Risk of Systemic Lupus Erythematosus Linked To Genetic Variation

Researchers identified that a single nucleotide polymorphism in the sequence of the CD40 gene, a gene with key functions in immune diseases, is associated with susceptibility to systemic lupus erythematosus. The study entitled “The association of CD40 polymorphisms with CD40 serum levels and risk of systemic lupus erythematosus” was published in the journal BMC Genetics.

The underlying causes for systemic lupus erythematosus (SLE) are still far from clear, but researchers suspect that the disease arises as a consequence of the interplay between genetic and environmental factors.

Recent studies associated variation (polymorphism) within the CD40 gene, a member of the tumor necrosis family of transmembrane glycoproteins with key roles in adaptive immunity, with the risk of developing autoimmune and inflammatory diseases. Notably, however, how CD40 single nucleotide polymorphism (SNP) impacts SLE is poorly understood. This receptor is expressed in various cell types, including B cells, endothelial cells, macrophages, dendritic cells, T cells, and fibroblasts.

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In this study, researchers investigated CD40 SNPs in the Chinese population, analyzing 205 patients with SLE (recruited at the Department of Dermatology, Affiliated Hospital of Youjiang Medical University for Nationalities, Guangxi, China) and 220 control subjects, matching SLE patients’ age and gender. Patients and control subjects’ genomic DNA was extracted from peripheral blood leukocytes and submitted to a Snapshot SNP genotyping assay. The team focused on three SNPs —  rs1883832C/T, rs1569723A/C and rs4810485G/T — and correlated them with SLE pathogenesis, together with the levels of soluble CD40 present in patients’ blood.

They found that one particular CD40 SNP (rs1883832C/T) and the levels of soluble CD40 were significantly associated with the risk of SLE in Chinese patients. In the light of these results, authors suggest that additional studies with increased number of patients are necessary to confirm and further understand how the CD40 gene polymorphism correlates with SLE susceptibility. The team further highlights that because genetic polymorphisms can vary between different ethnic groups, additional genomic studies should investigate how CD40 gene polymorphism correlates with SLE risk in different ethnicities.