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

Control of complement-induced inflammatory responses to SARS-CoV-2 infection by anti-SARS-CoV-2 antibodies

Dysregulated immune responses contribute to the excessive and uncontrolled inflammation observed in severe COVID-19. However, how immunity to SARS-CoV-2 is induced and regulated remains unclear. Here, we uncover the role of the complement system in the induction of innate and adaptive immunity to SARS-CoV-2. Complement rapidly opsonizes SARS-CoV-2 particles via the lectin pathway. Complement-opsonized SARS-CoV-2 efficiently induces type-I interferon and pro-inflammatory cytokine responses via activation of dendritic cells, which are inhibited by antibodies against the complement receptors (CR) 3 and 4. Serum from COVID-19 patients, or monoclonal antibodies against SARS-CoV-2, attenuate innate and adaptive immunity induced by complement-opsonized SARS-CoV-2. Blocking of CD32, the FcγRII antibody receptor of dendritic cells, restores complement-induced immunity. These results suggest that opsonization of SARS-CoV-2 by complement is involved in the induction of innate and adaptive immunity to SARS-CoV-2 in the acute phase of infection. Subsequent antibody responses limit inflammation and restore immune homeostasis. These findings suggest that dysregulation of the complement system and FcγRII signaling may contribute to severe COVID-19.

Predictors and prognostic factors influencing outcomes of anti-CD20 monoclonal antibodies in systemic lupus erythematosus: A systematic review update

BACKGROUND

Anti-C20 monoclonal antibodies (MAb), such as rituximab, are commonly used for the treatment of patients with severe or refractory systemic lupus erythematosus (SLE) but clinical outcomes are highly variable. We aimed to provide an update of a systematic review of predictive and prognostic factors of anti-CD20 MAb treatment in SLE.

METHODS

A systematic literature search was undertaken to identify predictive and prognostic factors of clinical response following treatment with anti-CD20 therapies in SLE patients. Studies examining rituximab published prior to 2015 were excluded. Risk of bias was assessed for randomized controlled trials (RCTs) using the Cochrane Collaboration (RoB2) tool for RCTs and the Quality In Prognosis Studies Tool (QUIPS) for cohort studies. A narrative synthesis of the evidence was undertaken and quality of evidence (QoE) was assessed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

From 850 studies identified, 17 studies met the inclusion criteria. A further 8 studies were identified and included through search updates. There were two post-hoc analyses of RCTs of rituximab, one RCT of ocrelizumab and one of obinutuzumab; and 16 cohort studies examining rituximab treatment. The overall QoE was low or very low. There was wide heterogeneity in definitions of clinical disease activity and outcome measures, non-standardized laboratory cut-offs, failure to account for confounders and multiple subgroup analyses of differing outcomes. B cell depletion as well as novel biomarkers, such as S100 proteins, FCGR genotype, anti-vimentin and anti-drug antibodies showed some evidence of prognostic value but QoE was limited due to moderate to high risk of bias, early phase of investigation and imprecision of results.

CONCLUSION

There has been no validation of previously identified prognostic factors to guide outcome in anti-CD20 treated lupus patients. Hypothesis-driven studies of several novel markers however, demonstrate prognostic value and require replication and validation to support their use in routine clinical practice.

PROSPERO REGISTRATION NUMBER

CRD42020220339.

FCGR3A-V158F gene polymorphism: A potential predictor for rituximab dosing optimization in Chinese patients with neuromyelitis optica spectrum disorder

BACKGROUND

Rituximab (RTX), an anti-CD20 monoclonal antibody, has shown promise in managing neuromyelitis optica spectrum disorders (NMOSD) by depleting B cells and reducing relapses. However, there is no consensus on the optimal RTX dosing regimen, and genetic factors, such as FCGR3A-V158F polymorphism, may influence treatment outcomes. This study investigates how FCGR3A-V158F genotypes influence RTX efficacy in Chinese NMOSD patients under varying dosing regimens and aims to optimize treatment protocols.

METHODS

We conducted a retrospective analysis of 25 Chinese NMOSD patients treated with RTX, grouped into standardized and low-dosage regimens. FCGR3A-V158F genotypes were determined, and treatment responses were evaluated, including relapse rates, time to first relapse (TFR), B-cell depletion, dose adjustments, and treatment retention.

RESULTS

Among all patients, 15 received standardized dosages, while 10 received varied induction doses (500 mg to 1200 mg) in low-dose regimens. For FCGR3A-V158F genotypes, 15 had the FF genotype, and 10 were V carriers (3 VV genotype, 7 VF genotype). Regardless of dosing, FF genotype patients had a higher relapse rate post-RTX treatment compared to V carriers (P < 0.05). None of the 3 VV genotype patients in either dose group experienced relapses post-RTX. In both dose groups, FF genotype patients had significantly shorter TFR and required more RTX dose adjustments post-RTX treatment compared to V carriers in the standardized dosage group (P < 0.05). FF genotype patients in the low dosage group were more likely to experience insufficient B-cell depletion, had lower treatment retention rates, and more discontinuations than V carriers in the standardized dosage group (P < 0.05). Insufficient B-cell depletion significantly predicted clinical relapses after RTX treatment (P < 0.05). In survival analysis, FF genotype patients, regardless of dosing, experienced earlier relapses post-RTX treatment (P < 0.05).

CONCLUSIONS

This study highlights the importance of RTX dosage selection in NMOSD treatment, particularly for FCGR3A-FF genotype patients. Standard-dose RTX therapy with vigilant monitoring of peripheral blood B-cell levels is recommended for these individuals to optimize treatment efficacy.

Inebilizumab reduces neuromyelitis optica spectrum disorder risk independent of FCGR3A polymorphism

Inebilizumab, a humanized, glycoengineered, IgG1 monoclonal antibody that depletes CD19+ B-cells, is approved to treat aquaporin 4 (AQP4) IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD). Inebilizumab is afucosylated and engineered for enhanced affinity to Fc receptor III-A (FCGR3A) receptors on natural killer cells to maximize antibody-dependent cellular cytotoxicity. Previously, the F allele polymorphism at amino acid 158 of the FCGR3A gene (F158) was shown to decrease IgG-binding affinity and reduce rituximab (anti-CD20) efficacy for NMOSD attack prevention. In contrast, our current findings from inebilizumab-treated NMOSD patients indicate similar clinical outcomes between those with F158 and V158 allele genotypes.

A review of genetic risk in systemic lupus erythematosus

INTRODUCTION

Systemic Lupus Erythematosus (SLE) is a complex multisystem autoimmune disease with a wide range of signs and symptoms in affected individuals. The utilization of genome-wide association study (GWAS) technology has led to an explosion in the number of genetic risk factors mapped for autoimmune diseases, including SLE.

AREAS COVERED

In this review, we summarize the more recent genetic risk loci mapped in SLE, which bring the total number of loci mapped to approximately 200. We review prioritization analyses of the associated variants and experimental validation of the putative causal variants. This includes the implementation of new bioinformatic techniques to align genomic and functional data and the use of transcriptomics with single-cell RNA-sequencing, CRISPR genome editing, and Massive Parallel Reporter Assays to analyze non-coding regulatory genetics.

EXPERT OPINION

Despite progress in identifying more genetic risk loci and variant-gene pairs for SLE, understanding its pathogenesis and applying findings clinically remains challenging. The polygenic risk score (PRS) has been used as an application of SLE genetics, but with limited performance in non-EUR populations. In the next few years, advancements in proteomics, post-translational modification estimation, and whole-genome sequencing will enhance disease understanding.

Treatment of lupus nephritis: consensus, evidence and perspectives

Despite the continuing development of immunomodulatory agents and supportive care, the prognosis associated with lupus nephritis (LN) has not improved substantially in the past decade, with end-stage kidney disease still developing in 5-30% of patients within 10 years of LN diagnosis. Moreover, inter-ethnic variation in the tolerance of, clinical response to and level of evidence regarding various therapeutic regimens for LN has led to variation in treatment prioritization in different international recommendations. Modalities that better preserve kidney function and reduce the toxicities of concomitant glucocorticoids are unmet needs in the development of therapeutics for LN. In addition to the conventional recommended therapies for LN, there are newly approved treatments as well as investigational drugs in the pipeline, including the newer generation calcineurin inhibitors and biologic agents. In view of the heterogeneity of LN in terms of clinical presentation and prognosis, the choice of therapies depends on a number of clinical considerations. Molecular profiling, gene-signature fingerprints and urine proteomic panels might enhance the accuracy of patient stratification for treatment personalization in the future.