Catharina Eriksson

International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies

Anti-nuclear antibodies (ANA) are fundamental for the diagnosis of autoimmune diseases, and have been determined by indirect immunofluorescence assay (IIFA) for decades. As the demand for ANA testing increased, alternative techniques were developed challenging the classic IIFA. These alternative platforms differ in their antigen profiles, sensitivity and specificity, raising uncertainties regarding standardisation and interpretation of incongruent results. Therefore, an international group of experts has created recommendations for ANA testing by different methods. Two groups of experts participated in this initiative. The European autoimmunity standardization initiative representing 15 European countries and the International Union of Immunologic Societies/World Health Organization/Arthritis Foundation/Centers for Disease Control and Prevention autoantibody standardising committee. A three-step process followed by a Delphi exercise with closed voting was applied. Twenty-five recommendations for determining ANA (1–13), anti-double stranded DNA antibodies (14–18), specific antibodies (19–23) and validation of methods (24–25) were created. Significant differences between experts were observed regarding recommendations 24–25 (p<0.03). Here, we formulated recommendations for the assessment and interpretation of ANA and associated antibodies. Notably, the roles of IIFA as a reference method, and the importance of defining nuclear and cytoplasmic staining, were emphasised, while the need to incorporate alternative automated methods was acknowledged. Various approaches to overcome discrepancies between methods were suggested of which an improved bench-to-bedside communication is of the utmost importance. These recommendations are based on current knowledge and can enable harmonisation of local algorithms for testing and evaluation of ANA and related autoantibodies. Last but not least, new more appropriate terminologies have been suggested.

A risk haplotype of STAT4 for systemic lupus erythematosus is over-expressed, correlates with anti-dsDNA and shows additive effects with two risk alleles of IRF5

Systemic lupus erythematosus (SLE) is the prototype autoimmune disease where genes regulated by type I interferon (IFN) are over-expressed and contribute to the disease pathogenesis. Because signal transducer and activator of transcription 4 (STAT4) plays a key role in the type I IFN receptor signaling, we performed a candidate gene study of a comprehensive set of single nucleotide polymorphism (SNPs) in STAT4 in Swedish patients with SLE. We found that 10 out of 53 analyzed SNPs in STAT4 were associated with SLE, with the strongest signal of association (P = 7.1 × 10−8) for two perfectly linked SNPs rs10181656 and rs7582694. The risk alleles of these 10 SNPs form a common risk haplotype for SLE (P = 1.7 × 10−5). According to conditional logistic regression analysis the SNP rs10181656 or rs7582694 accounts for all of the observed association signal. By quantitative analysis of the allelic expression of STAT4 we found that the risk allele of STAT4 was over-expressed in primary human cells of mesenchymal origin, but not in B-cells, and that the risk allele of STAT4 was over-expressed (P = 8.4 × 10−5) in cells carrying the risk haplotype for SLE compared with cells with a non-risk haplotype. The risk allele of the SNP rs7582694 in STAT4 correlated to production of anti-dsDNA (double-stranded DNA) antibodies and displayed a multiplicatively increased, 1.82-fold risk of SLE with two independent risk alleles of the IRF5 (interferon regulatory factor 5) gene.

Autoantibodies predate the onset of systemic lupus erythematosus in northern Sweden

IntroductionAutoantibodies have a central role in systemic lupus erythematosus (SLE). The presence of autoantibodies preceding disease onset by years has been reported both in patients with SLE and in those with rheumatoid arthritis, suggesting a gradual development of these diseases. Therefore, we sought to identify autoantibodies in a northern European population predating the onset of symptoms of SLE and their relationship to presenting symptoms.MethodsThe register of patients fulfilling the American College of Rheumatology criteria for SLE and with a given date of the onset of symptoms was coanalysed with the register of the Medical Biobank, Umeå, Sweden. Thirty-eight patients were identified as having donated blood samples prior to symptom onset. A nested case-control study (1:4) was performed with 152 age- and sex-matched controls identified from within the Medical Biobank register (Umeå, Sweden). Antibodies against anti-Sjögrens syndrome antigen A (Ro/SSA; 52 and 60 kDa), anti-Sjögrens syndrome antigen B, anti-Smith antibody, ribonucleoprotein, scleroderma, anti-histidyl-tRNA synthetase antibody, double-stranded DNA (dsDNA), centromere protein B and histones were analysed using the AtheNA Multi-Lyte ANA II Plus Test System on a Bio-Plex Array Reader (Luminex200). Antinuclear antibodies test II (ANA II) results were analysed using indirect immunofluorescence on human epidermal 2 cells at a sample dilution of 1:100.ResultsAutoantibodies against nuclear antigens were detected a mean (±SD) of 5.6 ± 4.7 years before the onset of symptoms and 8.7 ± 5.6 years before diagnosis in 63% of the individuals who subsequently developed SLE. The sensitivity (45.7%) was highest for ANA II, with a specificity of 95%, followed by anti-dsDNA and anti-Ro/SSA antibodies, both with sensitivities of 20.0% at specificities of 98.7% and 97.4%, respectively. The odds ratios (ORs) for predicting disease were 18.13 for anti-dsDNA (95% confidence interval (95% CI), 3.58 to 91.84) and 11.5 (95% CI, 4.54 to 28.87) for ANA. Anti-Ro/SSA antibodies appeared first at a mean of 6.6 ± 2.5 years prior to symptom onset. The mean number of autoantibodies in prediseased individuals was 1.4, and after disease onset it was 3.1 (P < 0.0005). The time predating disease was shorter and the number of autoantibodies was greater in those individuals with serositis as a presenting symptom in comparison to those with arthritis and skin manifestations as the presenting symptoms.ConclusionsAutoantibodies against nuclear antigens were detected in individuals who developed SLE several years before the onset of symptoms and diagnosis. The most sensitive autoantibodies were ANA, Ro/SSA and dsDNA, with the highest predictive OR being for anti-dsDNA antibodies. The first autoantibodies detected were anti-Ro/SSA.

Atherosclerosis in early rheumatoid arthritis: very early endothelial activation and rapid progression of intima media thickness

IntroductionIn this study we aimed to investigate whether there are indications of premature atherosclerosis, as measured by endothelial dependent flow-mediated dilation (ED-FMD) and intima media thickness (IMT), in patients with very early RA, and to analyze its relation to biomarkers of endothelial dysfunction, taking inflammation and traditional cardiovascular disease (CVD) risk factors into account.MethodsPatients from the three northern counties of Sweden diagnosed with early RA are followed in an ongoing prospective study of CVD co-morbidity. Of these, all patients aged ≤60 years were consecutively included in this survey of CVD risk factors (n = 79). Forty-four age and sex matched controls were included. IMT of common carotid artery and ED-FMD of brachial artery were measured using ultrasonography. Blood was drawn for analysis of lipids, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA)-mass, VonWillebrand factor (VWF), soluble intercellular adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM), sE-selectin, sL-selectin and monocyte chemotactic protein-1 (MCP-1). In a subgroup of 27 RA patients and their controls the ultrasound measurements were reanalysed after 18 months.ResultsThere were no significant differences between RA patients and controls in terms of IMT or ED-FMD at the first evaluation. However after 18 months there was a significant increase in the IMT among the patients with RA (P < 0.05). Patients with RA had higher levels of VWF, sICAM-1 (P < 0.05) and of MCP-1 (P = 0.001) compared with controls. In RA, IMT was related to some of the traditional CVD risk factors, tPA-mass, VWF (P < 0.01) and MCP-1 and inversely to sL-selectin (P < 0.05). In RA, ED-FMD related to sL-selectin (P < 0.01). DAS28 at baseline was related to PAI-1, tPA-mass and inversely to sVCAM-1 (P < 0.05) and sL-selectin (P = 0.001).ConclusionsWe found no signs of atherosclerosis in patients with newly diagnosed RA compared with controls. However, in patients with early RA, IMT and ED-FMD were, to a greater extent than in controls, related to biomarkers known to be associated with endothelial dysfunction and atherosclerosis. After 18 months, IMT had increased significantly in RA patients but not in controls.

Abnormal expression of chemokine receptors on T-cells from patients with systemic lupus erythematosus

The expressionof chemokinereceptors on T-cells and chemokinelevels in the blood was studied in 23 patients with SLE (ACR criteria), seven patients with rheumatoid arthritis (RA) and in 15 healthy controls using flow cytometry, RT-PCR and ELISA. The cell surface expression of the chemokine receptors CXCR5 and CCR6 was decreased in SLE patients compared with controls (P 0.051 and P 0.002, respectively). The decrease of CXCR5 was confined to SLE patients with inactive disease (SLEDAI < 6) compared with active disease (SLEDAI ≥6) and controls. CXCR2 and CCR1 were increased in patients with active SLE compared with patients with inactive disease (P 0.001 and P 0.01, respectively) and with controls (P 0.02 and P 0.053, respectively). The levels of the chemokines MIP-1b MCP-1, SDF-1a, IP-10 and RANTES were significantly elevated in SLE patients compared with controls. Patients with renal involvement had increased surface expression of CXCR3 and CCR3 (P 0.04 in both) and a lower level of soluble IP-10 compared with patients without renal disease (P 0.025) and compared with controls (P 0.001). The ratio between CCR5 and CCR3 was significantly increased in RA patients compared with SLE patients and controls supporting a Th1 overweight in RA. In conclusion, patients with SLE showed abnormal T-cell expression of several chemokine receptors and levels of soluble chemokines in their plasma/serum.

Genes identified in Asian SLE GWASs are also associated with SLE in Caucasian populations.

Recent genome-wide association studies (GWASs) conducted in Asian populations have identified novel risk loci for systemic lupus erythematosus (SLE). Here, we genotyped 10 single-nucleotide polymorphisms (SNPs) in eight such loci and investigated their disease associations in three independent Caucasian SLE case–control cohorts recruited from Sweden, Finland and the United States. The disease associations of the SNPs in ETS1, IKZF1, LRRC18-WDFY4, RASGRP3, SLC15A4, TNIP1 and 16p11.2 were replicated, whereas no solid evidence of association was observed for the 7q11.23 locus in the Caucasian cohorts. SLC15A4 was significantly associated with renal involvement in SLE. The association of TNIP1 was more pronounced in SLE patients with renal and immunological disorder, which is corroborated by two previous studies in Asian cohorts. The effects of all the associated SNPs, either conferring risk for or being protective against SLE, were in the same direction in Caucasians and Asians. The magnitudes of the allelic effects for most of the SNPs were also comparable across different ethnic groups. On the contrary, remarkable differences in allele frequencies between Caucasian and Asian populations were observed for all associated SNPs. In conclusion, most of the novel SLE risk loci identified by GWASs in Asian populations were also associated with SLE in Caucasian populations. We observed both similarities and differences with respect to the effect sizes and risk allele frequencies across ethnicities.

A candidate gene study of the type I interferon pathway implicates IKBKE and IL8 as risk loci for SLE

Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease in which the type I interferon pathway has a crucial role. We have previously shown that three genes in this pathway, IRF5, TYK2 and STAT4, are strongly associated with risk for SLE. Here, we investigated 78 genes involved in the type I interferon pathway to identify additional SLE susceptibility loci. First, we genotyped 896 single-nucleotide polymorphisms in these 78 genes and 14 other candidate genes in 482 Swedish SLE patients and 536 controls. Genes with P<0.01 in the initial screen were then followed up in 344 additional Swedish patients and 1299 controls. SNPs in the IKBKE, TANK, STAT1, IL8 and TRAF6 genes gave nominal signals of association with SLE in this extended Swedish cohort. To replicate these findings we extracted data from a genomewide association study on SLE performed in a US cohort. Combined analysis of the Swedish and US data, comprising a total of 2136 cases and 9694 controls, implicates IKBKE and IL8 as SLE susceptibility loci (Pmeta=0.00010 and Pmeta=0.00040, respectively). STAT1 was also associated with SLE in this cohort (Pmeta=3.3 × 10−5), but this association signal appears to be dependent of that previously reported for the neighbouring STAT4 gene. Our study suggests additional genes from the type I interferon system in SLE, and highlights genes in this pathway for further functional analysis.

Health-related quality of life in girls and boys with juvenile idiopathic arthritis: self- and parental reports in a cross-sectional study

BackgroundJuvenile Idiopathic Arthritis (JIA) affects children and adolescents with both short-term and long-term disability. These children also report lower health-related quality of life (HRQOL) compared to their healthy peers. However, there seems to be some discrepancies between self- and parent-reports, and gender differences need to be further studied. This study aims to describe HRQOL in girls and boys with JIA, and to explore gender differences in self-reports compared to parent-reports of HRQOL in children with JIA.MethodsFifty-three children and adolescents with JIA (70% girls and 30% boys) with a median age of 14 years (8–18 years), and their parents, participated in this cross-sectional study in Sweden. Data was systematically collected prior to ordinary visits at a Pediatric outpatient clinic, during a period of 16 months (2009–2010). Disability was assessed with the Childhood Health Assessment Questionnaire (CHAQ), and disease activity by physicians’ assessments and Erythrocyte Sedimentation Rate (ESR). The Pediatric Quality of Life Inventory 4.0 Generic Core Scales (PedsQL) was used to assess self- and parent-reports of HRQOL in the child.ResultsIn this sample of children with generally low disease activity and mild to moderate disability, more than half of the children experienced suboptimal HRQOL, equally in girls and boys. Significant differences between self- and parent-reports of child HRQOL were most evident among girls, with lower parent-reports regarding the girl’s physical- and psychosocial health as well as in the total HRQOL score. Except for the social functioning subscale, where parents’ reports were higher compared to their sons, there were no significant differences between boys- and parent-reports.ConclusionsMore than half of the girls and boys experienced suboptimal HRQOL in this sample, with no gender differences. However, there were differences between self- and parent-reports of child HRQOL, with most significant differences found among the girls. Thus, differences between self- and parent-reports of child HRQOL must be taken into account in clinical settings, especially among girls with JIA.

S-Calprotectin (S100A8/S100A9): A Potential Marker of Inflammation in Patients with Psoriatic Arthritis

Objective. To analyse levels of S100A8/S100A9 (calprotectin) and selected cytokines, in blood, in patients with psoriatic arthritis (PsA). Methods. Sixty-five patients with PsA were examined for clinical manifestations and laboratory measurements of S-calprotectin, ESR, hs-CRP, and selected cytokines. Thirty-two patients had mono-/oligoarthritis and 33 had polyarthritis. S-calprotectin, hs-CRP, and cytokines were measured using ELISA, immunoturbidimetry, and multiplex technology (Bio-Plex). Patients with PsA were compared with 31 healthy controls. Results. S-calprotectin and hs-CRP levels were significantly higher in patients with PsA compared with controls (P < 0.001 and P < 0.001, resp.). Patients suffering a polyarthritic disease pattern presented with significantly higher levels of S-calprotectin compared with controls and patients with mono-/oligoarthritis (P < 0.001 and P = 0.017, resp.). The levels of S-calprotectin correlated with hs-CRP (P < 0.001; r s = 0.441), swollen joint count (P = 0.002, r s = 0.397), and CXCL10 (P = 0.046, r s = 0.678) but not with any of the other cytokines evaluated. In multiple logistic regression analysis, S-calprotectin was the only variable significantly associated with psoriatic arthritis (P = 0.002, OR = 1.006, 95% CI = 1.002–1.010). Conclusion. S-calprotectin and hs-CRP levels were significantly higher in patients with PsA. A polyarthritic disease pattern showed higher levels of S-calprotectin than mono-/oligoarthritis. S-calprotectin is considered a potential marker of disease activity in patients with PsA.

Changes in chemokines and their receptors in blood during treatment with the TNF inhibitor infliximab in patients with rheumatoid arthritis

Objectives: Chemokines are involved in leucocyte recruitment into inflammatory sites. The release of certain chemokines is augmented by tumour necrosis factor (TNF). Infliximab, a monoclonal antibody that blocks the effects of TNF, is used for treatment of rheumatoid arthritis (RA). The effect of TNF blockage on chemokines is not fully understood. The aim of this study was to analyse the effects on chemokines and their receptors on peripheral mononuclear cells of anti-TNF treatment in RA patients. Method: Twelve patients with established RA who started treatment with infliximab and nine patients with early RA treated with other anti-rheumatic drugs were followed clinically for 30 weeks and chemokine levels in blood samples were analysed along with chemokine receptor expression on the surface of T cells and monocytes. Nine healthy subjects were included as a control group. Results: The chemokine CXCL10/IP-10 was significantly higher in RA patients than in healthy controls (p = 0.012). Two weeks after infliximab infusion, CXCL10/IP-10, CCL2/MCP-1, and CCL4/MIP-1β had decreased significantly (p = 0.005, 0.037, and 0.028, respectively), and after 30 weeks of treatment, soluble CD26 was significantly increased (p = 0.050). Several chemokine receptors on T cells were elevated in RA patients at inclusion. The expression of CCR2 and CXCR1 on T cells decreased significantly after infliximab treatment. Conclusions: The chemokines CXCL10/IP-10, CCL2/MCP-1, and CCL4/MIP-1β, mainly targeting the T-helper (Th)1 immune response, decreased after treatment with anti-TNF, suggesting a more pronounced effect on Th1 activity than on Th2-mediated response. Several chemokine receptors on blood T cells were elevated in RA patients, suggesting that they may be involved in the recruitment of T lymphocytes from the blood to affected tissues.