Objectives: To investigate the occurrence and dynamics of secretory component-containing antibodies towards citrullinated proteins (SC ACPA) in plasma from pre-symptomatic individuals subsequently developing rheumatoid arthritis (RA). Methods: We studied 319 individuals who had donated plasma prior to RA onset (median predating time 4.7 years), whereof 181 also donated samples after diagnosis. One hundred individuals were randomly selected from the same biobank cohorts to serve as controls. SC ACPA, total secretory IgA (TSIgA) and IgG ACPA were analysed in plasma by enzyme-linked immunoassays. Results: Circulating SC ACPA levels in pre-symptomatic individuals and RA patients were significantly increased compared with controls [median (interquartile range) 108 (108), 179 (248) and 12.5 (537) AU/ml, respectively; P < 0.001], and SC ACPA levels in RA patients were significantly increased compared with pre-symptomatic individuals (P < 0.001). SC ACPA increased, in terms of both levels and proportion of positive samples, closer to symptom onset and diagnosis. TSIgA was not elevated compared with controls either during the pre-dating time or after diagnosis. The earliest detected SC ACPA positive sample was 9 years before symptom onset, as compared with 11 years for IgG ACPA. Only two pre-dating samples were positive for SC ACPA and negative for IgG ACPA. Conclusions: Circulating SC ACPA responses arise and magnify during the asymptomatic phase of disease development in a subgroup of RA patients. This suggests mucosal involvement prior to both symptom onset and subsequent arthritis. As mirrored in the circulation, however, SC ACPA does not seem to precede the IgG ACPA response.

IntroductionEarly interventions are known to reduce disease activity and physical disability in rheumatoid arthritis (RA), but less is known about mental health, especially in the era of early active pharmacotherapy. Consequently, we compared long-term physical and mental disability in an early RA cohort (1996-1998) with a later cohort (2006-2008).MethodsWe compared 320 patients from our project Early Intervention in RA (1996-1998) (TIRA-1) with 463 patients from TIRA-2 (2006-2008). During the 8-year follow-up, pharmacotherapy and multi-professional interventions were offered according to guidelines. Disease Activity Score (DAS28), prescribed disease-modifying antirheumatic drugs (DMARDs), Health Assessment Questionnaire (HAQ), and Short Form Health Survey (SF-36) were registered yearly.ResultsSignificantly more patients were prescribed DMARDs in TIRA-2 than in TIRA-1, and initial improvements were seen for DAS28 and disability in both cohorts. At follow-up, TIRA-2 patients reported less physical disability (HAQ) and less mental disability (SF-36) than TIRA-1 patients. Despite improvements, 32% of the women and 21% of the men in the TIRA-2 cohort reported considerable disability (HAQ >= 1) at the 8-year follow-up.ConclusionsDespite improvements in our contemporarily treated TIRA-2 cohort, physical and mental disability was evident 8 years after diagnosis, especially among women. These results suggest a forthcoming need for person-centered non-pharmacological rehabilitation programs to optimize physical and mental function and to improve participation in daily life in RA. Also, the results highlight the need for developing new interventions directed at reducing disability.Key Points center dot Physical and mental disability is still considerable in contemporarily treated RA.center dot Interventions specifically aimed to reduce these disabilities need to be further developed.center dot Patients with severe disability need to be identified in clinical settings and offered person-centered rehabilitation.

Objective To compare work loss after starting tumour necrosis factor inhibitors (TNFi), rituximab, abatacept or tocilizumab in patients with rheumatoid arthritis (RA). Methods We used data from the Swedish Rheumatology Quality Register to identify patients aged 19-62 years who were treated with TNFi (n=15 093), rituximab (n=2123), abatacept (n=1877) or tocilizumab (n=1720) between 2007 and 2020. Data on work loss (0-365 days per year) from sick leave and disability pension were retrieved from linkage to the Social Insurance Agency. Patients in the different treatment arms were balanced regarding baseline covariates using inverse probability weighting (IPTW). Results Work loss increased for patients with RA until drug treatment initiation, reached a peak in the month after treatment initiation and then levelled off. Following IPTW, at 3 years before starting the treatment, there were no statistically significant differences in the mean annual adjusted work loss days between rituximab, abatacept or tocilizumab vs TNFi (mean difference vs TNFi: rituximab 1.1 days, 95% CI -4.5 to 6.7; abatacept 3.3, 95% CI -2.6 to 9.2; tocilizumab 1.2, 95% CI -4.9 to 7.3). At 3 years after starting the treatment (latest January 2021), there were also no statistically significant differences in the mean annual adjusted work loss days (mean difference: rituximab -4.8 days, 95% CI -11.3 to 1.7; abatacept 5.3, 95% CI -1.8 to 12.3; tocilizumab -0.6, 95% CI -7.7 to 6.5). Conclusions Taking channelling into account, patients with RA treated with TNFi, rituximab, abatacept or tocilizumab had similar trajectories of work loss from sick leave and disability pension until treatment initiation, and similar trend breaks and plateau 3 years thereafter.

Objectives To investigate the influence of genetic factors on persistence with treatment of early RA with MTX monotherapy. Methods We conducted a genome-wide association study (GWAS) in a sample of 3902 Swedish early-RA patients initiating MTX in DMARD monotherapy as their first-ever DMARD. The outcome, short- and long-term MTX treatment persistence, was defined as remaining on MTX at 1 and at 3 years, respectively, with no additional DMARDs added. As genetic predictors, we investigated individual SNPs, and then calculated a polygenic risk score (PRS) based on SNPs associated with RA risk. The SNP-based heritability of persistence was estimated overall and by RA serostatus. Results No individual SNP reached genome-wide significance (P < 5 x 10(-8)), either for persistence at 1 year or at 3 years. The RA PRS was not significantly associated with MTX treatment persistence at 1 year [relative risk (RR) = 0.98 (0.96-1.01)] or at 3 years [RR = 0.96 (0.93-1.00)]. The heritability of MTX treatment persistence was estimated to be 0.45 (0.15-0.75) at 1 year and 0.14 (0-0.40) at 3 years. The results in seropositive RA were comparable with those in the analysis of RA overall, while heritability estimates and PRS RRs were attenuated towards the null in seronegative RA. Conclusion Despite being the largest GWAS on an MTX treatment outcome to date, no genome-wide significant associations were detected. The modest heritability observed, coupled with the broad spread of suggestively associated loci, indicate that genetic influence is of polygenic nature. Nevertheless, MTX monotherapy persistence was lower in patients with a greater genetic disposition, per the PRS, towards RA.

Objectives To assess the association between venous thromboembolic (VTE) events and autoantibodies, following patients from RA diagnosis, measuring occurrence, levels and collective load of different autoantibodies against post-translational protein modifications, in particular recognizing citrullination (e.g. citrullinated fibrinogen) and RF by isotype. Methods A cohort of 2814 patients with newly diagnosed RA were followed for incident VTE through register linkages. Sera from RA diagnosis were centrally analysed for antibodies to second generation cyclic citrullinated peptides (anti-CCP2), 20 anti-citrullinated protein antibody (ACPA) fine-specificities, antibodies to additional protein modifications (carbamylation and acetylation) and RF by isotype. Association between baseline serology status and future VTE was analysed using Cox regression adjusted for age, sex and calendar period of RA diagnosis, overall and stratified by anti-CCP2 and RF positivity. Results During a median 16 years of follow-up, 213 first-ever VTE events were registered (5.0/1000 person-years). IgG anti-CCP2 (present in 65% of cohort) associated with VTE (hazard ratio [HR] = 1.33, 95% CI: 1.00, 1.78), in a dose-response manner. The risk of VTE increased with number of ACPA fine-specificities. IgM RF, but no other RF isotypes, associated with VTE (HR = 1.38, 95% CI: 1.04, 1.82). The associations were independent from smoking and HLA-DRB1 shared epitope alleles. None of the carbamylated or acetylated antibody reactivities associated with VTE. Conclusion Anti-CCP2, load of ACPA fine-specificities and IgM RF at RA diagnosis are associated with an increased risk of future VTE in RA. Antibodies to citrullinated fibrinogen did not differ substantially from other ACPA fine-specificities. Autoreactivity to other post-translational modifications was not associated with VTE risk.

Objectives: To further elucidate the role of the MHC in ankylosing spondylitis by typing 17 genes, searching for HLA-B∗27 independent associations and assessing the impact of sex on this male biased disease.

Methods: High-confidence two-field resolution genotyping was performed on 310 cases and 2196 controls using an n-1 concordance method. Protein-coding variants were called from next-generation sequencing reads using up to four software programs and the consensus result recorded. Logistic regression tests were applied to the dataset as a whole, and also in stratified sets based on sex or HLA-B∗27 status. The amino acids driving association were also examined.

Results: Twenty-five HLA protein-coding variants were significantly associated to disease in the population. Three novel protective associations were found in a HLA-B∗27 positive population, HLA-A∗24:02 (OR = 0.4, CI = 0.2–0.7), and HLA-A amino acids Leu95 and Gln156. We identified a key set of seven loci that were common to both sexes, and robust to change in sample size. Stratifying by sex uncovered three novel risk variants restricted to the female population (HLA-DQA1∗04.01, -DQB1∗04:02, -DRB1∗08:01; OR = 2.4–3.1). We also uncovered a set of neutral variants in the female population, which in turn conferred strong effects in the male set, highlighting how population composition can lead to the masking of true associations.

Conclusion: Population stratification allowed for a nuanced investigation into the tightly linked MHC region, revealing novel HLA-B∗27 signals as well as replicating previous HLA-B∗27 dependent results. This dissection of signals may help to elucidate sex biased disease predisposition and clinical progression.

Anti-citrullinated protein antibodies (ACPA) often precede onset of rheumatoid arthritis (RA) by years, and there is an urgent clinical need for predictors of arthritis development among such at-risk patients. This study assesses the prognostic value of ultrasound for arthritis development among ACPA-positive patients with musculoskeletal pain. We prospectively followed 82 ACPA-positive patients without clinical signs of arthritis at baseline. Ultrasound at baseline assessed synovial hypertrophy, inflammatory activity by power Doppler, and erosions in small joints of hands and feet. We applied Cox regression analyses to examine associations with clinical arthritis development during follow-up (median, 69 months; range, 24-90 months). We also compared the ultrasound findings among the patients to a control group of 100 blood donors without musculoskeletal pain. Clinical arthritis developed in 39/82 patients (48%) after a median of 6 months (range, 1-71 months). One or more ultrasound erosions occurred in 13/82 patients (16%), with none in control subjects (p < 0.001). Clinical arthritis development was more common among patients with baseline ultrasound erosions than those without (77 vs. 42%, p = 0.032), and remained significant in a multivariable Cox regression analysis that included previously described prognostic factors (HR 3.9, 95% CI 1.6-9.4, p = 0.003). Ultrasound-detected tenosynovitis was more frequent among the patients and associated with clinical arthritis development in a univariable analysis (HR 2.5, 95% CI 1.1-5.7, p = 0.031), but did not remain statistically significant in multivariable analysis. Thus, bone erosions detected by ultrasound are independent predictors of clinical arthritis development in an ACPA-positive at-risk population.

Soluble urokinase plasminogen activator receptor (suPAR) is intensively studied as a biomarker of inflammation and disease outcome in various diseases. In rheumatoid arthritis (RA), suPAR have shown an association with inflammation and swollen joints, but data on suPAR in relation to early disease course and disease progression are lacking. This study investigates the potential of suPAR to predict or reflect disease outcome in early RA. Serum suPAR was measured by enzyme-linked immunosorbent assay at disease onset and after 3 and 36 months in 252 patients from a Swedish prospective observational early RA cohort. Levels and changes of suPAR were analyzed in relation to the 28-joint disease activity score (DAS28) and joint damage according to the Larsen score at inclusion and during follow-up. 100 healthy blood donors served as controls. Circulating levels of suPAR were higher in RA patients at all time points as compared to healthy controls. Baseline suPAR was significantly associated with baseline disease activity whereas suPAR levels at 36 months were associated with joint damage at 36 months. No predictive value of suPAR levels or changes in suPAR levels over time were found. In conclusion, suPAR levels associate with disease activity in early untreated RA and reflects joint damage at later stages. Increased suPAR in established RA could indicate patients in need of frequent monitoring of joint status, irrespective of disease activity. In the view of suPAR as a rapidly emerging biomarker, it is important to be aware of its ability to reflect both inflammation and subsequent damage. (Translational Research 2021; 232:142-149)

Objectives. Considering growing evidence of mucosal involvement in RA induction, this study investigated circulating free secretory component (SC) in patients with either recent-onset RA or with ACPA and musculoskeletal pain. Methods. Two prospective cohorts were studied: TIRA-2 comprising 452 recent-onset RA patients with 3 years of clinical and radiological follow-up, and TIRx patients (n = 104) with ACPA IgG and musculoskeletal pain followed for 290 weeks (median). Blood donors and three different chronic inflammatory diseases served as controls. Free SC was analysed by sandwich ELISA. Results. Serum levels of free SC were significantly higher in TIRA-2 patients compared with TIRx and all control groups (P < 0.01). Among TIRx patients who subsequently developed arthritis, free SC levels were higher compared with all control groups (P < 0.05) except ankylosing spondylitis (P = 0.74). In TIRA-2, patients with ACPA had higher baseline levels of free SC compared with ACPA negative patients (P < 0.001). Free SC status at baseline did not predict radiographic joint damage or disease activity over time. In TIRx, elevated free SC at baseline trendwise associated with arthritis development during follow-up (P = 0.066) but this disappeared when adjusting for confounders (P = 0.72). Cigarette smoking was associated with higher levels of free SC in both cohorts. Conclusion. Serum free SC levels are increased in recent-onset RA compared with other inflammatory diseases, and associate with ACPA and smoking. Free SC is elevated before arthritis development among ACPA positive patients with musculoskeletal pain, but does not predict arthritis development. These findings support mucosal engagement in RA development.