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The bm12 Inducible Model of Systemic Lupus Erythematosus (SLE) in C57BL/6 Mice
Published on: November 1, 2015
Structural polymorphisms of complement receptor 1 (CR1) in systemic lupus erythematosus (SLE) patients and normal
J M Moulds1, J D Reveille, F C Arnett
1Department of Internal Medicine, University of Texas, Houston Medical School 77030, USA.
Insights
The complement receptor 1 (CR1) size polymorphism, specifically the CR1-C allele, is not a genetic risk factor for systemic lupus erythematosus (SLE). Frequencies of CR1 structural alleles do not differ between SLE patients and healthy controls across ethnic groups.
Area of Science:
- Immunogenetics
- Rheumatology
- Complement System Biology
Background:
- Complement receptor 1 (CR1) on erythrocytes plays a role in immune complex clearance.
- CR1 exhibits molecular weight polymorphism and variable C3b-binding sites, potentially impacting its function.
- Investigating CR1 size polymorphism is crucial for understanding its role in autoimmune diseases like SLE.
Purpose of the Study:
- To investigate the association between CR1 size polymorphism and systemic lupus erythematosus (SLE).
- To determine if the CR1-C allele, a smaller CR1 variant, is a genetic risk factor for SLE.
- To compare CR1 allele frequencies in SLE patients and ethnically matched healthy controls.
Main Methods:
- Erythrocytes from SLE patients and controls of three ethnic groups were analyzed for CR1 size polymorphism.
- Molecular weight analysis was performed to identify CR1 variants and potential degradation products.
- Allele frequencies were statistically compared between patient and control cohorts.
Main Results:
- The CR1-C allele was more frequent in African-Americans but showed no significant difference in frequency between SLE patients (9%) and controls (10%).
- A 160-kD band, resembling CR1-C, was identified as a proteolytic cleavage fragment in some patients.
- No significant difference in CR1 structural allele frequencies was observed between SLE patients and race-matched healthy controls.
Conclusions:
- The smallest CR1 form, CR1-C, is not a genetic risk factor for developing SLE.
- CR1 size polymorphism does not appear to be a significant genetic determinant for SLE susceptibility.
- Further research may explore other complement system components or CR1 functional variations in SLE pathogenesis.
Abstract:
CR1 exhibits a molecular weight polymorphism and variability in the number of C3b-binding sites. Because this may affect immune complex clearance, we used erythrocytes to investigate the CR1 size polymorphism in SLE patients from three ethnic groups. The CR1-C allele was found more frequently in African-Americans, but the frequency did not differ between controls (10%, n = 63) and SLE patients (9%, n = 79). A 160-kD band similar to CR1-C was noted in a number of patients and was shown to be a proteolytic cleavage fragment. The study shows that the smallest form of CR1, i.e. CR1-C, is not a genetic risk factor for SLE and that the frequencies of the CR1 structural alleles do not differ from race-matched healthy controls.
