Antinuclear antibodies measured by enzyme immunoassay in patients with systemic lupus erythematosus: relation to disease activity

Differential regulation of the interferon response in systemic lupus erythematosus distinguishes patients of Asian ancestry

OBJECTIVES

Type I interferon (IFN) plays a role in the pathogenesis of systemic lupus erythematosus (SLE), but insufficient attention has been directed to the differences in IFN responses between ancestral populations. Here, we explored the expression of the interferon gene signatures (IGSs) in SLE patients of European ancestry (EA) and Asian ancestry (AsA).

METHODS

We used gene set variation analysis with multiple IGS encompassing the response to both type 1 and type 2 IFN in isolated CD14+ monocytes, CD19+B cells, CD4+T cells and Natural Killer (NK) cells from patients with SLE stratified by self-identified ancestry. The expression of genes upstream of the IGS and influenced by lupus-associated risk alleles was also examined. Lastly, we employed machine learning (ML) models to assess the most important features classifying patients by disease activity.

RESULTS

AsA patients with SLE exhibited greater enrichment in the IFN core and IFNA2 IGS compared with EA patients in all cell types examined and, in the presence and absence of autoantibodies. Overall, AsA patients with SLE demonstrated higher expression of genes upstream of the IGS than EA counterparts. ML with feature importance analysis indicated that IGS expression in NK cells, anti-dsDNA, complement levels and AsA status contributed to disease activity.

CONCLUSIONS

AsA patients with SLE exhibited higher IGS than EA patients in all cell types regardless of autoantibody status, with enhanced expression of genetically associated genes upstream of the IGS potentially contributing. AsA, along with the IGS in NK cells, anti-dsDNA and complement, independently influenced SLE disease activity.

Longitudinal analysis of ANA in the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort

OBJECTIVES

A perception derived from cross-sectional studies of small systemic lupus erythematosus (SLE) cohorts is that there is a marked discrepancy between antinuclear antibody (ANA) assays, which impacts on clinicians' approach to diagnosis and follow-up. We compared three ANA assays in a longitudinal analysis of a large international incident SLE cohort retested regularly and followed for 5 years.

METHODS

Demographic, clinical and serological data was from 805 SLE patients at enrolment, year 3 and 5. Two HEp-2 indirect immunofluorescence assays (IFA1, IFA2), an ANA ELISA, and SLE-related autoantibodies were performed in one laboratory. Frequencies of positivity, titres or absorbance units (AU), and IFA patterns were compared using McNemar, Wilcoxon and kappa statistics, respectively.

RESULTS

At enrolment, ANA positivity (≥1:80) was 96.1% by IFA1 (median titre 1:1280 (IQR 1:640-1:5120)), 98.3% by IFA2 (1:2560 (IQR 1:640-1:5120)) and 96.6% by ELISA (176.3 AU (IQR 106.4 AU-203.5 AU)). At least one ANA assay was positive for 99.6% of patients at enrolment. At year 5, ANA positivity by IFAs (IFA1 95.2%; IFA2 98.9%) remained high, while there was a decrease in ELISA positivity (91.3%, p<0.001). Overall, there was >91% agreement in ANA positivity at all time points and ≥71% agreement in IFA patterns between IFA1 and IFA2.

CONCLUSION

In recent-onset SLE, three ANA assays demonstrated commutability with a high proportion of positivity and titres or AU. However, over 5 years follow-up, there was modest variation in ANA assay performance. In clinical situations where the SLE diagnosis is being considered, a negative test by either the ELISA or HEp-2 IFA may require reflex testing.

Anti-Nuclear Antibody Quantitation: Calibration and Harmonization Adjustment via Population Interrogation

BACKGROUND

The 2019 classification criteria for systemic lupus erythematosus (SLE) includes an initial criterion requiring the presence of an antinuclear antibody (ANA), positive at a titer of at least 1:80 on HEp-2 cells, or equivalent. However, results of ANA tests performed on HEp-2 cells vary when tested in different laboratories. Calibration of ANA assays by achieving a common specificity in healthy control populations offers the possibility of achieving harmonization via population interrogation, but the expected specificity in a healthy control population is not known.

METHODS

The studies used to determine the use of ANAs performed by immunofluorescence microscopy on HEp-2 cells as the entry criterion for classification of SLE were reanalyzed by a meta-analysis to determine the expected frequency of positive ANAs in healthy control populations at serum dilutions of 1:40 and 1:80.

RESULTS

Our meta-analysis demonstrated that the expected specificity in a healthy control population of ANA performed using serum diluted 1:80 is 91.3% (CI 86.1-94.7%). The expected specificity of ANA performed at 1:40 serum dilution is 79.2% (CI 72.3-84.8%).

CONCLUSION

One approach to achieving harmonization of ANA assays from different laboratories with each other and with expected performance would involve adjusting assays so that about 10% of a healthy control population has a positive ANA when tested at 1:80 dilution, and about 20% of the healthy control population has a positive ANA when tested at 1:40 dilution. This pragmatic approach to calibration and harmonization adjustment via population interrogation offers an opportunity for individual laboratories to be aligned with each other and with ANA performance expected for consistent categorization of patients with SLE.

Ginsenoside Rh1 Improves the Effect of Dexamethasone on Autoantibodies Production and Lymphoproliferation in MRL/lpr Mice

Ginsenoside Rh1 is able to upregulate glucocorticoid receptor (GR) level, suggesting Rh1 may improve glucocorticoid efficacy in hormone-dependent diseases. Therefore, we investigated whether Rh1 could enhance the effect of dexamethasone (Dex) in the treatment of MRL/lpr mice. MRL/lpr mice were treated with vehicle, Dex, Rh1, or Dex + Rh1 for 4 weeks. Dex significantly reduced the proteinuria and anti-dsDNA and anti-ANA autoantibodies. The levels of proteinuria and anti-dsDNA and anti-ANA autoantibodies were further decreased in Dex + Rh1 group. Dex, Rh1, or Dex + Rh1 did not alter the proportion of CD4+ splenic lymphocytes, whereas the proportion of CD8+ splenic lymphocytes was significantly increased in Dex and Dex + Rh1 groups. Dex + Rh1 significantly decreased the ratio of CD4+/CD8+ splenic lymphocytes compared with control. Con A-induced CD4+ splenic lymphocytes proliferation was increased in Dex-treated mice and was inhibited in Dex + Rh1-treated mice. Th1 cytokine IFN-γ mRNA was suppressed and Th2 cytokine IL-4 mRNA was increased by Dex. The effect of Dex on IFN-γ and IL-4 mRNA was enhanced by Rh1. In conclusion, our data suggest that Rh1 may enhance the effect of Dex in the treatment of MRL/lpr mice through regulating CD4+ T cells activation and Th1/Th2 balance.

Analysis of 15 patients with systemic lupus erythematosus manifesting with negative immunofluorescence anti-nuclear antibodies after treatment

The purpose of this study was to investigate the clinical and laboratorial characteristics of patients with systemic lupus erythematosus (SLE) manifesting with negative immunofluorescence anti-nuclear antibodies (IFANA) after treatment for the better understanding of negative conversion of IFANA. Demographic characteristics, clinical and laboratory data of hospitalized SLE patients between March 2006 and May 2011 were retrospectively reviewed. Fifteen cases with negative IFANA were identified in 960 patients. All of the 15 patients were severe, 11 patients manifested with nephritic range proteinuria and hypoalbuminemia, 8 patients were complicated with severe infection and all of the patients had been treated with glucocorticoid and immunosuppressant. Anti-ENA antibodies were positive in 4 of 15 patients. Eight patients died after average 1-year follow-up. Collectively, negative IFANA is mainly attributed to nephritic-range proteinuria; and large-dose glucocorticoid, immunosuppressant and severe infection are also important factors for negative IFANA. Antinuclear antibody can be detected in some SLE patients with negative IFANA by changing the detection method and titer. Negative conversion of IFANA often indicates unfavorable prognosis for severe patients.

Antinuclear antibodies: a marker associated with steroid dependence in patients with ulcerative colitis

BACKGROUND

The autoimmune phenomena and the autoantibody profile have acquired great importance in ulcerative colitis (UC). Few studies have explored antinuclear antibodies (ANAs) prevalence, but not its association with steroid dependence. We hypothesized that ANAs could be a factor associated to steroid dependence.

METHODS

Ninety-seven consecutive patients with UC were included. ANA titers and staining patterns were determined by indirect immunofluorescence. Gender, age, follow-up time, C-reactive protein (CRP), disease extent, Mayo Score Activity Index, extraintestinal manifestations, and steroid dependence were analyzed in univariate and multivariate models.

RESULTS

Ninety-seven patients were included and 49 (50.5%) were females; mean age was 41.7 +/- 22.2 years. Positivity for ANAs was encountered in 52 (53.5%) patients, and none for anti-dsDNA. The prevalence of ANAs was higher in steroid-dependent than in nonsteroid-dependent patients (77.8% versus 48.1%, P = 0.020; odds ratio [OR] = 3.8, 95% confidence interval [CI] 1.1-12.5), and in those with uveitis (100% versus 51.1%; P = 0.040) or pyoderma gangrenosum (100% versus 51.6%; P = 0.078). No association was observed with gender, age, CRP, disease extent, and Mayo Score Activity Index. The multiple regression analysis model showed an association between steroid dependence and ANAs (P = 0.033, OR = 3.9, 95% CI 1.4-14.9).

CONCLUSIONS

ANAs are associated with steroid dependence in UC patients. Further studies are required to determine the role of ANAs as serological markers for prediction of steroid dependence in order to perform early therapeutic interventions with biological agents.