Patients with ACPA-positive and ACPA-negative rheumatoid arthritis show different serological autoantibody repertoires and autoantibody associations with disease activity

Patients with rheumatoid arthritis (RA) can test either positive or negative for circulating anti-citrullinated protein antibodies (ACPA) and are thereby categorized as ACPA-positive (ACPA+) or ACPA-negative (ACPA-), respectively. In this study, we aimed to elucidate a broader range of serological autoantibodies that could further explain immunological differences between patients with ACPA+ RA and ACPA- RA. On serum collected from adult patients with ACPA+ RA (n = 32), ACPA- RA (n = 30), and matched healthy controls (n = 30), we used a highly multiplex autoantibody profiling assay to screen for over 1600 IgG autoantibodies that target full-length, correctly folded, native human proteins. We identified differences in serum autoantibodies between patients with ACPA+ RA and ACPA- RA compared with healthy controls. Specifically, we found 22 and 19 autoantibodies with significantly higher abundances in ACPA+ RA patients and ACPA- RA patients, respectively. Among these two sets of autoantibodies, only one autoantibody (anti-GTF2A2) was common in both comparisons; this provides further evidence of immunological differences between these two RA subgroups despite sharing similar symptoms. On the other hand, we identified 30 and 25 autoantibodies with lower abundances in ACPA+ RA and ACPA- RA, respectively, of which 8 autoantibodies were common in both comparisons; we report for the first time that the depletion of certain autoantibodies may be linked to this autoimmune disease. Functional enrichment analysis of the protein antigens targeted by these autoantibodies showed an over-representation of a range of essential biological processes, including programmed cell death, metabolism, and signal transduction. Lastly, we found that autoantibodies correlate with Clinical Disease Activity Index, but associate differently depending on patients' ACPA status. In all, we present candidate autoantibody biomarker signatures associated with ACPA status and disease activity in RA, providing a promising avenue for patient stratification and diagnostics.

Longitudinal Occurrence and Predictors of Patient-Provider Discordance Between Global Assessments of Disease Activity in Rheumatoid Arthritis: A Case-Control Study

OBJECTIVE

To identify longitudinal predictors of discordance between patients with rheumatoid arthritis (RA) and their health care providers, where patient global assessment of disease activity is substantially higher than provider global assessment.

METHODS

This retrospective case-control study included 102 cases with positive discordance (i.e., ≥25 mm between patient and provider global assessments) and 102 controls without discordance who were matched for age, sex, RA duration, and Clinical Disease Activity Index (CDAI) score. Data were collected at the baseline visit (date of diagnosis or earliest available visit), the index visit (participation in a previous cross-sectional study), and at up to 11 additional visits before the index visit. Data included patient characteristics, disease activity measures, Disease Activity Score in 28 joints (3-variable) using the C-reactive protein level (DAS28-CRP), and medications. Data were analyzed by using linear and logistic regression models with smoothing splines for nonlinear trends.

RESULTS

Overall, the mean age was 63 years, 75% of patients were female, and the mean RA duration was 10 years. Compared with controls, cases had higher rates of discordant visits during the 4 years before the index visit, and they had a higher CDAI score and DAS28-CRP earlier in the disease course. Cases more frequently had antinuclear antibodies, nonerosive disease, prior depression, or prior use of antidepressants or fibromyalgia medications. Disease-modifying medication use was not different between cases and controls.

CONCLUSION

The findings inform new hypotheses about the relationships of disease activity and antinuclear antibodies to the later occurrence of positive discordance among patients with RA.

Patient-provider discordance between global assessments of disease activity in rheumatoid arthritis: a comprehensive clinical evaluation

Background

Discordance between patients with rheumatoid arthritis (RA) and their rheumatology health care providers is a common and important problem. The objective of this study was to perform a comprehensive clinical evaluation of patient-provider discordance in RA.

Methods

A cross-sectional observational study was conducted of consecutive RA patients in a regional practice with an absolute difference of ≥ 25 points between patient and provider global assessments (possible points, 0–100). Data were collected for disease activity measures, clinical characteristics, comorbidities, and medications. In a prospective substudy, participants completed patient-reported outcome measures and underwent ultrasonographic assessment of synovial inflammation. Differences between the discordant and concordant groups were tested using χ² and rank sum tests. Multivariable logistic regression was used to develop a clinical model of discordance.

Results

Patient-provider discordance affected 114 (32.5%) of 350 consecutive patients. Of the total population, 103 patients (29.5%) rated disease activity higher than their providers (i.e., ‘positive’ discordance); only 11 (3.1%) rated disease activity lower than their providers and were excluded from further analysis. Positive discordance correlated with negative rheumatoid factor and anticyclic citrullinated peptide antibodies, lack of joint erosions, presence of comorbid fibromyalgia or depression, and use of opioids, antidepressants, or anxiolytics, or fibromyalgia medications. In the prospective study, the group with positive discordance was distinguished by higher pain intensity, neuropathic type pain, chronic widespread pain and associated polysymptomatic distress, and limited functional health status. Depression was found to be an important mediator of positive discordance in low disease activity whereas the widespread pain index was an important mediator of positive discordance in moderate-to-high disease activity states. Ultrasonography scores did not reveal significant differences in synovial inflammation between discordant and concordant groups.

Conclusions

The findings provide a deeper understanding of patient-provider discordance than previously known. New insights from this study include the evidence that positive discordance is not associated with unrecognized joint inflammation by ultrasonography and that depression and fibromyalgia appear to play distinct roles in determining positive discordance. Further work is necessary to develop a comprehensive framework for patient-centered evaluation and management of RA and associated comorbidities in patients in the scenario of patient-provider discordance.