Association of RIPK1 and RIPK2 Gene Polymorphisms with Rheumatoid Arthritis in a Chinese Han Population.

Abstract

Objects: Rheumatoid arthritis (RA) is a systemic autoimmune disease with an obscure pathogenesis. This study aims to identify the susceptibility conferred by specific single nucleotide polymorphisms (SNPs), namely rs17548629 within the RIPK1 gene and rs10094579 within the RIPK2 gene, in RA. Additionally, it investigates the associations between inflammatory markers and biochemical parameters at various stages of the disease.

Methods: We analyzed 394 patients with RA and 258 normal controls (NCs), examining SNPs within the RIPK1 (rs17548629) and RIPK2 (rs10094579) genes using polymerase chain reaction (PCR) and sequencing techniques. Profiles of RA patients were evaluated for inflammatory markers, including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), as well as biochemical parameters such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, glucose, uric acid, and creatinine. Additionally, disease-specific indicators included cyclic citrullinated peptide (CCP), rheumatoid factor (RF), antinuclear antibodies (ANA), and anti-keratin antibodies. The Disease Activity Score 28 (DAS28), based on ESR, was used to categorize RA patients into groups of high, moderate, or low disease activity.

Results: We found a significant association between the RIPK1 rs17548629 genotype and RA in the additive model (p < 0.001; OR = 3.23), over-dominant model (p < 0.001; OR = 0.27), and dominant model (p < 0.001; OR = 3.94). The frequency of the C allele at rs17548629 was significantly higher in NCs than in RA patients (p < 0.001; OR = 0.322). When compared with normal controls, the RIPK1 rs17548629 genotype demonstrated significant associations with both anti-CCP-positive RA patients (p < 0.001) and anti-CCP-negative RA patients (p < 0.001). Similarly, this genotype was associated with RF-positive RA patients (p < 0.001). Furthermore, the RIPK2 rs10094579 genotype was significantly associated with CRP levels in RA patients with low disease activity in the over-dominant model (p = 0.029; OR = 0.065, adjusted for age and sex).

Conclusion: The presence of the RIPK1 rs17548629 genotype is associated with RA under additive, co-dominant, and dominant models. The T allele mutation at rs17548629 increases the risk of RA in the Chinese population. The RIPK1 rs17548629 genotype was identified as being associated with RF-positive RA patients, whereas no significant association was observed in RF-negative individuals. These findings suggest that this SNP may modulate the risk of RA in an RF-dependent manner. Furthermore, the RIPK2 rs10094579 genotype correlates with CRP levels in RA patients exhibiting low disease activity. This association underscores the necessity for caution when reducing the dosage of therapy in RA patients with low disease activity who carry the CA genotype at RIPK2 rs10094579. Additional research is warranted to explore other genotypes that may influence RA susceptibility and to refine potential treatment strategies.