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

Therapeutic progress in the targeting of B cells in lupus nephritis: pathogenesis to clinical research

Lupus nephritis (LN) is a common complication in patients with systemic lupus erythematosus (SLE), where the key mechanism is the deposition of immune complexes in the kidneys, leading to renal damage. B lymphocytes play a crucial role in the pathogenesis of lupus nephritis through several pathways. These include the production of autoantibodies, which contribute to the deposition of immune complexes in the kidneys, activation of the complement system, and promotion of local inflammatory responses. Additionally, B cells act as antigen-presenting cells, facilitating T cell activation, and secrete proinflammatory cytokines that further exacerbate inflammation. Moreover, an imbalance in B cell subpopulations can worsen autoimmune damage, highlighting the complex role of B cells in the progression of LN. Targeting B cells has emerged as a promising therapeutic strategy, particularly for patients with relapsed or refractory LN. Recent advances in B cell-targeted therapies have shown significant clinical potential, offering new hope for better disease management. This review highlights the latest progress in B cell-targeted approaches for LN treatment and explores their potential to revolutionize care for this challenging condition.

B cell pathway dual inhibition for systemic lupus erythematosus: a prospective single-arm cohort study of telitacicept

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease associated with B-cell hyperactivity. Telitacicept is a transmembrane activator, calcium modulator, and cyclophilin ligand interactor-Fc fusion protein, which can neutralize both B-cell lymphocyte stimulator and a proliferation-inducing ligand. Patients with active SLE who received telitacicept were prospectively followed at month 1, 3, 6, 9, and 12 after telitacicept initiation. Thirty-seven participants were involved and followed for 6.00 [3.00, 6.00] months. SRI-4 rate at month 6 was 44.7%. The median dosage of prednisone was decreased by 43.8% (from 10 to 5.62 mg/d) at month 6. The anti-dsDNA level was significantly decreased, while complement levels were significantly increased at month 6 from baseline. Continuously significant reductions in serum immunoglobin (Ig)G IgA, and IgM levels were also observed. Patients experienced significant decreases in the numbers of total and naive B cells, whereas memory B cells and T cell populations did not change. The number of NK cells was significantly increased during the follow-up. At month 6, 58.3% (14 out of 24) patients experienced improved fatigue accessed by FACIT-Fatigue score exceeding the minimum clinically important difference of 4. Most adverse events were mild, but one each case of severe hypogammaglobulinemia, psychosis with suicidal behavior, and B-cell lymphoma were occurred. In our first prospective real-world study, telitacicept treatment led to a significant clinical and laboratory improvement of disease activity, as well as fatigue amelioration in patients with SLE. Safety profile was favorable overall, but more studies are greatly needed.

Belimumab treatment of adult idiopathic inflammatory myopathy

OBJECTIVE

To evaluate belimumab addition to the standard of care in patents with refractory idiopathic inflammatory myopathy (IIM).

METHODS

We conducted a 40-week multicentre, randomized, double-blind, placebo-controlled trial with 1:1 IV belimumab 10 mg/kg or placebo randomization and a 24-week open-label extension. Clinical responses were measured by the definition of improvement (DOI) and total improvement score (TIS). Flow cytometry analyses were performed on available samples before randomization, at 24 and 60-64 weeks. Descriptive statistics, t-test, Fisher's exact test and analysis of variance tests were used.

RESULTS

A total of 17 patients were randomized, 15 received five or more doses of belimumab or placebo and were included in the intention-to-treat analysis. More belimumab patients vs placebo attained a TIS ≥40 [55.5% vs 33.3%; P = non-significant (NS)] and achieved the DOI (33.3% vs 16.7%; P = NS) at weeks 40 and 64; the mean TIS was similar among groups. Two patients achieved major responses (TIS = 72.5) after week 40 in the belimumab arm and none in the placebo arm. No improvement in the placebo arm after switching to the open-label phase was observed. There was no steroid-sparing effect. No new safety signals were detected. Although total B cells were not reduced, belimumab induced naïve B cell depletion while enhancing the number and frequency memory B cells.

CONCLUSION

The study did not meet the primary endpoint and no statistically significant differences were observed in clinical responses between arms. More patients achieved sustained TIS ≥40 and reached the DOI. Most patients who received belimumab for >40 weeks had clinical improvement. Phenotypic changes in B cell populations were not associated with clinical responses.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov (https://clinicaltrials.gov/), NCT02347891.

Translational implications of newly characterized pathogenic pathways in systemic lupus erythematosus

Improved characterization of relevant pathogenic pathways in systemic lupus erythematosus (SLE) has been further delineated over the last decades. This led to the development of targeted treatments including belimumab and anifrolumab, which recently became available in clinics. Therapeutic targets in SLE encompass interferon (IFN) signaling, B-T costimulation including immune checkpoints, and increasing modalities of B lineage targeting, such as chimeric antigen receptor (CAR) T cells directed against CD19 or sequential anti-B cell targeting. Patient profiling based on characterization of underlying molecular abnormalities, often performed through comprehensive omics analyses, has recently been shown to better predict patients' treatment responses and also holds promise to unravel key molecular mechanisms driving SLE. SLE carries two key signatures, namely the IFN and B lineage/plasma cell signatures. Recent advances in SLE treatments clearly indicate that targeting innate and adaptive immunity is successful in such a complex autoimmune disease. Although those signatures may interact at the molecular level and provide the basis for the first selective treatments in SLE, it remains to be clarified whether these distinct treatments show different treatment responses among certain patient subsets. In fact, notwithstanding the remarkable amount of novel clues for innovative SLE treatment, harmonization of big data within tailored treatment strategies will be instrumental to better understand and treat this challenging autoimmune disorder. This review will provide an overview of recent improvements in SLE pathogenesis, related insights by analyses of big data and machine learning as well as technical improvements in conducting clinical trials with the ultimate goal that translational research results in improved patient outcomes.

Distinct gene dysregulation patterns herald precision medicine potentiality in systemic lupus erythematosus

OBJECTIVES

We aimed at investigating the whole-blood transcriptome, expression quantitative trait loci (eQTLs), and levels of selected serological markers in patients with SLE versus healthy controls (HC) to gain insight into pathogenesis and identify drug targets.

METHODS

We analyzed differentially expressed genes (DEGs) and dysregulated gene modules in a cohort of 350 SLE patients and 497 HC from the European PRECISESADS project (NTC02890121), split into a discovery (60%) and a replication (40%) set. Replicated DEGs qualified for eQTL, pathway enrichment, regulatory network, and druggability analysis. For validation purposes, a separate gene module analysis was performed in an independent cohort (GSE88887).

RESULTS

Analysis of 521 replicated DEGs identified multiple enriched interferon signaling pathways through Reactome. Gene module analysis yielded 18 replicated gene modules in SLE patients, including 11 gene modules that were validated in GSE88887. Three distinct gene module clusters were defined i.e., "interferon/plasma cells", "inflammation", and "lymphocyte signaling". Predominant downregulation of the lymphocyte signaling cluster denoted renal activity. By contrast, upregulation of interferon-related genes indicated hematological activity and vasculitis. Druggability analysis revealed several potential drugs interfering with dysregulated genes within the "interferon" and "PLK1 signaling events" modules. STAT1 was identified as the chief regulator in the most enriched signaling molecule network. Drugs annotated to 15 DEGs associated with cis-eQTLs included bortezomib for its ability to modulate CTSL activity. Belimumab was annotated to TNFSF13B (BAFF) and daratumumab was annotated to CD38 among the remaining replicated DEGs.

CONCLUSIONS

Modulation of interferon, STAT1, PLK1, B and plasma cell signatures showed promise as viable approaches to treat SLE, pointing to their importance in SLE pathogenesis.

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.