The Role of Neutrophil Extracellular Traps (NETs) in the Pathogenesis of Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease of unknown aetiology [...].

Markers of NETosis in Patients with Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Neutrophil Extracellular Traps (NETs) have been implicated in systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) pathogenesis. The myeloperoxidase-deoxyribonucleic acid (MPO-DNA) complex and nucleosomes are serum markers of NETosis. The aim of this study was to assess these NETosis parameters as markers for SLE and APS diagnosis and their association with clinical features and disease activity. A total of 138 people were included in the cross-sectional study: 30 with SLE without APS, 47 with SLE and APS, 41 patients with primary antiphospholipid syndrome (PAPS), and 20 seemingly healthy individuals. Serum MPO-DNA complex and nucleosome levels were determined via an enzyme-linked immunosorbent assay (ELISA). Informed consent was obtained from all subjects involved in the study. The Ethics Committee of the V.A. Nasonova Research Institute of Rheumatology (Protocol No. 25 dated 23 December 2021) approved the study. In patients with SLE without APS, the levels of the MPO-DNA complex were significantly higher compared to patients with SLE with APS, with PAPS, and healthy controls (p < 0.0001). Among patients with a reliable diagnosis of SLE, 30 had positive values of the MPO-DNA complex, of whom 18 had SLE without APS, and 12 had SLE with APS. Patients with SLE and positive MPO-DNA complex levels were significantly more likely to have high SLE activity (χ² = 5.25, p = 0.037), lupus glomerulonephritis (χ² = 6.82, p = 0.009), positive antibodies to dsDNA (χ² = 4.82, p = 0.036), and hypocomplementemia (χ² = 6.72, p = 0.01). Elevated MPO-DNA levels were observed in 22 patients with APS: 12 with SLE with APS and 10 with PAPS. There were no significant associations between positive levels of the MPO-DNA complex and clinical and laboratory manifestations of APS. The concentration of nucleosomes was significantly lower in the group of SLE patients (±APS) compared to controls and PAPS (p < 0.0001). In SLE patients, the frequency of low nucleosome levels was associated with high SLE activity (χ² = 13.4, p < 0.0001), lupus nephritis (χ² = 4.1, p = 0.043), and arthritis (χ² = 3.89, p = 0.048). An increase in the specific marker of NETosis, the MPO-DNA complex, was found in the blood serum of SLE patients without APS. Elevated levels of the MPO-DNA complex can be regarded as a promising biomarker of lupus nephritis, disease activity, and immunological disorders in SLE patients. Lower levels of nucleosomes were significantly associated with SLE (±APS). Low nucleosome levels were more common in patients with high SLE activity, lupus nephritis, and arthritis.

AB0116 NEW INFLAMMATORY MARKERS IN SYSTEMIC LUPUS ERYTHEMATOSUS AND ANTIPHOSPHOLIPID SYNDROME

Background

Thromboinflammation is a pathological process that is associated with uncontrolled inflammation, leading to hypercoagulability and thrombotic complications. Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are prototypical chronic thromboinflammatory diseases. Neutrophils are important cells in the development of systemic inflammation and thrombosis. Neutrophil reactivity (NEUT-RI), neutrophil granularity (NEUT-GI), immature granulocytes (IG), and neutrophil-to-lymphocyte ratio (NLR) are considered as inflammatory markers.

Objectives

To determine the role of parameters of neutrophil activation (NEUT-RI, NEUT-GI), immature granulocytes (absolute (IG#), relative (IG%) counts), NLR, ESR in assessing inflammation in SLE, primary APS (PAPS), and SLE with APS.

Methods

The study included 80 patients and 40 healthy donors (HD). Patients were classified into three groups: Group 1 included 37 patients with SLE. The median age of patients with SLE was 34 years [28-43]. Group 2 included 20 patients with SLE+ APS (45 years [37-49]). Group 3 included 23 patients with PAPS (38 years [34,5-47,5]). Current disease activity was evaluated with SLEDAI-2K and adjusted GAPSS (aGAPSS).

A complete blood count (WBC-white blood cell, NEUT#-absolute neutrophil count, NEUT-RI, NEUT-GI, IG%, IG count, NLR, thrombocytes, ESR-erythrocyte sedimentation rate) was performed with XN-1000 automated hematology analyzer (Sysmex, Japan).

Results

Patient characteristics are shown in Table 1. IG# and IG% levels were significantly increased in patients with SLE and SLE+APS compared to controls and PAPS. ESR levels was significantly higher in patients with SLE, SLE+APS, and PAPS compared to HD. There was no significant difference between NEUT-RI, NEUT-GI, NLR, fibrinogen and CRP levels in patients with SLE, SLE+APS, PAPS, and HD. The aGAPPS was positively correlated with the IG# (rs=0.46; р=0.028) and IG% levels (rs=0.49; р=0.017) in patients with PAPS. No correlation was found between the IG and SLEDAI 2K. The ESR was positively correlated with SLEDAI 2K in SLE patients (rs =0.54; р≤0.001).

Table 1.

Characteristics of patients with SLE, PAPS, SLE+APS, and healthy controls.

ParametersM±SD, Me [25%; 75%], n (%)SLE (n=37)PAPS (n=23)SLE+APS (n=20)Healthy donors (n=40)pSLEDAI 2K7 [3.5-13]-4 [2-8]-р=0.03*Anti-dsDNA, IU/ml41.6 [13.6-101]-22.2 [10.7-69.9]-NSaCL IgG,n,%2 (5.4)16 (69.5)11 (55.0)-p<0.001*aCL IgM,n,%04 (19)1 (5)-P=0.034*aB2GP1 IgG,n,%2 (5.4)15 (65.2)11 (55.0)-p<0.001*aB2GP1 IgM,n,%1 (2.7)5 (21.7)1 (5)-P=0.053*LA positivity, n,%1 (2.7)15 (65.2)9 (45)-p<0.001*Triple positive,n, %-14 (60.8)7 (35)-NSWBC, 109/l5.1 [3.8-7]5.6 [4.7-6.7]6.4 [4.9-7.7]6.2 [5.3-6.9]NSThrombocytes, 109/l231 [201-300]223.5 [189.5-270]226 [168-278]251 [210-290]NSNEUT#,109/l2.89 [1.84-3.71]3.6 [2.71-4.4]3.3 [3.1-5]3.55 [2.9-4.4]NSNEUT-RI, FI45.5 [43.8-47.3]44.2 [43.1-45.9]45.1 [43.5-47.3]44.0 [42.7-46.2]NSNEUT-GI, SI155.6 [151.6-158.0]154.85 [153.7-156.1]154 [151.2-157.8]153.7 [150.2-155.7]NSNLR1.8 [1.3-2.5]2.1 [1.4-3.1]2.3 [1.6-2,8]1.9 [1.5-2.4]NSESR, mm/h13 [7-20]14 [6.5-18]16 [13-19]7 [4-11]p<0.001*IG#,109/l0.02 [0.01-0.07]0.01 [0.01-0.02]0.03 [0.02-0.05]0.01 [0.01-0.02],p=0.002*IG%0.4 [0.3-1.1]0.2 [0.2-0.4]0.4[0.3-0.7]0.2 [0.2-0.3]p<0.001*CRP, mg/l2.2 [0.6-3.8]1.15 [1-1.4]2.5 [1.7-6.3]-NSFibrinogen, g/l.3.15 [2.8-3.6]3.35 [2.84-3.76]3.21 [2.9-3.8]-NS

*a statistically significant test result (p < 0.05); NS-not significant;FI- fluorescence intensity; SI- scatter intensity; fl- femtoliter.

Conclusion

Patients with SLE and SLE+APS had significantly higher levels of immature granulocytes than controls and PAPS patients. In PAPS, immature granulocytes were positively correlated with aGAPSS values.

The study was performed at V.A. Nasonova Research Institute of Rheumatology within the framework of the fundamental research FURS-2022-003.

Disclosure of Interests

None declared

AB0147 INFLAMMATORY AND NEUTROPHIL ACTIVATION MARKERS IN PATIENTS WITH BEHÇET’S DISEASE

Background

Behçet’s disease (BD) is a systemic variable vessel vasculitis with different clinical manifestations. BD does not have specific laboratory findings. Neutrophil hyperactivation is a major pathogenic factor in BD-related inflammation and tissue damage. Neutrophil reactivity (NEUT-RI), neutrophil granularity (NEUT-GI), immature granulocytes (IG), neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), and platelet-lymphocyte ratio (PLR) are considered as inflammatory markers. Their role in BD remains unclear.

Objectives

to determine the importance of parameters of neutrophil activation (NEUT-RI, NEUT-GI), immature granulocytes (absolute (IG#), relative (IG%) counts), NLR, MPV, PLR in assessing inflammation in BD.

Methods

29 patients with a reliable BD according to ICBD 2014 and 40 age-matched healthy donors (HD) without acute infectious diseases or cancer were included in the study (Table 1). Patients with BD were separated into two groups: 22 with active and 7 with inactive BD. Active BD was defined as involvement of at least two of the following features: oral ulcers, genital ulcers, uveitis, intestinal involvement, skin lesions, neurological involvement, arthritis, and vascular involvement. Current disease activity was evaluated with transformed Behçet’s Disease Current Activity Form (BDCAF). A complete blood count (WBC-white blood cell, NEUT#-an absolute neutrophil count, NEUT-RI, NEUT-GI, IG%, IG#, NLR, thrombocytes, MPV, PLR, ESR-erythrocyte sedimentation rate) was performed with XN-1000 automated hematology analyzer (Sysmex, Japan).

Table 1.

Comparative characteristics of patients with active/inactive BD and healthy controls.

Parameters M±SD, Me [25%; 75%], n (%)Active BD (n=22)Inactive BD (n=7)Healthy donors (n=40)pGender: male/female, n16/64/316 /24NSVascular involvement,n73-NSBDCAF5 [5; 8]1 [0; 3]-p<0.001*WBC, 109/l7.4 [5.9; 8.6]6.9 [6.5; 8.4]6.05 [5.2; 6.9]p=0.04*Thrombocytes, 109/l264.33±56.95305.11±104.82257.46±53.18NSNEUT#, 109/l3.91 [3.34; 5.03]3.89 [3.78; 5.5]3.41 [2.86; 4.13]NSNEUT-RI, FI45.95 [44.1; 47.1]46.25 [44.95; 47.75]43.7 [42.7; 46.2]р=0.049*NEUT-GI, SI154.84±4.05157.04±5.55153.37±4.7NSNLR1.64 [1.39; 1.91]1,9 [1.73; 2.6]1.83 [1.4; 2.28]NSESR, mm/6.5 [4.5; 17.0]12.0 [4.0; 15.0]7.0 [4.0; 11.0]NSIG#,109/l0.02 [0.01; 0.04]0.04 [0.01; 0.07]0.01 [0.01; 0.02]р=0.036*IG%0.3 [0.2; 0.4]0.45 [0.25; 0.65]0.2 [0.2; 0.3]р=0.018*CRP, mg/l2.5 [1.2; 7.4]2.45 [1.28; 4.65]-NSMPV, fl10.4 [9.7; 11.0]9.85 [9.6; 11.0]10.5 [10.1; 11.2]NSPLR116.45 [83.5; 138.6]151.55 [119.5; 171.1]137.1 [104.4; 160.1]NSFibrinogen, g/l3.48±0.82.88±0.4-NS

*a statistically significant test result (p ≤ 0.05); NS-not significant;FI- fluorescence intensity; SI- scatter intensity; fl- femtoliter.

Results

A WBC count was significantly higher in BD patients compared to controls (Table 1). Patients with active BD had a higher WBC count than inactive. Patients with BD were found to have significantly higher levels of IG#, IG%, and NEUT-RI compared to HD. There was no significant difference between NEUT-GI, NLR, MPV, PLR, and ESR levels in patients with BD and HD. No significant difference in NEUT-RI, NEUT-GI, NLR, IG #, IG%, PLR, or MPV between active and inactive BD was found. These hematological parameters did not correlate with the transformed BDCAF score. IG# levels positively correlated with total leukocyte count (rs=0.656, p<0.001) and the absolute neutrophil count (rs=0.548, p=0.002). There was a tendency to a positive correlation between IG# and NEUT-GI (rs=0.354, p=0.050) and a negative correlation between IG# and PLR (rs=-0.356, p=0.052).

Conclusion

Patients with BD had significantly higher total WBC counts, immature granulocyte levels, and neutrophil reactivity than controls. Except for the leukocytes, there was no statistically significant difference in the studied parameters between patients with active and inactive BD.

The study was performed at V.A. Nasonova Research Institute of Rheumatology within the framework of the fundamental research FURS-2022-003.

Disclosure of Interests

None declared

AB0663 COMPARING METHODS FOR DETERMINING ANTIBODIES TO SARS-CoV-2 USING A RAPID TEST AND ENZYME-LINKED IMMUNOSORBENT ASSAY

Background:

An accessible and sensitive and sensitive method for determining antibodies to a new coronavirus infection is often the key to timely provision of the necessary medical care to patients with rheumatic diseases

Objectives:

Compare methods for determining antibodies to SARS-CoV-2 using a rapid test and enzyme-linked immunosorbent assay (ELISA)

Methods:

Methods for determining antibodies to SARS-CoV-2 using an express test (Chromatographic express test SARS-CoV-2 IgG / IgM (Xiamen Biotime Biotechnology, China)) and by ELISA (Reagent kit for enzyme immunoassay of class G immunoglobulins and class M to SARS-CoV-2 (Vector-Best, Russia)) were compared.

80 patients were included with a diagnosis of rheumatoid arthritis 26 (33%), psoriatic arthritis - 9 (11%), osteoarthritis - 15 (19%), rheumatic heart disease 1 (1%), SLE 2 (3%), deramtomyositis 3 (4%), systemic sclerosis 5 (6%), systemic connective tissue diseases 4 (5%), including Sjogren’s syndrome, spondyloarthritis 15 (19%).

17 (21%) denied a history of COVID-19 symptoms. 63 (79%) noted any signs of COVID-19 3.095 ± 1.45 months before the test (Median 3 [2; 4] months). 63 (79%) noted any signs of COVID-19 109 ± 43 days before the test (Median 111 [78; 135] months). The ELISA method was considered the standard.

Results:

When comparing the results of the express test and the determination of IgG antibodies to SARS-CoV-2 in serum, the following was obtained: the sensitivity of the express test is 99%. When comparing the results of the express test and the determination of IgM antibodies to SARS-CoV-2 in serum, it was obtained: among 66 samples with a negative result by the express test method, IgM was detected in 6 cases by ELISA/ So, 7.5% of 80 samples were false negative. In 3 of 14 samples with a positive result by the express test, IgM by ELISA was not detected. So, 3.75% of 80 samples were false-positive. (Table 1). When comparing the results of the IgM express test and ELISA, the following was obtained: the sensitivity of the express test was 33%, the specificity was 85%.

Table 1.Antibodies, express-testAntibodies (ELISA), absentAntibodies (ELISA), presentRowTotalsIgGabsent011Row %0.00%100.00%present37679Row %3.80%96.20%Totals37780IgМabsent60666Row %90.91%9.09%present11314Row %78.57%21.43%Totals71980

Conclusion:

When comparing the results of the express test and the determination of IgG antibodies to SARS-CoV-2 in serum, the sensitivity of the express test is 99%. Determination of IgM antibodies to SARS-CoV-2 using a rapid test is less reliable than determination using ELISA.

Disclosure of Interests:

None declared.