Shared Epitope and Anti-Cyclic Citrullinated Peptide Antibodies: Relationship with Age at Onset and Duration of Disease in Rheumatoid Arthritis

A Review on Rheumatoid Arthritis Interventions and Current Developments

Rheumatoid arthritis is a chronic autoimmune disorder characterized by inflammation, swelling, and joint destruction primarily affecting the peripheral joints. In recent years, RA has become an alarming concern affecting more than 1.5% of the population worldwide. The majority of the drugs in clinical trials for rheumatoid arthritis are immunomodulatory. The development of novel drugs for RA is impending and scientists are exploring new strategies through various innovative approaches for RA drug development. Treat-to-target and window of opportunity hypothesis are the new approaches that are used to treat, improve outcomes, and prevent long-term use of ineffective therapy, respectively. Novel therapeutic agents (e.g. GM-CSF inhibitors, Matrix metalloproteinase inhibitors) and delivery systems (e.g., Liposomes, Superparamagnetic iron oxide nano particles (SPIONs)) are under investigation for more target based therapy with reduced side effects and toxicity. The new drug discovery and repositioning of previously FDA-approved drugs are also being considered for chronic inflammatory disorder. The review encompasses a vast array of information, including genetics, etiology, clinical symptoms, current treatment, and newer therapeutics approaches, focused on the development of RA interventions. The introduction of the bioinformatics-based approach in RA has also been significantly discussed in the review. This review provides a general understanding of the challenges and uncertainties in the treatment of RA and summarizes the evolving scenario as well as innovative approaches taken into consideration for drug development in rheumatoid arthritis.

Combined influence of genetic and environmental factors in age of rheumatoid arthritis onset

To study the combined effect of both genetic and environmental factors in the age of rheumatoid arthritis onset. Patients (n = 507). Shared epitope characterization was performed using Lifecodes HLA-SSO. Genotyping of protein tyrosine phosphatase non-receptor 22 (PTPN22) rs2476601 and signal transducers and activators of transcription 4 (STAT4) rs7574865 polymorphism was performed using fast real-time PCR System. Shared epitope, antibodies directed against cyclic citrulinated peptide (anti-CCP) antibodies and a higher level of education were associated with a younger age at disease onset (P = 0.033, P = 0.004 and P < 0.0001, respectively). Neither carriers of the minor allele of PTPN22 rs2476601 nor STAT4 rs7574 polymorphisms showed a significant association with a younger age at disease onset (P = 0.355, P = 0.065, respectively). We found an additive effect of the three genetic markers in the age at onset: subjects with three markers were associated with a disease onset 9.56, 8.61, and 6.41 years before than those with none, one, or two genetic markers (P = 0.004, P = 0.006 and P = 0.043, respectively). We also described the additive effect of shared epitope, anti-CCP antibodies, educational level, PTPN22, and STAT4 polymorphisms in age at onset. Patients with two, three, four, or five variables were associated with a significant younger age of disease onset (4.72 [0.05-9.38] years (P = 0.048), 9.56 [4.72-14.40] years (P < 0.0001), 12.74 [6.84-18.64] years (P < 0.0001), and 20.87 [10.40-37.17] years (P < 0.0001)). Risk factors for the development of rheumatoid arthritis are also associated, with an additive effect, with a younger age at disease onset.

A spectrum of susceptibility to rheumatoid arthritis within HLA-DRB1: stratification by autoantibody status in a large UK population

Previously-proposed rheumatoid arthritis (RA) HLA-DRB1 susceptibility and protective models were compared, based on amino acids at positions 67-74 and autoantibody combinations. 3 657 RA patients and 1 357 controls were studied using logistic regression, with secondary stratification by anti-citrullinated peptide antibodies(ACPA) and rheumatoid factor(RF). Susceptibility models were based on previously defined HLA-DRB1 shared epitope(SE) subgroups. (70)DERAA(74), D(70) and I(67) protective models were compared, adjusting for HLA-DRB1 SE. A hierarchy of risk was observed within the HLA-DRB1 SE, particularly for ACPA-positive and RF-positive RA: HLA-DRB1(*)0401∼(*)0404>(*)0101∼(*)1001 ((*)0404>(*)0101: P=0.0003). HLA-DRB1(*)0401/(*)0404 compound heterozygosity conferred a risk similar to (*)0401 homozygosity (P=0.70). Protective effects of D(70) and I(67) were similar. Predictions of the D(70) model fitted the data better than those of the I(67) model. The protective effect of D(70) showed a gene-dose effect (OR 0.82, 95% CI 0.73-0.92, P=5.8 × 10(-4)), but was only seen in RA patients positive for RF or ACPA. HLA-DRB1 SE alleles were also associated with ACPA-negative, RF-positive RA (OR 1.42 (1.15-1.76), P=0.0012). In conclusion, HLA-DRB1 SE alleles show heterogeneity in RA susceptibility; their major effect appears to be mediated by ACPA positivity, but a significant association of HLA-DRB1 SE with RF-positive, ACPA-negative RA was also observed. D(70) specifically protected against antibody-positive RA.