Unraveling the Etiology of Systemic Autoimmune Diseases: Peering into the Preclinical Phase of Disease

Longitudinal antinuclear antibody titers in systemic lupus erythematosus and other rheumatic diseases

Introduction

Antinuclear antibodies (ANAs) are a key feature of systemic lupus erythematosus (SLE) and marker of subclinical autoimmunity. Little is known about longitudinal ANA titers in individuals from the general population or in predicting clinical disease course in persons with rheumatic diseases.

Methods

We performed an exploratory analysis from an academic health system between 1999 and 2020 to assess intra-individual variation in ANAs longitudinally in persons with SLE, other ANA-associated rheumatic diseases, and ANA+ controls without rheumatic disease.

Results

Persons with SLE had a higher odds of positive ANA compared to those with other ANA-associated rheumatic diseases [OR 2.10, 95% CI (1.82, 2.43)] controlling for time and demographics (age, sex, race, ethnicity). Compared to ANA+ controls, the ANA titer strength was significantly higher for both the ANA-associated rheumatic disease (0.33 log units higher) and SLE groups (0.42 log units higher) controlling for demographics and time (p < 0.001 for both). Over time from the first positive ANA, titer strength significantly decreased for all three groups, with average monthly decreases ranging between 0.001 to 0.004 log titer units (p ≤ 0.001 for all).

Conclusion

Based on this analysis of electronic health data spanning two decades, ANA titers may be more dynamic than previously accepted in patients with SLE and ANA-associated rheumatic diseases, with average titers tending to be higher in early disease and decreasing over time.

Anti-Idiotypic mRNA Vaccine to Treat Autoimmune Disorders

The 80+ existing autoimmune disorders (ADs) affect billions with little prevention or treatment options, except for temporary symptomatic management, leading to enormous human suffering and a monumental financial burden. The autoantibodies formed in most ADs have been identified, allowing the development of novel anti-idiotypic antibodies to mute the autoantibodies using vaccines. Nucleoside vaccines have been successfully tested as antigen-specific immunotherapies (ASI), with mRNA technology offering multi-epitope targeting to mute multiple autoantibodies. This paper proposes using mRNA technology to produce anti-idiotypic antibodies with broad effectiveness in preventing and treating them. This paper delves into the state-of-the-art mRNA design strategies used to develop novel ASIs by selecting appropriate T cell and B cell epitopes to generate anti-idiotypic antibodies. The low cost and fast development of mRNA vaccines make this technology the most affordable for the global control of ADs.

Antinuclear antibody prevalence in a general pediatric cohort from Mexico City: discordance between immunofluorescence and multiplex assays

OBJECTIVE

To characterize antinuclear antibody (ANA) prevalence according to distinct assay methodologies in a pediatric cohort from Mexico City, and to further examine associations with age and sex.

METHODS

Serum ANA were measured by indirect immunofluorescence assay (IFA) and multiplex immunoassay in 114 children aged 9-17 years. IFA was considered positive at a cutoff titer of ≥1:80. Agreement between assay methods was assessed by kappa statistic. Sensitivity, specificity, and 95% confidence intervals (CIs) of the multiplex were computed with IFA as the reference standard.

RESULTS

Of the 114 children (mean age 14.7 [standard deviation 2.1] years; 54 [47%] female), 18 of 114 (15.8%) were ANA positive by IFA, and 11 of 114 (9.6%) by 11-antigen multiplex assay. ANA prevalence was higher in females compared with males by both of the methods (ratios 1.6-1.9 to 1). Agreement between tests was classified as slight by kappa (κ=0.177 [95% CI -0.051, 0.406]). The multiplex immunoassay had sensitivity of 22.2% (95% CI 6.4, 47.6) and specificity of 92.7% (95% CI 85.6, 97.0), and failed to capture 3 of 4 (75%) of the high-titer (≥1:1280) IFA-positives.

CONCLUSION

Up to 15% of children in this general population cohort were ANA positive, with a higher rate of positivity among females according to both assay methods. Substantial discordance in ANA results was found between IFA and multiplex methods, even for high-titer IFA positives. These findings underscore the need to sufficiently account for assay characteristics when interpreting ANA test results, and support IFA as the more appropriate assay for studies of subclinical autoimmunity.

Preclinical lupus

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is often preceded by immune dysregulation and clinical manifestations below the threshold for SLE classification. This review discusses current and evolving concepts about the preclassification period of SLE, including clinical and mechanistic observations, and potential avenues for early identification and intervention.

RECENT FINDINGS

Although incomplete lupus erythematosus (ILE) involves fewer clinical manifestations than SLE, ILE patients can suffer organ damage and early mortality. Common clinical features in ILE include antinuclear antibody seropositivity, polyarthritis, immunologic manifestations, and hematological disorders. Despite having lower disease activity and damage scores than SLE patients, ILE patients may develop pulmonary arterial hypertension, or renal, neurological, or peripheral vascular damage. The recently proposed Systemic Lupus International Collaborating Clinics SLE classification criteria could shift the period considered 'preclinical SLE'. Murine studies suggest that the balance of T-helper/T-regulatory cells, peroxisome proliferator-activated receptor γ activity, and plasmacytoid dendritic cell pathways may be valuable targets for early intervention.

SUMMARY

Advances in our understanding of early SLE, including stages before clinical features are fully developed, will improve our ability to identify individuals at high risk of classification for potential prevention trials, provide necessary information to improve diagnostic testing, and perhaps identify novel targets for directed therapeutics in clinical SLE.

Mercury Exposure and Antinuclear Antibodies among Females of Reproductive Age in the United States: NHANES

BACKGROUND

Immune dysregulation associated with mercury has been suggested, although data in the general population are lacking. Chronic exposure to low levels of methylmercury (organic) and inorganic mercury is common, such as through fish consumption and dental amalgams.

OBJECTIVE

We examined associations between mercury biomarkers and antinuclear antibody (ANA) positivity and titer strength.

METHODS

Among females 16-49 years of age (n = 1,352) from the National Health and Nutrition Examination Survey (NHANES) 1999-2004, we examined cross-sectional associations between mercury and ANAs (indirect immunofluorescence; cutoff ≥ 1:80). Three biomarkers of mercury exposure were used: hair (available 1999-2000) and total blood (1999-2004) predominantly represented methylmercury, and urine (1999-2002) represented inorganic mercury. Survey statistics were used. Multivariable modeling adjusted for several covariates, including age and omega-3 fatty acids.

RESULTS

Sixteen percent of females were ANA positive; 96% of ANA positives had a nuclear speckled staining pattern. Geometric mean (geometric SD) mercury concentrations were 0.22 (0.03) ppm in hair, 0.92 (0.05) μg/L blood, and 0.62 (0.04) μg/L urine. Hair and blood, but not urinary, mercury were associated with ANA positivity (sample sizes 452, 1,352, and 804, respectively), after adjusting for confounders: for hair, odds ratio (OR) = 4.10 (95% CI: 1.66, 10.13); for blood, OR = 2.32 (95% CI: 1.07, 5.03) comparing highest versus lowest quantiles. Magnitudes of association were strongest for high-titer (≥ 1:1,280) ANA: hair, OR = 11.41 (95% CI: 1.60, 81.23); blood, OR = 5.93 (95% CI: 1.57, 22.47).

CONCLUSIONS

Methylmercury, at low levels generally considered safe, was associated with subclinical autoimmunity among reproductive-age females. Autoantibodies may predate clinical disease by years; thus, methylmercury exposure may be relevant to future autoimmune disease risk.

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.

Pregnancy and delivery in women with chronic inflammatory arthritides with a specific focus on first birth

OBJECTIVE

To examine possible associations between chronic inflammatory arthritides and pregnancy outcomes with separate analyses of first and subsequent births before and after diagnosis.

METHODS

Linkage of data from a registry of patients with chronic inflammatory arthritides and the Medical Birth Registry of Norway enabled a comparison of pregnancy outcomes in women with chronic inflammatory arthritides and pregnancy outcomes in reference subjects. Outcomes of first birth and subsequent births before and after diagnosis were analyzed separately. Associations between chronic inflammatory arthritides and the women's health during pregnancy and delivery as well as perinatal outcomes were assessed in logistic regression analyses with adjustments for maternal age at delivery and gestational age.

RESULTS

We analyzed 128 first births and 151 subsequent births after diagnosis and 286 first births and 262 subsequent births before diagnosis in patients and compared them with first and subsequent births in reference subjects. Firstborn children of women diagnosed as having chronic inflammatory arthritides were more often preterm (odds ratio [OR] 1.85 [95% confidence interval (95% CI) 1.09-3.13]) and small for gestational age (OR 1.60 [95% CI 1.00-2.56]). They also had lower mean birth weight (P=0.01) and higher perinatal mortality (OR 3.26 [95% CI 1.04-10.24]). Birth by caesarean section (all classifications) was more frequent in patients than in reference subjects, and elective caesarean section was 2-fold more frequent in patients, both in first birth (OR 2.60 [95% CI 1.43-4.75]) and in subsequent births (OR 2.18 [95% CI 1.33-3.58]). No excess risks of clinical importance were observed prior to diagnosis of chronic inflammatory arthritides.

CONCLUSION

Excess risks were related to first birth in women diagnosed as having chronic inflammatory arthritides, including a higher rate of perinatal mortality. A higher caesarean section rate was related to all patient deliveries. Mainly, pregnancy outcomes before diagnosis did not differ from those in reference subjects.

Application of the immunological disease continuum to study autoimmune and other inflammatory events after vaccination

In vaccine safety monitoring, the evaluation of possible autoimmune events is challenging. Developing grouping systems based on pathophysiology, instead of organ systems, may enhance our ability to identify or verify associations between vaccines and adverse immunologically mediated events in clinical trials and post-licensure surveillance. Emerging data suggest that self-directed tissue inflammation occurs along a continuum from innate immune-driven diseases to adaptive immune-driven diseases. Herein, we develop this proposed classification for the vaccination setting in which inflammatory diseases are placed along a continuum according to the two major arms of the immune system, the innate immune arm (mediated by cells including neutrophils, macrophages and complement) and the adaptive immune arm (cell-mediated and humoral response). We incorporate hypersensitivity reactions and molecular mimicry vaccine-related reactions into this mechanistic scheme. We show how this could have important implications to assess mechanisms of potential immune-mediated adverse events following vaccination.