The role of KIR2DL3/HLA-C*0802 in Brazilian patients with rheumatoid vasculitis

From genetic variants to therapeutic targets: insights into understanding rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects multiple systems and is driven by various factors, including interactions between genetic and environmental elements. Over the past few decades, genome-wide association studies (GWAS) have been instrumental in regard to identifying genetic and environmental risk factors associated with RA susceptibility and pathogenesis. The recent discoveries of novel genetic susceptibility loci and pathways offer promising therapeutic targets for RA and precision medicine. More than 100 genetic loci have been identified in RA patients. In this review, we have focused on more than 40 genes that have been supported by evidence to be closely associated with the development of RA. These include genes involved in various mechanisms, such as loss of self-tolerance, autoimmune antibody production (e.g., HLA-DRB1, HLA-DPB1), inflammatory signaling and bone destruction (e.g., PTPN22, CCR6), complication (e.g., HLA-DQB1, IRF5), and differential drug responses (e.g., HLA-E, NKG2D). These novel players and mechanisms enhance our understanding of the RA pathogenesis and also provide a reference for personalized and precise medicine, including diagnosis and treatment.

Rheumatoid vasculitis in 2023: Changes and challenges since the biologics era

BACKGROUND

Significant changes in the epidemiology and natural history of rheumatoid vasculitis (RV) have occurred with the introduction of biological therapies such as TNF inhibitors (TNFi) and rituximab.

PURPOSE

This scoping review aims to address the key current challenges and propose updated criteria for RV. This will aid future descriptive observational studies and prospective therapeutic trials.

METHODOLOGY

The MEDLINE database was searched for eligible articles from inception through December 2022. Articles were selected based on language and publication date after 1998, corresponding to the approval of the first TNFi in rheumatic diseases.

RESULTS

Sixty articles were included in the review. The mean incidence of RV has decreased since the approval of biologic therapies in RA, from 9.1 (95% CI: 6.8-12.0) per million between 1988 and 2000 to 3.9 (95% CI: 2.3-6.2) between 2001 and 2010, probably due to significant improvement in RA severity and a decrease in smoking habits. Factors associated with an increased risk of RV include smoking at RA diagnosis, longer disease duration, severe RA, immunopositivity, and male gender (regardless of age). Homozygosity for the HLA-DRB104 shared epitope is linked to RV, while the presence of HLA-C3 is a significant predictor of vasculitis in patients without HLA-DRB104. Cutaneous (65-88%), neurologic (35-63%), and cardiac (33%) manifestations are common in RV, often associated with constitutional symptoms (70%). Histologic findings range from small vessel vasculitis to medium-sized necrotizing arteritis, but definite evidence of vasculitis is not required in the 1984 Scott and Bacon diagnostic criteria. Existing data on RV treatment are retrospective, and no formal published guidelines are currently available.

CONCLUSION

The understanding of RV pathogenesis has improved since its initial diagnostic criteria, with a wider range of clinical manifestations identified. However, a validated and updated criteria that incorporates these advances is currently lacking, impeding the development of descriptive observational studies and prospective therapeutic trials.

PRIMARY FUNDING SOURCE

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

A deep transcriptome meta-analysis reveals sex differences in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS), a chronic auto-immune, inflammatory, and degenerative disease of the central nervous system, affects both males and females; however, females suffer from a higher risk of developing MS (2-3:1 ratio relative to males). The precise sex-based factors influencing risk of MS are currently unknown. Here, we explore the role of sex in MS to identify molecular mechanisms underlying observed MS sex differences that may guide novel therapeutic approaches tailored for males or females.

METHODS

We performed a rigorous and systematic review of genome-wide transcriptome studies of MS that included patient sex data in the Gene Expression Omnibus and ArrayExpress databases following PRISMA statement guidelines. For each selected study, we analyzed differential gene expression to explore the impact of the disease in females (IDF), in males (IDM) and our main goal: the sex differential impact of the disease (SDID). Then, for each scenario (IDF, IDM and SDID) we performed 2 meta-analyses in the main tissues involved in the disease (brain and blood). Finally, we performed a gene set analysis in brain tissue, in which a higher number of genes were dysregulated, to characterize sex differences in biological pathways.

RESULTS

After screening 122 publications, the systematic review provided a selection of 9 studies (5 in blood and 4 in brain tissue) with a total of 474 samples (189 females with MS and 109 control females; 82 males with MS and 94 control males). Blood and brain tissue meta-analyses identified, respectively, 1 (KIR2DL3) and 13 (ARL17B, CECR7, CEP78, IFFO2, LOC401127, NUDT18, RNF10, SLC17A5, STMP1, TRAF3IP2-AS1, UBXN2B, ZNF117, ZNF488) MS-associated genes that differed between males and females (SDID comparison). Functional analyses in the brain revealed different altered immune patterns in females and males (IDF and IDM comparisons). The pro-inflammatory environment and innate immune responses related to myeloid lineage appear to be more affected in females, while adaptive responses associated with the lymphocyte lineage in males. Additionally, females with MS displayed alterations in mitochondrial respiratory chain complexes, purine, and glutamate metabolism, while MS males displayed alterations in stress response to metal ion, amine, and amino acid transport.

CONCLUSION

We found transcriptomic and functional differences between MS males and MS females (especially in the immune system), which may support the development of new sex-based research of this disease. Our study highlights the importance of understanding the role of biological sex in MS to guide a more personalized medicine.

Psoriasis and family history of psoriasis may not affect disease severity of rheumatoid arthritis

The incidence of psoriasis in patients with rheumatoid arthritis (RA) is higher than in the general population. In addition, psoriasis may negatively affect the severity of rheumatological diseases in patients with autoinflammatory or autoimmune diseases. In this study, we evaluated the effect of psoriasis or a family history of psoriasis on the characteristics of RA. This is a cross-sectional study. We included 737 RA patients who met the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) RA Classification Criteria, but did not meet the CASPAR psoriatic arthritis criteria. Subsequently, we compared disease activity, the need for biologic therapy, the number of conventional synthetic disease-modifying anti-rheumatic drugs taken, the frequency of erosive disease and extra-articular involvement, glucocorticoid doses and the Stanford Health Assessment Questionnaire scores between patients with and without a history of psoriasis, and patients with and without a family history of psoriasis. Thirteen (1.8%) patients had psoriasis, while 58 (7.9%) had a family history of psoriasis in first- or seconddegree relatives. All outcome parameters were found to be similar between the groups. We show that concomitant psoriasis has no effect on the evaluated disease characteristics of RA.

Rheumatoid Arthritis Susceptibility Is Associated with the KIR2DS4-Full of Killer-Cell Immunoglobulin-Like Receptor Genes in the Lur Population of Iran

Background

The pathophysiology underlying the progression and development of autoimmune conditions, such as Rheumatoid Arthritis (RA), is a result of dysregulations of the immune system. Research has explored the genetic alterations present in RA; however, limited studies have examined the role of Killer cell Immunoglobulin-like Receptors (KIR) and Human Leukocyte Antigen (HLA) molecules in RA. Therefore, the aim of this study was to examine KIR genes, their HLA ligands, and KIR-HLA compounds in patients with RA.

Methods

In this case-control study, a total of 50 patients with RA and 100 healthy individuals were enrolled. DNA samples were evaluated using PCR with sequence specific Primers (PCR-SSP). Odds ratio (OR) with a 95% confidence interval (CI) were reported.

Results

Among the KIR genes examined, KIR2DLA (p= 0.0255, OR= 0.389, 95% CI= 0.210-0.722) and KIR2DS4-full (p< 0.0001, OR= 6.163, 95% CI= 3.174-11.968) were observed to have a statistically significant correlation with disease susceptibility to RA. As an inhibitory gene, KIR2DLA was observed to have a protective effect against RA while KIR2DS4-full as an activating gene, was found to increase risk for RA. No significant associations were found between any of the other KIR genotypes, HLA ligands, or KIR-HLA compounds examined in this study to RA susceptibility.

Conclusion

In this study of RA in the Lur population of Iran, KIR2DS4-full was observed to increase susceptibility to RA, while KIR2DL5A was found to act as a protecting factor based on both the cross Table and regression analyses. Further research should focus on repeating this study in additional populations.

Association study between KIR polymorphisms and rheumatoid arthritis disease: an updated meta-analysis

Background

Currently published studies investigating association between the killer cell immunoglobulin-like receptor (KIR) gene polymorphisms and rheumatoid arthritis (RA) reported inconsistent and contradictory results. Hence, we aim to carry out this comprehensive meta-analysis of all eligible studies meeting the inclusion criteria to achieve precise and comprehensive relationships between genetic variations in KIR gene cluster and risk of RA.

Methods

Databases of Medline/PubMed and Scopus were searched to investigate case-control studies prior to May 2018. The associations between KIR gene polymorphisms and RA susceptibility were analyzed by computing the odds ratio (OR) and 95% confidence interval (95% CI) for each study.

Results

A total of 11 comparative case-control studies involving 1847 RA patients and 2409 healthy individuals were included in this meta-analysis. Four significant associations of 2DL3 (OR = 0.591, 95% CI = 0.351–0.994; P = 0.047), 2DL5 (OR = 0.716, 95% CI = 0.601–0.853; P < 0.001), 2DS5 (OR = 0.623, 95% CI = 0.393–0.988; P = 0.045), and 3DL3 (OR = 0.324, 95% CI = 0.129–0.814; P = 0.016) genes with decreased RA risk were discovered in this meta-analysis. Although, other KIR receptors including 2DL1, 2DL2, 2DL4, 3DL1, 3DL2, 3DS1, 2DS1-2DS4, and two pseudo gens of 2DP1 and 3DP1 displayed no significant association with predisposition to RA.

Conclusions

These findings provide reliable evidence that 2DL3, 2DL5, 3DL3, and 2DS5 might have a potential protective role for RA.

Connective Tissue Disorder-Associated Vasculitis

Vasculitides secondary to connective tissue diseases are classified under the category of 'vasculitis associated with systemic disease' in the revised International Chapel Hill Consensus Conference (CHCC) nomenclature. These secondary vasculitides may affect any of the small, medium or large vessels and usually portend a poor prognosis. Any organ system can be involved and the presentation would vary depending upon that involvement. Treatment depends upon the type and severity of presentation. In this review, we describe secondary vasculitis associated with rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, relapsing polychondritis, systemic sclerosis, Sjogren's syndrome and idiopathic inflammatory myositis, focusing mainly on recent advances in the past 3 years.

Vasculitis and inflammatory arthritis

Vasculitis has been described in most types of inflammatory arthritis. The best described and most widely recognised form is rheumatoid vasculitis. The incidence of systemic rheumatoid vasculitis has declined significantly following the general early use of methotrexate in the 1990s, and it is now a rare form of vasculitis. Treatment of rheumatoid vasculitis is conventionally with glucocorticoids and cyclophosphamide, but there is an increasing role for rituximab similar to that in other types of vasculitis. Despite these developments the mortality of rheumatoid vasculitis remains high. Vasculitis in other types of inflammatory arthritis is less well described and the treatment remains empirical.