Autoimmune Responses and Therapeutic Interventions for Systemic Lupus Erythematosus: A Comprehensive Review

Systemic Lupus Erythematosus (SLE) or Lupus is a multifactorial autoimmune disease of multiorgan malfunctioning of extremely heterogeneous and unclear etiology that affects multiple organs and physiological systems. Some racial groups and women of childbearing age are more susceptible to SLE pathogenesis. Impressive progress has been made towards a better understanding of different immune components contributing to SLE pathogenesis. Recent investigations have uncovered the detailed mechanisms of inflammatory responses and organ damage. Various environmental factors, pathogens, and toxicants, including ultraviolet light, drugs, viral pathogens, gut microbiome metabolites, and sex hormones trigger the onset of SLE pathogenesis in genetically susceptible individuals and result in the disruption of immune homeostasis of cytokines, macrophages, T cells, and B cells. Diagnosis and clinical investigations of SLE remain challenging due to its clinical heterogeneity and hitherto only a few approved antimalarials, glucocorticoids, immunosuppressants, and some nonsteroidal anti-inflammatory drugs (NSAIDs) are available for treatment. However, the adverse effects of renal and neuropsychiatric lupus and late diagnosis make therapy challenging. Additionally, SLE is also linked to an increased risk of cardiovascular diseases due to inflammatory responses and the risk of infection from immunosuppressive treatment. Due to the diversity of symptoms and treatment-resistant diseases, SLE management remains a challenging issue. Nevertheless, the use of next-generation therapeutics with stem cell and gene therapy may bring better outcomes to SLE treatment in the future. This review highlights the autoimmune responses as well as potential therapeutic interventions for SLE particularly focusing on the recent therapeutic advancements and challenges.

The development of immunosorbents for the treatment of systemic lupus erythematosus via hemoperfusion

Systemic lupus erythematosus (SLE) is an autoimmune disease (AID) that involves multiple organ systems and is characterized by elevated levels of autoantibodies (ANA) and immune complexes. The immunoadsorption technique uses an extracorporeal clearance process to remove pathogenic toxins from patients' blood and alleviate disease symptoms. An immunosorbent is a key component of the immunoadsorption system that determines therapeutic efficacy and safety. Immunosorbents are prepared by immobilizing antibodies, antigens, or ligands with specific physicochemical affinities on a supporting matrix. Immunosorbents and pathogenic toxins bind via affinity adsorption, which involves electrostatic interactions, hydrogen bonds, hydrophobic interactions, and van der Waals forces. Immunosorbents are classified on the basis of their interaction mechanism with toxins into three categories: non-selective, semi-selective, and highly selective. This review aimed to summarize the current status of various commercial immunosorbents that are used to treat SLE. Moreover, recent developments in immunosorbents have heightened the need for a brief discussion about specific ligands and a supporting matrix.

Immunoadsorption Improves Remission Rates of Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis and Severe Kidney Involvement

INTRODUCTION

The role of plasma exchange in treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with severe kidney involvement is controversial. It is urgent to find effective treatments to improve prognosis of AAV patients. In this retrospective study, the outcomes of immunoadsorption (IA) onto protein A in AAV patients with severe kidney involvement were evaluated.

METHODS

Clinical data of 60 patients with AAV and severe kidney involvement were analyzed. Patients received cyclophosphamide or rituximab for remission induction, among which 16 were additionally treated with IA. Remission, end-stage kidney disease (ESKD), death, and relapse were compared.

RESULTS

Of 60 patients, 56 patients (93.3%) were positive for myeloperoxidase (MPO)-ANCA. At diagnosis, the estimated glomerular filtration rate and Birmingham Vasculitis Activity Score (BVAS) was 13.0 (7.7, 18.7) mL/min/1.73 m2 and 11.1 ± 3.4, respectively. After 3-17 days (mean 10.4 days) of induction treatment, the disease activity decreased more obviously in the IA group (p = 0.022) than the control group. IA showed superior over standard regimen in clearance of MPO-ANCA within 3-31 days (median 11 days) after treatment (78.4% vs. 9.3%, p = 0.005). After a median follow-up of 20.2 months, remission was achieved more quickly (p = 0.035) and higher (hazard ratio (HR) = 2.3, 95% confidence interval (CI): 1.1∼7.2, p = 0.033) in the IA group than the control group. IA therapy showed an advantage in reducing death (HR = 0.2, 95% CI: 0.1∼0.9, p = 0.032). There was no difference in developing into ESKD in both groups (HR = 0.7, 95% CI: 0.3∼2.0, p = 0.504). Multivariate Cox regression analysis indicated that early-stage remission was an independent predictor for ESKD (HR = 0.03, 95% CI: 0.003∼0.25, p = 0.001) and death (HR = 0.07, 95% CI: 0.01∼0.51, p = 0.009).

CONCLUSION

IA treatment induces quicker and higher remission and lower mortality in AAV patients with severe kidney involvement. The early remission independently predicts the outcomes for these patients.

Meta-analysis on the efficacy and safety of immunoadsorption for systemic lupus erythematosus among Chinese population

To systematically evaluate the efficacy and safety of immunoadsorption (IAS) versus non-IAS for systemic lupus erythematosus (SLE) among Chinese population. A meta-analysis was performed by all the literatures germane to estimate the SLE patients treated with IAS and non-IAS from published randomized controlled trials (RCTs) from 1990 to February 2020. Mean differences (MDs), relative ratios (RRs), and 95% confidence intervals (CIs) were calculated, and the meta-analysis was conducted with Stata 12.0 software. A total of 18 RCTs involving 457 patients were included. The results of meta-analysis demonstrated that the IgG, Scr, Bun, ANA, 24-h urine protein, leptin, and TNF-α of IAS combined with a drug therapy group were lower than that of non-IAS, and the levels of C3 and C4 were higher than that of non-IAS after treatment in terms of laboratory parameters. In terms of adverse reactions, the incidence of fever or chills, low blood pressure, or bleeding risk was higher in the treatment group. However, there was no difference in the incidence of puncture point bleeding, thrombocytopenia, mild rash, death due to severe infection, tightness, palpitation, or chest tightness between the two groups. However, most of the adverse effects could be considered as tolerable after timely treatment. Our results indicate that IAS may be superior to non-IAS in treating SLE patients. However, due to the lower quality of included studies, high quality of multicenter, large sample size, randomized, and double-blind controlled trials are needed to validate the results.

Functional autoantibodies targeting G protein-coupled receptors in rheumatic diseases

G protein-coupled receptors (GPCRs) comprise the largest and most diverse family of integral membrane proteins that participate in different physiological processes such as the regulation of the nervous and immune systems. Besides the endogenous ligands of GPCRs, functional autoantibodies are also able to bind GPCRs to trigger or block intracellular signalling pathways, resulting in agonistic or antagonistic effects, respectively. In this Review, the effects of functional GPCR-targeting autoantibodies on the pathogenesis of autoimmune diseases, including rheumatic diseases, are discussed. Autoantibodies targeting β1 and β2 adrenergic receptors, which are expressed by cardiac and airway smooth muscle cells, respectively, have an important role in the development of asthma and cardiovascular diseases. In addition, high levels of autoantibodies against the muscarinic acetylcholine receptor M3 as well as those targeting endothelin receptor type A and type 1 angiotensin II receptor have several implications in the pathogenesis of rheumatic diseases such as Sjögren syndrome and systemic sclerosis. Expanding the knowledge of the pathophysiological roles of autoantibodies against GPCRs will shed light on the biology of these receptors and open avenues for new therapeutic approaches.

Clinical efficacy comparison of HA280 and DNA280 immunoadsorption column in treating systemic lupus erythematosus

OBJECTIVE

The aim of this study was to compare the efficacy of HA280 and DNA280 immunoadsorption (IA) column in treating systemic lupus erythematosus (SLE), and provide the basis for seeking cost-effective solution for SLE.

METHODS

Fifty-seven severe SLE patients receiving IA treatment from January 2007 to December 2013 were selected. They were divided into HA280 group (31 cases) and DNA280 group (26 cases), which used HA280 and DNA280 IA column, respectively. The efficacy, adverse reactions, and hospitalization cost of the two groups were compared.

RESULTS

Both two groups could effectively reduce the SLE-associated antibodies, immunoglobulins, complement levels, serum creatinine, blood urea nitrogen, and 24-h urine protein levels (P < 0.05). The efficiency and incidence of adverse reactions of two groups were similar (P > 0.05), while the hospitalization cost of HA280 group was significantly less than that of DNA280 group (P < 0.05).

CONCLUSIONS

Application of HA280 IA column in IA treatment is relatively the most cost-effective adjuvant therapy to severe SLE.

The role of autoimmunity in thromboangiitis obliterans (Buerger's disease)

Thromboangiitis obliterans (TAO), or Buerger's disease, is a nonatherosclerotic segmental vasculitis that affects the small- and medium-sized arteries and veins of the extremities and is strongly associated with tobacco exposure. The immunopathogenesis of TAO remains largely unknown. In the acute phase of the disease, macrophages and occasional giant cells are observed in the characteristic intraluminal thrombus with a relatively mild infiltration of CD4(+) and CD8(+) T cells and macrophages in the internal lamina. VCAM-1, ICAM-1, and E-selectin expression on the surface of vascular endothelial cells is increased. A variety of circulating autoreactive antibodies targeting endothelial cells and vessel wall components are associated with active disease. One recent report suggests that removal of circulating antibodies by immunoadsorption may decrease disease severity. TAO has been associated positively and negatively with various MHC class 1 and 2 genes; however, genetic testing is not currently used for clinical diagnosis or management. The possible links between tobacco exposure and loss of tolerance for vascular tissues, current management strategy for patients with TAO, and opportunities for translational science are discussed.

Treatment of severe neurological deficits with IgG depletion through immunoadsorption in patients with Escherichia coli O104:H4-associated haemolytic uraemic syndrome: a prospective trial

BACKGROUND

In May 2011, an outbreak of Shiga toxin-producing enterohaemorrhagic E coli O104:H4 in northern Germany led to a high proportion of patients developing post-enteritis haemolytic uraemic syndrome and thrombotic microangiopathy that were unresponsive to therapeutic plasma exchange or complement-blocking antibody (eculizumab). Some patients needed ventilatory support due to severe neurological complications, which arose 1 week after onset of enteritis, suggesting an antibody-mediated mechanism. Therefore, we aimed to assess immunoadsorption as rescue therapy.

METHODS

In our prospective non-controlled trial, we enrolled patients with severe neurological symptoms and confirmed recent E coli O104:H4 infection without other acute bacterial infection or raised procalcitonin concentrations. We did IgG immunoadsorption processing of 12 L plasma volumes on 2 consecutive days, followed by IgG replacement (0·5 g/kg intravenous IgG). We calculated a composite neurological symptom score (lowest score was best) every day and assessed changes before and after immunoadsorption.

FINDINGS

We enrolled 12 patients who initially presented with enteritis and subsequent renal failure; 10 (83%) of 12 patients needed renal replacement therapy by a median of 8·0 days (range 5-12). Neurological complications (delirium, stimulus sensitive myoclonus, aphasia, and epileptic seizures in 50% of patients) occurred at a median of 8·0 days (range 5-15) and mandated mechanical ventilation in nine patients. Composite neurological symptom scores increased in the 3 days before immunoadsorption to 3·0 (SD 1·1, p=0·038), and improved to 1·0 (1·2, p=0·0006) 3 days after immunoadsorption. In non-intubated patients, improvement was apparent during immunoadsorption (eg, disappearance of aphasia). Five patients who were intubated were weaned within 48 h, two within 4 days, and two patients needed continued ventilation for respiratory problems. All 12 patients survived and ten had complete neurological and renal function recovery.

INTERPRETATION

Antibodies are probably involved in the pathogenesis of severe neurological symptoms in patients with E coli O104:H4-induced haemolytic uraemic syndrome. Immunoadsorption can safely be used to rapidly ameliorate these severe neurological complications.

FUNDING

Greifswald University and Hannover Medical School.