis, during and after immunosuppressive treatment, immunological remission, and relapse) to evaluate the relationship between circulating PLA2R-MBC levels and disease activity.

Results

The level of PLA2R-MBCs in healthy controls (n=56) is less than or equal to 1.5% of the total MBC compartment. High circulating PLA2R-MBC levels were detected in two patients post-Rituximab despite achieving immunologic and proteinuric remission, as well as in two patients with negative serum autoantibody but increasing proteinuria. Elimination of these cells with Rituximab improved clinical outcomes. Moreover, five patients exhibited elevated PLA2R-MBC levels before disease relapse, followed by a rapid decline to baseline when relapse became clinically evident. COVID-19 vaccination or SARS-CoV-2 infection significantly affected the dynamics of circulating PLA2R-MBCs.

Conclusions

This study suggests that monitoring PLA2R-MBC levels in patients with PLA2R-MN may help refine and individualize immunosuppressive therapy and predict disease course and progression. The technology and findings may also have broader applications in the clinical management of other autoimmune diseases.

A nondepleting anti-CD19 antibody impairs B cell function and inhibits autoimmune diseases

B cells contribute to multiple aspects of autoimmune disorders, and B cell-targeting therapies, including B cell depletion, have been proven to be efficacious in treatment of multiple autoimmune diseases. However, the development of novel therapies targeting B cells with higher efficacy and a nondepleting mechanism of action is highly desirable. Here we describe a nondepleting, high-affinity anti-human CD19 antibody LY3541860 that exhibits potent B cell inhibitory activities. LY3541860 inhibits B cell activation, proliferation, and differentiation of primary human B cells with high potency. LY3541860 also inhibits human B cell activities in vivo in humanized mice. Similarly, our potent anti-mCD19 antibody also demonstrates improved efficacy over CD20 B cell depletion therapy in multiple B cell-dependent autoimmune disease models. Our data indicate that anti-CD19 antibody is a highly potent B cell inhibitor that may have potential to demonstrate improved efficacy over currently available B cell-targeting therapies in treatment of autoimmune conditions without causing B cell depletion.

Off-label use of rituximab in patients with systemic lupus erythematosus with extrarenal disease activity: a retrospective study and literature review

Introduction

Off-label rituximab is commonly used for patients with systemic lupus erythematosus (SLE) with extrarenal disease activity.

Methods

The outcomes and tolerability of rituximab in adult patients with non-renal SLE treated at our hospital from 2013 to 2020 were described. Patients were followed-up until December 2021. Data were retrieved from electronic medical records. Response was classified into complete, partial or no response according to the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI 2 K)-based definitions.

Results

A total of 44 cycles were administered to 33 patients. Median age was 45 years and 97% were female. Median follow-up was 5.9 years (IQR 3.7-7.2). The most frequent symptoms that motivated rituximab use were thrombocytopenia (30.3%), arthritis (30.3%), neurological manifestations (24.2%) and cutaneous lupus (15.2%). After most treatment cycles a partial remission was achieved. The median SLEDAI-2 K score declined from 9 (IQR 5-13) to 1.5 (IQR 0-4) (p < 0.00001). The median number of flares significantly declined after receiving rituximab. Platelet counts significantly improved in patients with thrombocytopenia and patients with skin disorders or neurological manifestations also had a partial or complete response. Only 50% of patients with a predominant joint involvement had either a complete or a partial response. The median time to relapse after the first cycle was 1.6 years (95% CI, 0.6-3.1). Anti-dsDNA levels decreased significantly after rituximab from a median of 64.3 (IQR 12-373.9) to 32.7 (IQR 10-173), p = 0.00338. The most frequent adverse events were infusion-related reactions (18.2%) and infections (57.6%). All patients needed further treatment to maintain remission or to treat new flares.

Conclusion

A partial or complete response was documented after most rituximab cycles in patients with non-renal SLE. Patients with thrombocytopenia, neurolupus, and cutaneous lupus had better response than those with a predominant joint involvement.

Anti-CD20 monoclonal antibody (mAb) therapy and colitis: A case series and review

The US Food and Drug Administration (FDA) recently issued a warning regarding ocrelizumab due to reports of colitis among patients taking this medication. Since it is the only FDA-approved therapy for primary progressive multiple sclerosis (PPMS), further research on this adverse event is necessary, and healthcare professionals should be informed of potential treatment options. In this review, we summarize the available data on the incidence of inflammatory colitis associated with anti-CD20 monoclonal antibodies (mAbs), such as ocrelizumab and rituximab, used in MS treatment. Although the exact pathophysiology of anti-CD20-induced colitis remains unknown, immunological dysregulation through treatment-mediated B-cell depletion has been proposed as a possible mechanism. Our study highlights the importance of clinicians being aware of this potential side effect, and patients taking these medications should be closely monitored for any new-onset gastrointestinal symptoms or diarrheal illness. Research indicates that prompt intervention with endoscopic examination and medical or surgical therapies can ensure timely and effective management, thus improving patient outcomes. However, large-scale studies are still needed to determine the associated risk factors and to establish definitive guidelines for the clinical evaluation of MS patients on anti-CD20 medications.

Gene Expression and Autoantibody Analysis Revealing Distinct Ancestry-Specific Profiles Associated With Response to Rituximab in Refractory Systemic Lupus Erythematosus

OBJECTIVE

Gene expression profiles are associated with the clinical heterogeneity of systemic lupus erythematosus (SLE) but are not well studied as biomarkers for therapy. We studied gene expression and response to rituximab in a multiethnic UK cohort who were refractory to standard therapy.

METHODS

We evaluated baseline expression levels of transcripts known to associate with clinical features of SLE using a 96-probe TaqMan array and whole blood samples from 213 patients with active SLE who had been prospectively enrolled in the British Isles Lupus Assessment Group (BILAG) Biologics Register. We measured autoantibodies using immunoprecipitation and enzyme-linked immunosorbent assays. We determined responses to first-cycle rituximab at 6 months from treatment start in 110 SLE patients by assessing BILAG 2004 disease activity.

RESULTS

Interferon gene expression scores were lower in patients of European ancestry than in all other ancestry groups. The relationship between blood interferon gene expression scores and scores annotated to plasmablasts, neutrophils, myeloid lineage, inflammation, and erythropoiesis differed between patients of European and non-European ancestries. Hierarchical clustering revealed 3 distinct non-European ancestry patient subsets with stratified responses to rituximab that were not explained by sociodemographic and clinical variables, with responses lowest in an interferon-low, neutrophil-high cluster and highest in a cluster with high expression levels across all signatures (P < 0.001). Clusters in European ancestry patients did not predict response to rituximab but segregated patients by global disease activity and renal involvement. In both ancestral groups, interferon-high clusters were associated with U1 RNP/Sm antibodies.

CONCLUSION

Ancestry appears central to the immunologic and clinical heterogeneity in SLE. These results suggest that ancestry, disease activity, and transcriptional signatures could each assist in predicting the effectiveness of B cell depletion therapies.

UBE2L3 regulates TLR7-induced B cell autoreactivity in Systemic Lupus Erythematosus

Both TLR7 and NF-κB hyperactivity are known to contribute to pathogenesis in Systemic Lupus Erythematosus (SLE), driving a pro-interferon response, autoreactive B cell expansion and autoantibody production. UBE2L3 is an SLE susceptibility gene which drives plasmablast/plasma cell expansion in SLE, but its role in TLR7 signalling has not been elucidated. We aimed to investigate the role of UBE2L3 in TLR7-mediated NF-κB activation, and the effect of UBE2L3 inhibition by Dimethyl Fumarate (DMF) on SLE B cell differentiation in vitro. Our data demonstrate that UBE2L3 is critical for activation of NF-κB downstream of TLR7 stimulation, via interaction with LUBAC. DMF, which directly inhibits UBE2L3, significantly inhibited TLR7-induced NF-κB activation, differentiation of memory B cells and plasmablasts, and autoantibody secretion in SLE. DMF also downregulated interferon signature genes and plasma cell transcriptional programmes. These results demonstrate that UBE2L3 inhibition could potentially be used as a therapy in SLE through repurposing of DMF, thus preventing TLR7-driven autoreactive B cell maturation.

CARs: a new approach for the treatment of autoimmune diseases

The development of chimeric antigen receptor (CAR)-based therapeutic interventions represented a breakthrough in cancer treatment. Following the success of the CAR-T-cell strategy, this novel therapeutic approach has been applied to other diseases, including autoimmune diseases. Using CAR-T cells to deplete pathological immune cells (i.e., B cells, autoreactive B or T cells, and accessory antigen-presenting cells (APCs)) has resulted in favorable outcomes in diseases characterized by excessive autoantibody levels or hyperactive lymphocyte cell numbers. The importance of immunosuppressive regulatory T cells (Tregs) in restoring immune tolerance has been well established, and CAR-Tregs have shown promising therapeutic potential in treating autoimmune diseases. Moreover, prior experience from the cancer field has provided sufficient paradigms for understanding how to optimize the structure and function of CARs to improve their function, persistence, stability and safety. In this review, we describe the potential application of CAR-T cells and CAR-Tregs in the treatment of autoimmune diseases, and we summarize the currently available strategies of gene editing and synthetic biological tools that have improved the practical application of CAR-based therapies.

Comprehensive genetic and functional analyses of Fc gamma receptors influence on response to rituximab therapy for autoimmunity

BACKGROUND

Rituximab is widely used to treat autoimmunity but clinical response varies. Efficacy is determined by the efficiency of B-cell depletion, which may depend on various Fc gamma receptor (FcγR)-dependent mechanisms. Study of FcγR is challenging due to the complexity of the FCGR genetic locus. We sought to assess the effect of FCGR variants on clinical response, B-cell depletion and NK-cell-mediated killing in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).

METHODS

A longitudinal cohort study was conducted in 835 patients [RA = 573; SLE = 262]. Clinical outcome measures were two-component disease activity score in 28-joints (2C-DAS28CRP) for RA and British Isles Lupus Assessment Group (BILAG)-2004 major clinical response (MCR) for SLE at 6 months. B-cells were evaluated by highly-sensitive flow cytometry. Single nucleotide polymorphism and copy number variation for genes encoding five FcγRs were measured using multiplex ligation-dependent probe amplification. Ex vivo studies assessed NK-cell antibody-dependent cellular cytotoxicity (ADCC) and FcγR expression.

FINDINGS

In RA, carriage of FCGR3A-158V and increased FCGR3A-158V copies were associated with greater 2C-DAS28CRP response (adjusted for baseline 2C-DAS28CRP). In SLE, MCR was associated with increased FCGR3A-158V, OR 1.64 (95% CI 1.12-2.41) and FCGR2C-ORF OR 1.93 (95% CI 1.09-3.40) copies. 236/413 (57%) patients with B-cell data achieved complete depletion. Homozygosity for FCGR3A-158V and increased FCGR3A-158V copies were associated with complete depletion in combined analyses. FCGR3A genotype was associated with rituximab-induced ADCC, and increased NK-cell FcγRIIIa expression was associated with improved clinical response and depletion in vivo. Furthermore, disease status and concomitant therapies impacted both NK-cell FcγRIIIa expression and ADCC.

INTERPRETATION

FcγRIIIa is the major low affinity FcγR associated with rituximab response. Increased copies of the FCGR3A-158V allele (higher affinity for IgG1), influences clinical and biological responses to rituximab in autoimmunity. Enhancing FcγR-effector functions could improve the next generation of CD20-depleting therapies and genotyping may stratify patients for optimal treatment protocols.

FUNDING

Medical Research Council, National Institute for Health and Care Research, Versus Arthritis.

Efficacy and safety of obinutuzumab in systemic lupus erythematosus patients with secondary non-response to rituximab

OBJECTIVES

Secondary inefficacy with infusion reactions and anti-drug antibodies (secondary non-depletion nonresponse, 2NDNR) occurs in 14% of SLE patients receiving repeated rituximab courses. We evaluated baseline clinical characteristics, efficacy and safety of obinutuzumab, a next-generation humanized type-2 anti-CD20 antibody licensed for haematological malignancies in SLE patients with 2NDNR to rituximab.

METHODS

We collated data from SLE patients receiving obinutuzumab for secondary non-response to rituximab in BILAG centres. Disease activity was assessed using BILAG-2004, SLEDAI-2K and serology before, and 6 months after, obinutuzumab 2× 1000 mg infusions alongside methylprednisolone 100 mg.

RESULTS

All nine patients included in the study received obinutuzumab with concomitant oral immunosuppression. At 6 months post-obinutuzumab, there were significant reductions in median SLEDAI-2K from 12 to 6 (P = 0.014) and total BILAG-2004 score from 21 to 2 (P = 0.009). Complement C3 and dsDNA titres improved significantly (both P = 0.04). Numerical, but not statistically significant improvements were seen in C4 levels. Of 8/9 patients receiving concomitant oral prednisolone at baseline (all >10 mg/day), 5/8 had their dose reduced at 6 months. Four of nine patients were on 5 mg/day and were in Lupus Low Disease Activity State following obinutuzumab. After obinutuzumab, 6/9 patients with peripheral B cell data achieved complete depletion, including 4/4 assessed with highly sensitive assays. Of the nine patients, one obinutuzumab non-responder required CYC therapy. One unvaccinated patient died from COVID-19.

CONCLUSIONS

Obinutuzumab appears to be effective and steroid-sparing in renal and non-renal SLE patients with secondary non-response to rituximab. These patients have severe disease with few treatment options but given responsiveness to B cell depletion, switching to humanized type-2 anti-CD20 therapy is a logical approach.

Efficacy of belimumab combined with rituximab in severe systemic lupus erythematosus: study protocol for the phase 3, multicenter, randomized, open-label Synbiose 2 trial

Background

Belimumab, an anti-B-cell activating factor antibody, is approved for the treatment of auto-antibody positive systemic lupus erythematosus with a high degree of disease activity. Anti-CD20 B cell depletion with rituximab is used in refractory SLE as well, although with variable responses. We hypothesized that incomplete B cell depletion, related to a surge in BAFF levels following rituximab treatment, can cause ongoing disease activity and flares. The Synbiose 1 study primarily focused on immunological effects and shows the preliminary clinical benefit of combined rituximab and belimumab in SLE. The Synbiose 2 study will evaluate the clinical efficacy of combining belimumab with rituximab in patients with severe SLE, allowing the tapering of prednisolone and mycophenolate.

Methods

Synbiose 2 is a phase 3, multicenter, randomized, controlled, open-label 2-year clinical trial. Seventy adults with severe SLE including lupus nephritis will be randomized 1:1 to receive either standard of care consisting of prednisolone and mycophenolate as induction and maintenance treatment, or belimumab and rituximab combined with standard of care as induction treatment, followed by prednisolone and belimumab as maintenance treatment. The primary objective is to assess whether combined B cell therapy will lead to a reduction of treatment failure. Secondary endpoints are complete and partial clinical and renal response and the improvement of SLE-specific autoimmune phenomena. Safety endpoints include the incidence of adverse events, with a special interest in infections.

Discussion

The Synbiose 2 trial is the first multicenter phase 3 clinical trial investigating combined B cell targeted therapy in SLE, including lupus nephritis. The outcome of this study will provide further evidence for the clinical efficacy of this new treatment strategy in severe SLE.

Trial registration

ClinicalTrials.gov NCT03747159. Registered on 20 November 2018.

Emerging concepts of type I interferons in SLE pathogenesis and therapy

Type I interferons have been suspected for decades to have a crucial role in the pathogenesis of systemic lupus erythematosus (SLE). Evidence has now overturned several long-held assumptions about how type I interferons are regulated and cause pathological conditions, providing a new view of SLE pathogenesis that resolves longstanding clinical dilemmas. This evidence includes data on interferons in relation to genetic predisposition and epigenetic regulation. Importantly, data are now available on the role of interferons in the early phases of the disease and the importance of non-haematopoietic cellular sources of type I interferons, such as keratinocytes, renal tubular cells, glial cells and synovial stromal cells, as well as local responses to type I interferons within these tissues. These local effects are found not only in inflamed target organs in established SLE, but also in histologically normal skin during asymptomatic preclinical phases, suggesting a role in disease initiation. In terms of clinical application, evidence relating to biomarkers to characterize the type I interferon system is complex, and, notably, interferon-blocking therapies are now licensed for the treatment of SLE. Collectively, the available data enable us to propose a model of disease pathogenesis that invokes the unique value of interferon-targeted therapies. Accordingly, future approaches in SLE involving disease reclassification and preventative strategies in preclinical phases should be investigated.

B cells in systemic lupus erythematosus: Targets of new therapies and surveillance tools

B cell hyperactivity is a hallmark of the complex autoimmune disease systemic lupus erythematosus (SLE), which has justified drug development focusing on B cell altering agents during the last decades, as well as the off-label use of B cell targeting biologics. About a decade ago, the anti-B cell activating factor (BAFF) belimumab was the first biological agent to be licensed for the treatment of adult patients with active yet non-renal and non-neuropsychiatric SLE, to later be expanded to include treatment of pediatric SLE and, recently, lupus nephritis. B cell depletion is recommended as an off-label option in refractory cases, with the anti-CD20 rituximab having been the most used B cell depleting agent to date while agents with a slightly different binding specificity to CD20 such as obinutuzumab have also shown promise, forming a part of the current pipeline. In addition, terminally differentiated B cells have also been the targets of experimental therapies, with the proteasome inhibitor bortezomib being one example. Apart from being promising drug targets, B and plasma cells have also shown promise in the surveillance of patients with SLE, especially for monitoring B cell depleting or B cell altering therapies. Inadequate B cell depletion may signify poor expected clinical response to rituximab, for example, while prominent reductions in certain B cell subsets may signify a protection against flare development in patients treated with belimumab. Toward an era with a richer therapeutic armamentarium in SLE, including to a large extent B cell altering treatments, the challenge that emerges is to determine diagnostic means for evidence-based therapeutic decision-making, that uses clinical information, serological markers, and gene expression patterns to guide individualized precision strategies.

B cell-targeted therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that primarily affects women of childbearing age. There is no disease more heterogeneous than SLE as patients experience a myriad of manifestations and unpredictable periods of heightened disease activity. This heterogeneity not only makes it difficult for treatment decisions and prognostication, but has made drug development quite challenging. Despite these challenges, belimumab, voclosporin, and anifromulab, approved by the United States Food and Drug Administration (FDA) to treat SLE or lupus nephritis (LN), enhanced our armamentarium of traditional therapies, such as hydroxychloroquine, corticosteroids, and immunosuppressives. However, there remains a dire need to develop therapies that offer greater efficacy and safety. Patients with SLE produce excessive amounts of autoantibodies and cytokines that result in inflammation and organ damage. While a considerable number of potential drug development targets exist, there has been much attention focused on B cells. Strategies have included direct B cell killing, modulation of B cell function, inhibition of molecules essential to B cell growth and survival, and acceleration of autoantibody clearance, to name just a few. In this article, we review SLE clinical trials evaluating experimental agents that target B cells or plasma cells.

Predicting Sustained Clinical Response to Rituximab in Moderate to Severe Systemic Manifestations of Primary Sjögren Syndrome

OBJECTIVE

To assess outcomes of repeat rituximab cycles and identify predictors of sustained clinical response in systemic manifestations of primary Sjögren syndrome (pSS).

METHODS

An observational study was conducted in 40 rituximab-treated patients with pSS. Clinical response was defined as a 3-point or more reduction in the European League Against Rheumatism (EULAR) Sjögren Disease Activity Index (ESSDAI) at 6 months from baseline. Peripheral blood B cells were measured using highly sensitive flow cytometry. Predictors of sustained response (within two rituximab cycles) were analyzed using penalized logistic regression.

RESULTS

Thirty-eight out of 40 patients had moderate to severe systemic disease (ESSDAI >5). Main domains were articular (73%), mucocutaneous (23%), hematological (20%), and nervous system (18%). Twenty-eight out of 40 (70%) patients were on concomitant immunosuppressants. One hundred sixty-nine rituximab cycles were administered with a total follow-up of 165 patient-years. In cycle 1 (C1), 29/40 (73%) achieved ESSDAI response. Of C1 responders, 23/29 received retreatment on clinical relapse, and 15/23 (65%) responded. Of the 8/23 patients who lost response, these were due to secondary non-depletion and non-response (2NDNR; 4/23 [17%] as we previously observed in systemic lupus erythematosus with antirituximab antibodies, inefficacy = 2/23, and other side effects = 2/23). Within two cycles, 13/40 (33%) discontinued therapy. In multivariable analysis, concomitant immunosuppressant (odds ratio 7.16 [95% confidence interval: 1.37-37.35]) and achieving complete B-cell depletion (9.78 [1.32-72.25]) in C1 increased odds of response to rituximab. At 5 years, 57% of patients continued on rituximab.

CONCLUSION

Our data suggest that patients with pSS should be co-prescribed immunosuppressant with rituximab, and treatment should aim to achieve complete depletion. About one in six patients develop 2NDNR in repeat cycles. Humanized or type 2 anti-CD20 antibodies may improve clinical response in extra-glandular pSS.

Disparity in peripheral and renal B-cell depletion with rituximab in systemic lupus erythematosus: an opportunity for obinutuzumab?

OBJECTIVES

To investigate key factors that may contribute to the variability of rituximab-mediated peripheral and renal B cell depletion (BCD) in SLE.

METHODS

We analysed: (i) CD19+ B cell counts in patients with SLE before and 1, 2, 3 and 6 months after treatment with rituximab, comparing them with RA patients; (ii) the presence of B cells in renal biopsies after rituximab therapy; (iii) whether the duration of BCD correlated with patient demographics and B cell expression of CD20 and FcγRIIb; and (iv) the effect of B cell activation factor (BAFF) on the efficiency of rituximab and obinutuzumab at inducing BCD in whole blood assays, in vitro.

RESULTS

In SLE (n = 71), the duration of BCD was shorter compared with RA (n = 27). B cells were detectable in renal biopsy samples (n = 6) after treatment with rituximab in all patients with poor response while peripheral blood B cells remained low or undetectable in the same patients. There were no significant relationships between peripheral BCD and patient age, disease duration, serum C3 levels or the level of expression of B cell surface proteins CD20 and FcγRIIb. Obinutuzumab was more efficient than rituximab at inducing BCD in whole blood assays, regardless of excess BAFF.

CONCLUSIONS

BCD in SLE is less efficient than in RA. Renal B cell presence following rituximab treatment was associated with poor outcomes. No significant relationships between any measured B cell related, clinical or laboratory parameters and the efficiency of BCD by rituximab was found. Obinutuzumab was superior to rituximab at inducing BCD.

Altered Balance of Pro-Inflammatory Immune Cells to T Regulatory Cells Differentiates Symptomatic From Asymptomatic Individuals With Anti-Nuclear Antibodies

Systemic Autoimmune Rheumatic Diseases (SARDs) are characterized by the production of anti-nuclear antibodies (ANAs). ANAs are also seen in healthy individuals and can be detected years before disease onset in SARD. Both the immunological changes that promote development of clinical symptoms in SARD and those that prevent autoimmunity in asymptomatic ANA+ individuals (ANA+ NS) remain largely unexplored. To address this question, we used flow cytometry to examine peripheral blood immune populations in ANA+ individuals, with and without SARD, including 20 individuals who subsequently demonstrated symptom progression. Several immune populations were expanded in ANA+ individuals with and without SARD, as compared with ANA- healthy controls, particularly follicular and peripheral T helper, and antibody-producing B cell subsets. In ANA+ NS individuals, there were significant increases in T regulatory subsets and TGF-ß1 that normalized in SARD patients, whereas in SARD patients there were increases in Th2 and Th17 helper cell levels as compared with ANA+ NS individuals, resulting in a shift in the balance between inflammatory and regulatory T cell subsets. Patients with SARD also had increases in the proportion of pro-inflammatory innate immune cell populations, such as CD14+ myeloid dendritic cells, and intermediate and non-classical monocytes, as compared to ANA+ NS individuals. When comparing ANA+ individuals without SARD who progressed clinically over the subsequent 2 years with those who did not, we found that progressors had significantly increased T and B cell activation, as well as increased levels of LAG3+ T regulatory cells and TGF-ß1. Collectively, our findings suggest that active immunoregulation prevents clinical autoimmunity in ANA+ NS and that this becomes impaired in patients who progress to SARD, resulting in an imbalance favoring inflammation.

Early Changes in B and Plasma Cell Subsets and Traditional Serological Markers as Predictors of SRI-4 Response to Therapy in Systemic Lupus Erythematosus

Objective

With the premise of the hypothesis that early biological responses to therapy for active systemic lupus erythematosus (SLE) portend later clinical improvements, we studied changes in B cell subsets and traditional serological markers in relation to clinical response to standard therapy (ST) with or without the addition of belimumab.

Patients and Methods

We analyzed data from the BLISS-76, BLISS-SC, and BLISS Northeast Asia trials (N = 1712). Circulating CD19⁺ B cell subsets were determined by flow-cytometry. We studied associations of relative to baseline percentage changes in circulating B and plasma cell subsets, anti-dsDNA antibody levels and complement levels with SLE Responder Index (SRI)-4 response after 52 weeks of treatment. Changes occurring through week 8 were deemed "rapid," through week 24 "early," and thereafter "delayed".

Results

In the analysis of the entire cohort, SRI-4 responders showed more prominent decreases from baseline through week 52 in CD19⁺CD20⁺CD27^- naïve B cells (median change: -61.2% versus -50.0%; P = 0.004), CD19⁺CD20^-CD27 ^bright plasmablasts (-44.9% versus -33.3%; P = 0.011), and CD19⁺CD20^-CD138⁺ long-lived plasma cells (-48.2% versus -37.1%; P = 0.024), and a more prominent rapid (+92.0% versus +66.7%; P = 0.002) and early (+60.0% versus +49.5%; P = 0.033) expansion of CD19⁺CD20⁺CD27⁺ memory B cells than non-responders. More prominent rapid reductions in anti-dsDNA (-14.8% versus -8.7%; P = 0.043) and increases in C3 (+4.9% versus +2.1%; P = 0.014) and C4 levels (+11.5% versus +8.3%; P = 0.017) were documented in SRI-4 responders compared with non-responders among patients who received add-on belimumab, but not among patients who received non-biological ST alone.

Conclusion

SRI-4 responders showed a more prominent rapid expansion of memory B cells and more prominent delayed reductions in naïve B cells, plasmablasts and long-lived plasma cells. Moreover, clinical response to belimumab was associated with preceding more prominent reductions of anti-dsDNA and increases in C3 and C4 levels. Monitoring biological changes may prove useful in SLE patient surveillance and early treatment evaluation.

Can we predict if patients with SLE will require more than one cycle of rituximab?

OBJECTIVE

To identify clinical and serological features that distinguish patients with SLE who require single as opposed to repeated rituximab (RTX) cycles.

METHODS

All 175 SLE patients followed up at University College Hospital from 2000 onwards were retrospectively reviewed. They were divided into a one-RTX-cycle group and a multiple-cycle group (2 or more cycles). Patients included had a follow-up of at least 3 years after their first RTX cycle, unless they needed a second infusion sooner.

RESULTS

A total of 131 patients were included; 44 (33.6%) received one cycle of RTX and 87 (66.4%) received two or more. The former were older at diagnosis (31.4 vs 21 years, P < 0.001) and at first RTX infusion (39.9 vs 29 years, P < 0.001). This group of patients had more organs/systems involved (P = 0.044), more leukopenia, lymphopenia and thrombocytopenia (P = 0.001, P < 0.0001 and P = 0.003, respectively) and lower C3 levels (P = 0.035). They also had fewer immunosuppressive drugs before RTX therapy compared with those who required multiple RTX cycles (P = 0.003). There was no statistical difference in either the clinical or serological response after the first RTX cycle between both groups. Furthermore, patients who had received more immunosuppressive treatments were more likely to require more than one cycle of RTX infusions (P = 0.007).

CONCLUSIONS

RTX is an effective option for SLE patients with severe flares. Patients who received more immunosuppressive drugs were more likely to receive more than one set of RTX infusions. This suggests that RTX is best used for SLE patients with no history of refractory disease.

Circulating IgG4+ Plasmablast Count as a Diagnostic Tool in Autoimmune Pancreatitis

Background & Aims

Type 1 autoimmune pancreatitis (AIP) is an IgG4-related disease whose diagnosis is challenging. The aim of this study was to investigate the diagnostic value of circulating total and IgG4+ plasmablasts in differentiating this condition from the other main pancreatic diseases.

Methods

Patients with type 1 AIP (n = 19) were prospectively enrolled in a tertiary center together with patients suffering from type 2 or not otherwise specified (NOS) AIP (n = 10), pancreatic adenocarcinoma (n = 17), chronic pancreatitis (n = 20), and intraductal papillary mucinous neoplasia or chronic asymptomatic pancreatic hyperenzymemia (n = 21) as control groups. Flow cytometry was used to measure the total plasmablast and IgG4+ plasmablast number by gating peripheral blood CD45+CD19+CD38hiCD20-CD24-CD27+ and CD45+CD19+CD38hiCD20-CD24-CD27+IgG4+ cells, respectively. In patients with AIP, these cell populations were also evaluated after 1 month of therapy, after 2-4 months from the end of treatment, and after 1 year from the enrollment. The study was approved by the local ethics committee (protocol number: 59133, 30/11/2017).

Results

Total plasmablast quantification was capable of discriminating type 1 AIP from all the other pancreatic disorders with a sensitivity of 47% and a specificity of 81%, according to a cutoff of 4500 cells/mL (AUC = 0.738), whereas IgG4+ plasmablast count distinguished type 1 AIP from all the other pancreatic disorders with a sensitivity of 80% and a specificity of 97% when applying a cutoff of 210 IgG4+ cells/mL (AUC = 0.879). The basal IgG4+ plasmablast number was significantly higher (P = .0001) in type 1 AIP than in type 2/NOS AIP, decreased after steroid therapy, and increased at disease relapse.

Conclusion

IgG4+ plasmablast count represents a potentially useful biomarker to differentiate type 1 from type 2/NOS AIP and from other pancreatic diseases.

Early B Cell and Plasma Cell Kinetics Upon Treatment Initiation Portend Flares in Systemic Lupus Erythematosus: A Post-Hoc Analysis of Three Phase III Clinical Trials of Belimumab

Objective

To investigate changes in B cell subsets in relation to disease flares upon initiation of standard therapy (ST) plus belimumab or placebo in patients with systemic lupus erythematosus (SLE).

Patients and Methods

Using data from the BLISS-76, BLISS-SC and BLISS Northeast Asia trials, we investigated associations of relative to baseline rapid (through week 8) and early (through week 24) changes in peripheral B cell subsets, anti-dsDNA and complement levels with the occurrence of disease flares from week 24 through week 52 (Mann-Whitney U tests) or the entire study follow-up (Cox regression analysis), assessed using the SELENA-SLEDAI Flare Index.

Results

Patients on ST alone who flared displayed less prominent early decreases in CD19+CD20-CD138+ long-lived plasma cells (-16.1% versus -35.1%; P=0.012). In all arms combined, patients who developed severe flares showed less prominent early decreases in CD19+CD20-CD138+ long-lived plasma cells (-23.5% versus -39.4%; P=0.028) and CD19+CD27brightCD38bright SLE-associated plasma cells (-19.0% versus -27.8%; P=0.045). After adjustment for rapid changes, early increases in overall CD19+CD20+ B cells (HR: 1.81; 95% CI: 1.08-3.05; P=0.024) and early increases or no return after a rapid expansion in CD19+CD20+CD27+ memory B cells (HR: 1.58; 95% CI: 1.18-2.11; P=0.002) portended subsequent severe flares. Patients who developed flares of any severity showed no or less prominent rapid (0.0% versus -12.5%; P<0.001) or early (-1.9% versus -21.7%; P<0.001) decreases in anti-dsDNA levels, and patients who developed severe flares showed no or less prominent early decreases in anti-dsDNA levels (0.0% versus -13.3%; P=0.020). Changes in complement levels exhibited no ability to distinguish flaring from non-flaring patients.

Conclusions

Increase or lack of decrease in certain circulating B cell subsets or anti-dsDNA levels upon treatment initiation for active SLE heralded subsequent severe disease flares. A rapid expansion of memory B cells may signify sustained response to therapy when followed by a subsequent drop, while no return or delayed increases in memory B cells may portend flaring. Peripheral B cell and serological marker kinetics may help identify patients in whom therapeutic modifications could protect against flare development, and may hence prove a useful complement to traditional surveillance and early treatment evaluation in SLE.

A glimpse into the future of systemic lupus erythematosus

This viewpoint article on a forecast of clinically meaningful changes in the management of systemic lupus erythematosus (SLE) in the next 10 years is based on a review of the current state of the art. The groundwork has been laid by a robust series of classification criteria and treatment recommendations that have all been published since 2019. Building on this strong foundation, SLE management predictably will take significant steps forward. Assessment for lupus arthritis will presumably include musculoskeletal sonography. Large-scale polyomics studies are likely to unravel more of the central immune mechanisms of the disease. Biomarkers predictive of therapeutic success may enter the field; the type I interferon signature, as a companion for use of anifrolumab, an antibody against the common type I interferon receptor, is one serious candidate. Besides anifrolumab for nonrenal SLE and the new calcineurin inhibitor voclosporin in lupus nephritis, both of which are already approved in the United States and likely to become available in the European Union in 2022, several other approaches are in advanced clinical trials. These include advanced B cell depletion, inhibition of costimulation via CD40 and CD40 ligand (CD40L), and Janus kinase 1 (Jak1) and Tyrosine kinase 2 (Tyk2) inhibition. At the same time, essentially all of our conventional therapeutic armamentarium will continue to be used. The ability of patients to have successful SLE pregnancies, which has become much better in the last decades, should further improve, with approaches including tumor necrosis factor blockade and self-monitoring of fetal heart rates. While we hope that the COVID-19 pandemic will soon be controlled, it has highlighted the risk of severe viral infections in SLE, with increased risk tied to certain therapies. Although there are some data that a cure might be achievable, this likely will remain a challenge beyond 10 years from now.

A Personalized Rituximab Retreatment Approach Based on Clinical and B-Cell Biomarkers in ANCA-Associated Vasculitis

Background

Time to relapse after rituximab for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is variable, and optimal retreatment strategy has remained unclear. In AAV following rituximab induction, the study objective was to evaluate clinical and B-cell predictors of relapse in order to develop a retreatment algorithm.

Methods

A retrospective observational study was conducted in 70 rituximab-treated ANCA-associated vasculitis patients followed up for over 10 years. Complete response (CR) was defined as Birmingham Vasculitis Activity Score v3.0 = 0. Retreatment was given on clinical relapse, defined as new features or worsening of persistent disease (not by biomarker status). Peripheral B-cell subsets were measured using highly sensitive flow cytometry. Predictors were tested using multivariable Cox regression.

Results

Median time to retreatment for cycles 1–5 were 84, 73, 67, 60, and 73 weeks. Over 467 patient-years follow-up, 158 relapses occurred in 60 patients; 16 (in 15 patients) were major (renal = 7, neurological = 4, ENT = 3, and respiratory = 2). The major-relapse rate was 3.4/100 patient-years. In multivariable analysis, concomitant immunosuppressant [HR, 0.48 (95% CI, 0.24–0.94)], achieving CR [0.24 (0.12–0.50)], and naïve B-cell repopulation at 6 months [0.43 (0.22–0.84)] were associated with longer time to relapse. Personalized retreatment using these three predictors in this cohort would have avoided an unnecessary fixed retreatment in 24% of patients. Area under the receiver operating characteristic for prediction of time to relapse was greater if guided by naïve B-cell repopulation than if previously evaluated ANCA and/or CD19⁺ cells return at 6 months had been used, 0.82 and 0.53, respectively.

Conclusion

Our findings suggest that all patients should be coprescribed oral immunosuppressant. Those with incomplete response or with absent naïve B cells should be retreated at 6 months. Patients with complete response and naïve repopulation should not receive fixed retreatment. This algorithm could reduce unnecessary retreatment and warrant investigation in clinical trials.

Aberrant expression of inhibitory receptors on B cells in patients with Graves' disease

The pathophysiological mechanism underlying Graves' disease (GD) remains incompletely understood. Inhibitory receptors on B cells are critical for humoral immunity, which plays a key role in GD pathogenesis. This study aimed to investigate B cell subsets distribution and inhibitory receptor expression on these subsets in GD patients. Peripheral blood was drawn from 41 healthy controls and 46 GD patients (21 patients with moderate GD, 25 patients with severe GD). B cell subset distribution and CD22, CD32b and CD72 expression on B cells were analyzed by flow cytometry. Serum cytokines were examined by enzyme-linked immunosorbent assay (ELISA). Compared with healthy controls, the naïve B cell percentage was increased, while the preswitched memory and conventional memory B cell percentages were decreased. The inhibitory receptors expression, especially CD32b, on B cell subsets was significantly decreased in patients with GD. In addition, the inhibitory receptors expression on B cell subsets from severe GD patients exhibited a decreasing trend compared with those from moderate GD patients. These results suggest that abnormal B cell subset distribution occurs in GD. Impaired inhibitory receptors, in particular CD32b, play a crucial role in GD pathogenesis and might be a therapeutic target to rebuild self-immune tolerance in GD.

Effectiveness of Belimumab After Rituximab in Systemic Lupus Erythematosus : A Randomized Controlled Trial

BACKGROUND

B-cell depletion with rituximab is commonly used for patients with systemic lupus erythematosus (SLE) that is refractory to conventional therapy, but it yields variable responses. We hypothesized that high B-cell activating factor (BAFF) levels after rituximab can cause disease flares, thereby limiting its effectiveness.

OBJECTIVE

To obtain preliminary evidence for efficacy of the anti-BAFF therapeutic belimumab after rituximab in SLE.

DESIGN

Phase 2, randomized, double-blind (patients, assessors, researchers, care providers), placebo-controlled, parallel-group, superiority trial. (ISRCTN: 47873003).

SETTING

England.

PARTICIPANTS

Fifty-two patients who had SLE that was refractory to conventional treatment and whose physicians had recommended rituximab therapy were recruited between 2 February 2017 and 28 March 2019.

INTERVENTION

Participants were treated with rituximab and 4 to 8 weeks later were randomly assigned (1:1) to receive intravenous belimumab or placebo for 52 weeks.

MEASUREMENTS

The prespecified primary end point was serum IgG anti-double-stranded DNA (anti-dsDNA) antibody levels at 52 weeks. Secondary outcomes included incidence of disease flares and adverse events.

RESULTS

At 52 weeks, IgG anti-dsDNA antibody levels were lower in patients treated with belimumab compared with placebo (geometric mean, 47 [95% CI, 25 to 88] vs. 103 [CI, 49 to 213] IU/mL; 70% greater reduction from baseline [CI, 46% to 84%]; P < 0.001). Belimumab reduced risk for severe flare (BILAG-2004 grade A) compared with placebo (hazard ratio, 0.27 [CI, 0.07 to 0.98]; log-rank P = 0.033), with 10 severe flares in the placebo group and 3 in the belimumab group. Belimumab did not increase incidence of serious adverse events. Belimumab significantly suppressed B-cell repopulation compared with placebo (geometric mean, 0.012 [CI, 0.006 to 0.014] vs. 0.037 [CI, 0.021 to 0.081] × 10⁹/L) at 52 weeks in a subset of patients (n = 25) with available data.

LIMITATIONS

Small sample size; biomarker primary end point.

CONCLUSION

Belimumab after rituximab significantly reduced serum IgG anti-dsDNA antibody levels and reduced risk for severe flare in patients with SLE that was refractory to conventional therapy. The results suggest that this combination could be developed as a therapeutic strategy.

PRIMARY FUNDING SOURCE

Versus Arthritis.

Percentage of residual B cells after 2 weeks of rituximab treatment predicts the improvement of systemic sclerosis-associated interstitial lung disease

The benefit of rituximab (RTX) for systemic sclerosis-associated interstitial lung disease (SSc-ILD) has been shown in previous clinical trials. However, predictors of RTX efficacy have not been clarified. We investigated whether B-cell responsiveness to RTX is related to therapeutic effect. Ten SSc-ILD patients treated with RTX in an independent clinical trial (Japan Registry of Clinical Trials, jRCTs031180373) were included in this analysis. Peripheral B-cell counts were examined retrospectively before RTX administration (baseline) and at 2, 4, 12, and 24 weeks after the first RTX administration, along with percent-predicted forced vital capacity (%FVC) before and 24 weeks after RTX treatment. Relative to baseline, the percentage of residual peripheral blood B cells at 2 weeks after RTX was negatively correlated with the %FVC improvement at the 24-week assessment (r = -0.41, p = 0.04). In the subgroup with less than 5% B-cell persistence at week 2, %FVC at the 24-week assessment was significantly improved compared to baseline (p = 0.02). In another subgroup with more than 5% residual B cells, %FVC was not significantly different after 24 weeks compared to baseline (p = 0.41). In conclusion, the removal rate of B cells after 2 weeks of RTX treatment may be a useful surrogate marker of subsequent SSc-ILD improvement.

B-cell depletion with obinutuzumab for the treatment of proliferative lupus nephritis: a randomised, double-blind, placebo-controlled trial

Objective

Randomised trials of type I anti-CD20 antibodies rituximab and ocrelizumab failed to show benefit in proliferative lupus nephritis (LN). We compared obinutuzumab, a humanised type II anti-CD20 monoclonal antibody that induces potent B-cell depletion, with placebo for the treatment of LN in combination with standard therapies.

Methods

Patients with LN receiving mycophenolate and corticosteroids were randomised to obinutuzumab 1000 mg or placebo on day 1 and weeks 2, 24 and 26, and followed through week 104. The primary endpoint was complete renal response (CRR) at week 52. Exploratory analyses through week 104 were conducted. The prespecified alpha level was 0.2.

Results

A total of 125 patients were randomised and received blinded infusions. Achievement of CRR was greater with obinutuzumab at week 52 (primary endpoint, 22 (35%) vs 14 (23%) with placebo; percentage difference, 12% (95% CI −3.4% to 28%), p=0.115) and at week 104 (26 (41%) vs 14 (23%); percentage difference, 19% (95% CI 2.7% to 35%), p=0.026). Improvements in other renal response measures, serologies, estimated glomerular filtration rate and proteinuria were greater with obinutuzumab. Obinutuzumab was not associated with increases in serious adverse events, serious infections or deaths. Non-serious infusion-related reactions occurred more frequently with obinutuzumab.

Conclusions

Improved renal responses through week 104 were observed in patients with LN who received obinutuzumab plus standard therapies compared with standard therapies alone. Obinutuzumab was well tolerated and no new safety signals were identified.

Trial registration number

NCT02550652.

30 Years of Biotherapeutics Development-What Have We Learned?

Since the birth of biotechnology, hundreds of biotherapeutics have been developed and approved by the US Food and Drug Administration (FDA) for human use. These novel medicines not only bring significant benefit to patients but also represent precision tools to interrogate human disease biology. Accordingly, much has been learned from the successes and failures of hundreds of high-quality clinical trials. In this review, we discuss general and broadly applicable themes that have emerged from this collective experience. We base our discussion on insights gained from exploring some of the most important target classes, including interleukin-1 (IL-1), tumor necrosis factor α (TNF-α), IL-6, IL-12/23, IL-17, IL-4/13, IL-5, immunoglobulin E (IgE), integrins and B cells. We also describe current challenges and speculate about how emerging technological capabilities may enable the discovery and development of the next generation of biotherapeutics.

Therapeutic efficacy of anti-CD19 CAR-T cells in a mouse model of systemic lupus erythematosus

Dysregulated B-cell activation plays pivotal roles in systemic lupus erythematosus (SLE), which makes B-cell depletion a potential strategy for SLE treatment. The clinical success of anti-CD19 CAR-T cells in treating B-cell malignancies has attracted the attention of researchers. In this study, we aimed to investigate the feasibility of applying anti-CD19 CAR-T cell therapy to SLE treatment in a mouse disease model. We constructed murine anti-CD19 CARs with either CD28 or 4-1BB as the intracellular costimulatory motif and evaluated the therapeutic function of the corresponding CAR-T cells by infusing them into MRL-lpr mice. Furthermore, anti-CD19 CAR-T cells were transferred to MRL-lpr mice before the onset of disease to determine their role in SLE prevention. According to our observations, compared with antibody treatment, the adoptive transfer of our anti-CD19 CAR-T cells showed a more sustained B-cell-depletion effect in MRL-lpr mice. The transfer of syngeneic anti-CD19 CAR-T cells not only prevented disease pathogenesis before the onset of disease symptoms but also displayed therapeutic benefits at a later stage after disease progression. We also tried to optimize the treatment strategy and found that compared with CAR-T cells with the CD28 costimulatory motif, CAR-T cells with the 4-1BB costimulatory motif showed better therapeutic efficiency without cell enrichment. Taken together, these results show that anti-CD19 CAR-T cell therapy was effective in the prevention and treatment of a murine model of SLE, indicating its potential for clinical use in patients.

Ocrelizumab for the Treatment of Multiple Sclerosis: Safety, Efficacy, and Pharmacology

The success of selective B-cells depleting therapies, as the anti-CD20 antibodies, in patients with multiple sclerosis (MS) has confirmed that B-cells are critical in the immune pathogenesis of the disease. Ocrelizumab, a humanized monoclonal antibody that selectively targets CD20+ B-cells, profoundly suppresses acute inflammatory disease activity, representing a highly effective therapy for relapsing-remitting multiple sclerosis (RRMS). It is also the first proven therapy able to slow disability progression in primary progressive multiple sclerosis (PPMS), particularly in patients with signs of acute radiological activity before being enrolled. Effectiveness has widely been demonstrated in randomized clinical trials (RCTs), and recently confirmed in open-label extension trials. Here, we review the role of B-cells in MS, the mechanism of action of ocrelizumab, its pharmacokinetics and pharmacodynamics, and the clinical data supporting its use, as well as safety data. We focus on issues related to the maintenance of immunocompetence, essential to ensure an immune response to either a primary infection or a vaccination. Lastly, we discuss about the possible role of ocrelizumab as an exit strategy from natalizumab-treated patients at risk of developing multifocal progressive leukoencephalopathy. In view of using ocrelizumab chronically, collecting long-term safety data and finding strategies to minimize adverse events will be extremely relevant.

Dependence on Autophagy for Autoreactive Memory B Cells in the Development of Pristane-Induced Lupus

The production of autoantibodies by autoreactive B cells plays a major role in the pathogenesis of lupus. Increases in memory B cells have been observed in human lupus patients and autoimmune lpr mice. Autophagy is required for the maintenance of memory B cells against viral infections; however, whether autophagy regulates the persistence of autoantigen-specific memory B cells and the development of lupus remains to be determined. Here we show that memory B cells specific for autoantigens can be detected in autoimmune lpr mice and a pristane-induced lupus mouse model. Interestingly, B cell-specific deletion of Atg7 led to significant loss of autoreactive memory B cells and reduced autoantibody production in pristane-treated mice. Autophagy deficiency also attenuated the development of autoimmune glomerulonephritis and pulmonary inflammation after pristane treatment. Adoptive transfer of wild type autoreactive memory B cells restored autoantibody production in Atg7-deficient recipients. These data suggest that autophagy is important for the persistence of autoreactive memory B cells in mediating autoantibody responses. Our results suggest that autophagy could be targeted to suppress autoreactive memory B cells and ameliorate humoral autoimmunity.

Meant to B: B cells as a therapeutic target in systemic lupus erythematosus

B cells have a prominent role in the pathogenesis of systemic lupus erythematosus (SLE). They are mediators of inflammation through the production of pathogenic antibodies that augment inflammation and cause direct tissue and cell damage. Multiple therapeutic agents targeting B cells have been successfully used in mouse models of SLE; however, these preclinical studies have led to approval of only one new agent to treat patients with SLE: belimumab, a monoclonal antibody targeting B cell-activating factor (BAFF). Integrating the experience acquired from previous clinical trials with the knowledge generated by new studies about mechanisms of B cell contributions to SLE in specific groups of patients is critical to the development of new treatment strategies that will help to improve outcomes in patients with SLE. In particular, a sharper focus on B cell differentiation to plasma cells is warranted.

High-Throughput Detection of Autoantigen-Specific B Cells Among Distinct Functional Subsets in Autoimmune Donors

Antigen-specific B cells (ASBCs) can drive autoimmune disease by presenting autoantigen to cognate T cells to drive their activation, proliferation, and effector cell differentiation and/or by differentiating into autoantibody-secreting cells. Autoantibodies are frequently used to predict risk and diagnose several autoimmune diseases. ASBCs can drive type 1 diabetes even when immune tolerance mechanisms block their differentiation into antibody-secreting cells. Furthermore, anti-histidyl tRNA synthetase syndrome patients have expanded IgM⁺ Jo-1-binding B cells, which clinically diagnostic IgG Jo-1 autoantibodies may not fully reflect. Given the potential disconnect between the pathologic function of ASBCs and autoantibody secretion, direct study of ASBCs is a necessary step towards developing better therapies for autoimmune diseases, which often have no available cure. We therefore developed a high-throughput screening pipeline to 1) phenotypically identify specific B cell subsets, 2) expand them in vitro, 3) drive them to secrete BCRs as antibody, and 4) identify wells enriched for ASBCs through ELISA detection of antibody. We tested the capacity of several B cell subset(s) to differentiate into antibody-secreting cells following this robust stimulation. IgM⁺ and/or IgD⁺, CD27^- memory, memory, switched memory, and B_ND B cells secreted B cell receptor (BCR) as antibody following in vitro stimulation, whereas few plasmablasts responded. Bimodal responses were observed across autoimmune donors for IgM⁺ CD21^lo and IgM^- CD21^lo B cells, consistent with documented heterogeneity within the CD21^lo subset. Using this approach, we detected insulin-binding B cell bias towards CD27^- memory and CD27⁺ memory subsets in pre-symptomatic type 1 diabetes donors. We took advantage of routine detection of Jo-1-binding B cells in Jo-1+ anti-histidyl tRNA synthetase syndrome patients to show that Jo-1-binding B cells and total B cells expanded 20-30-fold using this culture system. Overall, these studies highlight technology that is amenable to small numbers of cryopreserved peripheral blood mononuclear cells that enables interrogation of phenotypic and repertoire attributes of ASBCs derived from autoimmune patients.

Relevant domains and outcome measurement instruments in Neuropsychiatric Systemic Lupus Erythematosus: a systematic literature review

OBJECTIVES

Although neuropsychiatric involvement in Systemic Lupus Erythematosus (NPSLE) is one of the most complex and troubling manifestations of the disease, validated outcome instruments to be used as sensitive endpoints in controlled clinical trials are lacking. We set out a systematic literature review (SLR) to identify outcome measurement instruments and domains used to assess NPSLE.

METHODS

The Preferred Reporting Items for systematic reviews and Meta-analysis (PRISMA) guidelines were used. Articles available in English (1967-2020), listed in PubMed, EMBASE, PsycINFO, Cochrane Library and EULAR outcome measures library were screened. All domains and outcome measurement instruments were characterized according to the OMERACT Filter 2.1, considering core areas (manifestations/abnormalities, life impact, death/lifespan, societal/resource use) and contextual factors.

RESULTS

Of 3,392 abstracts evaluated, 83 studies were included in the SLR (15,974 patients, females 89.9%). Eligible studies included domains and instruments pertinent to all core areas defined by OMERACT, except for "societal/resource use". The most common core areas were "manifestations/abnormalities", covering 10 domains pertinent to laboratory and instrumental markers, indexes and neuropsychiatric dimension (cognitive, neurologic and psychiatric field), and "life impact", covering 7 domains related to physical function (from both the perspective of the patient and the physician), pain and quality of life.

CONCLUSION

Our study revealed great heterogeneity in the instruments derived from populations with NPSLE and none of these had high-quality evidence. This supports the need to develop and further validate a core domain set and outcome measurement instruments to promote clinical research in this field, enhancing comparability across studies.

Multipotent Mesenchymal Stromal Cells in Rheumatoid Arthritis and Systemic Lupus Erythematosus; From a Leading Role in Pathogenesis to Potential Therapeutic Saviors?

The pathogenesis of the autoimmune rheumatological diseases including rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) is complex with the involvement of several immune cell populations spanning both innate and adaptive immunity including different T-lymphocyte subsets and monocyte/macrophage lineage cells. Despite therapeutic advances in RA and SLE, some patients have persistent and stubbornly refractory disease. Herein, we discuss stromal cells' dual role, including multipotent mesenchymal stromal cells (MSCs) also used to be known as mesenchymal stem cells as potential protagonists in RA and SLE pathology and as potential therapeutic vehicles. Joint MSCs from different niches may exhibit prominent pro-inflammatory effects in experimental RA models directly contributing to cartilage damage. These stromal cells may also be key regulators of the immune system in SLE. Despite these pro-inflammatory roles, MSCs may be immunomodulatory and have potential therapeutic value to modulate immune responses favorably in these autoimmune conditions. In this review, the complex role and interactions between MSCs and the haematopoietically derived immune cells in RA and SLE are discussed. The harnessing of MSC immunomodulatory effects by contact-dependent and independent mechanisms, including MSC secretome and extracellular vesicles, is discussed in relation to RA and SLE considering the stromal immune microenvironment in the diseased joints. Data from translational studies employing MSC infusion therapy against inflammation in other settings are contextualized relative to the rheumatological setting. Although safety and proof of concept studies exist in RA and SLE supporting experimental and laboratory data, robust phase 3 clinical trial data in therapy-resistant RA and SLE is still lacking.

A reverse translational study on the effect of rituximab, rituximab plus belimumab, or bortezomib on the humoral autoimmune response in SLE

Objectives

SLE is a severe autoimmune disease characterized by autoreactive B cells and IC formation, which causes systemic inflammation. B cell–targeted therapy could be a promising treatment strategy in SLE patients; nevertheless, randomized clinical trials have not always been successful. However, some groups have demonstrated beneficial effects in severe SLE patients with off-label rituximab (RTX) with belimumab (BLM), or bortezomib (BTZ), which targeted different B cells subsets. This study assembled sera from SLE cohorts treated with RTX+BLM (n = 15), BTZ (n = 11) and RTX (n = 16) to get an in-depth insight into the immunological effects of these therapies on autoantibodies and IC formation.

Methods

Autoantibodies relevant for IC formation and the avidity of anti-dsDNA were determined by ELISA. IC-mediated inflammation was studied by complement levels and ex vivo serum-induced neutrophil extracellular trap formation.

Results

Reductions in autoantibodies were observed after all approaches, but the spectrum differed depending upon the treatment. Specifically, only RTX+BLM significantly decreased anti-C1q. Achieving seronegativity of ≥1 autoantibody, specifically anti-C1q, was associated with lower disease activity. In all SLE patients, the majority of anti-dsDNA autoantibodies had low avidity. RTX+BLM significantly reduced low-, medium- and high-avidity anti-dsDNA, while RTX and BTZ only significantly reduced medium avidity. IC-mediated inflammation, measured by C3 levels and neutrophil extracellular trap formation, improved after RTX+BLM and RTX but less after BTZ.

Conclusion

This study demonstrated the impact of different B cell–targeted strategies on autoantibodies and IC formation and their potential clinical relevance in SLE.

Rituximab - The first twenty years

It is now two decades since Rituximab was first used in the treatment of patients with systemic lupus erythematosus. There have been many challenges but in spite of failing to meet its primary endpoints in two clinical trials it is widely used for many aspects of lupus, its side-effects and the possibility that combining it with Benlysta may be of value. We also consider the proposal that it may provide a useful initial therapy. In this review, we consider the place of Rituximab in the treatment of lupus and anticipate how developments in fully-humanized anti-CD20 monoclonals may well extend the "therapeutic life" of B-cell depletion as a viable treatment option.

Anti-CD20 monoclonal antibodies in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is an autoimmune inflammatory condition with a wide spectrum of disease manifestations and severities, resulting in significant morbidity and mortality. The aetiopathogenesis of SLE is complex. Young women and certain ethnicities are commonly affected, suggesting a significant hormonal and genetic influence. Diverse immunological abnormalities have been described. A characteristic abnormality is the presence of autoantibodies, implicating a central role for B cells in disease pathogenesis and/or perpetuation. Whilst conventional therapies have improved outcomes, a great unmet need remains. Recently, biological therapies are being explored. B-cell depletion therapy with rituximab has been in use off-label for nearly two decades. Inconsistent results between uncontrolled and controlled studies have raised doubts about its efficacy. In this review, we will focus on B cell abnormalities and the rationale behind B-cell depletion therapy with anti-CD20 monoclonal antibody (mAb), rituximab, will be explored including an evaluation of clinical and trial experience. Finally, we will discuss the mechanistic basis for considering alternative anti-CD20 mAbs.

Management of inflammatory neurologic and psychiatric manifestations of systemic lupus erythematosus: A systematic review

BACKGROUND

The neurological and psychiatric manifestations of systemic lupus erythematosus (NPSLE) are a heterogeneous group of conditions with variable clinical presentation and significant morbidity and mortality.

OBJECTIVES

Our aim was to comprehensively assess and present the evidence for treatments used in the management of inflammatory NPSLE.

METHODS

Medline, Embase, CINHAL and Cochrane CENTRAL were searched from 1990 to end of March 2019 using key words that related to NPSLE and treatment. Included studies comprised clinical trials, observational studies or case series with ≥5 patients and sufficient data related to treatment and outcome in NPSLE patients.

RESULTS

There were 7222 studies identified in the search, of which 90 were included in the review. There was a notable paucity of clinical trials, with only two randomised controlled trials and one pilot study. Treatment categories included corticosteroids (14 studies), cyclophosphamide (18 studies), synthetic DMARDs (7 studies), biologic therapies (14 studies), therapeutic plasma exchange (6 studies), intravenous immunoglobulin (2 studies), autologous stem cell transplant (3 studies), other therapies (8 studies), combination therapies (6 studies), studies with grouped outcome data (5 studies) and observational studies with therapy-specific associations (7 studies). Corticosteroids are accepted as first line treatment in NPSLE and there is low-moderate evidence supporting their benefit. Moderate evidence, based on consistent data in numerous studies and some trial data, supports the use of cyclophosphamide in the treatment of NPSLE. Limited data support some synthetic DMARDs such as mycophenolate, azathioprine and intrathecal methotrexate. In refractory disease, low-moderate evidence supports rituximab therapy and limited evidence supports benefit following autologous stem cell transplant. Regarding adjuvant treatments, limited evidence favours addition of plasma exchange, intravenous immunoglobulin and hydroxychloroquine. There exists very limited data for other therapies.

CONCLUSION

There are multiple therapeutic options for the management of inflammatory NPSLE including systemic, biologic and interventional therapies; however, currently there is a paucity of high-quality trial data to guide firm recommendations. In order to better understand the optimal treatment of NPSLE and its different subtypes, further well-designed clinical trials are needed.