Assessment of anti-nucleosome antibody (ANuA) isotypes for the diagnosis and prediction of systemic lupus erythematosus and lupus nephritis activity.

Our study aims to investigate the serum levels of anti-nucleosome antibody (ANuA) isotypes in patients with systemic lupus erythematosus (SLE) and clarify ANuA isotypes that may diagnose and predict SLE. We detected anti-nucleosome antibodies (ANuA) in the serum from 120 patients with SLE, 99 patients suffering from other autoimmune diseases (OAD), and 50 healthy controls by performing IgG-, IgA-, and IgM-specific ELISAs. The serum levels of total anti-nuclear antibodies (ANA IgG), ANuA IgG subclasses (IgG1, IgG2, IgG3, and IgG4), anti-dsDNA antibodies, and the avidities of ANA IgG were also analysed using ELISAs. The levels of three ANuA isotypes (IgG, IgA, and IgM) were significantly higher in patients with SLE than in patients with OAD and healthy controls (p < 0.05). Moreover, the concentrations of ANuA isotypes increased in the active SLE and lupus nephritis (LN) groups and in patients with SLE presenting high-avidity IgG ANA (p < 0.05). Furthermore, ANuA isotype levels decreased significantly with drug therapy, while anti-dsDNA IgG levels decreased with the same trend. Additionally, ANuA isotypes were positively related to the SLEDAI (SLE Disease Activity Index) score, RAI (relative avidity index) of high-avidity IgG ANAs, and serum anti-dsDNA IgG levels. Last, the sensitivity and specificity values for SLE were 83.33 and 96.67% for ANuA IgG, 85.83 and 93.33% for ANuA IgA, and83.33 and 86.67% for ANuA IgM, respectively. The sensitivity and specificity values for LN were 61.67 and 96.67% for ANuA IgG, 49.17 and 96.67% for ANuA IgA, and 52.50 and 96.67% for ANuA IgM, respectively. In conclusion, we evaluated whether ANuA isotypes represent a diagnostic tool to predict SLE activity and define subsets of patients with LN.

Chemokine CXCL1 as a potential marker of disease activity in systemic lupus erythematosus.

OBJECTIVES: The chemokine CXCL1, known as growth-related oncogene α (GRO-α), is a potent chemoattractant and regulator of neutrophils. The purpose of our study was to evaluate the regulatory response of CXCL1 in the serum of patients with systemic lupus erythematosus (SLE) in the active stage of disease and to assess whether it was implicated in the pathogenesis/inflammatory process in lupus. METHODS: CXCL1 serum concentrations were examined in 90 SLE patients, 56 other autoimmune diseases (OADs) patients and 100 healthy controls using enzyme-linked immunosorbent methodology. RESULTS: SLE patients exhibited significant increases in serum CXCL1 concentrations [1492.86 (735.47-2887.34) pg/ml] compared with OADs patients [155.88 (10.77-366.78) pg/ml] and healthy controls [13.58 (8.46-37.22) pg/ml] (p < 0.001). Moreover, the level of CXCL1 decreased as the level of anti-dsDNA IgG decreased after treatment between the anti-dsDNA-positive SLE patients and the anti-dsDNA-negative SLE patients. Additionly, serum CXCL1 concentrations were related to different disease activity levels in SLE and lupus nephritis (LN) and high avidity of IgG ANAs (HA IgG ANAs) (p < 0.05). Furthermore, CXCL1 serum concentrations were significantly correlated with the SLE Disease Activity Index(SLEDAI) score, relative avidity index (RAI) of HA IgG ANAs and the levels of anti-dsDNA IgG, CRP, ESR, albumin, C3 and C4.Additionally, Statistical analysis revealed that positivity for IgG ANA (p < 0.001), the presence of HA IgG ANAs (p = 0.001) and the logarithmic level of anti-dsDNA IgG (p = 0.021) were significantly associated with the logarithmic level of CXCL1 with standard partial regression coefficients (95% CI) of 2.371 (1.734-3.009), 1.231 (0.52-1.937) and 0.409 (0.062-0.755), respectively. Finally, using cutoff points of 1182.17 pg/mL and 1500.31 pg/mL, serum CXCL1 levels had a similar sensitivity of 76% and specificity of 100% and 75% for the diagnosis of active SLE and LN, respectively. CONCLUSIONS: Serum CXCL13 concentrations might represent a potential marker of disease activity in systemic lupus erythematosus.