Comparison of autoantibody specificities between traditional and bead-based assays in a large, diverse collection of patients with systemic lupus erythematosus and family members

Autoantibodies persist in relatives to systemic lupus erythematosus patients during 12 years follow-up

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease with presence of autoantibodies and characteristic multi-organ involvement. Relatives of SLE patients have an increased risk of autoantibody production and autoimmune diseases.

Methods

In 2001, 226 first degree relatives (FDRs) of a population-based cohort of SLE patients were examined for the prevalence of autoantibodies and self-reported health complaints. In 2013, 143 FDRs were re-investigated and deceased’s medical records were examined.

Results

Participants and non-participants were comparable regarding baseline characteristics, while deceased FDRs were older than participants, but with comparable ANA status. ANA status at baseline correlated to ANA status at follow-up. At follow-up, two FDRs reported SLE and 15 FDRs other autoimmune diseases. No observation at baseline alone could predict self-reported health. During follow-up 33 died at median age 76 years. Three deceased FDRs were diagnosed with an autoimmune disease.

Conclusion

The study showed that FDRs of SLE patients have an increased prevalence of ANA compared to healthy controls. The prevalence increased during follow-up, and ANA positive FDRs at baseline were prone to be ANA positive at follow-up. ANA positive FDRs had more self-reported autoimmune diseases, including SLE and rheumatoid arthritis, than reported from other population-based investigations.

Altered type II interferon precedes autoantibody accrual and elevated type I interferon activity prior to systemic lupus erythematosus classification

OBJECTIVES

The relationship of immune dysregulation and autoantibody production that may contribute to systemic lupus erythematosus (SLE) pathogenesis is unknown. This study evaluates the individual and combined contributions of autoantibodies, type I interferon (IFN-α) activity, and IFN-associated soluble mediators to disease development leading to SLE.

METHODS

Serial serum specimens from 55 individuals collected prior to SLE classification (average timespan=4.3 years) and unaffected healthy controls matched by age (±5 years), gender, race and time of sample procurement were obtained from the Department of Defense Serum Repository. Levels of serum IFN-α activity, IFN-associated mediators and autoantibodies were evaluated and temporal relationships assessed by growth curve modelling, path analysis, analysis of covariance and random forest models.

RESULTS

In cases, but not matched controls, autoantibody specificities and IFN-associated mediators accumulated over a period of years, plateauing near the time of disease classification (p<0.001). Autoantibody positivity coincided with or followed type II IFN dysregulation, preceding IFN-α activity in growth curve models, with elevated IFN-α activity and B-lymphocyte stimulator levels occurring shortly before SLE classification (p≤0.005). Cases were distinguished by multivariate random forest models incorporating IFN-γ, macrophage chemoattractant protein (MCP)-3, anti-chromatin and anti-spliceosome antibodies (accuracy 93% >4 years pre-classification; 97% within 2 years of SLE classification).

CONCLUSIONS

Years before SLE classification, enhancement of the type II IFN pathway allows for accumulation of autoantibodies and subsequent elevations in IFN-α activity immediately preceding SLE classification. Perturbations in select immunological processes may help identify at-risk individuals for further clinical evaluation or participation in prospective intervention trials.

Plasmacytoid dendritic cells and type 1 interferon promote peripheral expansion of forkhead box protein 3(+) regulatory T cells specific for the ubiquitous RNA-binding nuclear antigen La/Sjögren's syndrome (SS)-B

RNA-binding nuclear antigens are a major class of self-antigen to which immune tolerance is lost in rheumatic diseases. Serological tolerance to one such antigen, La/Sjögren's syndrome (SS)-B (La), is controlled by CD4(+) T cells. This study investigated peripheral tolerance to human La (hLa) by tracking the fate of hLa-specific CD4(+) T cells expressing the transgenic (Tg) 3B5.8 T cell receptor (TCR) after adoptive transfer into lymphocyte-replete recipient mice expressing hLa as a neo-self-antigen. After initial antigen-specific cell division, hLa-specific donor CD4(+) T cells expressed forkhead box protein 3 (FoxP3). Donor cells retrieved from hLa Tg recipients displayed impaired proliferation and secreted interleukin (IL)-10 in vitro in response to antigenic stimulation. Transfer of highly purified FoxP3-negative donor cells demonstrated that accumulation of hLa-specific regulatory T cells (Treg ) was due primarily to expansion of small numbers of donor Treg . Depletion of recipient plasmacytoid dendritic cells (pDC), but not B cells, severely hampered the accumulation of FoxP3(+) donor Treg in hLa Tg recipients. Recipient pDC expressed tolerogenic markers and higher levels of co-stimulatory and co-inhibitory molecules than B cells. Adoptive transfer of hLa peptide-loaded pDC into mice lacking expression of hLa recapitulated the accumulation of hLa-specific Treg . Blockade of the type 1 interferon (IFN) receptor in hLa Tg recipients of hLa-specific T cells impaired FoxP3(+) donor T cell accumulation. Therefore, peripheral expansion of Treg specific for an RNA-binding nuclear antigen is mediated by antigen-presenting pDC in a type 1 IFN-dependent manner. These results reveal a regulatory function of pDC in controlling autoreactivity to RNA-binding nuclear antigens.

Dysregulation of innate and adaptive serum mediators precedes systemic lupus erythematosus classification and improves prognostic accuracy of autoantibodies

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with a poorly understood preclinical stage of immune dysregulation and symptom accrual. Accumulation of antinuclear autoantibody (ANA) specificities is a hallmark of impending clinical disease. Yet, many ANA-positive individuals remain healthy, suggesting that additional immune dysregulation underlies SLE pathogenesis. Indeed, we have recently demonstrated that interferon (IFN) pathways are dysregulated in preclinical SLE. To determine if other forms of immune dysregulation contribute to preclinical SLE pathogenesis, we measured SLE-associated autoantibodies and soluble mediators in samples from 84 individuals collected prior to SLE classification (average timespan = 5.98 years), compared to unaffected, healthy control samples matched by race, gender, age (±5 years), and time of sample procurement. We found that multiple soluble mediators, including interleukin (IL)-5, IL-6, and IFN-γ, were significantly elevated in cases compared to controls more than 3.5 years pre-classification, prior to or concurrent with autoantibody positivity. Additional mediators, including innate cytokines, IFN-associated chemokines, and soluble tumor necrosis factor (TNF) superfamily mediators increased longitudinally in cases approaching SLE classification, but not in controls. In particular, levels of B lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL) were comparable in cases and controls until less than 10 months pre-classification. Over the entire pre-classification period, random forest models incorporating ANA and anti-Ro/SSA positivity with levels of IL-5, IL-6, and the IFN-γ-induced chemokine, MIG, distinguished future SLE patients with 92% (±1.8%) accuracy, compared to 78% accuracy utilizing ANA positivity alone. These data suggest that immune dysregulation involving multiple pathways contributes to SLE pathogenesis. Importantly, distinct immunological profiles are predictive for individuals who will develop clinical SLE and may be useful for delineating early pathogenesis, discovering therapeutic targets, and designing prevention trials.

The use and abuse of diagnostic/classification criteria

In rheumatic diseases, classification criteria have been developed to identify well-defined homogenous cohorts for clinical research. Although they are commonly used in clinical practice, their use may not be appropriate for routine diagnostic clinical care. Classification criteria are being revised with improved methodology and further understanding of disease pathophysiology, but they still may not encompass all unique clinical situations to be applied for diagnosis of heterogenous, rare, evolving rheumatic diseases. Diagnostic criteria development is challenging primarily due to difficulty for universal application given significant differences in the prevalence of rheumatic diseases based on geographical area and clinic settings. Despite these shortcomings, the clinician can still use classification criteria for understanding the disease as well as a guide for diagnosis with a few caveats. We present the limits of current classification criteria, their use and abuse in clinical practice, and how they should be used with caution when applied in clinics.

Some aspects of interactivity between endocrine and immune systems required for successful reproduction

BACKGROUND

In successful reproduction, endocrine and immune systems closely interact. We here attempt to further elucidate the relationship between androgen levels, systemic activation of the immune system and reproductive success in infertile women, utilizing 2 distinct infertile patient cohorts.

METHODS

In Group 1, we investigated 322 women (ages 38.6+/-5.4 years) at initial presentation; in Group 2 125 women undergoing in vitro fertilization (169 IVF cycles, ages 38.9+/-5.5 years). In Group 1, we assessed androgens and an immune panel, previously demonstrated to discriminate between activated quiescent immune systems; in Group 2, utilizing the same immune panel, we investigated whether immune system activation relates to embryo quality in IVF cycles.

RESULTS

No individual immune test within the immune panel was associated with androgen levels. The total/free testosterone ratio (TT/FT) was, however, significantly associated with presence of gammopathies (in IgG, IgM, IgA, IgE; P=0.026). Surprisingly, immune system activation was associated with significantly improved embryo quality (P=0.008), a finding persistent after adjustment for age and repeat IVF cycles (P=0.006).

CONCLUSIONS

Association of immune system activation with improved embryo quality concurs with previously reported immune activation in association with normal functional ovarian reserve (FOR) and normal androgen levels, while, counter intuitively, hypoandrogenism and low FOR are associated with lack of immune system activation. Mild immune system activation, therefore, likely appears essential for establishment of pregnancy, and may be regulated by androgens.

Environmental influences on systemic lupus erythematosus expression

The etiology of systemic lupus erythematosus (SLE) is unknown, but multiple genetic, epigenetic, and environmental risk factors have been implicated. The inheritance of genes alone is not sufficient for developing SLE, suggesting the influence of environmental triggers on disease expression. Despite the tremendous amount of progress in elucidating potential environmental risk factors for SLE, much more needs to be done. An interdisciplinary approach to studies of the causes and, ultimately, prevention of SLE is needed. This article reviews what is understood about the epidemiology of the relationship between environmental exposures and SLE, in addition to emerging areas of study.

Disease activity in systemic lupus erythematosus correlates with expression of the transcription factor AT-rich-interactive domain 3A

OBJECTIVE

Systemic lupus erythematosus (SLE) is a complex and multifactorial autoimmune disease with striking clinical, immunologic, and genetic heterogeneity, despite nearly ubiquitous antinuclear antibody (ANA) production. Multiple gene polymorphisms have been associated with the disease, but these individually account for only a very small percentage of overall SLE risk. In earlier studies, constitutive expression of the DNA-binding protein AT-rich-interactive domain 3A (ARID3a) in transgenic mouse B lymphocyte lineage cells led to spontaneous ANA production and preferential development of B cells associated with production of polyreactive antibodies. Therefore, we undertook this study to determine whether ARID3a was overexpressed in B lymphocytes of SLE patients and whether ARID3a expression was associated with disease severity.

METHODS

A cross-section of SLE patients, rheumatoid arthritis patients, and age- and sex-matched controls was analyzed longitudinally for lupus disease activity, numbers of ARID3a+ peripheral blood mononuclear B cells from multiple B cell subsets, and immunoglobulin and cytokine levels.

RESULTS

Fifty of 115 SLE patients (43%) had dramatically increased numbers of ARID3a+ B cells compared to healthy controls. ARID3a was not expressed in naive B cells of healthy controls, but was abundant in these precursors of antibody-secreting cells in SLE patients. Total numbers of ARID3a+ B cells correlated with increased disease activity as defined by SLE Disease Activity Index scores in individuals assessed at 3 time points.

CONCLUSION

These findings identify B cell anomalies in SLE that allow stratification of patient samples based on ARID3a expression and implicate ARID3a as a potential marker of CD19+ B lymphocytes correlated with disease activity.

Diagnostic value of serum complement C3 and C4 levels in Chinese patients with systemic lupus erythematosus

In 2009, hypocomplementemia involving C3, C4, and total hemolytic complement (CH50) was proposed as an immunologic criterion to enhance the sensitivity of systemic lupus erythematosus (SLE) classification criteria. This study evaluated the diagnostic value of low serum complement C3 and C4 levels in Chinese patients with SLE. In total, 2452 patients were enrolled in this study (158 with SLE and 2294 with other diseases). Receiver operating characteristic analysis showed that the optimal C3 and C4 cut-off levels for a diagnosis of SLE were 0.785 g/L (sensitivity, 77.9%; specificity, 81.5%) and 0.145 g/L (sensitivity, 80.1%; specificity, 83.2%), respectively. The prevalence of a low C3 or C4 level alone was similar between patients with SLE and those with other diseases, while the prevalence of simultaneously low C3 and C4 levels was higher in patients with SLE (73.42%). Antinuclear antibody had a high sensitivity (96.64%) and low negative likelihood ratio (0.04). Hypocomplementemia with positive antinuclear antibody had a high positive likelihood ratio. Inclusion of hypocomplementemia as a classification criterion for SLE resulted in a 16.18% increase in the number of patients assigned to the SLE group (from 136 to 158 patients). Hypocomplementemia was highly prevalent in patients with hematological disease (41.94%). These results suggest that hypocomplementemia has important diagnostic value for SLE by improving the sensitivity of the diagnosis of SLE. C3 and C4 should be tested simultaneously because a low C3 or C4 level alone is not a suitable immunological criterion.

Preclinical systemic lupus erythematosus

Preclinical lupus encompasses a spectrum from enhanced SLE risk without clinical symptoms to individuals with autoantibodies and some SLE clinical features without meeting ACR classification. Studies have identified antibody and serological biomarkers years before disease onset. Incomplete lupus and undifferentiated connective tissue disease may occur during preclinical disease periods, but only 10-20% of these individuals transition to SLE and many have a mild disease course. Further studies are warranted to characterize biomarkers of early disease, identify individuals in need of close monitoring or preventive interventions, and elucidate mechanisms of disease pathogenesis without confounding factors of immunosuppressive medications or organ damage.

Patterns of ambulatory medical care utilization and rheumatologist consultation predating the diagnosis of systemic lupus erythematosus: a national population-based study

OBJECTIVE

To investigate the records of ambulatory medical care from patients predating the diagnosis of systemic lupus erythematosus (SLE) using nationwide, population-based claims data.

METHODS

The frequencies and costs of ambulatory medical care utilization in 337 newly-diagnosed SLE cases between 2004 and 2010, identified from Taiwan's National Health Insurance Research Database, were compared with 1,348 controls who were frequency matched for sex, age, and the catastrophic illness certificate application year of the cases.

RESULTS

Patients with SLE had a median frequency of ambulatory medical care utilization compared with controls one year prior to the index date (22 vs. 2, P<0.001). The differences were significant throughout all eight annual periods. Similarly, the inflation-adjusted costs of ambulatory medical care utilization in patients with SLE increased annually over the study period, from a median of US$18 eight years prior to the index date to US$680 one year prior to the index date. Diseases of the respiratory system (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 460-519), digestive system (ICD-9-CM codes 520-579), musculoskeletal system and connective tissue (ICD-9-CM codes 710-739, excluding 710.0), and skin and subcutaneous tissue (ICD-9-CM codes 680-709) were the top four common causes of visits in the 0.5 to 2 year period preceding the index date and percentages of SLE patients suffered from these disorders increased progressively over the study period. Only 56.4% of the patients with SLE had consulted a rheumatologist and most of the serology tests were done within one year predating the index date.

CONCLUSIONS

Increased frequencies and costs of ambulatory care utilization among Taiwanese patients with SLE occurred several years predating their definitive SLE diagnosis. When multisystemic disorders are presented in young female patients, the possibility of SLE should be considered and screened with tools such as the antinuclear antibody test.

Spatial environmental modeling of autoantibody outcomes among an African American population

In this study of autoimmunity among a population of Gullah African Americans in South Carolina, the links between environmental exposures and autoimmunity (presence of antinuclear antibodies (ANA)) have been assessed. The study population included patients with systemic lupus erythematosus (n = 10), their first degree relatives (n = 61), and unrelated controls (n = 9) where 47.5% (n = 38) were ANA positive. This paper presents the methodology used to model ANA status as a function of individual environmental influences, both self-reported and measured, while controlling for known autoimmunity risk factors. We have examined variable dimension reduction and selection methods in our approach. Following the dimension reduction and selection methods, we fit logistic spatial Bayesian models to explore the relationship between our outcome of interest and environmental exposures adjusting for personal variables. Our analysis also includes a validation "strip" where we have interpolated information from a specific geographic area for a subset of the study population that lives in that vicinity. Our results demonstrate that residential proximity to exposure site is important in this form of analysis. The use of a validation strip network demonstrated that even with small sample numbers some significant exposure-outcome relationships can be detected.

Smoking is not associated with autoantibody production in systemic lupus erythematosus patients, unaffected first-degree relatives, nor healthy controls

OBJECTIVE

The objective of this paper is to examine whether smoking is associated with autoantibody production in systemic lupus erythematosus (SLE) patients, unaffected first-degree relatives (FDR) of individuals with SLE--a group at increased risk of developing SLE--or unaffected, unrelated controls.

METHODS

Detailed demographic, environmental, clinical, and therapeutic information was collected by questionnaire on 1242 SLE patients, 981 FDRs, and 946 controls in the Lupus Family Registry and Repository; a blood sample was obtained. All sera were tested for multiple lupus autoantibodies by immunofluorescence and luminex bead-based assays. Generalized estimating equations, adjusting for age, gender, and ethnicity and accounting for correlation within families, were used to assess smoking status with the dichotomous outcome variables of positivity for SLE status, positivity of ANA by immunofluorescence (≥1:120), positivity for ≥1 autoantibody by the luminex assay, and positivity for each of the 11 autoantibodies.

RESULTS

Current smoking was associated with being positive for ≥1 autoantibody (excluding ANA) (adjusted OR = 1.53, 95% CI 1.04-2.24) in our subjects with SLE. No association was observed in unaffected FDRs or healthy controls. Former smoking was associated with anti-Ro/SS-A60 in our unaffected FDRs. There was an increased association with anti-nRNP A seropositivity, as well as a decreased association with anti-nRNP 68 positivity, in current smokers in SLE subjects.

CONCLUSIONS

No clear association between smoking status and individual autoantibodies was detected in SLE patients, unaffected FDRs, nor healthy controls within this collection. The association of smoking with SLE may therefore manifest its risk through mechanisms outside of autoantibody production, at least for the specificities tested.

Systemic lupus erythematosus diagnostics in the 'omics' era

Systemic lupus erythematosus is a complex autoimmune disease affecting multiple organ systems. Currently, diagnosis relies upon meeting at least four out of eleven criteria outlined by the ACR. The scientific community actively pursues discovery of novel diagnostics in the hope of better identifying susceptible individuals in early stages of disease. Comprehensive studies have been conducted at multiple biological levels including: DNA (or genomics), mRNA (or transcriptomics), protein (or proteomics) and metabolites (or metabolomics). The 'omics' platforms allow us to re-examine systemic lupus erythematosus at a greater degree of molecular resolution. More importantly, one is hopeful that these 'omics' platforms may yield newer biomarkers for systemic lupus erythematosus that can help clinicians track the disease course with greater sensitivity and specificity.

Imaging DNA with fluorochrome bearing metals

Molecules that fluoresce upon binding DNA are widely used in assaying and visualizing DNA in cells and tissues. However, using light to visualize DNA in animals is limited by the attenuation of light transmission by biological tissues. Moreover, it is now clear that DNA is an important mediator of dead cell clearance, coagulation reactions, and an immunogen in autoimmune lupus. Attaching metals (e.g., superparamagnetic nanoparticles, gadolinium ions, radioactive metal ions) to DNA-binding fluorochromes provides a way of imaging DNA in whole animals, and potentially humans, without light. Imaging metal-bearing, DNA-binding fluorochromes and their target DNA by magnetic resonance imaging may shed light on the many key roles of DNA in health and disease beyond the storage of genetic information.

Multiple Autoantibodies Display Association with Lymphopenia, Proteinuria, and Cellular Casts in a Large, Ethnically Diverse SLE Patient Cohort

Purpose. This study evaluates high-throughput autoantibody screening and determines associated systemic lupus erythematosus (SLE) clinical features in a large lupus cohort. Methods. Clinical and demographic information, along with serum samples, were obtained from each SLE study participant after appropriate informed consent. Serum samples were screened for 10 distinct SLE autoantibody specificities and examined for association with SLE ACR criteria and subcriteria using conditional logistic regression analysis. Results. In European-American SLE patients, autoantibodies against 52 kD Ro and RNP 68 are independently enriched in patients with lymphopenia, anti-La, and anti-ribosomal P are increased in patients with malar rash, and anti-dsDNA and anti-Sm are enriched in patients with proteinuria. In African-American SLE patients, cellular casts associate with autoantibodies against dsDNA, Sm, and Sm/nRNP. Conclusion. Using a high-throughput, bead-based method of autoantibody detection, anti-dsDNA is significantly enriched in patienets with SLE ACR renal criteria as has been previously described. However, lymphopenia is associated with several distinct autoantibody specificities. These findings offer meaningful information to allow clinicians and clinical investigators to understand which autoantibodies correlate with select SLE clinical manifestations across common racial groups using this novel methodology which is expanding in clinical use.