Efficacy of a sequential treatment by belimumab in monogenic systemic lupus erythematosus

How to treat monogenic SLE?

Systemic lupus erythematosus is a rare and life-threatening autoimmune disease characterized by autoantibodies against double-stranded DNA, with an immunopathology that remains partially unclear. New insights into the disease have been provided by the discovery of key mutations leading to the development of monogenic SLE, occurring in the context of early-onset disease, syndromic lupus, or familial clustering. The increased frequency of discovering these mutations in recent years, thanks to the advent of genetic screening, has greatly enhanced our understanding of the immunopathogenesis of SLE. These monogenic defects include defective clearance of apoptotic bodies, abnormalities in nucleic acid sensing, activation of the type-I interferon pathway, and the breakdown of tolerance through B or T cell activation or lymphocyte proliferation due to anomalies in TLR signalling and/or NFκB pathway overactivation. The translation of genetic discoveries into therapeutic strategies is presented here, within the framework of personalized therapy.

Early-onset lupus nephritis

Early-onset systemic lupus erythematous (SLE) is a distinct clinical entity characterized by the onset of disease manifestations during childhood. Despite some similarities to patients who are diagnosed during adulthood, early-onset SLE typically displays a greater disease severity, with aggressive multiorgan involvement, lower responsiveness to classical therapies, and more frequent flares. Lupus nephritis is one of the most severe complications of SLE and represents a major risk factor for long-term morbidity and mortality, especially in children. This review focuses on the clinical and histological aspects of early-onset lupus nephritis, aiming at highlighting relevant differences with adult patients, emphasizing long-term outcomes and discussing the management of long-term complications. We also discuss monogenic lupus, a spectrum of conditions caused by single gene variants affecting the complement cascade, extracellular and intracellular nucleic acid sensing and processing, and occasionally other metabolic pathways. These monogenic forms typically develop early in life and often have clinical manifestations that resemble sporadic SLE, whereas their response to standard treatments is poor.

[Rare Autoimmune Diseases Role of Genetics - Example of Systemic Lupus Erythematosus]

Systemic lupus erythematosus (SLE) presents a complex clinical landscape with diverse manifestations, suggesting a multifactorial etiology. However, the identification of rare monogenic forms of the disease has shed light on specific genetic defects underlying SLE pathogenesis, offering valuable insights into its underlying mechanisms and clinical heterogeneity. By categorizing these monogenic forms based on the implicated signaling pathways, such as apoptotic body clearance, type I interferon signaling, JAK-STAT pathway dysregulation, innate immune receptor dysfunction and lymphocytic abnormalities, a more nuanced understanding of SLE's molecular basis emerges. Particularly in pediatric populations, where monogenic forms are more prevalent, routine genetic testing becomes increasingly important, with a diagnostic yield of approximately 10% depending on the demographic and methodological factors involved. This approach not only enhances diagnostic accuracy but also informs personalized treatment strategies tailored to the specific molecular defects driving the disease phenotype.

Mendelian Causes of Autoimmunity: the Lupus Phenotype

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is characterized by its large heterogeneity in terms of clinical presentation and severity. The pathophysiology of SLE involves an aberrant autoimmune response against various tissues, an excess of apoptotic bodies, and an overproduction of type-I interferon. The genetic contribution to the disease is supported by studies of monozygotic twins, familial clustering, and genome-wide association studies (GWAS) that have identified numerous risk loci. In the early 70s, complement deficiencies led to the description of familial forms of SLE caused by a single gene defect. High-throughput sequencing has recently identified an increasing number of monogenic defects associated with lupus, shaping the concept of monogenic lupus and enhancing our insights into immune tolerance mechanisms. Monogenic lupus (moSLE) should be suspected in patients with either early-onset lupus or syndromic lupus, in male, or in familial cases of lupus. This review discusses the genetic basis of monogenic SLE and proposes its classification based on disrupted pathways. These pathways include defects in the clearance of apoptotic cells or immune complexes, interferonopathies, JAK-STATopathies, TLRopathies, and T and B cell dysregulations.

Safety and efficacy of biologics in childhood systemic lupus erythematosus: a critical systematic review

Biologic agents are increasingly being used to treat adult patients with systemic lupus erythematosus (SLE). However, the available data on biologic agents' use in childhood-onset SLE (cSLE) remains limited. To collate available evidence related to the efficacy and safety of using biologic agents in cSLE. The study followed the PRISMA checklist for reporting the data and conducted a thorough search using PubMed, Cochrane Library, and Scopus from January 2005 to August 2023. Only articles meeting specific criteria were included, focusing on cSLE, the use of biologic agents, and having outcome measures at six- and 12-month follow-ups for safety and efficacy. Case reports were excluded, and four independent reviewers screened the articles for accuracy, with a fifth reviewer resolving any discrepancies that arose to achieve a consensus. The final selection included 18 studies with a total of 593 patients treated with biologic agents for severe and/ or refractory cSLE. The most common indication for using biologic agents was lupus nephritis. Rituximab was used in 12 studies, while belimumab was used in six studies. The studies evaluated the efficacy of biologic agents based on SLE disease activity scores, laboratory parameter improvements, and reduced corticosteroid dosage. Positive outcomes were reported, with improvements in renal, hematologic, and immunologic parameters along with mild adverse effects, mostly related to mild infections and infusion reactions. Belimumab and rituximab have shown promise as potential treatments for severe and refractory cSLE cases, leading to decreased disease activity and complete or partial remission in many patients with an acceptable safety profile. However, further research is needed to better understand their benefits and potential risks in these patients. Key Points • This review emphasizes the lack of sufficient randomized controlled trials exploring the use of biologics in childhood systemic lupus erythematosus (cSLE). • Treatment plans for cSLE are being derived from those used for adult systemic lupus erythematosus. • According to current evidence, belimumab and rituximab can be potential treatment options for refractory and severe cases of cSLE. • Additional studies are required to reach more definitive conclusions.

Vasculitis and vasculopathy associated with inborn errors of immunity: an overview

Systemic autoinflammatory diseases (SAIDs) are disorders of innate immunity, which are characterized by unprovoked recurrent flares of systemic inflammation often characterized by fever associated with clinical manifestations mainly involving the musculoskeletal, mucocutaneous, gastrointestinal, and nervous systems. Several conditions also present with varied, sometimes prominent, involvement of the vascular system, with features of vasculitis characterized by variable target vessel involvement and organ damage. Here, we report a systematic review of vasculitis and vasculopathy associated with inborn errors of immunity.

Phenotype and disease course differences in monogenic and sporadic childhood lupus

OBJECTIVE

To report the differences in phenotypic characteristics, disease course, and outcome in monogenic and sporadic childhood lupus (SC-lupus) from a single tertiary childhood lupus clinic.

METHODS

A descriptive, observational, cross-sectional study was conducted. Data were retrospectively collected at the last follow-up visit on patients with monogenic lupus proven by genetic variants and SC-lupus seen between June 1997 and July 2022. SC-lupus patients were selected by systematic sampling from lupus patients presenting to our lupus clinic; the first patient was chosen randomly, and the subsequent patients were chosen at intervals of three. Data comprised the clinical and laboratory findings, disease activity using the SLEDAI, and damage measured by the pSDI.

RESULTS

A total of 54 patients with a median disease duration of 6.8 (IQR 3.5-10.5) years were included. There were 27 patients with monogenic lupus and 27 patients with SC-lupus, with a median age at disease onset of 3.5 (IQR 1.0-6.0), and 9.5 (IQR 7.0-11.8), respectively. (p < 0.05). The rate of consanguinity and family history of lupus were higher in monogenic lupus patients. The two groups were comparable. However, monogenic lupus patients showed more gastrointestinal tract symptoms, and failure to thrive (p < 0.05). They also had more infections. The frequency of the autoantibody profile was higher in monogenic lupus patients. Belimumab was more frequently used in monogenic lupus while rituximab in SC-lupus patients. Monogenic lupus patients had a higher mean SLEDAI, but statistically, it was insignificant. Patients with monogenic lupus had greater disease damage, with a higher mean pSDI and a higher mortality rate (p < 0.05).

CONCLUSION

Patients with monogenic lupus are likely to have an early disease onset and a strong family history of lupus, as well as a guarded prognosis, which is likely due to the disease's severity and frequent infections. These differences may be related to the high consanguinity rate and underlying genetic variants.

Monogenic lupus: Tracing the therapeutic implications from single gene mutations

Monogenic lupus, a distinctive variant of systemic lupus erythematosus (SLE), is characterized by early onset, family-centric clustering, and heightened disease severity. So far, over thirty genetic variations have been identified as single-gene etiology of SLE and lupus-like phenotypes. The critical role of these gene mutations in disrupting various immune pathways is increasingly recognized. In particular, single gene mutation-driven dysfunction within the innate immunity, notably deficiencies in the complement system, impedes the degradation of free nucleic acid and immune complexes, thereby promoting activation of innate immune cells. The accumulation of these components in various tissues and organs creates a pro-inflammatory microenvironment, characterized by a surge in pro-inflammatory cytokines, chemokines, reactive oxygen species, and type I interferons. Concurrently, single gene mutation-associated defects in the adaptive immune system give rise to the emergence of autoreactive T cells, hyperactivated B cells and plasma cells. The ensuing spectrum of cytokines and autoimmune antibodies drives systemic disease manifestations, primarily including kidney, skin and central nervous system-related phenotypes. This review provides a thorough overview of the single gene mutations and potential consequent immune dysregulations in monogenic lupus, elucidating the pathogenic mechanisms of monogenic lupus. Furthermore, it discusses the recent advances made in the therapeutic interventions for monogenic lupus.

Belimumab for the treatment of pediatric patients with lupus nephritis

INTRODUCTION

The FDA approved the anti-BAFF monoclonal antibody, belimumab, in 2011 for adult systemic lupus erythematosus (SLE), in 2019 for pediatric SLE, in 2020 for adult lupus nephritis (LN), and in 2022 for pediatric LN.

AREAS COVERED

We performed a PUBMED database search through November 2022, using 'belimumab and lupus nephritis,' 'belimumab and childhood systemic lupus erythematosus,' 'belimumab and pediatric systemic lupus erythematosus,' and 'belimumab and juvenile systemic lupus erythematosus' as the search phrases. We also vetted pertinent references cited in the papers gleaned from the above search, and we drew from our personal literature collections.

EXPERT OPINION

Based on clinical-trials and real-world experience, belimumab is useful and safe in adult SLE and LN. In contrast and despite FDA approval, evidence of effectiveness in pediatric SLE and pediatric LN is very limited. Whereas there was a trend favoring belimumab in the only randomized, controlled trial to date in pediatric SLE, the difference between the belimumab and placebo groups failed to achieve statistical significance. Moreover, there have been no randomized, controlled trials for belimumab in pediatric LN. Based largely on information gleaned from experience in adults, the clinician can cautiously prescribe belimumab to his/her pediatric LN patient and hope for benefit.

Belimumab in childhood systemic lupus erythematosus: A review of available data

Introduction

Childhood systemic lupus erythematosus (cSLE) is a complex multisystem autoimmune disease. In 2019, belimumab was approved for the clinical treatment for cSLE, making it the only biological agent approved for cSLE children aged 5 and older in 60 years.

Objective

To review emerging evidence on belimumab in cSLE published up to April 2022, so as to provide information for clinical decision-making.

Method

A comprehensive search of relevant publications up to the date of April 2022 in PUBMED, EMBASE, WOS, COCHRANE, ClinicalTrials.gov, CBM, CNKI and WANFANG was performed using the following criteria: (a) English and Chinese language studies; (b) RCT studies, cohort studies, or case-control studies; (c) patients with age &lt;18; (d) Observational studies or case series studies contain more than 5 patients. All relevant literature was independently screened and reviewed by at least two reviewers and the obtained literature data were extracted and reviewed by two authors.

Results

Five publications met the inclusion/exclusion criteria for cSLE: one randomized controlled trial, one retrospective cohort study, and three case series. There was a high degree of heterogeneity among several studies, and the availability of baseline and outcome data provided was uneven.

Conclusion

At present, there is a lack of high-quality clinical trials of belimumab in the treatment of cSLE. Based on the current research, it is believed that the use of belimumab can inhibit cSLE activity, reduce the dose of corticosteroids and immunosuppressants, and delay kidney damage. Also it shows clinical benefit in alleviating symptoms of monogenic cSLE refractory to standard therapy. More studies are urgently needed to validate the clinical efficacy of belimumab in cSLE and to evaluate its long-term safety in pediatric populations to promote evidence-based practice.