Association Study Of FcγrⅢa Single-Nucleotide Polymorphisms, Haplotypes And Copy Number With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE), also known as lupus, is a chronic autoimmune disease that causes the immune system attacks its own cells and tissues, resulting in the formation of autoimmune antibodies or immune complexes causing inflammation and tissue damage, which is the main feature of systemic lupus erythematosus. Systemic lupus cause various diseases of various organs, including the heart, the joints, skin, lungs, blood vessels, liver, kidneys, and nervous system. Lesions involving the kidneys which accounted for35%-90%, can cause autoimmune damage to both kidneys of systemic lupus erythematosus, accompanied by significant kidney damage, so systemic lupus erythematosus (SLE) kidney disease called lupus nephritis (LN). More performance for the duration of SLE disease exacerbation and remission alternating, usually can not predict when the onset. And the incidence rate showed significant racial differences, such as the high incidence of African Americans at three times the general population. There is no cure for lupus erythematosus, steroids and immunosuppressive drugs are used to relieve symptoms.The pathogenesis of systemic lupus erythematosus is not very clear, but most of that is due to genes, autoantibodies, immune complexes, endocrine hormones, environmental factors and other complex combination of factors. Currently, the study of the pathogenesis of SLE are mostly concentrated on its susceptibility genes, especially on gene polymorphism, there have been a lot of studies have shown that certain gene polymorphisms are acssociated with SLE and lupus nephritis, such as IFN-γgene polymorphism+874T/A (rs2430561) and interleukin IL-10promoter polymorphism-1082G/A (rs1800896) in Brazilians lupus nephritis; interleukin IL-10promoter locus-1082G/A,-819T/C gene and-592A/C polymorphism are associated with systemic lupus erythematosus in young children of Thailand; interleukin IL-10promoter locus-592A/C’s polymorphisms affect Chinese population lupus nephritis kidney disease and renal pathology related activities; IL-22RA1and Toll-like receptor gene polymorphisms3/7/8TLRs are displayed with different degrees of systemic lupus erythematosus nephritis correlation. Recently, these susceptible gene studies have been concentrated on genetic polymorphisms of FcyR receptor family. There are three groups of FcyR receptor family (CD64, CD32, CD16), while FcyRⅡa, FcyRⅢa, FcyRⅢb presence and influence FcyR polymorphisms affinity of the antibody which is considered as SLE pathogenesis and immune complexes Clear disorders, leading to SLE and lupus nephritis. Genome Wide Association Studies (GWAS) has proved that FCGR2A, FCGR2B, FCGR3A and FCGR3B affect receptor binding ability of IgG and immune complex (IC), has been shown to be associated with autoimmune diseases, particularly in the main thing is the system has been demonstrated lupus erythematosus, rheumatoid arthritis and Kawasaki disease related. For example, FcyRⅢa have a lower affinity for the SNP rs396991allele encoding phenylalanine (176F) has been demonstrated is associated with systemic lupus erythematosus and nephritis in some reports.Although a large number of studies have confirmed FcyRⅢa-176F/V to change the affinity of the receptor and the ligand, and in some populations associated with lupus nephritis. However, the correlation between the three alleles present in nt66of the FcyRIIIa receptor extracellular domain of the amino acid residues (66R/H/L)(rs10127939) polymorphism and gene copy number variation (CNV) association with SLE has been rarely reported. Therefore, we collected a lot of SLE patients and healthy blood samples; study the disease association with SLE and lupus nephritis. This research is very important for understanding of the pathogenesis of lupus, as well as forecasting, early diagnosis and treatment of diseases. For example, a person may carry risk genotypes, so we can avoid the risk of environmental factors, reduce the risk of disease occurrence, individualized treatment based on genotype, reduce the side effects of treatment, reduce treatment costs and improve the quality of life of patients.1. Binding assay of FcyRIIIa SNPs with hIgG and immune complexBackground:Currently, the majority of studies indicate the presence of two genetic polymorphisms in FCGR3A genes, one F176V (rs396991), the other is a triallelic66R/H/L (rs10127939) single nucleotide polymorphism, but the current research focus for all the genes is F176V alleles, this allele has different binding affinity with hIgG and IgG immune complexes, but there is no research study showing another triallelic non-synonymous polymorphism FcyRⅢa-66R/H/L can influence the receptor binding affinity with IgG and the IgG immune complexes. Therefore, this study focuses on these two SNPs. Objective:To study the gene and its expression FCGR3A protein receptor FcyRIIIa affect the hIgG binding ability and ability to clear hIgG immune complexes. Methods:established a mice stable cell line ⅡA1.6A206can simultaneously express FcyRⅢa SNPs. Then using flow cytometry methods to detect FcyRIIIa SNP binding affinity with hIgG and hIgG immune complex. Results:66R-176V and66H-176V66L-176V have much higher binding compacity with IgG and IgG immune complexes. Conclusion:In addition to FcyRIIIa biallelic SNP, FcyRIIIa triallelic66R/H/L (rs10127939) SNP also affect the hIgG and IC binding.2. Determination of FCGR3A SNPs genotypes and their association with lupus and lupus nephirtisBackground:Systemic Lupus Erythematosus and lupus nephritis are closely associated with the formation and clearance of antigen-antibody complexes. FcyRIIIa has close relationships with lupus nephritis because of it has lower affinity to hIgG and hIgG immune complex. FcyRIIIa gene polymorphism may cause the change of immune ability of cells to clear the antigen-antibody complexes, and individual susceptibility to Lupus Erythematosus or lupus nephritis. Objective:to study whether FcyRIIIa-F176V gene polymorphism combind with FcyRIIIa-66R/H/L SNP is associated with Systemic Lupus Erythematosus (SLE), lupus nephritis (LN) in a large population of European and African. Methods:We got total1728patients with systemic lupus erythematosus (366cases of lupus nephritis in patients of African,213cases of lupus snephritis in patients of European),2404conducted case-control study in healthy volunteers. We extract the DNA from whole blood samples, Pyrosequencing assay was used to detect FcyRIIIa-F176V and FcyRIIIa-66R/H/L genotype in the overall normal population and patients and its distribution among different populations. Statistical analysis will be conduct to determin whether the two SNPs is associated with Systemic Lupus Erythematosus. Results:low hIgG and IC binding affinity, FcyRIIIa-176F allele is associated with systemic lupus erythematosus nephritis in the African American (P=0.0609), but in European Americans, there was no significant correlation between systemic lupus erythematosus, lupus nephritis (P>0.10). African-American SLE nephritis with FcyRIIIa binding capacity with low66R/H/L and176F (IgG) haplotypes (P=0.03) or genotypic combinations in conjunction with low group related (p=0.002). But this was not found in the gene polymorphism associated with lupus nephritis with European-Americans. Conclusion:Combined haplotypes of66R/H/L and176F enhanced risk of African-Americans with lupus nephritis. 3. Determination of FCGR3A CNV and its assocoation with lupusBackground:copy number variation of DNA (CNVs) exists in natural populations which is a common form of genomic variants. In recent years, along with advances in experimental techniques, CNV map has been continuously improving, refining the crowd; lots of CNVs and relevance of the disease were being reported. CNV associated studies of complex diseases have become important elements of medical genetics. Objective:to study the gene copy number variation in the FCGR3A CNV and SLE (systemic lupus erythematosus) nephritis and Lupus (Lupus nephritis, LN) associated with the disease. Methods:We got total1728patients with systemic lupus erythematosus (366cases of lupus nephritis in patients of African,213cases of lupus snephritis in patients of European),2404conducted case-control study in healthy volunteers. We extract the DNA from whole blood samples, Pyrosequencing assay was used to detect FCGR3A gene copy number variation (CNV) and SNPs CNV, probability of CNV in the normal population and patients, as well as the difference between its different ethnic groups. Exploring whether FCGR3A gene copy number variation given in Systemic Lupus Erythematosus (SLE) or lupus nephritis (Lupus nephritis,LN) risk of disease development. Results:the distribution among FCGR3A CNV in SLE and healthy volunteers, as well as in SLE patients with or without distribution there is no significant difference between patients with nephritis. Conclusion:FCGR3A CNVs in both African Americans and European Americans are not linked to Systemic Lupus Erythematosus (SLE) or lupus nephritis (LN).