CCR5 promoter region polymorphisms in systemic lupus erythematosus

Area of Science:

• Immunogenetics
• Rheumatology
• Molecular Biology

Background:

• Systemic lupus erythematosus (SLE) is a complex autoimmune disease with a poorly understood genetic basis.
• The chemokine receptor CCR5 plays a role in immune cell trafficking and inflammation, making its genetic variants potential contributors to SLE pathogenesis.

Purpose of the Study:

• To investigate the association between CCR5 promoter region polymorphisms and SLE development.
• To analyze CCR5 genotypes and haplotypes in ethnically diverse SLE patients and controls.

Main Methods:

• Genotyping of CCR5 promoter polymorphisms (rs1799864, rs1799988, rs41469351, rs1800023, rs1800024) and CCR5Δ32 allele using PCR-RFLP and direct sequencing.
• Comparison of genotype and haplotype frequencies between 382 SLE patients and 375 controls of European and African ancestry.
• Binary logistic regression analysis to assess disease risk and clinical associations.

Main Results:

• European-derived SLE patients had a higher frequency of the CCR5 wild-type genotype and a lower frequency of the HHG*2 haplotype, both associated with increased SLE risk.
• Significant differences in HHA/HHB, HHC, and HHG*2 haplotype frequencies were observed between African-derived SLE patients and controls.
• CCR5Δ32 was a protective factor against SLE in European-derived individuals and a susceptibility factor for class IV nephritis in African-derived individuals.

Conclusions:

• CCR5 promoter polymorphisms are significant disease modifiers in SLE.
• The CCR5Δ32 polymorphism exhibits differential effects on SLE development and nephritis risk across ethnic groups.
• Specific CCR5 haplotypes (HHA/HHB, HHC, HHG*2) may influence CCR5 expression and contribute to SLE pathogenesis in African-derived populations.