Age-related rheumatoid factors. Incidence and characteristics

Polymyalgia rheumatica and giant cell arteritis induced by immune checkpoint inhibitors: A systematic literature review highlighting differences from the idiopathic forms

INTRODUCTION

An altered immune tolerance disturbed by immune checkpoint inhibitors (ICIs) may contribute to new-onset polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). This systematic literature review (SLR) examines the characteristics of PMR and GCA-like syndromes following anticancer treatment with ICIs, summarizing their demographic, clinical and treatment-related features to provide insights whether they differ from the idiopathic forms.

METHODS

The SLR was conducted in Medline and EMBASE databases from inception to July 2024, and in the EULAR/ACR abstract database (2021-2023). ICI-induced PMR and GCA syndromes were compared to the primary forms of the diseases using data from studies that included both groups as comparators. For manuscripts lacking direct comparisons, we summarized the main findings and discussed the differences using systematic reviews or large observational studies on the primary forms.

RESULTS

From 1237 screened abstracts, 46 met the inclusion criteria, involving 358 patients (314 with ICI-PMR and 44 with ICI-GCA). ICI-PMR had an estimated pooled prevalence of 0.1% [95% CI: 0.07%, 0.14%] among ICI recipients and 15.9% [95% CI: 12.6%, 19.9%] among patients experiencing rheumatic immune-related adverse events. Patients with ICI-PMR had a male-to-female ratio of 1.7:1 and a mean age of 71 ± 4 years. Most cases were associated with PD1/PDL1 blockers (87%). Clinical features included inflammatory pain in the girdles (100%), though pelvic girdle involvement was under-reported in some cases (3/28 studies). Peripheral arthritis was present in 35% of patients. Laboratory tests showed normal or slightly elevated inflammatory markers in 26% of cases. Glucocorticoids (GCs) led to symptom improvement in 84% of cases although 20% required immunosuppressive treatment and 14% experienced relapses. ICI-GCA had a prevalence of 0.06% among ICI recipients, with equal gender distribution and a mean age of 71 ± 5 years. Most patients received anti-PD1/PDL1 blockers (57%). Clinical manifestations included cephalic symptoms (75%), permanent visual loss (23%) and symptoms related to large-vessel involvement (54%). High-dose GCs were effective, with 96% achieving remission, though 17% experienced relapses.

CONCLUSIONS

ICI-induced PMR and GCA may have distinct clinical profiles compared to idiopathic forms, with potentially milder symptoms and better treatment responses. Further studies are needed to confirm these findings and better understand the long-term outcomes and pathophysiology of these conditions.

Metabolic syndrome in rheumatoid arthritis patients: Relationship among its clinical components

BACKGROUND

Metabolic syndrome (MetS) prevalence in rheumatoid arthritis (RA) patients is known to vary considerably across the world. This study aimed to determine the prevalence of MetS in RA patients from western Mexico and to analyze the interrelation of the MetS components with the clinical variables of RA.

METHODS

This case-control study included 216 RA patients and 260 control subjects (CS). MetS prevalence was determined according to the NCEP/ATP III and the Latin American Consensus of the Latin American Diabetes Association (ALAD) criteria.

RESULTS

MetS was observed in 30.6% RA patients and 33.3% of controls (p > 0.05) according to NCEP/ATP III and 28.7% in RA patients and 31.1% for controls using ALAD criteria. Total cholesterol, LDL-C, and Castelli's I-II indexes were lower in RA (p < 0.001) than in CS. The RA patients with MetS had more swollen joints than those without MetS (p = 0.018). In RA patients with MetS, DAS-28 score correlated with smoking index (rho = 0.4601, p = 0.0004) and VLDL-C (rho = 0.3108, p = 0.0056); similarly, rheumatoid factor (RF) correlated with age (rho = 0.2031, p = 0.0027), smoking index (rho = 0.3404, p < 0.0001), triglycerides (rho = 0.1958, p = 0.0039), and VLDL-C (rho = 0.1761, p = 0.0162).

CONCLUSIONS

The MetS prevalence in RA patients from western Mexico is not higher than controls; however, in RA patients with MetS, some inflammatory markers are associated with MetS components; thus, the control of MetS in RA could be beneficial to regulate disease activity.

Serologic Diagnosis of Rheumatoid Arthritis

Accurate diagnosis of inflammatory arthritides remains a challenge because of substantial clinical overlap. To achieve a granular classification for informing clinical decisions, numerous potential serologic biomarkers have been identified. Rheumatologists have settled on rheumatoid factor and anti-citrullinated protein antibodies for the diagnosis of rheumatoid arthritis (RA) based on specificity and sensitivity and their ability to be integrated into clinical algorithms. These biomarkers should be interpreted in their specific clinical context. This article discusses the serologic basis for the diagnosis of RA, how these biomarkers have framed conceptualization of the pathogenesis of RA, and the inherent limitations in their use.

Rheumatoid arthritis-associated autoantibodies in non-rheumatoid arthritis patients with mucosal inflammation: a case-control study

Introduction

Rheumatoid arthritis–associated autoantibodies (RA-AAB) can be present in serum years before clinical onset of rheumatoid arthritis (RA). It has been hypothesized that initiation of RA-AAB generation occurs at inflamed mucosal surfaces, such as in the oral cavity or lungs. The aim of this study was to assess systemic presence of RA-AAB in patients without RA who had oral or lung mucosal inflammation.

Methods

The presence of RA-AAB (immunoglobulin A [IgA] and IgG anti-cyclic citrullinated peptide 2 antibodies (anti-CCP2), IgM and IgA rheumatoid factor (RF), IgG anti-carbamylated protein antibodies and IgG and IgA anti-citrullinated peptide antibodies against fibrinogen, vimentin and enolase) were determined in sera of non-RA patients with periodontitis (PD, n = 114), bronchiectasis (BR, n = 80) or cystic fibrosis (CF, n = 41). Serum RA-AAB levels were compared with those of periodontally healthy controls (n = 36). Patients with established RA (n = 86) served as a reference group. Association of the diseases with RA-AAB seropositivity was assessed with a logistic regression model, adjusted for age, sex and smoking.

Results

Logistic regression analysis revealed that IgG anti-CCP seropositivity was associated with BR and RA, whereas the association with PD was borderline significant. IgA anti-CCP seropositivity was associated with CF and RA. IgM RF seropositivity was associated with RA, whereas the association with BR was borderline significant. IgA RF seropositivity was associated with CF and RA. Apart from an influence of smoking on IgA RF in patients with RA, there was no influence of age, sex or smoking on the association of RA-AAB seropositivity with the diseases. Anti-CarP levels were increased only in patients with RA. The same held for IgG reactivity against all investigated citrullinated peptides.

Conclusion

Although overall levels were low, RA-AAB seropositivity was associated with lung mucosal inflammation (BR and CF) and may be associated with oral mucosal inflammation (PD). To further determine whether mucosal inflammation functions as a site for induction of RA-AAB and precedes RA, longitudinal studies are necessary in which RA-AAB of specifically the IgA isotype should be assessed in inflamed mucosal tissues and/or in their inflammatory exudates.

Effects of smoking and shared epitope on the production of anti-citrullinated peptide antibody in a Japanese adult population

OBJECTIVE

Anti-citrullinated peptide antibody (ACPA) and rheumatoid factor (RF) are markers to rheumatoid arthritis (RA). Smoking and shared epitope (SE) in HLA-DRB1 are associated with the production of these autoantibodies in RA. Detailed distribution and characterization of ACPA and RF in the general population have remained unclear. We aimed to evaluate positivity of ACPA and RF in a general Japanese population and to detect correlates, including genetic components.

METHODS

ACPA and RF were quantified in 9,804 Japanese volunteers ages 30-75 years. Logistic regression analyses were performed to evaluate the effects of candidates of correlates on the autoantibody positivity. A genome-wide association study (GWAS) was performed using 394,239 single nucleotide polymorphisms for 3,170 participants, and HLA-DRB1 alleles were imputed based on the GWAS data.

RESULTS

A total of 1.7% and 6.4% of subjects were positive for ACPA and RF, respectively, and the 2 markers showed a significant correlation (P = 2.0 × 10(-23) ). Old age was associated with ACPA positivity (P = 0.00062). Sex, smoking, SE, and other candidates of correlates did not have significant effects. Interaction between smoking and SE positivity was not apparent, but smoking showed a significant association with high levels of ACPA (P = 0.0019).

CONCLUSION

ACPA and RF could be detected in 1.7% and 6.4% of the Japanese adult population without RA, respectively. ACPA and RF were suggested to share mechanisms even in healthy populations. Old age was associated with increasing ACPA positivity. While positivity of ACPA and RF was not associated with SE and smoking, an association between high ACPA and smoking was observed.

Age specific prevalence of antibodies against Chlamydia pneumoniae in Iceland

Chlamydia pneumoniae is a newly recognized common cause of respiratory tract infections. The aim of this study was to examine its prevalence in Iceland. The study was based on 1020 serum samples from individuals 0-99 years old. The samples were divided into 10-year age groups. IgG and IgM antibodies were determined with microimmunofluorescence assay. An IgG titer > or = 32 and IgM titer > or = 16 were considered positive. The prevalence of positive IgG titer in the study population was 53 +/- 16% (mean +/- SD, age group range 14-66%). Neither seasonal nor gender-based difference in IgG antibody prevalence was demonstrated. It was lowest in the youngest group, 0-9 years old (p < 0.001), but rose linearly to age 70 (p < 0.005). 34 samples were IgM positive on initial testing; most from the older age groups. 12 were rheumatoid factor positive as well. After treatment with caprine antihuman IgG antibodies all became negative. The prevalence of C. pneumoniae infections is high in Iceland according to these results and similar to that in neighbouring countries. The presence of IgM rheumatoid factor may cause false positive tests for pathogen-specific IgM by immune complex binding with pathogen-specific IgG, thereby requiring its removal before testing.