RESUMEN
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by activation of the type I interferon (IFN) pathway. Here we convincingly replicate association of the IFN regulatory factor 5 (IRF5) rs2004640 T allele with SLE in four independent case-control cohorts (P = 4.4 x 10(-16)) and by family-based transmission disequilibrium test analysis (P = 0.0006). The rs2004640 T allele creates a 5' donor splice site in an alternate exon 1 of IRF5, allowing expression of several unique IRF5 isoforms. We also identify an independent cis-acting variant associated with elevated expression of IRF5 and linked to the exon 1B splice site. Haplotypes carrying the variant associated with elevated expression and lacking the exon 1B donor site do not confer risk of SLE. Thus, a common IRF5 haplotype driving elevated expression of multiple unique isoforms of IRF5 is an important genetic risk factor for SLE, establishing a causal role for type I IFN pathway genes in human autoimmunity.
Asunto(s)
Factores Reguladores del Interferón/fisiología , Lupus Eritematoso Sistémico/genética , Empalme del ARN/fisiología , Estudios de Casos y Controles , Estudios de Cohortes , Genotipo , Haplotipos , Humanos , Factores Reguladores del Interferón/genética , Datos de Secuencia Molecular , Polimorfismo GenéticoRESUMEN
To determine whether the IL2/IL21 region, a general autoimmunity locus, contributes to the observed variation in response to rituximab in patients with systemic lupus erythematosus as well as to analyze its influence in a cohort including other autoimmune diseases. rs6822844 G/T polymorphism at the IL2-IL21 region was analyzed by TaqMan assay in 84 systemic lupus erythematosus (SLE) and 60 different systemic autoimmune diseases Spanish patients receiving rituximab. Six months after the first infusion patients were classified, according to the EULAR criteria, as good responders, partial responders and non-responders. A statistically significant difference was observed in GG genotype frequency between responder (total and partial response) (83.56%) and non-responder (45.45%) SLE patients (p=0.010, odds ratio (OR)=6.10 [1.28-29.06]). No association with the response was evident in the group of patients with autoimmune diseases other than lupus. Furthermore, when both groups of patients were pooled in a meta-analysis, a reduced statistical significance of the association was observed (p=0.024, OR=3.53 [1.06-11.64]). Our results show for a first time that IL2-IL21 region seems to play a role in the response to rituximab in SLE patients but not in other autoimmune diseases.
Asunto(s)
Anticuerpos Monoclonales de Origen Murino/farmacología , Enfermedades Autoinmunes/tratamiento farmacológico , Interleucina-2/genética , Interleucinas/genética , Lupus Eritematoso Sistémico/tratamiento farmacológico , Farmacogenética/métodos , Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/inmunología , Regulación de la Expresión Génica , Genotipo , Humanos , Lupus Eritematoso Sistémico/genética , Lupus Eritematoso Sistémico/inmunología , Oportunidad Relativa , Polimorfismo de Nucleótido Simple/genética , Rituximab , EspañaRESUMEN
BACKGROUND: Several lines of evidence suggest that chemokines and cytokines play an important role in the inflammatory development and progression of systemic lupus erythematosus. The aim of this study was to evaluate the relevance of functional genetic variations of RANTES, IL-8, IL-1alpha, and MCP-1 for systemic lupus erythematosus. METHODS: The study was conducted on 500 SLE patients and 481 ethnically matched healthy controls. Genotyping of polymorphisms in the RANTES, IL-8, IL-1alpha, and MCP-1 genes were performed using a real-time polymerase chain reaction (PCR) system with pre-developed TaqMan allelic discrimination assay. RESULTS: No significant differences between SLE patients and healthy controls were observed when comparing genotype, allele or haplotype frequencies of the RANTES, IL-8, IL-1alpha, and MCP-1 polymorphisms. In addition, no evidence for association with clinical sub-features of SLE was found. CONCLUSION: These results suggest that the tested functional variation of RANTES, IL-8, IL-1alpha, and MCP-1 genes do not confer a relevant role in the susceptibility or severity of SLE in the Spanish population.