Belimumab in the treatment of systemic lupus erythematous: An evidence based review of its place in therapy

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Calcinosis Cutis and Calciphylaxis in Autoimmune Connective Tissue Diseases

Calcinosis represents a severe complication of several autoimmune disorders. Soft-tissue calcifications have been classified into five major types: dystrophic, metastatic, idiopathic, iatrogenic, and calciphylaxis. Autoimmune diseases are usually associated with dystrophic calcifications, including calcinosis cutis, occurring in damaged or devitalized tissues in the presence of normal serum levels of calcium and phosphate. In particular, calcinosis cutis has been described in dermatomyositis, polymyositis, juvenile dermatomyositis, systemic sclerosis, systemic lupus erythematosus, primary Sjögren's syndrome, overlap syndrome, mixed connective tissue disease, and rheumatoid arthritis. Calciphylaxis, a severe and life-threatening syndrome presenting with vascular calcifications and thrombosis, has also been associated with some autoimmune conditions. Due to the potentially disabling character of calcinosis cutis and calciphylaxis, physicians' awareness about the clinical presentation and management of these diseases should be increased to select the most appropriate treatment option and avoid long-term complications. In this review, we aim to analyze the clinical features of calcinosis cutis and calciphylaxis associated with autoimmune diseases, and the main treatment strategies evaluated up to now for treating this potentially disabling disease.

Mechanism of Action and Efficacy of Immunosupressors in Lupus Nephritis

Approximately 70% of the patients with systemic lupus erythematosus will have clinical evidence of kidney damage during their evolution. Patients with impaired renal function at onset and those with recurrent flares have a poor prognosis. Understanding the mechanism of action of immunosuppressants is essential for proper prescription. Steroids inhibit the DNA sequence that promotes the release of inflammatory cytokines. Phosphoramide mustard, metabolite of cyclophosphamide, cross-link with the DNA, causing the aggregation of an alkyl group, causing cell death. Mycophenolate inhibits inosine monophosphate dehydrogenase, prevents de novo synthesis of guanine, inducing cell arrest in S phase. Azathioprine blocks the synthesis of purines and induces apoptosis. Calcineurin inhibitors prevent the dephosphorylation of NFAT and reduce the production of interleukin 2. Antimalarials alter the enzymatic release of lysosomes by increasing intravesicular pH. The mechanism of action of rituximab is related to complement-dependent cytotoxicity and the elimination of anti-CD20-labeled B cells. Progress in the knowledge and management of low doses of steroids may change the current paradigm and reduce the frequency of related adverse events. Mycophenolate seems to be a better choice than cyclophosphamide for induction, it is also preferred over azathioprine as a maintenance immunosuppressive agent, although azathioprine is preferred in women with a desire for conception, those pregnant, or with low resources. For treatment-resistant cases, tacrolimus, rituximab or belimumab may be effective. Ongoing clinical trials with new drugs offer promising results.

Azithromycin alleviates systemic lupus erythematosus via the promotion of M2 polarisation in lupus mice

Our previous study demonstrated that azithromycin could promote alternatively activated (M2) macrophages under lupus conditions in vitro, which might be beneficial for lupus treatment. Thus, the aim of this study was to further confirm whether azithromycin can drive M2 polarisation in lupus and ultimately alleviate systemic lupus erythematosus (SLE) in vivo. Lymphocyte-derived DNA (ALD-DNA)-induced mice (induced lupus model) and MRL-Fas^lpr mice (spontaneous lupus model) were both used in the experiment. First, we observed symptoms of lupus by assessing the levels of serum anti-dsDNA antibodies and serum creatinine and renal pathology. We found that both murine models showed increased levels of serum anti-dsDNA antibodies and creatinine, enhanced glomerular fibrosis and cell infiltration, basement membrane thickening and elevated IgG deposition. After azithromycin treatment, all these medical indexes were alleviated, and kidney damage was effectively reversed. Next, macrophage polarisation was assessed in the spleen and kidneys. Macrophage infiltration in the spleen was notably decreased after azithromycin treatment in both murine models, with a remarkably elevated proportion of M2 macrophages. In addition, the expression of interleukin (IL)-1, IL-6, tumour necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), CD86, toll-like receptor (TLR)2 and TLR4 was extremely downregulated, while the expression of transforming growth factor (TGF)-β, arginase-1 (Arg-1), chitinase-like 3 (Ym-1), found in inflammatory zone (Fizz-1) and mannose receptor (CD206) was significantly upregulated in the kidneys after azithromycin treatment. Taken together, our results indicated for the first time that azithromycin could alleviate lupus by promoting M2 polarisation in vivo. These findings exploited the newly discovered potential of azithromycin, a conventional drug with verified safety, affordability and global availability, which could be a novel treat-to-target strategy for SLE via macrophage modulation.

B Cell-Activating Factor Promotes B Cell Survival in Ectopic Lymphoid Tissues in Nasal Polyps

Ectopic lymphoid tissues (eLTs) characterized by B cell aggregation contribute to the local immunoglobulin production in nasal polyps (NPs). B cell-activating factor (BAFF) is vital for B cell survival, proliferation, and maturation. The purpose of this study is to investigate whether BAFF is involved in the B cell survival and eLT formation in NPs. The mRNA and protein levels of BAFF in NP tissues with and without eLTs were detected by PCR and ELISA assay, respectively. The cellular sources of BAFF and active caspase-3-positive B cells in NPs were studied by immunofluorescence staining. B cells purified from NP tissues were stimulated with BAFF and were analyzed by flow cytometry. Stromal cells purified from NP tissues were stimulated with lymphotoxin (LT) α₁β_2, and BAFF levels in culture supernatants were analyzed by ELISA. Compared with those in control tissues and NPs without eLTs, the BAFF levels were elevated in NPs with eLTs. Abundant BAFF-positive cells and few active caspase-3-positive apoptotic B cells were found in NPs with eLTs, in contrast to those in NPs without eLTs. There was a negative correlation between the numbers of BAFF-positive cells and frequencies of apoptotic B cells in total B cells in NP tissues. BAFF protected nasal polyp B cells from apoptosis in vitro. Stromal cells were an important cellular source of BAFF in NPs with eLTs. LTα₁β₂ induced BAFF production from nasal stromal cells in vitro. We propose that BAFF contribute to eLT formation in NPs by promoting B cell survival.

A label-free impedance assay in endothelial cells differentiates the activation and desensitization properties of clinical S1P1 agonists

Sphingosine-1 phosphate receptor-1 (S1P1 ) activation maintains endothelial barrier integrity, whereas S1P1 desensitization induces peripheral blood lymphopenia. The latter is exploited in the approval and/or late-stage development of receptor-desensitizing agents targeting the S1P1 receptor in multiple sclerosis, such as siponimod, ozanimod, and ponesimod. SAR247799 is a recently described G protein-biased S1P1 agonist that activates S1P1 without desensitization and thus has endothelial-protective properties in patients without reducing lymphocytes. As SAR247799 demonstrated endothelial-protective effects at sub-lymphocyte-reducing doses, the possibility exists that other S1P1 modulators could also exhibit endothelial-protective properties at lower doses. To explore this possibility, we sought to quantitatively compare the biased properties of SAR247799 with the most advanced clinical molecules targeting S1P1 . In this study, we define the β-arrestin pathway component of the impedance profile following S1P1 activation in a human umbilical vein endothelial cell line (HUVEC) and report quantitative indices of the S1P1 activation-to-desensitization ratio of various clinical molecules. In a label-free impedance assay assessing endothelial barrier integrity and disruption, the mean estimates (95% confidence interval) of the activation-to-desensitization ratios of SAR247799, ponesimod, ozanimod, and siponimod were 114 (91.1-143), 7.66 (3.41-17.2), 6.35 (3.21-12.5), and 0.170 (0.0523-0.555), respectively. Thus, we show that SAR247799 is the most G protein-biased S1P1 agonist currently characterized. This rank order of bias among the most clinically advanced S1P1 modulators provides a new perspective on the relative potential of these clinical molecules for improving endothelial function in patients in relation to their lymphocyte-reducing (desensitization) properties.

[Resistant and progressive cutaneous lupus erythematosus treated with belimumab: A retrospective monocentric study]

BACKGROUND

Belimumab is currently approved for the treatment of active systemic lupus erythematosus (SLE). The aim of our study was to evaluate the efficacy of belimumab in the treatment of cutaneous lupus erythematosus (CLE), resistant to conventional therapy.

PATIENTS AND METHODS

Seven patients with resistant and progressive LEC and treated with belimumab were retrospectively analyzed. The efficacy and safety of belimumab were evaluated with the CLASI, RCLASI and DLQI scores, after 6 to 12 months of treatment.

RESULTS

Eighty-three percent of patients demonstrated a significant clinical improvement based on the CLASI and RCLASI activity scores, including 1 complete and 4 partial responses, without worsening of CLASI and RCLASI damage scores. Eighty percent of patients also showed an improvement of their quality of life (DLQI). Oral corticosteroids were discontinued in all patients. Tolerance was acceptable with only one serious adverse event (bacteriema).

CONCLUSION

Our study suggests the clinical efficiency of belimumab in a series of 7 patients presenting a resistant and progressive CLE.

Belimumab treatment in rhupus: A case report with severe skin involvement

Patients with rhupus characteristically exhibit symmetric polyarthritis and clinical manifestations suggestive of systemic lupus erythematosus (malar rash, photosensitivity, hematological manifestations, serositis, and/or skin involvement) and positive anti-dsDNA. Treatment is unclear and it can include disease-modifying rheumatic drugs like hydroxyl chloroquine, or methotrexate or, in refractory cases, rituximab or abatacept. We report a case of 31-year-old female who present with rhupus with skin acute lesions treated with belimumab. This is the first case of rhupus treated with this drug described in the literature.

BAFF-driven B cell hyperplasia underlies lung disease in common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency and is frequently complicated by interstitial lung disease (ILD) for which etiology is unknown and therapy inadequate.

METHODS

Medical record review implicated B cell dysregulation in CVID ILD progression. This was further studied in blood and lung samples using culture, cytometry, ELISA, and histology. Eleven CVID ILD patients were treated with rituximab and followed for 18 months.

RESULTS

Serum IgM increased in conjunction with ILD progression, a finding that reflected the extent of IgM production within B cell follicles in lung parenchyma. Targeting these pulmonary B cell follicles with rituximab ameliorated CVID ILD, but disease recurred in association with IgM elevation. Searching for a stimulus of this pulmonary B cell hyperplasia, we found B cell-activating factor (BAFF) increased in blood and lungs of progressive and post-rituximab CVID ILD patients and detected elevation of BAFF-producing monocytes in progressive ILD. This elevated BAFF interacts with naive B cells, as they are the predominant subset in progressive CVID ILD, expressing BAFF receptor (BAFF-R) within pulmonary B cell follicles and blood to promote Bcl-2 expression. Antiapoptotic Bcl-2 was linked with exclusion of apoptosis from B cell follicles in CVID ILD and increased survival of naive CVID B cells cultured with BAFF.

CONCLUSION

CVID ILD is driven by pulmonary B cell hyperplasia that is reflected by serum IgM elevation, ameliorated by rituximab, and bolstered by elevated BAFF-mediated apoptosis resistance via BAFF-R.

FUNDING

NIH, Primary Immune Deficiency Treatment Consortium, and Rare Disease Foundation.

Refractory lupus nephritis: When, why and how to treat

Refractory lupus nephritis indicates an inadequate response to lupus nephritis therapy. It implies persisting or worsening disease activity despite therapy, but the definition is complicated by the parameters of response, proteinuria and renal function, that do not discriminate clearly between activity and irreversible damage. Understanding the causes of refractory disease and developing treatment strategies is important because these patients are more likely to develop poor outcomes, especially end stage renal disease. This review explores current concepts and definitions of refractory disease and summarises treatment approaches that have been used in observational cohort studies and case series. We highlight the importance of optimising adherence to the prescribed immunosuppressive and supportive measures and avoidance of diagnostic delay. Treatment options include higher dose glucocorticoid, switching between cyclophosphamide and mycophenolate acid derivates, or addition of rituximab, the latter potentially in combination with belimumab. Less evidence supports extracorporeal treatment (plasma exchange or immunoadsorption), calcineurin inhibitors (cyclosporine A or tacrolimus), intravenous immunoglobulin and stem cell transplantation. Improvements in understanding what refractory disease is and how definitions can be integrated into treatment pathways has the potential to enhance lupus nephritis outcomes.

Immunogenicity, safety and tolerability of anti-pneumococcal vaccination in systemic lupus erythematosus patients: An evidence-informed and PRISMA compliant systematic review and meta-analysis

The immunological perturbations associated with systemic lupus erythematosus (SLE) put many patients at a higher risk of infections, including pneumococcal pneumonia. However, the uptake and utility of anti-pneumococcal vaccines in SLE patient is both controversial and not completely agreed upon. Indeed, several epidemiological studies of anti-pneumococcal vaccine safety and efficacy in SLE have reported short-term immunogenicity with elevated anti-pneumococcal antibody titres but inconsistent long-term findings, with some studies finding poor responses, mainly for long-term immune protection. Moreover, the safety and efficacy of the pneumococcal vaccine in SLE patients remains controversial due to the different types of anti-pneumococcal vaccines, and the heterogeneity of SLE patients. Several reviews addressing anti-pneumococcal vaccination in SLE patients exist, however, to the best of our knowledge, the present is the first systematic review and meta-analysis. To better understand the efficacy and safety of pneumococcal vaccination in SLE, a comprehensive literature search was performed identifying 18 studies, which have been included in the present systematic review and meta-analysis. All studies were designed as longitudinal investigations, 2, in particular, were of high quality, being randomized, double-blind trials (RCTs). Four studies had control groups. Total sample size included 601 participants. Vaccine immunogenicity in terms of subjects with protective antibody titers ranged from 36% to 97.6%. According to our systematic review and metanalysis, high erythrocyte sedimentation rate (ESR), older age, earlier SLE onset, high disease activity, and immunosuppressive therapy were predictors of poor immunogenicity, although belimumab was found to have no significant impact. With regard to safety, no serious adverse events were found, with up to one third of cases reporting mild/low-grade complaints. In conclusion, due to the high risk of pneumococcal infection in SLE patients and given the safety and, at least partial, effectiveness, according to our systematic review and meta-analysis, in such patients, preventive strategies mainly by immunization, are required in all age groups and, in those needing immunosuppressive therapy, immunization should be given prior the initiation of the treatment. PROSPERO registration code CRD42018103605.

Systemic Lupus Erythematosus in Primary Care: An Update and Practical Messages for the General Practitioner

Systemic Lupus Erythematosus (SLE) is a complex chronic autoimmune disease that manifests a wide range of organ involvement. Traditionally, the diagnosis and management of SLE is provided at secondary and tertiary centers to ensure prompt initiation of treatment, adequate control of flares and prevention of irreversible organ damage. Notwithstanding, the role of primary care in SLE is also emerging as there are still significant unmet needs such as the diagnostic delay at the community level and the high burden of therapy- and disease-related comorbidities. In the present review, we summarize practical messages for primary care physicians and general practitioners (GPs) concerning early diagnosis and proper referral of patients with SLE. In addition, we discuss the main comorbidities complicating the disease course and the recommended preventative measures, and we also provide an update on the role and current educational needs of GPs regarding the disease.