Dataset Information

Serum IgG2 antibody multicomposition in systemic lupus erythematosus and lupus nephritis (Part 1): cross-sectional analysis.

ABSTRACT:

Objectives

Serum anti-dsDNA and anti-nucleosome IgGs have been proposed as signatures for SLE and LN in limited numbers of patients. We sought to show higher sensitivity and specificity of the same antibodies with the IgG2 isotype and included IgG2 antibodies vs specific intracellular antigens in the analysis.

Methods

A total of 1052 SLE patients with (n = 479) and without (n = 573) LN, recruited at different times from the beginning of symptoms, were included in the study. Patients with primary APS (PAPS, n = 24), RA (RA, n = 24) and UCTD (UCTD, n = 96) were analysed for comparison. Anti-nucleosome (dsDNA, Histone2A, Histone3), anti-intracellular antigens (ENO1), anti-annexin A1 and anti-C1q IgG2 were determined by non-commercial techniques.

Results

The presence in the serum of the IgG2 panel was highly discriminatory for SLE/LN vs healthy subjects. Serum levels of anti-dsDNA and anti-C1q IgG2 were more sensitive than those of IgGs (Farr radioimmunoassay/commercial assays) in identifying SLE patients at low-medium increments. Of more importance, serum positivity for anti-ENO1 and anti-H2A IgG2 discriminated between LN and SLE (ROC T0-12 months), and high levels at T0-1 month were detected in 63% and 67%, respectively, of LN, vs 3% and 3%, respectively, of SLE patients; serum positivity for each of these was correlated with high SLEDAI values. Minor differences existed between LN/SLE and the other rheumatologic conditions.

Conclusion

Nephritogenic IgG2 antibodies represent a specific signature of SLE/LN, with a few overlaps with other rheumatologic conditions. High levels of anti-ENO1 and anti-H2A IgG2 correlated with SLE activity indexes and were discriminatory between SLE patients limited to the renal complication and other SLE patients.

Trial registration

The Zeus study was registered at https://clinicaltrials.gov, NCT02403115.

SUBMITTER: Bruschi M

PROVIDER: S-EPMC8487649 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Cardiovascular disease is common in patients with systemic lupus erythematosis (SLE) and lupus nephritis (LN). Up to 80% of children with SLE develop kidney disease, which is also associated with increased risk for cardiovascular disease and death compared to those without renal involvement. Hepcidin is an iron-regulatory protein which may contribute to atherosclerosis and is elevated in autoimmune disease. Pulse wave velocity (PWV) is a validated indicator of arterial stiffness, an early marker of cardiovascular risk, and is increased in children with SLE versus healthy controls. Our objective was to quantify hepcidin and PWV in children with SLE and investigate if those with biopsy-proven LN have higher hepcidin levels and higher PWV compared to those without kidney disease. METHODS:Cross-sectional analysis with hepcidin was measured via ELISA assay in 16 children aged 10-21 years with SLE recruited from a single center. Subjects were classified as having LN if histologic evidence of the disease was documented on a clinical renal biopsy. Serum hepcidin was quantified using a validated competitive enzyme-linked immunoassay. Carotid-femoral PWV was measured using applanation tonometry. Wilcoxon rank sum testing was used to compare median levels of hepcidin, PWV, and other continuous variables by nephritis status. RESULTS:The cohort (n = 16) was 93.8% female and 68.8% African-American with mean (SD) 16 (3.6) years. 37.5% (n = 6) had LN. Overall median (IQR) hepcidin was 34.4 (18.9, 91.9) ng/ml, and PWV 4.4 (4, 4.6) meters/second. Although significance was limited by small sample size, both hepcidin and PWV were higher in the subjects with LN. Median (IQR) hepcidin in subjects with LN was 71.5 (26.4, 116.4) ng/ml compared to 27.9 (18.7, 59.7) ng/ml in those with SLE(p = 0.19). Similarly, median (IQR) PWV in those with LN was 4.4 (4.4, 4.9) meters/second compared to 3 (3.75, 4.55) meters/second in those with without kidney involvement (p = 0.10). CONCLUSION:PWV and serum hepcidin were higher in subjects with LN compared to those with SLE alone, suggesting that elevated hepcidin levels may be associated with morbid CV changes in children with LN. This association, along with identification of additional predictors of arterial stiffness in patients with LN, warrants further investigation.