Autoantibodies and self-reported health complaints in relatives of systemic lupus erythematosus patients: a community based approach

First-degree relatives of patients with systemic lupus erythematosus: Autoreactivity but not autoimmunity?

BACKGROUND

Systemic lupus erythematosus (SLE) is a disorder with a complex immunopathogenesis. It is well known that the disease begins with immunological alterations and autoantibody appearance in the serum years before clinical onset. As SLE has a strong tendency to familial aggregation, first-degree relatives (FDRs) constitute a group at elevated risk. The current understanding is that external risk factors trigger underlying immune dysregulations, leading to overt disease in those with elevated genetic risk.

OBJECTIVE

This cross-sectional study investigates the degree to which clinical features, external risk factors, and immunological profiles differ in SLE FDRs from healthy individuals and SLE patientts.

METHODS

Three groups were studied: Lupus patient FDRs (n = 56), healthy controls (n = 20), and SLE patients (n = 20). FDRs and healthy participants completed a detailed clinical questionnaire that included questions regarding smoking and estrogen drug history. All participants were tested for the presence of the following antinuclear autoantibodies (ANAs) against: nRNP/Sm, Sm, Ro60, Ro-52, La, Scl-70, PM-Scl, PM- Scl, Jo-1, CENP B, PCNA, dsDNA, nucleosomes, histones, RibP, AMA M2, DFS70, and eight soluble cytokines, including transforming growth factor-β (TGF-β), vitamin D levels, and antibodies against Epstein-Barr virus (EBV).

RESULTS

Compared with the healthy controls, FDRs had higher titers of ANA, more specific staining immunofluorescent patterns, and more autoantibody specificities. Furthermore, FDRs differed significantly in their TGF-β levels from the other two groups. In FDRs, some clinical features (hair loss, skin, and oral ulcer-like lesions) were associated with higher ANA titers and some (oral ulcer-like lesions) with the anti-Ro60-specific antibody. Interestingly, there was an association between ANA titers and levels of antibodies against EBV only in the FDR group.

CONCLUSION

First-degree relatives display unique clinical and immunological profiles, placing them between healthy individuals and SLE patients, with a balance between compensated immune dysregulation and disease-developing potential. A possible association between ANA titer and the number of clinical complaints is observed, which needs to be confirmed in more extensive studies.

Discerning Risk of Disease Transition in Relatives of Systemic Lupus Erythematosus Patients Utilizing Soluble Mediators and Clinical Features

OBJECTIVE

Systemic lupus erythematosus (SLE) and other autoimmune diseases cause significant morbidity. Identifying populations at risk of developing SLE is essential for curtailing irreversible inflammatory damage. The aim of this study was to identify factors associated with transition to classified disease that would inform our understanding of the risk of SLE.

METHODS

Previously identified blood relatives of patients with SLE, who had <4 American College of Rheumatology (ACR) classification criteria for SLE at baseline, were enrolled in this follow-up study (n = 409 unaffected relatives). Participants provided detailed family, demographic, and clinical information, including the SLE-specific portion of the Connective Tissue Disease Screening Questionnaire (SLE-CSQ). Serum and plasma samples were tested for the presence of lupus-associated autoantibodies and 52 soluble mediators. Generalized estimating equations (GEEs) were applied to identify factors predictive of disease transition.

RESULTS

Of the 409 unaffected relatives of SLE patients, 45 (11%) had transitioned to classified SLE at follow-up (mean time to follow-up 6.4 years). Relatives who transitioned to SLE displayed more lupus-associated autoantibody specificities and higher SLE-CSQ scores (P < 0.0001) at baseline than did relatives who did not transition. Importantly, those who had developed SLE during the follow-up period also had elevated baseline plasma levels of inflammatory mediators, including B lymphocyte stimulator, stem cell factor (SCF), and interferon-associated chemokines (P ≤ 0.02), with concurrent decreases in the levels of regulatory mediators, transforming growth factor β (TGFβ), and interleukin-10 (P ≤ 0.03). GEE analyses revealed that baseline SLE-CSQ scores or ACR scores (number of ACR criteria satisfied) and plasma levels of SCF and TGFβ, but not autoantibodies, were significant and independent predictors of SLE transition (P ≤ 0.03).

CONCLUSION

Preclinical alterations in levels of soluble mediators may predict transition to classified disease in relatives of SLE patients. Thus, immune perturbations precede SLE classification and can help identify high-risk relatives for rheumatology referral and potential enrollment in prevention trials.

Association of IFIH1 and pro-inflammatory mediators: Potential new clues in SLE-associated pathogenesis

Antiviral defenses are inappropriately activated in systemic lupus erythematosus (SLE) and association between SLE and the antiviral helicase gene, IFIH1, is well established. We sought to extend the previously reported association of pathogenic soluble mediators and autoantibodies with mouse Mda5 to its human ortholog, IFIH1. To better understand the role this gene plays in human lupus, we assessed association of IFIH1 variants with soluble mediators and autoantibodies in 357 European-American SLE patients, first-degree relatives, and unrelated, unaffected healthy controls. Association between each of 135 genotyped SNPs in IFIH1 and four lupus-associated plasma mediators, IL-6, TNF-α, IFN-β, and IP-10, were investigated via linear regression. No significant associations were found to SNPs orthologous to those identified in exon 13 of the mouse. However, outside of this region there were significant associations between IL-6 and rs76162067 (p = 0.008), as well as IP-10 and rs79711023 (p = 0.003), located in a region of IFIH1 previously shown to directly influence MDA-5 mediated IP-10 and IL-6 secretion. SLE patients and FDRs carrying the minor allele for rs79711023 demonstrated lower levels of IP-10, while only FDRs carrying the minor allele for rs76162067 demonstrated an increased level of IL-6. This would suggest that the change in IP-10 is genotypically driven, while the change in IL-6 may be reflective of SLE transition status. These data suggest that IFIH1 may contribute to SLE pathogenesis via altered inflammatory mechanisms.

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.

Reproductive and hormonal risk factors for antinuclear antibodies (ANA) in a representative sample of U.S. women

BACKGROUND

Autoantibodies are of growing interest in cancer research as potential biomarkers; yet, the determinants of autoimmunity are not well understood. Antinuclear antibodies (ANA) are common in the general population and are more prevalent in women and older adults. Here, we examined the relationship of ANA with reproductive and hormonal factors in a representative sample of U.S. women.

METHODS

We analyzed data on reproductive history and exogenous hormone use in relation to serum ANA in 2,037 females ages 12 years and older from the National Health and Nutrition Examination Survey (NHANES; 1999-2004). Estimated ANA prevalences were adjusted for sampling weights. Prevalence ORs (POR) and 95% confidence intervals (CI) were adjusted for age, race, and poverty-income ratio, and models were stratified by menopause status.

RESULTS

In premenopausal women ages 20 years and older, ANA prevalence was associated with parity (P < 0.001; parous vs. nulliparous POR = 2.0; 95% CI, 1.2-3.4), but in parous women, ANA did not vary by number of births, age at first birth, years since last birth, or breastfeeding. In postmenopausal women, ANA prevalence was associated with an older age at menarche (P = 0.019; age 16-20 vs. 10-12 years POR = 3.0; 95% CI, 1.6-5.9), but not with parity. Oral contraceptives and estrogen therapy were not associated with a higher ANA prevalence.

CONCLUSIONS

Childbearing (having had one or more births) may explain age-associated elevations in ANA prevalence seen in premenopausal women.

IMPACT

These findings highlight the importance of considering reproductive history in studies of autoimmunity and cancer in women.

Twins discordant for myositis and systemic lupus erythematosus show markedly enriched autoantibodies in the affected twin supporting environmental influences in pathogenesis

Background

Studies of twin pairs discordant for autoimmune conditions provide a unique opportunity to explore contributing factors triggered by complex gene-environment interactions.

Methods

In this cross-sectional study, thirty-one monozygotic or dizygotic twin pairs discordant for myositis or systemic lupus erythematosus (SLE), along with matched healthy controls were evaluated for antibodies against a panel of 21 autoantigens.

Results

Autoantibody profiling revealed that 42% of the affected twins showed significant seropositivity against autoantigens in the panel. In many of these affected twins, but none of healthy controls, there were high levels of autoantibodies detected against two or more autoantigens commonly seen in systemic autoimmune diseases including Ro52, Ro60, RNP-70 K and/or RNP-A. In contrast, only 10% (3/31) of the unaffected twins showed seropositivity and these immunoreactivities were against single autoantigens not seen in systemic autoimmune diseases. While no significant differences in autoantibodies were detected between the affected or unaffected twins against thyroid peroxidase, transglutaminase and several cytokines, 23% of the affected twins with myositis showed autoantibodies against the gastric ATPase. Analysis of the monozygotic twins separately also revealed a higher frequencies of autoantibodies in the affected twins compared to the unaffected twins (P = 0.046). Lastly, clinical analysis of both the affected monozygotic and dizygotic twins revealed that the autoantibody seropositive affected twins had a greater global disease activity score compared to seronegative affected twins (P = 0.019).

Conclusion

The findings of significantly more autoantibodies in the affected twins with myositis and SLE compared to the unaffected twins are consistent with potential non-genetic factors playing a role in autoantibody production and pathogenesis of these autoimmune disorders.

Studies of Filipino patients with systemic lupus erythematosus: autoantibody profile of first-degree relatives

This study surveyed the frequency of autoantibodies among un-affected first-degree relatives (FDRs) of Filipino systemic lupus erythematosus (SLE) patients compared with healthy un-related Filipino controls. The sensitivity, specificity and predictive value of the autoantibodies for SLE diagnosis were also assessed in this Filipino cohort. Filipino patients included in the University of Santo Tomas (UST) Lupus Database and un-affected FDRs were recruited. Healthy controls included those with no known personal or family history of autoimmune disease. The following autoantibodies were tested in all subjects: anti-nuclear antibody (ANA), anti-dsDNA, anti-Ro/SSA, anti-chromatin, anti-thyroid microsome, and anti-cardiolipin antibodies. Participants included 232 SLE patients, 546 FDRs, and 221 healthy controls. Median age of patients was 27 (range 8-66) years with median disease duration of 27.5 (range 1-292) months. Median age of FDRs was 42.0 (range 5-87) years. Compared with healthy controls, there were significantly more FDRs with positive ANA at titers 1 : 40 to 1 : 160 (p < 0.001) and 1 : 320 (p = 0.003), anti-Ro/SSA (4.94% versus 0.45%, p = 0.003), and anti-dsDNA ≥ 5.0 IU/ml (4.58% versus 1.36%, p = 0.031). ANA titer ≥1  :  160, anti-dsDNA, anti-Ro/SSA and anti-chromatin had the highest predictive value for SLE diagnosis. These findings reinforce the role of genetic influence in SLE risk among Filipinos, with a significant proportion of un-affected FDRs of SLE patients testing positive for autoantibodies compared with healthy Filipino controls. A longitudinal observational study in this same cohort will determine which proportion of these un-affected FDRs will evolve into clinical SLE disease in the future.

Prevalence of antinuclear antibodies in 3 groups of healthy individuals: blood donors, hospital personnel, and relatives of patients with autoimmune diseases

Antinuclear antibodies (ANA) are frequently found in healthy populations. To define the prevalence, pattern, and titer of ANA in different groups of the healthy Mexican population, we studied 304 individuals, classified into 3 groups: 104 blood donors, 100 hospital personnel working at The State General Hospital, which included doctors, laboratory technicians, and nurses; and 100 relatives of patient diagnosed either with systemic lupus erythematosus or rheumatoid arthritis, all of them apparently healthy at the time of study. We determined ANA using immunofluorescence microscopy performed on HEp-2 cells. Fluorescence was detected in 165 serum samples (54.3%). The most frequent pattern was the speckled (50.3%). The most frequent dilution was 1:40 (35.4%), followed by 1:80 (13.4%), 1:160 (3.2%), and 1:320 (1.3%).Regarding the results by study group, we found a trend toward higher ANA levels in group 2 (hospital personnel), compared with group 1 (blood donors) and group 3 (relatives of patients), a trend also reflected by the increasing frequency of serum titers of 1:80 and higher (P = 0.074). According to occupation, medical doctors showed a higher incidence of speckled pattern when compared with other occupations (P = 0.022). Medical doctors (n = 75) showed also higher titers of this particular pattern (P = 0.03). In group 3, relatives of patients with systemic lupus erythematosus showed the speckled pattern more frequently than relatives of patients with rheumatoid arthritis, in low titers (P = 0.017). We suggest that ANA tests showing speckled pattern should be at a 1:160 titer or higher to be considered positive; other patterns such as homogeneous, peripheral, or centromeric might be considered positive even at low titers (</=1:40) although this needs investigation.ANA should generally not be tested without clinical indication. Positive ANA finding in the absence of physical signs and symptoms has limited diagnostic utility and should always be interpreted by a rheumatologist, in the context of clinical symptoms and results of laboratory tests for specific autoantibodies. Populations such as doctors and relatives of patients with autoimmune disease tend to presents increased ANA titers.

Vaccination of healthy subjects and autoantibodies: from mice through dogs to humans

Vaccination against pathogenic microorganisms is one of the major achievements of modern medicine, but due to an increasing number of reports of adverse reactions the vaccination procedure has induced also considerable debate. It is well known that certain infections are involved in triggering the production of autoantibodies, which could lead to autoimmune adverse reactions in genetically predisposed subjects. Based on these findings it was assumed that vaccinations might induce similar autoimmune reactions. At present there is no clear-cut evidence that vaccinations are associated with overt autoimmune diseases but it has been demonstrated that in genetically predisposed persons vaccination can trigger the production of autoantibodies and autoimmune adverse reactions. The first studies investigating the production of autoantibodies following vacination were done in dogs and mice. Several studies investigated the production of autoantibodies following vaccination in patients with autoimmune diseases, but there are only limited data on the autoimmune responses after vaccinations in apparently healthy humans. This review summarizes current evidence on the vaccinationinduced autoantibodies in apparently healthy subjects including studies in animals and humans.

Circulating Surfactant Protein D Is Decreased in Systemic Lupus Erythematosus

Objective.

Deficiencies of innate immune molecules like mannan binding lectin (MBL) have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Surfactant protein D (SP-D) and MBL belong to the same family of innate immune molecules — the collectins, which share important structural and functional properties. We aimed to compare concentrations of serum SP-D in patients with SLE and in healthy controls, and to investigate if SP-D is associated with selected disease indicators. We investigated the possible association of the Met11Thr polymorphism with disease, since this polymorphism is an important determinant for serum level, oligomerization pattern, and function of SP-D.

Methods.

Serum SP-D was measured using a 5-layer ELISA in 70 SLE patients and 1476 healthy subjects. DNA was genotyped for the Met11Thr variant.

Results.

Median SP-D level in serum was 911 ng/ml (95% CI 776–1118) in patients and 1068 ng/ml (95% CI 901–1246) in controls (p = 0.0004). Circulating SP-D did not differ significantly in patients with high, intermediate, or low SLE disease activity. Similarly, SP-D did not correlate with C-reactive protein, erythrocyte sedimentation rate, and anti-dsDNA seropositivity. Genetic analysis did not support an association of the Met11Thr genotype with SLE.

Conclusion.

These findings suggest that low SP-D, unrelated to conventional disease indicators, represents an aspect of SLE etiopathogenesis.

Reduced proportions of natural killer T cells are present in the relatives of lupus patients and are associated with autoimmunity

Introduction

Systemic lupus erythematosus is a genetically complex disease. Currently, the precise allelic polymorphisms associated with this condition remain largely unidentified. In part this reflects the fact that multiple genes, each having a relatively minor effect, act in concert to produce disease. Given this complexity, analysis of subclinical phenotypes may aid in the identification of susceptibility alleles. Here, we used flow cytometry to investigate whether some of the immune abnormalities that are seen in the peripheral blood lymphocyte population of lupus patients are seen in their first-degree relatives.

Methods

Peripheral blood mononuclear cells were isolated from the subjects, stained with fluorochrome-conjugated monoclonal antibodies to identify various cellular subsets, and analyzed by flow cytometry.

Results

We found reduced proportions of natural killer (NK)T cells among 367 first-degree relatives of lupus patients as compared with 102 control individuals. There were also slightly increased proportions of memory B and T cells, suggesting increased chronic low-grade activation of the immune system in first-degree relatives. However, only the deficiency of NKT cells was associated with a positive anti-nuclear antibody test and clinical autoimmune disease in family members. There was a significant association between mean parental, sibling, and proband values for the proportion of NKT cells, suggesting that this is a heritable trait.

Conclusions

The findings suggest that analysis of cellular phenotypes may enhance the ability to detect subclinical lupus and that genetically determined altered immunoregulation by NKT cells predisposes first-degree relatives of lupus patients to the development of autoimmunity.

Protein array autoantibody profiles for insights into systemic lupus erythematosus and incomplete lupus syndromes

The objective of this study was to investigate the prevalence and clinical significance of a spectrum of autoantibodies in systemic lupus erythematosus and incomplete lupus syndromes using a proteome microarray bearing 70 autoantigens. Microarrays containing candidate autoantigens or control proteins were printed on 16-section slides. These arrays were used to profile 93 serum samples from patients with systemic lupus erythematosus (SLE (n = 33), incomplete LE (ILE; n = 23), first-degree relatives (FDRs) of SLE patients (n = 20) and non-autoimmune controls (NC; n = 17). Data were analysed using the significance analysis of microarray (SAM) and clustering algorithms. Correlations with disease features were determined. Serum from ILE and SLE patients contained high levels of IgG autoantibodies to 50 autoantigens and IgM autoantibodies to 12 autoantigens. Elevated levels of at least one IgG autoantibody were detected in 26% of SLE and 19% of ILE samples; elevated IgM autoantibodies were present in 13% of SLE and 17% of ILE samples. IgG autoantibodies segregated into seven clusters including two specific for DNA and RNA autoantigens that were correlated with the number of lupus criteria. Three IgG autoantibody clusters specific for collagens, DNA and histones, were correlated with renal involvement. Of the four IgM autoantibody clusters, two were correlated negatively with the number of lupus criteria; none were correlated with renal disease. The IgG : IgM autoantibody ratios generally showed a stepwise increase in the groups following disease burden from NC to SLE. Insights derived from the expanded autoantibody profiling made possible with the antigen array suggest differences in autoreactivity in ILE and SLE. Determining whether the IgM aurotreactivity that predominates in ILE represents an early stage prior to IgG switching or is persistent and relatively protective will require further longitudinal studies.