SLE and Serum Complement: Causative, Concomitant or Coincidental?

Celastrol ameliorates lupus by promoting apoptosis of autoimmune T cells and preventing autoimmune response in MRL/lpr mice

OBJECTIVE

Celastrol is a bioactive constituent extracted from Tripterygium wilfordii (thunder god vine). It has been demonstrated to have a therapeutic effect on experimental disease models for chronic inflammatory and immune disorders. In the present study, we investigated whether and how celastrol exerts a regulatory effect on the autoimmune response in MRL/lpr mice.

METHODS

We performed an in vivo study to determine the therapeutic effects of celastrol in MRL/lpr mice and then further investigated the underlying mechanism of celastrol in the regulation of the autoimmune response in MRL/lpr mice.

RESULTS

Celastrol showed a therapeutic effect in MRL/lpr mice by preventing the enlargement of the spleen and lymph nodes, alleviating renal injury, and reducing the levels of ANA and anti-double-stranded DNA antibodies. Furthermore, celastrol suppressed the in vivo inflammatory response in MRL/lpr mice by reducing the serum levels of multiple cytokines, including interleukin (IL)-6, tumour necrosis factor (TNF) and interferon (IFN)-γ, and the production of multiple antibody subsets, including total IgG, IgG1 and IgG2b. In vitro, celastrol reduced anti-CD3 antibody stimulation-induced T helper 1 and TNF-producing cells in CD4+ T cells of MRL/lpr mice. In addition, celastrol significantly affected B cell differentiation and prevented the generation of plasma cells from B cells in MRL/lpr mice by reducing the frequency of activated and germinal centre B cells. Celastrol treatment also affected T cell differentiation and significantly reduced central memory T cell frequencies in MRL/lpr mice. Importantly, celastrol treatment specifically promoted apoptosis of CD138+ but not CD138- T cells to suppress autoimmune T cell accumulation in MRL/lpr mice.

CONCLUSIONS

Celastrol exerted therapeutic effects on lupus by specifically promoting apoptosis of autoimmune T cells and preventing the progression of autoimmune response.

Upregulation of CX3CR1 expression in circulating T cells of systemic lupus erythematosus patients as a reflection of autoimmune status through characterization of cytotoxic capacity

OBJECTIVE

This study investigated CX3CR1 expression in human peripheral blood T lymphocytes and their subsets, exploring changes in SLE patients and its diagnostic potential.

METHODS

Peripheral blood samples from 31 healthy controls and 50 SLE patients were collected. RNA-Seq data from SLE patient PBMCs were used to analyze CX3CR1 expression in T cells. Flow cytometry determined CX3CR1-expressing T lymphocyte subset proportions in SLE patients and healthy controls. Subset composition and presence of GZMB, GPR56, and perforin in CX3CR1+ T lymphocytes were analyzed. T cell-clinical indicator correlations were assessed. ROC curves explored CX3CR1's diagnostic potential for SLE.

RESULTS

CX3CR1+CD8+ T cells exhibited higher GPR56, perforin, and GZMB expression than other T cell subsets. The proportion of CX3CR1+ was higher in TEMRA and lower in Tn and TCM. PMA activation reduced CX3CR1+ T cell proportions. Both RNA-Seq and flow cytometry revealed elevated CX3CR1+ T cell proportions in SLE patients. Significantly lower perforin+ and GPR56+ proportions were observed in CX3CR1+CD8+ T cells in SLE patients. CX3CR1+ T cells correlated with clinical indicators.

CONCLUSION

CX3CR1+ T cells display cytotoxic features, with heightened expression in CD8+ T cells, particularly in adult SLE patients. Increased CX3CR1 expression in SLE patient T cells suggests its potential as an adjunctive diagnostic marker for SLE.

Complement levels during the first trimester predict disease flare and adverse pregnancy outcomes in systemic lupus erythematosus: A network meta-analysis on 532 pregnancies

BACKGROUND

Complement levels have been proposed as candidate biomarkers of disease activity and obstetric risk in systemic lupus erythematosus (SLE) pregnancies, but their reliability has been questioned due to the physiologic fluctuations of complement during gestation. Thus, this network meta-analysis aimed at assessing the clinical significance of complement fluctuations in lupus pregnant women.

METHODS

Corresponding authors of 19 studies meeting inclusion criteria were invited to contribute with additional data including C3 and C4 levels [before pregnancy, at conception, in every trimester (T) and 3 months after delivery]; data were pooled together in a network meta-analysis.

RESULTS

A total of 532 lupus women from four studies were included in the analysis. In SLE women, C3 and C4 increased progressively during gestation: levels remained stable during T1 and peaked in T2 to decrease in T3. Patients with previous lupus nephritis (LN) and those who experienced flares during pregnancy had significantly lower mean levels of C3 and C4 at all timepoints. The lowest levels of complement were observed, particularly during T1, in patients with LN and gestational flare. Both reduction and the lack of increase of C3 and C4 levels at T1 versus conception were associated with gestational flares, particularly in LN patients. Pregnancies with flare had a statistically significant higher rate of maternal and fetal complications(60% versus 50.3%; p = 0.03).

CONCLUSIONS

Low complement levels, particularly in T1, were associated with a higher frequency of gestational flare. Either reduction or smaller increase of C3 and/or C4 levels, even within normal range, might predict flares especially in early gestation.

Phospholipase D4 as a signature of toll-like receptor 7 or 9 signaling is expressed on blastic T-bet + B cells in systemic lupus erythematosus

BACKGROUND

In systemic lupus erythematosus (SLE), autoreactive B cells are thought to develop by-passing immune checkpoints and contribute to its pathogenesis. Toll-like receptor (TLR) 7 and 9 signaling have been implicated in their development and differentiation. Although some B cell subpopulations such as T-bet + double negative 2 (DN2) cells have been identified as autoreactive in the past few years, because the upregulated surface markers of those cells are not exclusive to them, it is still challenging to specifically target autoreactive B cells in SLE patients.

METHODS

Our preliminary expression analysis revealed that phospholipase D4 (PLD4) is exclusively expressed in plasmacytoid dendritic cells (pDCs) and B cells in peripheral blood mononuclear cells (PBMCs) samples. Monoclonal antibodies against human PLD4 were generated, and flow cytometry analyses were conducted for PBMCs from 23 healthy donors (HDs) and 40 patients with SLE. In vitro cell culture was also performed to study the conditions that induce PLD4 in B cells from HDs. Finally, recombinant antibodies were synthesized from subpopulations of PLD4 + B cells from a patient with SLE, and their antinuclear activity was measured through enzyme-linked immunosorbent assay.

RESULTS

pDCs from both groups showed comparable frequency of surface PLD4 expression. PLD4 + B cells accounted for only a few percent of HD B cells, whereas they were significantly expanded in patients with SLE (2.1% ± 0.4% vs. 10.8% ± 1.2%, P < 0.005). A subpopulation within PLD4 + B cells whose cell size was comparable to CD38 + CD43 + plasmablasts was defined as "PLD4 + blasts," and their frequencies were significantly correlated with those of plasmablasts (P < 0.005). PLD4 + blasts phenotypically overlapped with double negative 2 (DN2) cells, and, in line with this, their frequencies were significantly correlated with several clinical markers of SLE. In vitro assay using healthy PBMCs demonstrated that TLR7 or TLR9 stimulation was sufficient to induce PLD4 on the surface of the B cells. Finally, two out of three recombinant antibodies synthesized from PLD4 + blasts showed antinuclear activity.

CONCLUSION

PLD4 + B cells, especially "blastic" ones, are likely autoreactive B cells undergoing TLR stimulation. Therefore, PLD4 is a promising target marker in SLE treatment.

The correlation between trajectories of serum C3 variability and clinical course in Pediatric-onset systemic lupus erythematosus

OBJECTIVE

The aim of this study is to investigate the usefulness which 2-year trajectories of C3 variability have in predicting clinical remission and systemic corticosteroids (SCS) use in pediatric patients with systemic lupus erythematosus (pSLE).

METHODS

We recruited 189 confirmed pSLE patients from the electronic database of our hospital, all had undergone SCS treatment. The follow up period was 4.17-14.83 years. We used Group-Based Trajectory modeling to divide the patients into four different trajectory groups by their initial 2-year C3 variability. We divided the patients into groups A, B or C by their clinical course and SCS use. Statistical methods included Kruskal-Wallis and Chi-square tests and logic regression test.

RESULTS

There were 4 separate trajectories. The distribution of groups A, B and C in these 4 trajectories showed a significant difference (p = 0.005). Initial C3 and C4 levels in these 4 revealed significant differences (p ≦ 0.001, p ≦ 0.016). When compared to other trajectories, trajectory1 showed a higher risk for persistent SCS use (p < 0.05). The distributions of severe clinical manifestations, including proteinuria, hematuria, CNS involvement and thrombocytopenia were different in these 4 trajectories (p = 0.003). Nevertheless, none of the above manifestations contributed to the risk of persistent SCS use.

CONCLUSIONS

We have found 4 distinct C3 trajectories in pSLE patients. Distributions of clinical outcome groups were different in these 4 trajectories. Patients with trajectory1 displayed a higher risk for persistent SCS use, thus an earlier institution of immunosuppressant(s) and biological agents can be considered for these children.

Interferons and systemic lupus erythematosus: Pathogenesis, clinical features, and treatments in interferon-driven disease

Type I interferons (IFNs) have recently received a lot of attention with the elucidation of the pathogenesis of systemic lupus erythematosus (SLE). Type I IFNs are associated with many SLE symptoms and play a role in the pathogenesis of autoimmune diseases that may occur concurrently with SLE, such as Sjögren's syndrome, antiphospholipid syndrome, myositis, scleroderma, and interferonopathy. Type I IFNs could be the link between these diseases. However, direct measurement of type I IFN levels and the IFN gene signature is currently unavailable in clinical practice. This review discusses type I IFN signalling in SLE, investigates the role of type I IFN in the clinical manifestations and symptoms associated with SLE and other IFN-related diseases, and discusses the clinical tests that can be used to diagnose SLE and measure disease activity. In addition, the role of type I IFN-blocking therapies as potential treatments for SLE is discussed.

Gut microbiota: a newly identified environmental factor in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that predominantly affects women of childbearing age and is characterized by the damage to multiple target organs. The pathogenesis of SLE is complex, and its etiology mainly involves genetic and environmental factors. At present, there is still a lack of effective means to cure SLE. In recent years, growing evidence has shown that gut microbiota, as an environmental factor, triggers autoimmunity through potential mechanisms including translocation and molecular mimicry, leads to immune dysregulation, and contributes to the development of SLE. Dietary intervention, drug therapy, probiotics supplement, fecal microbiome transplantation and other ways to modulate gut microbiota appear to be a potential treatment for SLE. In this review, the dysbiosis of gut microbiota in SLE, potential mechanisms linking gut microbiota and SLE, and immune dysregulation associated with gut microbiota in SLE are summarized.

Does kidney biopsy in pediatric lupus patients "complement" the management and outcomes of silent lupus nephritis? Lessons learned from a pediatric cohort

BACKGROUND

Silent lupus nephritis (SLN) is systemic lupus erythematosus (SLE) without clinical and laboratory features of kidney involvement but with biopsy-proven nephritis. This study aims to describe and compare the baseline characteristics and outcomes of pediatric SLN with overt LN (OLN) and to identify associated risk factors and biochemical markers.

METHODS

In this retrospective, observational study, multivariate logistic regression and receiver operating characteristic (ROC) analyses studied age, sex, race, serum complements, anti-double-stranded-DNA antibody, anti-Smith antibody, eGFR, and proliferative nephritis.

RESULTS

In our cohort of 69 patients, 47 were OLN, and 22 were SLN. OLN (OR = 4.9, p = 0.03) and non-African Americans (AA) (OR = 13.0, p < 0.01) had higher odds, and increasing C3 and C4 were associated with lower odds of proliferative nephritis (OR 0.95 and 0.65 per one unit increase in C3 and C4, respectively, p < 0.01). They demonstrated a good discriminative ability to detect proliferative nephritis as assessed by the area under the ROC curve (C3 = 0.78, C4 = 0.78). C3 and C4 in proliferative SLN and OLN were comparable and significantly lower than their non-proliferative counterparts. No association was observed between age, sex, anti-double-stranded-DNA antibody, anti-Smith antibody, eGFR, and proliferative nephritis. Proliferative SLN and OLN patients received similar treatments. Adverse events were identified in the proliferative OLN only.

CONCLUSIONS

Lower complement levels are associated with proliferative lesions in pediatric LN-both SLN and OLN. The non-AA population had higher odds of having proliferative nephritis than the AA. Prospective, randomized, long-term follow-up of proliferative SLN patients is needed to ascertain the beneficial effect of early diagnosis and treatment. A higher resolution version of the Graphical abstract is available as Supplementary information.

The mosaic of autoimmunity - Finally discussing in person. The 13th international congress on autoimmunity 2022 (AUTO13) Athens

While autoimmunity is a branch of medicine linked to every single organ system via direct and indirect pathways, meeting in person to discuss autoimmunity during the 13^th international congress on autoimmunity (AUTO13) with participants from all over the world had a very good reason. The mechanisms involved in autoimmune diseases are of extreme importance and in fact critical in understanding the course of diseases as well as selecting proper therapies. COVID-19 has served as a great example of how autoimmunity is deeply involved in the disease and directly correlated to severity, morbidity, and mortality. For instance, initially the term cytokine storm dominated, then COVID-19 was addressed as the new member of the hyperferritinemic syndrome, and also the use of immunosuppressants in patients with COVID-19 throughout the pandemic, all shed light on the fundamental role of autoimmunity. Unsurprisingly, SARS-CoV-2 was called the “autoimmune virus” during AUTO13. Subsequently, the correlation between autoimmunity and COVID-19 vaccines and post-COVID, all were discussed from different autoimmune aspects during the congress. In addition, updates on the mechanisms of diseases, autoantibodies, novel diagnostics and therapies in regard to autoimmune diseases such as antiphospholipid syndrome, systemic lupus erythematosus, systemic sclerosis and others, were discussed in dedicated sessions. Due to the magnificence of the topics discussed, we aimed to bring in our article hereby, the pearls of AUTO13 in terms of updates, new aspects of autoimmunity, and interesting findings. While more than 500 abstract were presented, concluding all the topics was not in reach, hence major findings were summarized.

Elevated levels of C3 , C4 , and CH50 of the complement system in ICU and non‐ICU patients with COVID ‐19

Purpose

SARS‐CoV‐2 infection has spread in each corner of the world. Many health systems have dealt with it intensively. The complement system is an instrumental component in the inflammatory immune response and plays a role in the activation of blood coagulation. Our understanding of the pathophysiology of SARS‐CoV‐2 is still limited but is constantly expanding. This study aimed to determine changes in the complement system in intensive care unit (ICU) and non‐ICU patients with COVID‐19.

Methods

In a cross‐sectional study, plasma levels of C3, C4, and CH50 were determined in two groups of ICU and non‐ICU patients with COVID‐19 to understand the potential effects of SARS‐CoV‐2 on the innate immune system. The assays of C3 and C4 were conducted using turbidimetry method. The CH50 test was conducted using the functional method.

Results

The present study revealed that the C3, C4, and CH50 plasma levels were 142.48 ± 30.38 mg/dL, 32.58 ± 8.78 mg/dL, and 61.74 ± 19.54%, respectively. These results indicate high levels of complement components C3 and C4 and complement function (CH50) in patients with COVID‐19 than normal ranges. Plasma levels of C3, C4, and CH50 were higher in ICU patients than in non‐ICU COVID‐19 groups.

Conclusion

These results indicate that the innate immune system was activated in both ICU and non‐ICU patients in response to SARS‐CoV‐2 infection. Further studies with a larger number of COVID‐19 patients and additional testing of complement components (C3a and C5a) may reveal the role of COVID‐19 infection in the activation of the complement system.

Activity of Protein S-C4b Binding Protein and Total TFPI Levels in Egyptian SLE Patients: A Cross-Sectional Study

BACKGROUND: Systemic lupus erythematosus (SLE) is an immune disorder with alternating active and remission phases. Cardiovascular diseases and thrombosis are the major causes of mortality in SLE. The anticoagulant activity of Protein S (PS) is complemented by C4 binding protein (C4BP) and tissue factor pathway inhibitor (TFPI). AIM: This study aims to determine the extent of change in the levels of PS activity, C4BP, and total TFPI in active SLE in comparison to the SLE remission phase and their association with thrombosis during SLE flare. METHODS: The study included 180 Egyptian SLE patients who were classified into two groups: 100 SLE cases as the active group and 80 SLE cases as the remission group. The PS activity levels were processed on automated coagulation analyzers, whereas the C4BP and total TFPI levels were measured via enzyme-linked immunosorbent assay. RESULTS: The PS activity and C4BP levels were lower in the active SLE cases than in the remitted ones (p < 0.05). The levels of PS activity and C4BP were revealed to be independent predictors of SELENA-SLEDAI flare scores. In active SLE cases, the PS activity and C4BP levels were rated as excellent and fair classifiers of thrombotic risk in SLE flare, respectively. The total TFPI levels showed no association with SLE activity or its thrombotic consequences. CONCLUSIONS: The levels of PS activity and C4BP act as important biomarkers for SLE activity. Both can be implanted as predictive tools for thrombosis during activity.

A Novel Serum tsRNA for Diagnosis and Prediction of Nephritis in SLE

Objective

Dysregulation of transfer RNA (tRNA)-derived small noncoding RNA (tsRNA) signatures in human serum has been found in various diseases. Here, we determine whether the signatures of tsRNAs in serum can serve as biomarkers for diagnosis or prognosis of systemic lupus erythematosus (SLE).

Methods

Initially, small RNA sequencing was employed for the screening serum tsRNAs obtained from SLE patients, followed by validation with TaqMan probe-based quantitative reverse transcription-PCR (RT-PCR) assay. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic efficacy. The biological functions of tsRNAs were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) assay.

Results

We first analyzed tsRNA signatures in SLE serum and identified that tRF-His-GTG-1 was significantly upregulated in SLE serum. The combination of tRF-His-GTG-1 and anti-dsDNA could serve as biomarkers for diagnosing SLE with a high area under the curve (AUC) of 0.95 (95% CI = 0.92–0.99), sensitivity (83.72%), and specificity (94.19%). Importantly, the noninvasive serum tRF-His-GTG-1 could also be used to distinguish SLE with LN or SLE without LN with AUC of 0.81 (95% CI, 0.73–0.88) and performance (sensitivity 66.27%, specificity 96.15%). Moreover, the serum tsRNA is mainly secreted via exosome and can directly target signaling molecules that play crucial roles in regulating the immune system.

Conclusion

In this study, it has been demonstrated for the first time that serum tsRNAs can be employed as noninvasive biomarkers for the efficient diagnosis and prediction of nephritis in SLE.

Determination of the Risk Factors Contributing to the Development of Neuropsychiatric Lupus in a Systemic Lupus Erythematosus Cohort

Background

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a complex, varied clinical presentation that is both more common and has poor outcomes in women of color. SLE outcomes also seem to be influenced by socioeconomic factors. Neuropsychiatric lupus (NPL) is a common manifestation of SLE that is difficult to diagnose and treat and has poor clinical outcomes. There is no clear relationship between NPL and SLE-related autoantibodies, and this contributes to the difficulty in diagnosing NPL. As a result, NPL is a significant contributor to morbidity and mortality in patients with SLE.

Objective

The purpose of this study was to examine the relationship between serological and socioeconomic factors in the development of NPL in our patient cohort and determine the risk factors for the development of NPL.

Methods

This was an SLE single-center, retrospective chart review study that was performed at a university-based tertiary referral center. Patients aged 18 and older who meet the American College of Rheumatology (ACR) 1997 criteria and were seen between June 1st, 2015, and June 1st, 2019, were included in this study. Overall, 629 patients with SLE were identified, and 263 patients were included. Demographic and serological data were collected. Supplemental socioeconomic information for each zip code in Southwest Virginia was obtained from the United States Government Census website. Continuous variables were analyzed using the T-test or Mann-Whitney U test. Categorical variables were analyzed using chi-square tests or Fisher’s exact tests. Statistical analysis was performed using SAS9.4, and p-value < 0.05 was considered statistically significant.

Results

We reviewed a number of risk factors including age, sex, race, and median household income (MHI), noting no statistical relationship between these factors and the diagnosis of NPL. We did find that the presence of antiphospholipid antibodies (aPL) was significantly associated with a diagnosis of NPL and that complement 4 (C4) levels trended toward statistical significance.

Conclusion

In our cohort of patients, there was no relationship between age, sex, race, and median household income, and the diagnosis of NPL. There was a statistically significant relationship between aPL and the diagnosis of NPL. Other SLE-related antibodies showed no statistical relationship with the diagnosis of NPL. Although not statistically significant, there was a trend toward significance between complement 4 (C4) levels and the diagnosis of NPL.

Fibrinogen and Antifibrinolytic Proteins: Interactions and Future Therapeutics

Thrombus formation remains a major cause of morbidity and mortality worldwide. Current antiplatelet and anticoagulant therapies have been effective at reducing vascular events, but at the expense of increased bleeding risk. Targeting proteins that interact with fibrinogen and which are involved in hypofibrinolysis represents a more specific approach for the development of effective and safe therapeutic agents. The antifibrinolytic proteins alpha-2 antiplasmin (α2AP), thrombin activatable fibrinolysis inhibitor (TAFI), complement C3 and plasminogen activator inhibitor-2 (PAI-2), can be incorporated into the fibrin clot by FXIIIa and affect fibrinolysis by different mechanisms. Therefore, these antifibrinolytic proteins are attractive targets for the development of novel therapeutics, both for the modulation of thrombosis risk, but also for potentially improving clot instability in bleeding disorders. This review summarises the main properties of fibrinogen-bound antifibrinolytic proteins, their effect on clot lysis and association with thrombotic or bleeding conditions. The role of these proteins in therapeutic strategies targeting the fibrinolytic system for thrombotic diseases or bleeding disorders is also discussed.

LangChuangHeJi decoction ameliorates lupus via preventing accumulation of CD138+ T cells in MRL/lpr mice

LangChuangHeJi (LCHJ) decoction has been used as a supplementary therapy to reduce the dose of prednisone and improve the therapeutic effects in systemic lupus erythematosus (SLE) maintenance. We aimed to explore the underlying mechanisms of the therapeutic effects of LCHJ. Spleen and lymph node weight, renal tissue histology, anti-dsDNA and anti-nuclear antibody levels in serum, and urinary protein levels were measured to evaluate the therapeutic effects. We further measured serum levels of multiple cytokines and antibody subsets, and performed flow cytometry analysis to observe effects of LCHJ on the frequency and activation of T cells and T cell subsets, as well as accumulation of plasma cells in splenocytes of MRL/lpr mice. LCHJ exhibited significant therapeutic effects on MRL/lpr mice. LCHJ significantly controlled the in vivo inflammation and dramatically prevented the accumulation of DN T and plasma cells in MRL/lpr mice. Moreover, LCHJ significantly suppressed the accumulation of CD138+ T cells in MRL/lpr mice, which led to the decreased production of the anti-dsDNA antibody in vivo. LCHJ significantly decreased CD4+CD138+ T cells originated from CD4+CD138- T cells, which subsequently prevented the accumulation of CD138+ T cells in MRL/lpr mice. Our results indicated that LCHJ alleviated renal injuries and prevented the enlargement of the spleen and lymph nodes by suppressing DN T cell accumulation, and reduced anti-dsDNA antibody secretion by preventing the accumulation of CD138+ T cells.

Complement system deregulation in SAPHO syndrome revealed by proteomic profiling

SAPHO syndrome is an inflammatory disease invading the skin and bones, whose diagnosis has been difficult due to its low incidence and diversified manifestation. We investigated the serum proteomic profile of SAPHO patients to identify key proteins associated with SAPHO syndrome, trying to find clinical biomarkers or functional molecules for this rare disease. Blood samples from 8 SAPHO patients and 8 healthy controls were detected and analyzed using data independent acquisition (DIA) method to identify differentially expressed proteins (DEPs) specific to SAPHO. A total of 57 differentially expressed proteins were identified (p < 0.05, fold change >1.2), in which 27 proteins were upregulated and 30 downregulated. DEPs may participate in GO terms such as "lipid particle" and "Notch signaling pathway", as well as KEGG pathways including "complement and coagulation cascades" and "mTOR signaling pathway". The overexpression of inhibitors of the complement system (CFH and C4BP), were verified in a larger cohort (16 SAPHO patients, 8 AS patients and 24 healthy controls) with ELISA, and the combined diagnostic ability of CFH and C4BP was predicted by ROC curve with an AUC of 0.91, which may be molecular candidates for further study on diagnosis and pathology of this rare disease. SIGNIFICANCE: Our research provided the first insight into plasma proteomic profile for SAPHO patients，offering potential biomarkers for disease diagnosis. We found that inhibitors of complement system such as CFH and C4BP were up-regulated in SAPHO syndrome, which may play important roles in the pathogenesis of SAPHO syndrome.

Association between toxic organochlorine levels in human serum and systemic lupus erythematosus

Organochlorines (OCs) are groups of highly toxic pesticides with known immunotoxicity. The present work aimed to study the potential association between serum residues of OCs and the risk of developing systemic lupus erythematosus (SLE) as well as correlating to the clinical-laboratory manifestations in a sample of Egyptian SLE patients. A cross-sectional study was conducted on 132 patients environmentally exposed to OCs. Patients were diagnosed as SLE based on the American College of Rheumatology (ACR) revised criteria. Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2K) score was calculated to stratify the disease severity. Blood and urine samples were collected to measure the levels of OCs, serological markers, and urinary protein. The most frequently detected OCs were p,p'-DDE; lindane; and hexachlorobenzene (HCB). The risk of developing SLE was significantly associated with detected p,p'-DDE and HCB (B value 7.704 and 14.33, respectively). Hexachlorobenzene, in addition, was significantly associated with increased SLEDAI-2K score and polycythemia. Lindane was significantly associated with hypocomplementemia, cardiac manifestations of SLE, anemia, and leucopenia. In conclusion, the detected OCs p,p'-DDE and HCB are associated with increased risk of SLE in Egyptian patients and correlates to the manifestations of disease severity.

Post Hoc Biomarker Analyses from a Phase 4, Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial of Repository Corticotropin Injection (Acthar® Gel) for Persistently Active Systemic Lupus Erythematosus

INTRODUCTION

We conducted post hoc analyses of biomarker results from a multicenter, randomized, double-blind, placebo-controlled study of repository corticotropin injection (RCI; Acthar® Gel) in patients with persistently active systemic lupus erythematosus (SLE) despite treatment with moderate-dose glucocorticoids.

METHODS

Adults with active SLE and moderate to severe rash and/or arthritis were enrolled in the primary study. Patients had active SLE despite treatment with stable glucocorticoids, antimalarials, and nonsteroidal anti-inflammatory drugs and/or immunosuppressants. Patients were randomly assigned to 80 U of RCI or placebo subcutaneously every other day for 4 weeks and then twice weekly through week 24. Blood samples were analyzed for serum cytokines and complement proteins using enzyme-linked immunosorbent or Luminex assays and for circulating leukocytes using flow cytometry. Biomarker levels were reported as percentages of the baseline and were further evaluated in subgroups stratified by baseline SLE Disease Activity Index-2000 (SLEDAI-2K) scores (< 10 vs. ≥ 10), baseline anti-double-stranded DNA levels (< 15 IU/mL vs. ≥ 15 IU/mL), and BILAG-based Combined Lupus Assessment (BICLA) responses at week 20 and 24.

RESULTS

RCI treatment resulted in reduced levels of B cell-activating factor and interleukin-6 cytokines in all subgroups compared with placebo. RCI treatment also resulted in lower levels of CD19⁺ B cells and CD19⁺IgD^-CD27^-CD95⁺ atypical activated memory B cells than did placebo in the higher baseline disease activity subgroups and in BICLA non-responders. Furthermore, RCI treatment led to greater increases in complement component (C)3 and C4 levels than did placebo in the higher baseline disease activity subgroups and in BICLA responders.

CONCLUSIONS

RCI may reduce inflammation through B cell immunomodulation in patients with persistently active SLE, particularly in those with higher disease activity.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02953821.

Biomarkers Associated with Organ-Specific Involvement in Juvenile Systemic Lupus Erythematosus

Juvenile systemic lupus erythematosus (JSLE) is characterised by onset before 18 years of age and more severe disease phenotype, increased morbidity and mortality compared to adult-onset SLE. Management strategies in JSLE rely heavily on evidence derived from adult-onset SLE studies; therefore, identifying biomarkers associated with the disease pathogenesis and reflecting particularities of JSLE clinical phenotype holds promise for better patient management and improved outcomes. This narrative review summarises the evidence related to various traditional and novel biomarkers that have shown a promising role in identifying and predicting specific organ involvement in JSLE and appraises the evidence regarding their clinical utility, focusing in particular on renal biomarkers, while also emphasising the research into cardiovascular, haematological, neurological, skin and joint disease-related JSLE biomarkers, as well as genetic biomarkers with potential clinical applications.

A small fragment of factor B as a potential inhibitor of complement alternative pathway activity

BACKGROUND

The complement system is a key player in innate immunity and a modulator of the adaptive immune system. Among the three pathways of complement, the alternative pathway (AP) accounts for most of the complement activation. Factor B (FB) is a major protease of the AP, making it a promising target to inhibit the AP activity in conditions of uncontrolled complement activation.

METHODS

Based on the data obtained from sequence analysis and conformational changes associated with FB, we expressed and purified a recombinant FB fragment (FBfr). We tested the inhibitory activity of the protein against the AP by in vitro assays.

RESULTS

FBfr protein was proven to inhibit the complement AP activity when tested by C3b deposition assay and rabbit erythrocyte hemolytic assay.

CONCLUSION

Our recombinant FBfr was able to compete with the native human FB, which allowed it to inhibit the AP activity. This novel compound is a good candidate for further characterization and testing to be used in complement diagnostic tests and as a drug lead in the field of complement therapeutics.

Systemic lupus erythematosus multiorgan flare with quiescent serologic markers

Systemic lupus erythematosus (SLE) can affect almost every organ with differing degrees of severity. Typically, SLE activity is associated with hypocomplimentaemia and elevated double-stranded DNA (dsDNA) levels. We describe a case of a severe multiorgan lupus flare including lupus cerebritis, autoimmune haemolytic anaemia, lupus nephritis and lupus myopericarditis with normal complement and dsDNA levels. This highlights the importance of understanding the heterogeneous nature of SLE flares.

Urinary MCP-1 and TWEAK as non-invasive markers of disease activity and treatment response in patients with lupus nephritis in South Africa

BACKGROUND

Treatment of patients with lupus nephritis (LN) requires judicious use of immunosuppression. Novel biomarkers may be useful for monitoring disease activity and treatment response. We assessed the utility of urinary monocyte chemoattractant protein-1 (uMCP-1) and urinary tumour necrosis factor-like weak inducer of apoptosis (uTWEAK) for disease activity and treatment response monitoring in South Africans with LN.

METHODS

We recruited consenting patients with active LN confirmed on kidney biopsy. Urinary levels of MCP-1 and TWEAK were assayed at baseline and after completion of induction therapy using ELISA methods. We also collected relevant demographic, clinical and biochemical data for patients included in this study.

RESULTS

The mean age of patients in this study was 29.8 ± 10.7 years, 60% were patients of mixed ancestry, 70% had proliferative LN and mean spot urine proteinuria at baseline was 0.37 (0.18-0.59) g/mmolCr. At completion of induction therapy, the level of uMCP-1 had reduced to 314.5 (IQR: 197.0-622) pg/mgCr from a baseline of 1092.7 (IQR 578.6-1848) pg/mgCr (P = 0.06) while uTWEAK had reduced to 36.0 (IQR 17.0-88.0) pg/mgCr from 159.0 (IQR: 88.5-295.5) pg/mgCr (P = 0.03). For patients reaching early complete or partial remission (n = 17), both biomarkers had significantly declined in their urine: uMCP-1 (P = 0.018) and uTWEAK (P = 0.015). There was no reduction of both biomarkers in patients not achieving remission and no association between uMCP-1 or uTWEAK with renal histological features.

CONCLUSION

Our study shows that uMCP-1 and uTWEAK are elevated in patients with active LN, correlated with the remission status (response to treatment) at the end of induction therapy and can, therefore, be useful for monitoring disease activity and treatment response.

Anti-complement C5 therapy with eculizumab in three cases of critical COVID-19

Respiratory failure and acute kidney injury (AKI) are associated with high mortality in SARS-CoV-2-associated Coronavirus disease 2019 (COVID-19). These manifestations are linked to a hypercoaguable, pro-inflammatory state with persistent, systemic complement activation. Three critical COVID-19 patients recalcitrant to multiple interventions had skin biopsies documenting deposition of the terminal complement component C5b-9, the lectin complement pathway enzyme MASP2, and C4d in microvascular endothelium. Administration of anti-C5 monoclonal antibody eculizumab led to a marked decline in D-dimers and neutrophil counts in all three cases, and normalization of liver functions and creatinine in two. One patient with severe heart failure and AKI had a complete remission. The other two individuals had partial remissions, one with resolution of his AKI but ultimately succumbing to respiratory failure, and another with a significant decline in FiO2 requirements, but persistent renal failure. In conclusion, anti-complement therapy may be beneficial in at least some patients with critical COVID-19.

The Complement System in the Pathophysiology of Pregnancy and in Systemic Autoimmune Rheumatic Diseases During Pregnancy

The complement system plays a double role in pregnancy exerting both protective and damaging effects at placental level. Complement activation at fetal-maternal interface participates in protection against infectious agents and helps remove apoptotic and necrotic cells. Locally synthesized C1q contributes to the physiologic vascular remodeling of spiral arteries characterized by loss of smooth muscle cells and transformation into large dilated vessels. Complement activation triggered by the inflammatory process induced by embryo implantation can damage trophoblast and other decidual cells that may lead to pregnancy complications if the cells are not protected by the complement regulators CD55, CD46, and CD59 expressed on cell surface. However, uncontrolled complement activation induces placental alterations resulting in adverse pregnancy outcomes. This may occur in pathological conditions characterized by placental localization of complement fixing antibodies directed against beta2-glycoprotein 1, as in patients with anti-phospholipid syndrome, or circulating immune complexes deposited in placenta, as in patients with systemic lupus erythematosus. In other diseases, such as preeclampsia, the mechanism of complement activation responsible for complement deposits in placenta is unclear. Conflicting results have been reported on the relevance of complement assays as diagnostic and prognostic tools to assess complement involvement in pregnant patients with these disorders.

Association between complement 4 copy number variation and systemic lupus erythematosus: a meta-analysis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple genetic mutations. Complement 4 (C4) copy number variation (CNV) is a target-of-interest located on chromosome 6. C4 encodes for either of the two C4 paralogs, C4A or C4B, and low C4 levels have been associated with SLE activity. In this study, we conducted a meta-analysis to comprehensively understand the role of C4 CNV in SLE. Three databases (PubMed, Embase, and Web of Science) were searched for relevant studies. Two investigators independently extracted and evaluated data from eligible studies. Associations between C4 CNV and SLE were estimated by odds ratios (OR) and 95% confidence intervals (95% CI). Further analysis was conducted using the STATA 12.0 software. A total of eight case-control studies were included in the analysis with 4107 SLE patients and 5889 healthy controls. Six studies used TaqMan real-time PCR to genotype C4 CNV, with 1 study used paralog ratio test and other one used multiplex ligation-dependent probe amplification (MLPA). Lower total C4 CNV and C4A CNV were associated with SLE in the overall analysis (pooled OR: 1.55, 95% CI: 1.23-1.95; pooled OR: 1.86, 95% CI: 1.51-2.29). The subgroup analysis found that total C4 CNV and lower C4A CNV were significantly associated with SLE in Caucasians (pooled OR: 1.84, 95% CI: 1.60-2.12; pooled OR: 2.23, 95% CI:1.92-2.59). However, the association was not detected in East Asians. Lastly, SLE was not associated with C4B CNV, long C4 CNV, or short C4 CNV. The meta-analysis confirmed that lower total C4 CNV and lower C4A CNV are associated with SLE in certain populations. Future studies should consider other ethnic groups to further investigate the relationship between the C4 gene and SLE.

The impact of obesity on disease activity, damage accrual, inflammation markers and cardiovascular risk factors in systemic lupus erythematosus

BACKGROUND

We aimed to evaluate the relationships between obesity metrics including Body Mass Index (BMI), waist to height ratio (WtHR) and fat mass percentage, and disease activity, damage accrual, inflammation markers and traditional cardiovascular risk factors in SLE patients.

METHODS

A cross-sectional study was conducted on a sample of 275 patients (90.5% females; mean age 46.37±13.85 years). Disease activity was assessed with the SLE disease activity index (SLEDAI-2K), and disease-related organ damage was assessed using the SLICC/ACR damage index (SDI). Biochemical variables of lipids profile, high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), anti-dsDNA titers and complement components C3 and C4 serum levels were measured. Blood pressure and ankle-brachial index (ABI) were also calculated.

RESULTS

Significant differences were observed between normal-weight, overweight and obese patients in SLEDAI (2.60±2.48 vs. 2.71±2.65 vs. 3.84±3.02; P=0.004), SDI (0.76±1.10 vs. 1.09±1.24 vs. 1.57±1.54; P=0.002), hsCRP (2.15±2.93 vs. 3.24±3.63 vs. 5.30±5.63 mg/dL; P<0.001), complement C3 level (99.92±24.45 vs. 111.38±27.41 vs. 123.16±28.96 mg/dL; P<0.001), triglycerides serum levels (85.99±41.68 vs. 102.35±50.88 vs. 129.12±61.59 mg/dL; P<0.001) and systolic blood pressure (112.28±16.35 vs. 124.25±17.94 vs. 132.78±16.71 mmHg; P=0.001) after adjusting for age and sex.

CONCLUSIONS

Patients with SLE who are obese have worse disease activity and damage accrual, higher levels of inflammation markers hs-CRP and C3 complement, increased triglycerides serum levels and systolic blood pressure levels in comparison with overweight or normal weight SLE patients, supporting that optimizing weight in SLE patients should be a potential target to improve SLE outcomes.

Revisiting the complement system in systemic lupus erythematosus

Introduction: Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease, characterized by the production of autoantibodies. Numerous mechanisms contribute to the pathogenesis and autoimmunity in SLE. One of the most important mechanisms is the defective function of the early complement components that are involved in clearing the immune-complexes and apoptotic debris. Major evidence supporting this hypothesis is the development of severe lupus in individuals with monogenic defects in any one of the early complement components such as C1q, C1 s, C1 r, C2, or C4.Areas covered: In this review, we discuss hereditary defects in classical complement components and their clinical manifestations, acquired defects of complements in lupus, the role of complements in the pathogenesis of antiphospholipid antibody syndrome and lupus nephritis, and laboratory assessment of complement components and their functions. Articles from the last 20 years were retrieved from PubMed for this purpose.Expert opinion: Complements have a dual role in the pathogenesis of SLE. On one hand, deficiency of complement components predisposes to lupus, while, on the other, excess complement activation plays a role in the organ damage. Understanding the intricacies of the role of complements in SLE can pave way for the development of targeted therapies.

Total Serum Calcium Level Is Negatively Correlated With Systemic Lupus Erythematosus Activity

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease and hypocomplementemia signifies disease activity. Several studies have shown that calcium may help maintain optimum function of immune system and metabolism in SLE. The aim of our study was to analyze the relationship between total serum calcium level and SLE activity. A total of 66 patients with SLE and 214 healthy controls were included in this study. Our results showed lower serum levels of calcium (P < .001), complement C3 (P < .001), complement C4 (P < .001), and albumin (P < .001) in patients with SLE. A negative correlation was found between serum calcium level and systemic lupus erythematosus disease activity index (SLEDAI) rating (r = -0.394, P = .001). Additionally, serum level of calcium was positively correlated with serum complement C3 level (r = 0.366, P = .003) in patients with SLE, while no such correlation was found between serum calcium level and complement C4 (r = -0.190, P = .126). Likewise, patients with SLE with normal serum calcium level showed higher complement C3 level (P < .01) than that of patients with low serum calcium level. Overall, the results displayed that patients with SLE have lower serum calcium level compared to healthy controls, and the serum calcium level is positively correlated with SLEDAI rating and serum complement C3 level in patients with SLE. In conclusion, the total serum calcium level is negatively correlated with SLE disease activity.

Dietary Habits in Patients with Systemic Lupus Erythematosus

Patients with systemic lupus erythematosus (SLE) are often interested in which diets to follow. Our aim was to investigate which dietary habits were common among our patients, and which of them were in correlation with laboratory parameters of disease activity, such as complement values and 24-h proteinuria. This study included 76 patients with SLE in clinical remission with a 6-month flare free period. They completed a specialized, self-administered, 23-item food frequency questionnaire about their weekly dietary habits. Basic anthropometric data, levels of C3 and C4, and 24-h proteinuria were recorded and analyzed with respect to their dietary habits. The majority of patients had a normal body mass index of 18.5-25 kg/m², and worked out regularly. The most frequently consumed foods reported by the patients were fruits, milk, vegetables, meat, pasta, rice, and bread. Decreased values of C3 were found in 34 (44.7%) patients, and decreased values of C4 in 28 (36.8%) patients. Decreased values of C3 were found in patients who often consumed meat (P = .015), and decreased values of C4 in patients who often consumed fast food (P = .043). Patients who often consumed fast food demonstrated a decreasing trend of C3 (P = .060), and patients who often consumed fried food had a decreasing trend of C4 (P = .051). Significant correlation between daily proteinuria and dietary habits was not found. Dietary habits can influence the disease course of SLE. Our study confirms that decreased levels of complement compounds C3 and C4, which are possible predictors of disease activation, are associated with frequent consumption of low quality proteins and food rich in calories.

Towards Precision Medicine in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a remarkable condition characterised by diversity amongst its clinical features and immunological abnormalities. In this review, we attempt to capture the major immunological changes linked to the pathophysiology of lupus and discuss the challenge it presents in moving towards the concept of precision medicine. Currently broadly similar types of drugs, e.g., steroids, immunosuppressives, hydroxychloroquine are used to treat many of the diverse clinical features of SLE. We suspect that, as the precise immunopathological abnormalities differ between the various organs/systems in lupus patients, it will be some time before precision medicine can be fully applied to SLE.

Role of angiopoietin-2 in inflammatory autoimmune diseases: A comprehensive review

Angiogenesis is defined as the growth of new capillaries sprouting from pre-existing vasculature. Pathological angiogenesis signals can lead to dysregulated development of new vessels. Inflammation is accompanied by pathological angiogenesis. During an inflammatory process, newly formed blood vessels provide oxygen and nutrients to the inflamed tissue, facilitating the transport of inflammatory cells. Therefore, angiogenesis is closely related to pathogenesis of inflammatory autoimmune diseases. As a member of the angiopoietin family, Angiopoietin-2 (Ang-2) plays an irreplaceable role in angiogenesis. This review will narrate the expression of Ang-2 and its role in inflammatory autoimmune diseases. Collecting this information may improve the acquaintance of Ang-2 and provide a theoretical foundation for clinical trials and drug development in the future.

Clinical aspects and risk factors of lupus nephritis: a retrospective study of 156 adult patients

Objective

To analyze the clinical manifestations, laboratory indexes, disease activity, and pathological types of lupus nephritis (LN) in adult patients.

Methods

We retrospectively analyzed the clinical manifestations, laboratory indexes, and pathological classifications of 156 adult patients first diagnosed with LN between July 2013 and November 2017. Patients were categorized according to the following criteria: active or inactive LN, LN with or without renal damage, and mild or severe LN.

Results

Immunoglobulin G and A levels, 24-hour proteinuria, and anti-dsDNA, anti-Sm, and anti-ribosomal P protein antibody positivity rates were all significantly increased in patients with active LN compared with inactive LN. Anti-dsDNA antibody positivity and 24-hour proteinuria were significantly increased, whereas hemoglobin, serum albumin, and C3 and C4 levels were significantly decreased in patients with LN and renal damage compared with those without renal damage. Anti-dsDNA and anti-Sm antibody positivity rates and 24-hour proteinuria were significantly increased, while hemoglobin, serum albumin, C3 and C4 levels, and estimated glomerular filtration rate were significantly decreased in patients with severe LN compared with patients with mild LN.

Conclusions

LN can display various clinical manifestations, laboratory indexes, levels of disease activity, and pathological types in adult patients.

Disordered intestinal microbes are associated with the activity of Systemic Lupus Erythematosus

Intestinal dysbiosis is implicated in Systemic Lupus Erythematosus (SLE). However, the evidence of gut microbiome changes in SLE is limited, and the association of changed gut microbiome with the activity of SLE, as well as its functional relevance with SLE still remains unknown. Here, we sequenced 16S rRNA amplicon on fecal samples from 40 SLE patients (19 active patients, 21 remissive patients), 20 disease controls (Rheumatoid Arthritis (RA) patients), and 22 healthy controls (HCs), and investigated the association of functional categories with taxonomic composition by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). We demonstrated SLE patients, particularly the active patients, had significant dysbiosis in gut microbiota with reduced bacterial diversity and biased community constitutions. Amongst the disordered microbiota, the genera Streptococcus, Campylobacter, Veillonella, the species anginosus and dispar, were positively correlated with lupus activity, while the genus Bifidobacterium was negatively associated with the disease activity. PICRUSt analysis showed metabolic pathways were different between SLE and HCs, and also between active and remissive SLE patients. Moreover, we revealed that a random forest model could distinguish SLE from RA and HCs (area under the curve (AUC) = 0.792), and another random forest model could well predict the activity of SLE patients (AUC = 0.811). In summary, SLE patients, especially the active patients, show an apparent dysbiosis in gut microbiota and its related metabolic pathways. Amongst the disordered microflora, four genera and two species are associated with lupus activity. Furthermore, the random forest models are able to diagnose SLE and predict disease activity.