Association of FCGR2A-R/H131 polymorphism with susceptibility to systemic lupus erythematosus among Asian population: a meta-analysis of 20 studies

The FCGR2A Is Associated with the Presence of Atherosclerotic Plaques in the Carotid Arteries-A Case-Control Study

BACKGROUND

Atherosclerotic plaques in carotid arteries (APCA) are a prevalent condition with severe potential complications. Studies continuously search for innovative biomarkers for APCA, including those participating in cellular metabolic processes, cell adhesion, immune response, and complement activation. This study aimed to assess the relationship between APCA presence and a broad range of cardiometabolic biomarkers in the general population.

METHODS

The study group consisted of consecutive participants of the population study Bialystok PLUS. The proximity extension assay (PEA) technique from the Olink Laboratory (Uppsala, Sweden) was used to measure the levels of 92 cardiometabolic biomarkers.

RESULTS

The study comprised 693 participants (mean age 48.78 ± 15.27 years, 43.4% males, N = 301). APCA was identified in 46.2% of the participants (N = 320). Of the 92 biomarkers that were investigated, 54 were found to be significantly linked to the diagnosis of APCA. After adjusting for the traditional risk factors for atherosclerosis in multivariate analysis, the only biomarker that remained significantly associated with APCA was FCGR2A.

CONCLUSION

In the general population, the prevalence of APCA is very high. A range of biomarkers are linked with APCA. Nonetheless, the majority of these associations are explained by traditional risk factors for atherosclerosis. The only biomarker that was independently associated with APCA was the FCGR2A.

Gene Co-expression Networks Identifies Common Hub Genes Between Cutaneous Sarcoidosis and Discoid Lupus Erythematosus

In this study we analyzed gene co-expression networks of three immune-related skin diseases: cutaneous sarcoidosis (CS), discoid lupus erythematosus (DLE), and psoriasis. We propose that investigation of gene co-expression networks may provide insights into underlying disease mechanisms. Microarray expression data from two cohorts of patients with CS, DLE, or psoriasis skin lesions were analyzed. We applied weighted gene correlation network analysis (WGCNA) to construct gene-gene similarity networks and cluster genes into modules based on similar expression profiles. A module of interest that was preserved between datasets and corresponded with case/control status was identified. This module was related to immune activation, specifically leukocyte activation, and was significantly increased in both CS lesions and DLE lesions compared to their respective controls. Protein-protein interaction (PPI) networks constructed for this module revealed seven common hub genes between CS lesions and DLE lesions: TLR1, ITGAL, TNFRSF1B, CD86, SPI1, BTK, and IL10RA. Common hub genes were highly upregulated in CS lesions and DLE lesions compared to their respective controls in a differential expression analysis. Our results indicate common gene expression patterns in the immune processes of CS and DLE, which may have indications for future therapeutic targets and serve as Th1-mediated disease biomarkers. Additionally, we identified hub genes unique to CS and DLE, which can help differentiate these diseases from one another and may serve as unique therapeutic targets and biomarkers. Notably, we find common gene expression patterns in the immune processes of CS and DLE through utilization of WGCNA.

An update on genetic susceptibility in lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple system involvement and positive serum autoantibodies. Lupus nephritis (LN) is the most common and serious complication of SLE, and it is the main cause of death in patients with SLE. Abnormalities in the immune system lead to LN and involve a variety of cells (T cells, B cells, macrophages, NK cells, etc.), cytokines (interleukin, tumor necrosis factor α, etc.) and their related pathways. Previous studies have shown that the interactions of genetic, epigenetic and environmental factors contribute to the pathogenesis and development of LN. In recent years, one genome-wide association study (GWAS) and a number of gene association studies have explored the susceptibility genes of LN, including immunization-, inflammation-, adhesion- and other pathway-related genes. These genes participate in or suggest the pathogenesis and progression of LN. In this review, we summarize the genetic susceptibility of LN and discuss the possible mechanism underlying the susceptibility genes of LN.

An update on genetic susceptibility in lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple system involvement and positive serum autoantibodies. Lupus nephritis (LN) is the most common and serious complication of SLE, and it is the main cause of death in patients with SLE. Abnormalities in the immune system lead to LN and involve a variety of cells (T cells, B cells, macrophages, NK cells, etc.), cytokines (interleukin, tumor necrosis factor α, etc.) and their related pathways. Previous studies have shown that the interactions of genetic, epigenetic and environmental factors contribute to the pathogenesis and development of LN. In recent years, one genome-wide association study (GWAS) and a number of gene association studies have explored the susceptibility genes of LN, including immunization-, inflammation-, adhesion- and other pathway-related genes. These genes participate in or suggest the pathogenesis and progression of LN. In this review, we summarize the genetic susceptibility of LN and discuss the possible mechanism underlying the susceptibility genes of LN.

Key gene co-expression modules and functional pathways involved in the pathogenesis of Graves' disease

Graves' disease (GD) is a common autoimmune thyroid disease characterized by positive thyroid stimulating hormone receptor antibody. To better understand its molecular pathogenesis, we adopted the weighted gene co-expression network analysis to reveal co-expression modules of key genes involved in the pathogenesis of GD, protein-protein interaction network analysis to identify the hub genes related to GD development and functional analyses to explore their possible functions. Our results showed that 1) a total of 2667 differentially expressed genes in our microarray study and 16 different gene co-expression modules were associated with GD, and 2) the most significant module was associated with the percentage of macrophages, T follicular helper cells and CD4⁺ memory T cells and mainly enriched in immune regulation and immune response. Overall, our study reveals several key gene co-expression modules and functional pathways involved in GD, which provides some novel insights into the pathogenesis of GD.

A Case-Control Study on Association of Ulcerative Colitis with FCGR2A Gene Polymorphisms in Chinese Patients

BACKGROUND AND AIMS

The Fc gamma receptor IIa (FcγRIIa), encoded by FCGR2A gene, has been suggested to play a crucial role in immunity by linking immunoglobulin G antibody-mediated responses with cellular effector and regulatory functions. Polymorphisms in FCGR2A have been shown to affect FcγRIIa/antibody interactions and have been potentially implicated in several autoimmune and inflammatory conditions. This study was designed to analyze the association between ulcerative colitis (UC) and FCGR2A polymorphisms in the Chinese population.

MATERIALS AND METHODS

A total of 422 patients with UC and 710 unaffected controls were recruited. Five single nucleotide polymorphisms of FCGR2A (rs1801274, rs10800309, rs4657039, rs511278, and rs6696854) were genotyped by SNaPshot. Analyses for linkage disequilibrium (LD) and haplotype studies of FCGR2A were performed for all study subjects.

RESULTS

The frequency of the minor homozygote (CC) of the rs1801274 SNP of FCGR2A was shown to be significantly lower in patients with UC than in controls (7.1% vs. 12.1%, p = 0.008). Two haplotype blocks, formed by FCGR2A (rs4657039, rs6696854, and rs10800309) and FCGR2A (rs1801274 and rs511278), respectively, were observed in the subsequent LD analysis. The TC haplotype constructed by the major allele of FCGR2A (rs1801274 and rs511278) was more prevalent in UC patients compared with controls (65.2% vs. 60.2%, p = 0.017).

CONCLUSIONS

The minor homozygote (CC) of FCGR2A (rs1801274) may contribute to decrease the susceptibility to UC and the TC haplotype formed by FCGR2A (rs1801274 and rs511278) may increase the risk of UC in the Chinese population.

B-cell-intrinsic function of TAPP adaptors in controlling germinal center responses and autoantibody production in mice

Control of B-cell signal transduction is critical to prevent production of pathological autoantibodies. Tandem PH domain containing proteins (TAPPs) specifically bind PI(3,4)P2, a phosphoinositide product generated by PI 3-kinases and the phosphatase SHIP. TAPP KI mice bearing PH domain-inactivating mutations in both TAPP1 and TAPP2 genes, uncoupling them from PI(3,4)P2, exhibit increased BCR-induced activation of the kinase Akt and develop lupus-like characteristics including anti-DNA antibodies and deposition of immune complexes in kidneys. Here, we find that TAPP KI mice develop chronic germinal centers (GCs) with age and show abnormal expression of B-cell activation and memory markers. Upon immunization with T-dependent Ag, TAPP KI mice develop functional but abnormally large GCs, associated with increased GC B-cell survival. Disruption of chronic GCs in TAPP KI mice by deletion of the costimulatory molecule ICOS abrogate anti-DNA and anti-nuclear antibody production in TAPP KI mice, indicating an essential role for GCs. Moreover, TAPP KI B cells are sufficient to drive chronic GC responses and recapitulate the autoimmune phenotype in BM chimeric mice. Our findings demonstrate a B-cell-intrinsic role of TAPP-PI(3,4)P2 interaction in regulating GC responses and autoantibody production and suggest that uncontrolled Akt activity in B cells can drive autoimmunity.

Recapitulation of Candidate Systemic Lupus Erythematosus-Associated Variants in Koreans

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organ systems. Although the etiology of SLE remains unclear, it is widely accepted that genetic factors could be involved in its pathogenesis. A number of genome-wide association studies (GWASs) have identified novel single-nucleotide polymorphisms (SNPs) associated with the risk of SLE in diverse populations. However, not all the SNP candidates identified from non-Asian populations have been validated in Koreans. In this study, we aimed to replicate the SNPs that were recently discovered in the GWAS; these SNPs have not been validated in Koreans or have only been replicated in Koreans with an insufficient sample size to conclude any association. For this, we selected five SNPs (rs1801274 in FCGR2A and rs2286672 in PLD2, rs887369 in CXorf21, rs9782955 in LYST, and rs3794060 in NADSYN1). Through the replication study with 656 cases and 622 controls, rs1801274 in FCGR2A was found to be significantly associated with SLE in Koreans (odds ratio, 1.26, 95% confidence interval, 1.06 to 1.50; p = 0.01 in allelic model). This association was also significant in two other models (dominant and recessive). The other four SNPs did not show a significant association. Our data support that FCGR polymorphisms play important roles in the susceptibility to SLE in diverse populations, including Koreans.

The His131Arg substitution in the FCGR2A gene (rs1801274) is not associated with the severity of influenza A(H1N1)pdm09 infection

BACKGROUND

The virulence and pathogenicity of different influenza strains are responsible for a more or less severe disease. Recent studies have attempted to understand how host genetic factors may influence the clinical presentation of the disease. In the present study, the His131Arg (rs1801274) polymorphism was investigated in individuals from a Brazilian admixed population with a diagnosis of influenza A(H1N1)pdm09 infection.

METHODS

In the present study, the influence of the His131Arg (rs1801274) polymorphism, a variant of the FCGR2A gene, was investigated in 436 patients with a diagnosis of influenza A(H1N1)pdm09, evaluated at health services in the northern and northeastern regions of Brazil between June 2009 and August 2010. Patients were divided into a group of non-hospitalized patients (n = 192) and a group of hospitalized patients (n = 244; 100 of them died).

RESULTS

No significant difference in the allele or genotype frequencies of the rs1801274 polymorphism was observed between groups (p = 0.952 and p = 0.388). Multinomial logistic regression showed no effect of the rs1801274 polymorphism on severity or death of patients from the Brazilian admixed population (p = 0.368 and p = 0.469).

CONCLUSIONS

The rs1801274 polymorphism is not associated with severe disease in patients infected with influenza A(H1N1)pdm09.

Polymorphism of FCGR2A, FCGR2C, and FCGR3B Genes in the Pathogenesis of Sarcoidosis

We have previously presented evidence that the polymorphism of the FCGR3A gene, encoding the receptor for Fc fragment of immunoglobulin G IIIa (FcγRIIIa) plays a role in the enhancement of circulating immune complexes (CIs) with the occurrence of Mycobacterium tuberculosis heat shock proteins in patients with sarcoidosis (SA). The immunocomplexemia might be caused by decreased affinity of CIs to Fcγ receptors, with the subsequently decreased receptor clearance by immune cells. In the present study we examined whether the polymorphisms of other related genes (FCGR2A, FCGR2C, FCGR3B) encoding other activatory Fcγ receptors, could have a similar effect. To this end, we genotyped 124 patients with sarcoidosis and 148 healthy volunteers using polymerase chain reaction with sequence-specific primers. We revealed a significant decrease in the percentage of the FCGR2A and FCGR2C variants that ensure effective CIs clearance, with a concomitant increase of less functional variants of these genes in Stages I/II, compared with Stages III/IV of SA. There was no aberration in FCGR3B allele/genotype frequencies. We conclude that the FCGR2A and FCGR2C polymorphisms may also contribute to immunocomplexemia present in SA. The assessment of FCGR genes could become a tool in presaging a clinical course of sarcoidosis and in its personalized therapy.