Two-Parametric Immunological Score Development for Assessing Renal Involvement and Disease Activity in Systemic Lupus Erythematosus

Autoantibodies associated with systemic sclerosis in three autoimmune diseases imprinted by type I interferon gene dysregulation: a comparison across SLE, primary Sjögren's syndrome and systemic sclerosis

OBJECTIVE

SLE, primary Sjögren's syndrome (pSS) and systemic sclerosis (SSc) are heterogeneous autoimmune diseases with a dysregulated type I interferon (IFN) system. The diseases often show overlapping clinical manifestations, which may result in diagnostic challenges. We asked to which extent SSc-associated autoantibodies are present in SLE and pSS, and whether these link to serum IFN-α, clinical phenotypes and sex. Samples with clinical data from patients with SSc and healthy blood donors (HBDs) served as controls. Finally, the diagnostic performance of SSc-associated autoantibodies was evaluated.

METHODS

Samples from well-characterised subjects with SLE (n=510), pSS (n=116), SSc (n=57) and HBDs (n=236) were analysed using a commercially available immunoassay (EuroLine Systemic Sclerosis Profile (IgG)). IFN-α was quantified by ELISA. Self-reported data on Raynaud's phenomenon (RP) were available.

RESULTS

With exceptions for anti-Ro52/SSA and anti-Th/To, SSc-associated autoantibodies were more frequent in SSc than in SLE, pSS and HBDs regardless of sex. IFN-α levels correlated with the number of positive SSc-associated autoantibodies (r=0.29, p<0.0001) and associated with Ro52/SSA positivity (p<0.0001). By using data from SLE, SSc and HBDs, RP was significantly associated with topoisomerase I, centromere protein (CENP)-B, RNA polymerase III 11 kDa, RNA polymerase III 155 kDa and PM-Scl100 whereas Ro52/SSA associated inversely with RP. In SLE, CENP-A was associated with immunological disorder, CENP-B with serositis and Ku with lupus nephritis. By combining analysis of ANA (immunofluorescence) with SSc-associated autoantibodies, the diagnostic sensitivity reached 98% and the specificity 33%.

CONCLUSIONS

The 13 specificities included in the EuroLine immunoassay are commonly detected in SSc, but they are also frequent among individuals with other diseases imprinted by type I IFNs. These findings are valuable when interpreting serological data on patients with suspected SSc, especially as patients may present with disease manifestations overlapping different rheumatological diseases. In SLE, we observed associations between manifestations and SSc-associated autoantibodies which have not previously been reported.

Overview on the role of complement-specific autoantibodies in diseases

The complement system is recognized as a major pathogenic or contributing factor in an ever-growing number of diseases. In addition to inherited factors, autoantibodies to complement proteins have been detected in various systemic and organ-specific disorders. These include antibodies directed against complement components, regulators and receptors, but also protein complexes such as autoantibodies against complement convertases. In some cases, the autoantibodies are relatively well characterized and a pathogenic role is incurred and their detection has diagnostic value. In other cases, the relevance of the autoantibodies is rather unclear. This review summarizes what we know of complement specific autoantibodies in diseases and identifies unresolved questions regarding their functional effect and relevance.

The predictive value of fibrinogen‐to‐albumin ratio in the active, severe active, and poor prognosis of systemic lupus erythematosus: A single‐center retrospective study

Objective

To evaluate the prediction and effect of fibrinogen‐to‐albumin ratio (FAR) on active, severe active, and poor prognosis of systemic lupus erythematosus (SLE).

Methods

One hundred and sixty‐eight patients with SLE who were treated in our hospital were enrolled, the clinical data, laboratory indexes, and disease prognosis of all patients were collected and analyzed.

Results

Triglyceride (TG), FAR, ESR, and anti‐dsDNA (+) were the influencing factors, while complement 3 (C3) was the protective factor of active SLE, the odds ratio (OR) values were 2.968, 3.698, 2.114, 2.727, and 0.652, respectively (p < 0.05). FAR, ESR, and anti‐dsDNA (+) were the influencing factors, while C3 was the protective factor of severe active SLE, the OR values were 3.791, 1.953, 2.187, and 0.742, respectively (p < 0.05). SLE disease activity index (SLEDAI), TG, FAR, and anti‐dsDNA (+) were the influencing factors, while C3 was the protective factor of poor prognosis SLE, the OR values were 3.024, 2.293, 3.012, 2.323, and 0.801, respectively (p < 0.05). FAR and FIB were positively correlated with SLEDAI, while ALB was negatively correlated with SLEDAI, the related coefficient (r) were 0.398, 0.267, −0.270, respectively. The receiver operating curve (ROC) analysis showed that the predictive values of FAR for active, severe active and poor prognosis SLE were 0.769, 0.769, and 0.734, respectively, were significant higher than FIB and ALB (p < 0.05).

Conclusion

Fibrinogen‐to‐albumin ratio was an influencing factor of active, severe active, and poor prognosis SLE had higher predictive value than FIB and ALB for the activity and prognosis of SLE.

Associations of C-reactive protein isoforms with systemic lupus erythematosus phenotypes and disease activity

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a large production of autoantibodies and deficient clearance of cellular waste. The disease typically oscillates between episodes of elevated disease activity and quiescent disease. C-reactive protein (CRP) is a pentameric acute-phase protein usually reflecting inflammation and tissue damage. However, despite increased inflammation and elevated interleukin-6, the levels of CRP typically remain low or only slightly raised in SLE. Under certain conditions, pentameric CRP (pCRP) can dissociate into its monomeric isoform (mCRP), which mainly has been ascribed pro-inflammatory properties. The present study aims to investigate the potential relationship between pCRP and mCRP, respectively, with disease activity and clinical features of SLE.

Methods

The levels of pCRP and mCRP were measured, by turbidimetry (high-sensitive) and sandwich enzyme-linked immunosorbent assay (ELISA) respectively, in serum samples from 160 patients with SLE and 30 patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Twenty-two of the SLE cases were selected for analysis at two time-points; quiescent disease and active disease. The two CRP isoforms were evaluated in relation to disease activity and clinical features in the two diseases.

Results

Levels of pCRP and mCRP were significantly lower in SLE than AAV (p < 0.001) and the ratio of mCRP/pCRP was higher in SLE compared to AAV. The mCRP/pCRP ratio was higher for patients in remission and able to significantly separate between active/quiescent disease in paired, but not in non-paired, samples from patients with SLE. Significant correlations were observed with SLICC/ACR damage index for pCRP levels as well as inversely with the mCRP/pCRP ratio. Lower mCRP levels associated with malar rash.

Conclusion

As the interrelationship between the two isoforms appear to (a) discriminate between quiescent and active SLE and (b) differ between SLE and AAV, our data indicates that the two CRP isoforms could exert contrasting immunological effects and/or reflect different milieus. Given the biological effects of mCRP, it is possible that altered levels may indicate increased opsonization of immune complexes and apoptotic debris, and thereby prevent their deposition outside the reticuloendothelial system and manifestations such as lupus nephritis and lupus-related skin disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02831-9.

Serum amyloid A-to-albumin ratio as a potential biomarker to predict the activity, severity, and poor prognosis of systemic lupus erythematosus

Objectives

To evaluate the predictive value of serum amyloid A‐to‐albumin ratio (SAR) for active systemic lupus erythematosus (SLE), severe active SLE, and poor prognosis of SLE.

Methods

One hundred and eighty‐six patients with SLE undergoing treatment in our hospital were selected. The demographic characteristics, clinical data, and disease prognosis of all patients were collected and analyzed.

Results

There were significant differences in SLEDAI, total glyceride (TG), serum amyloid A (SAA), SAR, urinary microalbumin‐to‐creatinine ratio (ACR), erythrocyte sedimentation rate (ESR), albumin (ALB), complement 3 (C3), anti‐dsDNA, anti‐Sm positive rate, and anti‐dsDNA positive rate between active SLE and stable SLE patients. TG, SAR, C3, ACR, and positive anti‐dsDNA were independent influencing factors of active SLE, and the odds ratio (OR) values were 2.342, 10.921, 0.832, 1.451, and 2.476, respectively. The area under curves (AUCs) of SAA, ALB, and SAR for predicting active SLE and severe active SLE were 0.743, 0.724, 0.787, 0.711, 0.686, and 0.733, respectively. The AUC of SAR for predicting the poor prognosis of active SLE was 0.719. High SAR, high ACR, low C3, and positive anti‐dsDNA were high risk factors for poor prognosis. Kaplan–Meier (K‐M) survival analysis showed that patients with high SAR, high ACR, low C3, and positive anti‐dsDNA had shorter continuous remission time than that with low SAR, low ACR, high C3, and negative anti‐dsDNA.

Conclusion

SAR had high predictive value for active SLE, severe active SLE, and poor prognosis of SLE. High SAR may be a potential marker for predicting the activity and prognosis of Chinese patients with SLE.

The role of Dickkopf-1 as a biomarker in systemic lupus erythematosus and active lupus nephritis

Background

Systemic lupus erythematosus (SLE) is a chronic disease which is mainly attributed to autoantibodies, cytokines, and immune complex deposition. Studies have demonstrated that cytokines and autoantibodies were strongly associated with renal diseases and can be used for the prediction of patients with lupus nephritis (LN). However, antibodies to dsDNA and the reduction of complements were also detected in non-LN patients as well as clinically non-active SLE patients. The current study was performed to detect the role of serum DKK-1 as a biomarker for the identification of SLE patients and patients with LN and its relation to disease activity and severity. The study was conducted on fifty clinically diagnosed SLE patients who were diagnosed according to Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE, in addition to thirty healthy control volunteers matched for age and sex. Assessment of SLE disease activity was done using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Assessment of SLE disease severity was done using the Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) damage index. Serum levels of DKK-1 were measured for all participants by ELISA using commercially available kits.

Results

DKK-1 serum levels were significantly higher among active lupus nephritis cases as compared with SLE cases with no LN and with healthy controls (9197.60 μg/uL ± 2939.2 μg/uL vs. 6405.15 μg/uL ± 2018.91 μg/uL vs. 2790.33 μg/uL ± 833.49 μg/uL) respectively (p-values < 0.001). DKK-1 concentration was significantly higher among SLE patients with positive as compared with negative anti-double-stranded DNA (dsDNA) antibodies (p-value < 0.001). According to receiver operating characteristic (ROC) curve analysis, serum DKK-1 level diagnosed the SLE at a statistically significant level with a 98% sensitivity and 70% specificity and serum DKK-1 level also diagnosed active lupus nephritis at a 90% sensitivity and 63% specificity.

Conclusion

DKK-1 could diagnose SLE and lupus nephritis with high sensitivity and specificity. Serum DKK-1 is a reliable biomarker for the identification of SLE and patients with LN and could be used as a key molecule for the diagnosis of SLE and as a prognostic indicator of LN.

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren's syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver-kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti-nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD-associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE-cases without known AILD (n = 272), 26 (9·6%) had PBC-associated autoantibodies, 15 (5·5%) AIH-associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC-associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC-criteria. AMA-M2 detected by immunoblot was the most common PBC-associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH-criteria. The patient with combined AIH/PBC-serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC-associated, 12 (10·8%) AIH-associated autoantibodies and two overlapped. PBC-associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD-associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody-negative and -positive patients.

Clinical efficacy and safety of rituximab in lupus nephritis

BACKGROUND

Long-term treatment programs with low toxicity represent a therapeutic challenge in lupus nephritis (LN). Although a therapeutic benefit of rituximab (RTX) has been reported in LN patients who have failed conventional treatment, the results are controversial. We aimed to assess the clinical efficacy and safety of RTX as a new immunosuppressive medicine in the treatment of LN with a meta-analysis.

METHODS

Based on predetermined criteria, PubMed, Embase, and Cochrane Library were used to identify the eligible studies. Cochrane Review Manager version 5.3 was applied to pool the data extracted from individual investigations and provide summary effect estimates.

RESULTS

Twenty-four studies with 940 patients were analyzed. In case series trials with specific LN assessment, the complete remission (CR) rate at 12 months was 35.9% (95% CI: 24.2%-49.5%), and total remission (TR: CR plus partial remission) was 73.4% (95% CI: 66.0%-79.7%). In controlled trials, RTX was associated with a higher probability of TR (OR =2.02, 95% CI: 1.23-3.32, P<0.01). The CR in the RTX group was higher than that in the control group, although there was no significant difference between the two groups (OR =1.98, 95% CI: 0.90-4.39, P>0.05). Additionally, RTX treatment significantly decreased proteinuria (mean difference: -2.79, 95% CI: -3.95 to -1.62, P<0.01) as well as the renal activity index in patients with LN (mean difference: -3.46, 95% CI: -4.43 to -2.50, P<0.01). In controlled trials, the relative risks of the adverse events of infection and infusion reaction were not notably different between the two groups.

CONCLUSION

RTX is a promising therapy for the treatment of LN due to significant clinical efficacy and a favorable safety profile. In future studies, larger study populations and longer-term time points may identify additional important patient-centered outcomes.