The IRF5 rs2004640 (G/T) polymorphism is not a genetic risk factor for systemic lupus erythematosus in population from south India

Genetic polymorphisms in genes involved in the type I interferon system (STAT4 and IRF5): association with Asian SLE patients

Systemic lupus erythematosus (SLE) is a common autoimmune disease with a polymorphic clinical presentation involving multisystem damages with significant differences in prevalence and disease severity among different ethnic groups. Although genetic, hormonal, and environmental factors have been demonstrated to contribute a lot to SLE, the pathogenesis of SLE is still unknown. Numerous evidence revealed that gene variants within the type I interferons (IFN) signaling pathway performed the great genetic associations with autoimmune diseases including SLE. To date, through genome-wide association studies (GWAS), genetic association studies showed that more than 100 susceptibility genes have been linked to the pathogenesis of SLE, among which TYK2, STAT1, STAT4, and IRF5 are important molecules directly connected to the type I interferon signaling system. The review summarized the genetic associations and the detailed risk loci of STAT4 and IRF5 with Asian SLE patients, explored the genotype distributions associated with the main clinical manifestations of SLE, and sorted out the potential reasons for the differences in susceptibility in Asia and Europe. Moreover, the therapies targeting STAT4 and IRF5 were also evaluated in order to propose more personalized and targeted treatment plans in SLE.

Cytotoxic T Lymphocyte Antigen 4 Gene +49 A/G (rs231775) Polymorphism and Susceptibility to Systemic Lupus Erythematosus

AIM

To assess the probable role of +49AG polymorphism in susceptibility to SLE in an Egyptian population.

BACKGROUND

Systemic lupus erythematosus (SLE) is a compound inflammatory chronic disease distinguished through the release of autoantibodies. Cytotoxic T lymphocyte associated antigen-4 is a main down controller of T-cell response; its dysregulation could affect SLE pathogenesis by altered T cells activation to self-antigens.

OBJECTIVES

To evaluate the CTLA-4 +49AG allelic and genotype frequency in a sample of the Egyptian population and correlate them with disease susceptibility and clinical severity.

MATERIALS AND METHODS

Including 100 patients with SLE and 100 healthy controls (age and gender matched), CTLA-4 exon 1 49 A>G Genotyping was done using Real-Time PCR.

RESULTS

No difference was noticed in genotype or allele distributions of the studied polymorphism between both groups. Similar genotypes and allele frequencies were established for the 2 groups after their stratification by the age of disease onset, clinical course, or severity.

CONCLUSION

CTLA-4 +49AG gene polymorphism is not linked with the liability to develop SLE in the studied Egyptian population. Yet it is significantly related to disease severity.

Association between the interferon regulatory factor 5 rs2004640 functional polymorphism and systemic lupus erythematosus: an updated meta-analysis

OBJECTIVE

The aim of this study is to determine whether the functional interferon regulatory factor 5 ( IRF5) polymorphism rs2004640 is associated with susceptibility to systemic lupus erythematosus (SLE) in multiple ethnic populations.

METHODS

A meta-analysis was conducted on the T allele of the IRF5 rs2004640 polymorphism in all study participants as well as each ethnic population.

RESULTS

Twenty research articles that included 28 comparative studies of 20,892 patients and 24,930 controls were included in the meta-analysis. The Asian population had a much lower prevalence of the T allele than any other study population at 28%, and the European population had the highest prevalence of the T allele at 52%. Meta-analysis showed an association between the IRF5 rs2004640 polymorphism and SLE in all participants (odds ratio = 1.472, 95% confidence interval = 1.370-1.582, p < 0.001). Analysis after stratification by ethnicity indicated that the IRF5 rs2004640 T allele is significantly associated with SLE in Europeans, Asians, Latin Americans and Arabs.

CONCLUSIONS

This meta-analysis confirms that the IRF5 rs2004640 polymorphism is associated with SLE susceptibility in different ethnic groups, and that its prevalence is ethnicity dependent.