CR2 – systemic lupus erythematosus

A single case–control study in 150 Korean SLE patients and 50 SLE patients with osteonecrosis of the femoral head (ONFH) identified three CR2 polymorphisms—rs3813946 (5′-UTR), rs311306 (intron 1), and rs17615 (exon 10; p.Ser639Asn)—that were associated with increased ONFH risk under a recessive model ([PMID:27446959]). Haplotypes containing these variants conferred an OR of ~3.7 for ONFH in SLE, but no replication in independent SLE cohorts or segregation data are available.

Functional immunoassays using a CR2–IgG fusion protein to capture iC3b/C3dg from plasma revealed a threefold higher signal in 144 SLE patients versus 144 healthy controls (p < 0.0001), demonstrating elevated complement activation through CR2 in SLE ([PMID:32431705]). Taken together, limited genetic association and concordant functional data support a modulatory role for CR2 in SLE pathophysiology. Key Take-home: CR2 variants may influence SLE complications and CR2-based assays could serve as biomarkers of complement activation in SLE.

References

• BioMed Research International • 2016 • Association of Complement Receptor 2 Gene Polymorphisms with Susceptibility to Osteonecrosis of the Femoral Head in Systemic Lupus Erythematosus. PMID:27446959
• Frontiers in Immunology • 2020 • Complement Receptor 2 Based Immunoassay Measuring Activation of the Complement System at C3-Level in Plasma Samples From Mice and Humans. PMID:32431705

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