FCGR2A Polymorphisms Research Articles

Effect of Fcγ-receptor 3a (FCGR3A) gene polymorphisms on rituximab therapy in Hungarian patients with rheumatoid arthritis

BackgroundRheumatoid arthritis (RA) treatment includes the use of the anti-CD20 monoclonal antibody rituximab (RTX). RTX acts through Fcγ-receptors (FCGR) on effector natural killer cells and macrophages and it can be...

A phase II trial of lenalidomide plus rituximab in previously untreated follicular non-Hodgkin’s lymphoma (NHL): CALGB 50803 (Alliance)

BackgroundThis multicenter, phase II trial tested the tolerability and efficacy of lenalidomide plus rituximab in patients with previously untreated follicular lymphoma (FL). Patients and methodsPatients with grade 1–3a FL, stage 3–4 or bulky stage 2, FL international prognostic index (FLIPI) 0–2, and no prior therapy were eligible to receive rituximab 375mg/m2 weekly during cycle 1 and day 1 of cycles 4, 6, 8, and 10, plus lenalidomide 20–25mg on days 1–21 for twelve 28-day cycles. The primary objectives were to evaluate response rates [complete (CR) and overall] and time to progression. Secondary objectives included toxicity, response according to polymorphisms in FcgR2A and FcgR3A, and changes in circulating pro-angiogenic cells. ResultsFrom October 2010 to September 2011, 66 patients were enrolled. Median age was 53years, 34 were female, 15 had bulky disease, 21 were FLIPI 0-1, 43 FLIPI 2, and 2 FLIPI 3. One patient withdrew before receiving treatment. Fifty-one patients completed 12 cycles of lenalidomide. Reasons for discontinuation included withdrawal (n=6), adverse events (n=6), progression (n=2). Grade 3–4 hematologic toxicity included neutropenia (21%), lymphopenia (9%), and thrombocytopenia (2%), infection (11%), and rash (8%). Grade 1–2 toxicity included fatigue (78%), diarrhea (37%), rash (32%), and febrile neutropenia in one patient. The overall response rate was 95%; the CR rate was 72% (95% confidence interval, 60% to 83%). With a median follow-up of 5years, the 2- and 5-year progression-free survival were 86% and 70%, respectively, and the 5-year overall survival was 100%. There was no association between CR rate or PFS and FLIPI, histological grade, bulky disease, FcgR2A/FcgR3A polymorphism, or change in circulating endothelial cell/hematopoietic progenitor cell. ConclusionLenalidomide plus rituximab was associated with low rates of grade 3–4 toxicity, yielded a CR rate and PFS similar to chemotherapy-based treatment and may represent a reasonable alternative to immunochemotherapy in previously untreated FL. ClinicalTrials.gov IdentifierNCT01145495.

FC gamma receptor polymorphisms in patients with immune thrombocytopenia

ABSTRACTIntroduction: Immune thrombocytopenia (ITP) is an autoimmune blood disease of unknown etiology. The aim of our study was to investigate a possible role of FCGR2A and FCGR3A polymorphisms in the development of primary ITP.Methods: We analyzed 125 adult patients with ITP and 120 healthy controls. Genotyping was performed by using PCR-RFLP methods.Results: Our results showed significantly higher frequency of high-affinity FCGR3A-158V allele in patients with ITP compared with control subjects (47.2% versus 37.5%; p = 0.037). We did not find significant differences in the genotype distribution or allele frequencies for FCGR2A-131H/R between patients and controls, p = 0.652 and p = 0.478. In the groups of patients with unresponsive and responsive ITP we found significantly different genotype distribution and allele frequencies for FCGR3A, p = 0.036 and p = 0.008 respectively. There was no significant difference in genotype and allele frequencies for FCGR2A between these two groups of patients. Our results confirmed that the combination of high-affinity FCGR2A-131H and FCGR3A-158V allele was more common in patients with ITP than in controls (55% versus 40%; p = 0.024).Conclusion: Our results suggest possible role of FCGR3A polymorphism in the etiology, development and clinical outcome of ITP, but larger prospective studies are needed to confirm these results.

The influence of FCGR2A and FCGR3A polymorphisms on the survival of patients with recurrent or metastatic squamous cell head and neck cancer treated with cetuximab

FCGR2A-H131R and FCGR3A-V157F are single-nucleotide polymorphisms known to influence the outcome of patients treated with rituximab, cetuximab and trastuzumab. We investigated the impact of these polymorphisms on the clinical outcome of 103 patients with recurrent or metastatic squamous cell carcinoma of the head and neck treated with a platinum compound, fluorouracil and cetuximab as palliative first-line therapy. The survival of patients with FCGR2A-131H/H and/or FCGR3A-157V/V genotypes was significantly longer compared with patients carrying 131R and 157F alleles (median progression-free survival (PFS): 5.5 vs 4.1 months, P=0.02; median overall survival: 10.2 vs 7.2 months, P=0.04). In multivariate analysis, the FCGR2A and 3A genotypes as well as the time between initial diagnosis and relapse of disease not amenable to curative therapy remained the only independent prognostic factors for PFS. The results are in line with previous reports in colorectal cancer patients and confirm the possible value of genetic polymorphisms of immunocompetent cells for the success of cetuximab treatment.

Fcγ receptor expression on splenic macrophages in adult immune thrombocytopenia.

Splenic macrophages play a key role in immune thrombocytopenia (ITP) pathogenesis by clearing opsonized platelets. Fcγ receptors (FcγR) participate in this phenomenon, but their expression on splenic macrophages and their modulation by treatment have scarcely been studied in human ITP. We aimed to compare the phenotype and function of splenic macrophages between six controls and 24 ITP patients and between ITP patients according to the treatments they received prior to splenectomy. CD86, human leucocyte antigen D-related (HLA-DR) and FcγR expression were measured by flow cytometry on splenic macrophages. The major FcγR polymorphisms were determined and splenic macrophage function was assessed by a phagocytosis assay. The expression of the activation markers CD86 and HLA-DR was higher on splenic macrophages during ITP compared to controls. While the expression of FcγR was not different between ITP and controls, the phagocytic function of splenic macrophages was reduced in ITP patients treated with intravenous immunoglobulin (IVIg) within the 2weeks prior to splenectomy. The FCGR3A (158V/F) polymorphism, known to increase the affinity of FcγRIII to IgG, was over-represented in ITP patients. Thus, these are the first results arguing for the fact that the therapeutic use of IVIg during human chronic ITP does not modulate FcγR expression on splenic macrophages but decreases their phagocytic capabilities.

Fc-Gamma Receptor Polymorphisms Are Associated with Susceptibility to and Recovery from Pediatric Immune Thrombocytopenia

Introduction: Immune thrombocytopenia (ITP) in children is a rare autoimmune disorder characterized by isolated thrombocytopenia. Platelet specific autoantibodies are often present leading to accelerated clearance of opsonized platelets by Fc-gamma receptor (FcγR) bearing phagocytes, particularly in the spleen. Both activating FcγRs as well as the inhibitory FcγRIIb are subject to genetic variation that affects their function. This includes mutations resulting in loss of expression; for example only the FCGR2C*ORF with an open reading frame leads to FcγRIIc expression. On myeloid and natural killer cells, FcγRIIc expression enhances IgG-mediated activation. Similarly, functional FcγRIIb polymorphisms also exist (FCGR2B*232I/T), with the FCGR2B*232T variant being functionally impaired in downregulating activating FcγRs and the B-cell receptor. We evaluated whether FcγR polymorphisms are associated with occurrence of ITP, response to intravenous immunoglobulin (IVIg) therapy and recovery in children with newly diagnosed ITP.Patients and methods: Children aged 3 months-16 years with newly diagnosed ITP, a platelet count below 20x109/L and with mild to moderate bleeding were included in the randomized multicenter TIKI trial (Therapy with or without IVIg for Kids with acute ITP; NTR study ID TC1563). Patients were randomized to receive either a single dose of IVIg (0.8 g/kg) or to receive careful observation and medical treatment only in case of severe bleeding. At diagnosis, blood samples were taken to perform the multiplex ligation-dependent probe amplification (MLPA) assay, assessing copy number variations and detecting all known FcγR polymorphisms.Results: From May 2009 until May 2015, 180 newly diagnosed patients were enrolled in this part of our study. ITP patients showed an FcγR profile different from that of healthy controls, with an overrepresentation of FCGR2C*ORF (31.7% versus 19.6%, p=0.007) and its associated promoter 2B.2, a higher allele frequency of FCGR3A*158V (41.4% versus 32.8%; p=0.019), and less often FCGR3B-HNA1a (9.4% versus 18.1%, p=0.032). In the observation group (n=81), all children with complete recovery at 1 week (n=17) were homozygous for 232I in FCGR2B (p=0.016). In patients randomized to receive IVIg, complete response rate after one week was 68.4%; complete responders were either homozygous FCGR2B*232I or heterozygous FCGR2B*232I/232T. No complete responses to IVIg were seen in the three patients with the homozygous FCGR2B*232T genotype (p=0.03). In patients with a homozygous FCGR2B*232I genotype combined with the 2B.4 promoter haplotype, complete response rate was significantly higher than in patients lacking this combination (93.3% versus 64.6%, respectively; p=0.03).Conclusion: Functional FcγR polymorphisms in FCGR2C, FCGR3A and FCGR3B genes are associated with newly diagnosed ITP in children. Furthermore, the less functional 232T-FcγRIIb isoform is associated with the lack of early recovery, either with or without IVIg treatment. FcγR profiles can be regarded as a risk factor to develop ITP during childhood. FcγR profiles are associated with the clinical course and response to IVIg treatment suggesting that determination of the FcγR profile can be of additional value in patient counselling and decision algorithms whether or not to start IVIg treatment in ITP. DisclosuresNo relevant conflicts of interest to declare.

Epidermal growth factor receptor (EGFR) pathway polymorphisms as predictive markers of cetuximab toxicity in locally advanced head and neck squamous cell carcinoma (HNSCC) in a Spanish population

ObjectivesTo examine the relationship between polymorphisms of the epidermal growth factor receptor (EGFR) pathway and toxicity in head and neck squamous cell carcinoma (HNSCC) patients treated with cetuximab. Material and methodsMulticenter, retrospective, observational pilot study which included 110 patients with histologically-confirmed human papillomavirus (HPV) negative HNSCC in locally advanced stages (III-IVA-B) and who were treated with chemotherapy and radiotherapy plus cetuximab between 2003 and 2013. Genetic analyses for single nucleotide polymorphisms (SNP) in genes EGFR, CCDN1, FCGR2A, FCGR3A and KRAS-LCS6 were performed though available allelic discrimination assay and/or polymerase chain reaction-restriction fragment length polymorphism methods. ResultsAcneiform rash was observed in 55.5% of patients, dry skin in 45.5% and pruritus in 20.9%. A significant association with dry skin and global cetuximab-related toxicity was observed for the KRAS-LCS6 (rs61764370) variant (p<0.05); carriers of the G allele (genotypes TG+GG) in the dominant model were observed to have a decreased susceptibility of developing dry skin (OR=0.287 [95%CI=0.119–0.695]). Carriers of the A (GA+AA) allele for EGFR (rs2227983) showed a decreased risk of suffering from pruritus (OR=0.345 [0.124–0.958]). Similarly, KRAS (rs1801274) was related with lower global cetuximab-related toxicity (OR=0.266 [0.114–0.622]). ConclusionThis pilot study provides preliminary evidence supporting genetic variation of EGFR (rs2227983), KRAS (rs61764370) and FCGR2A (rs180127) as useful biomarkers for predicting reduced skin toxicity in HNSCC patients treated with a cetuximab-based therapy. Alternative therapeutic options should be explored for these patients.

Association of Polymorphisms in FCGR2A and FCGR3A With Degree of Trastuzumab Benefit in the Adjuvant Treatment of ERBB2/HER2–Positive Breast Cancer

ImportancePreclinical models and studies in the metastatic and neoadjuvant settings suggest that single nucleotide polymorphisms in FCGR3A and FCGR2A may be associated with differential response to trastuzumab in the treatment of ERBB2/HER2–positive breast cancer, by modulating antibody-dependent cell-mediated cytotoxic effects.ObjectiveTo evaluate the effect of FCGR2A and FCGR3A polymorphisms on trastuzumab efficacy in the adjuvant treatment of ERBB2/HER2–positive breast cancer.Design, Setting, and ParticipantsThis is a retrospective analysis of patients enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31 trial, a phase 3 cooperative group study conducted between 2000 and 2005. The NSABP B-31 trial randomized 2119 women with surgically resected node-positive, ERBB2/HER2–positive breast cancer to treatment with doxorubicin and cyclophosphamide followed by paclitaxel or the same regimen with the addition of 1 year of weekly trastuzumab. Patients were accrued at cooperative group sites across the United States and Canada. This analysis was performed between 2013 and 2016.InterventionsDoxorubicin and cyclophosphamide followed by paclitaxel or the same regimen with the addition of 1 year of weekly trastuzumab.Main Outcomes and MeasuresDisease-free survival.ResultsThe genotyped cohort (N = 1251) resembled the entire B-31 cohort based on clinical variables and the degree of benefit from trastuzumab. Median follow-up time was 8.2 years in the genotyped samples. The disease-free survival probability at 3, 5, and 8 years was 74% (95% CI, 71%-79%), 66% (95% CI, 62%-71%), and 58% (95% CI, 54%-63%) in patients who received ACT and 86% (95% CI, 83%-89%), 82% (95% CI, 79%-85%), and 78% (95% CI, 74%-81%) in patients who received ACTH. Addition of trastuzumab significantly improved patient outcome (hazard ratio [HR], 0.46; 95% CI, 0.37-0.57; P < .001). The expected trend for interaction between polymorphisms and trastuzumab was observed for both genes, but only FCGR3A-158 polymorphism reached statistical significance for interaction (P < .001). As hypothesized, patients with genotypes FCB3A-158V/V or FCB3A-158V/F received greater benefit from trastuzumab (HR, 0.31; 95% CI, 0.22-0.43; P < .001) than patients who were homozygous for the low-affinity allele (HR, 0.71; 95% CI, 0.51-1.01; P = .05).Conclusions and RelevanceThe FCGR3A-158 polymorphism is predictive of trastuzumab efficacy in this cohort of patients with early ERBB2/HER2–positive breast cancer. Patients who are homozygous for phenylalanine at this position represent a considerable proportion of the population and, in contrast to previously reported analyses from similarly designed trials, our results indicate that trastuzumab may be less efficacious in these patients.Trial Registrationclinicaltrials.gov Identifier: NCT00004067

New polymorphisms associated with response to anti-TNF drugs in patients with moderate-to-severe plaque psoriasis.

Anti-tumor necrosis factor (anti-TNF) drugs are effective against psoriasis, although 20-30% of patients are nonresponders. Few pharmacogenomic studies have been performed to predict the response to anti-TNF drugs in psoriasis. We studied 173 polymorphisms to establish an association with the response to anti-TNF drugs in patients with moderate-to-severe plaque psoriasis (N=144). We evaluated the response using PASI75 at 3, 6 and 12 months. The results of the multivariate analysis showed an association between polymorphisms in PGLYR4, ZNF816A, CTNNA2, IL12B, MAP3K1 and HLA-C genes and the response at 3 months. Besides, the results for polymorphisms in IL12B and MAP3K1 were replicated at 6 months. We also obtained significant results for IL12B polymorphism at 1 year. Moreover, polymorphisms in FCGR2A, HTR2A and CDKAL1 were significant at 6 months. This is the first study to show an association with these polymorphisms. However, these biomarkers should be validated in large-scale studies before implementation in clinical practice.

No association between FCGR2A and FCGR3A polymorphisms in Guillain-Barré Syndrome in a Brazilian population

The pathogenesis of Guillain-Barré Syndrome (GBS) is not entirely understood, but includes infection-induced aberrant immune responses. Genetic polymorphisms in Fc gamma receptor genes (FCGR) have been associated with GBS. We assessed whether polymorphisms rs1801274 in FCGR2A and rs396991 in FCGR3A were associated with GBS in a Brazilian population. We genotyped 141 GBS cases and 364 healthy controls from Brazil for both polymorphisms. The FCGR genotypes and alleles frequencies did not differ significantly between GBS and controls. In addition, there was no genetic association with either severity or clinical outcomes. We conclude that these FCGR polymorphisms are not associated with susceptibility to Guillain-Barré Syndrome in this Brazilian population.

The FCGR3A polymorphism predicts the response to rituximab-based therapy in patients with non-Hodgkin lymphoma: a meta-analysis.

Epidemiological studies have assessed the association between Fc gamma receptor IIIA (FCGR3A) 158 V/F and the response to rituximab-based therapy in patients with non-Hodgkin lymphoma (NHL), but the findings have been inconsistent. We performed this meta-analysis to obtain a better assessment of this relationship. Electronic database searches were conducted for relevant studies. A pooled odds ratio (OR) with a 95% confidence interval (95% CI) was used to assess the strength of the association. Analyses of the subgroup and publication bias were conducted. A total of 10 studies involving 1050 patients were analyzed. In all the genetic models, no clear relationship was found between the FCGR3A 158 V/F polymorphism and the response to rituximab-based therapy in NHL patients. When categorized by ethnicity, Asian individuals with the FCGR3A 158 V/V allele (OR = 4.37; 95% CI = 1.07-17.73; P = 0.039) or the non-F/(FV + VV) (OR = 2.50; 95% CI = 1.04-5.98; P = 0.040) allele have a significantly higher complete response rate (CR) compared to FF individuals. No obvious heterogeneities were observed. In addition, no statistical evidence for a publication bias was found. Our study suggested that the FCGR3A 158 V/F polymorphism can predict the treatment response to rituximab-based chemotherapy in NHL patients, especially for Asian individuals.

FCGR3A/2A polymorphisms and diffuse large B-cell lymphoma outcome treated with immunochemotherapy: a meta-analysis on 1134 patients from two prospective cohorts.

Single nucleotide polymorphisms (SNPs) in FCγ-receptor genes FCGR3A (rs396991) and FCGR2A (rs1801274) influence the affinity of the Fc portion of anti-CD20 immunoglobulin G1 monoclonal antibody. Their roles in diffuse large B-cell lymphoma (DLBCL) treated with rituximab in combination with anthracycline-based chemotherapy remain controversial. To address this question, we genotyped FCGR2A and FCGR3A SNPs in two prospective DLBCL cohorts from Lymphoma Study Association trials (N = 554) and Iowa/Mayo Specialized Program Of Research Excellence (N = 580). Correlations with treatment response and hematological toxicity were assessed in Lymphoma Study Association. Correlation with event-free survival (EFS) and overall survival (OS) was performed in both cohorts, followed by a meta-analysis to increase power. Our study shows the absence of correlation between these SNPs and treatment response. Grades 3 and 4 febrile neutropenia during treatment was more frequently observed in FCGR3A VV (39%) than VF (29%) and FF (32%) carriers (p = 0.04). Our analysis for EFS and OS shows that FCGR3A was not associated with outcome. In a meta-analysis using an ordinal model, FCGR2A (per R allele) was associated with a better EFS (hazard ratio = 0.87; 95%CI, 0.76-0.99; p = 0.04) and OS (hazard ratio = 0.86; 95%CI, 0.73-1.00; p = 0.05) which was not altered after adjustment for the International Prognostic Index. Overall, our data demonstrate that patients with DLBCL with the low-affinity FCγRIIA RR had an unexpectedly better outcome than FCγRIIA H carriers. Whether rituximab efficacy is improved in FCγRIIA RR patients due a clearance reduction or other functions of FCγRIIA in DLBCL should be investigated (clinicaltrials.gov identifiers: NCT00135499, NTC00135499 NCT00140595, NCT00144807, NCT00144755, NCT01087424, and NCT00301821). Copyright © 2016 John Wiley & Sons, Ltd.

Effect of FCGR3A Polymorphisms on Antibody-dependent Cetuximab-mediated Cytotoxicity in A549 Cells

To investigate the effect of FCGR3A polymorphisms on the antibody-dependent cell-mediated cytotoxicity (ADCC) activity induced by cetuximab against A549 cells. A549 cell line was used as target cells and NKTm cells as effector cells. FCGR3A polymorphisms were detected by direct sequencing. The ADCC activity mediated by cetuximab was assessed by CCK-8 assay. Three genotypes of FCGR3A were detected:V/V,V/F,and F/F. The ADCC activity of NKTm cells with these three different genotypes mediated by cetuximab were significantly different (P=0.0015). NKTm cells with FCGR3A-158V/V genotypes had significantly higher ADCC activity than FCGR3A-V/F or F/F genotypes (P<0.01),whereas the ADCC activity between V/F and F/F genotype showed no statistical significance(P>0.05). FCGR3A polymorphisms have an impact on ADCC activity mediated by cetuximab in NKTm cells.

Lack of survival advantage with autologous stem-cell transplantation in high-risk neuroblastoma consolidated by anti-GD2 immunotherapy and isotretinoin.

Since 2003, high-risk neuroblastoma (HR-NB) patients at our center received anti-GD2 antibody 3F8/GM-CSF + isotretinoin – but not myeloablative therapy with autologous stem-cell transplantation (ASCT). Post-ASCT patients referred from elsewhere also received 3F8/GM-CSF + isotretinoin. We therefore accrued a study population of two groups treated during the same period and whose consolidative therapy, aside from ASCT, was identical. We analyzed patients enrolled in 1st complete/very good partial remission (CR/VGPR). Their event-free survival (EFS) and overall survival (OS) were calculated from study entry. Large study size allowed robust statistical analyses of key prognosticators including MYCN amplification, minimal residual disease (MRD), FCGR2A polymorphisms, and killer immunoglobulin-like receptor genotypes of natural killer cells. The 170 study patients included 60 enrolled following ASCT and 110 following conventional chemotherapy. The two cohorts had similar clinical and biological features. Five-year rates for ASCT and non-ASCT patients were, respectively: EFS 65% vs. 51% (p = .128), and OS 76% vs. 75% (p = .975). In multivariate analysis, ASCT was not prognostic and only MRD-negativity after two cycles of 3F8/GM-CSF correlated with significantly improved EFS and OS. Although a trend towards better EFS is seen with ASCT, OS is near identical. Cure rates may be similar, as close surveillance detects localized relapse and effective salvage treatments are applied. ASCT may not be needed to improve outcome when anti-GD2 immunotherapy is used for consolidation after dose-intensive conventional chemotherapy.

Association of a coding polymorphism in Fc gamma receptor 2A and graft survival in re-transplant candidates

The family of Fc gamma receptors (FcγRs) is involved in mediating immunological effector functions. FcγRs are differentially expressed on immune cells and can act either activating or inhibitory, with FcγR2A belonging to the first group. The polymorphism H131R (rs1801274) in FCGR2A has been associated with acute rejection and can shift the overall balance between activating and inhibitory FcγRs. Anti-HLA allo-antibodies in transplant recipients have been identified as risk factor for organ survival after transplantation. In this study we genotyped FCGR2A H131R in 200 patients who had undergone kidney transplantation and experienced loss of graft function. FCGR2A polymorphism was related to graft survival and anti-HLA antibodies. Graft survival was calculated as the time interval between transplantation and return to chronic dialysis after transplantation. The gene frequency of FCGR2A R/R131 was found significantly more often in patients with earlier (⩽60months) compared to patients with later (>60months) graft failure. Overall patients homozygous for R/R131 had a significantly shorter graft survival, compared to H/H131 or H/R131 which is even more pronounced, when anti-HLA antibodies were present. These data suggest, that FCGR2A polymorphisms constitute a risk factor for graft loss following kidney transplantation and that this effect is related to anti-HLA antibodies.

Variation at FCGR2A and functionally related genes is associated with the response to anti-TNF therapy in rheumatoid arthritis.

ObjectiveAnti-TNF therapies have been highly efficacious in the management of rheumatoid arthritis (RA), but 25–30% of patients do not show a significant clinical response. There is increasing evidence that genetic variation at the Fc receptor FCGR2A is associated with the response to anti-TNF therapy. We aimed to validate this genetic association in a patient cohort from the Spanish population, and also to identify new genes functionally related to FCGR2A that are also associated with anti-TNF response.MethodsA total of 348 RA patients treated with an anti-TNF therapy were included and genotyped for FCGR2A polymorphism rs1081274. Response to therapy was determined at 12 weeks, and was tested for association globally and independently for each anti-TNF drug (infliximab, etanercept and adalimumab). Using gene expression profiles from macrophages obtained from synovial fluid of RA patients, we searched for genes highly correlated with FCGR2A expression. Tag SNPs were selected from each candidate gene and tested for association with the response to therapy.ResultsWe found a significant association between FCGR2A and the response to adalimumab (P=0.022). Analyzing the subset of anti-CCP positive RA patients (78%), we also found a significant association between FCGR2A and the response to infliximab (P=0.035). DHX32 and RGS12 were the most consistently correlated genes with FCGR2A expression in RA synovial fluid macrophages (P<0.001). We found a significant association between the genetic variation at DHX32 (rs12356233, corrected P=0.019) and a nominally significant association between RGS12 and the response to adalimumab (rs4690093, uncorrected P=0.040). In the anti-CCP positive group of patients, we also found a nominally significant association between RGS12 and the response to infliximab (rs2857859, uncorrected P=0.042).ConclusionsIn the present study we have validated the FCGR2A association in an independent population, and we have identified new genes associated with the response to anti-TNF therapy in RA.

Identification of an association between genomic hypomethylation of FCGR2A and susceptibility to Kawasaki disease and intravenous immunoglobulin resistance by DNA methylation array.

Kawasaki disease (KD) is characterized by systemic vasculitis, and it is the most common acquired heart disease in children. However, the etiology and immunopathogenesis of KD are still unclear. A genome-wide association study (GWAS) identified polymorphisms in CD40, BLK, and FCGR2A as the susceptibility genes for KD. No epigenetic array studies of KD have previously been published. This study was undertaken to investigate differences in DNA methylation in patients with KD as compared to controls. The HumanMethylation27 BeadChip (Illumina) was used to survey the differences in DNA methylation between KD patients and controls. DNA methylation array validation was performed in a separate cohort by pyrosequencing assay and reporter gene assays. Messenger RNA (mRNA) expression was determined, and the association of methylation with response to intravenous immunoglobulin (IVIG) treatment was analyzed. HumanMethylation27 BeadChip assay showed a 15% difference in methylation of 10 genes between KD patients and controls. The FCGR2A cg24422489 group, which was recently reported to be associated with KD susceptibility in a GWAS, had significant hypomethylation of 15.54% less in the KD group than in the control group. Validation of FCGR2A methylation in another cohort also showed significant hypomethylation in the KD group (5 of 5 CpG sites [P < 0.01]; n = 43 in the KD group and n = 55 in the control group). KD patients with IVIG resistance showed hypomethylation of 5 CpG sites (P < 0.05). FCGR2A mRNA expression was significantly increased in patients in the acute stage of KD compared to controls. Reporter gene assays indicated that the CpG sites of the FCGR2A promoter region were sufficient to modulate gene expression. This is the first study to examine the DNA methylation array in KD and identify a role of hypomethylation of FCGR2A in susceptibility to KD and IVIG resistance.

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.

Novel association of FCGR2A polymorphism with age-related macular degeneration (AMD) and development of a novel CFH real-time genotyping method.

Age-related macular degeneration (AMD) is a degenerative ocular disease, which may lead to loss of central vision. In Caucasian populations, a strong correlation has been established with polymorphism Y402H (rs1061170) in the complement factor H gene (CFH). The H131R polymorphism (rs1801274) in the FCGR2A gene has been associated with many inflammatory diseases, but has not been investigated in relation to AMD. The goal of our study was the development of a novel method for Y402H (g.43097C>T) genotyping, the confirmation of its association with AMD in the Greek population and the investigation of the H131R polymorphism in AMD. DNAs were extracted from blood samples of 120 patients with the severe wet form of AMD and 103 age- and sex-matched controls, all of whom were clinically evaluated. A real-time PCR and melting curve analysis method for Y402H genotyping was developed in the LightCycler platform, after in silico design of appropriate primers and probes. Genotyping for H131R was performed using a real-time PCR method previously described by our group. The novel genotyping method for Y402H in the CFH gene is fast, reproducible (Efficiency=1.79, reproducibility CVCq=3.33%, Tm C allele 53.36 °C and T allele 61.91 °C, ΔTm=8.55) and accurate as results were confirmed with the gold standard DNA Sequencing method. The present study confirmed the association between CFH Y402H SNP and wet AMD in the Greek population (OR=1.77, p=0.002). FCGR2A H131R polymorphism was investigated for the first time in this present study for possible correlation with wet AMD and a statistically significant association was detected (OR=1.74, p=0.006), that awaits further confirmation in a larger set of samples.

The Fc gamma receptor IIa R131H polymorphism is associated with inhibitor development in severe hemophilia A

The development of factor (F) VIII neutralizing alloantibodies (inhibitors) is a major complication of treatment with FVIII concentrates in hemophilia A and the etiology is still poorly understood. The low-affinity Fc gamma receptors (FcγR), which are expressed on immune cells, provide an important link between cellular and humoral immunity by interacting with IgG subtypes. Genetic variations of the genes encoding FcγRs (FCGR genes) have been associated with susceptibility to infectious and autoimmune diseases. The aim of this study was to investigate the association between genetic variation of FCGR and inhibitor development in severe hemophilia A. In this case-control study samples of 85 severe hemophilia A patients (siblings from 44 families) were included. Single nucleotide polymorphisms and copy number variation of the FCGR2 and FCGR3 gene cluster were studied in an FCGR-specific multiplex ligation-dependent probe amplification assay. Frequencies were compared in a generalized estimating equation regression model. Thirty-six patients (42%) had a positive history of inhibitor development. The polymorphism 131R > H in the FCGR2A gene was associated with an increased risk of inhibitor development (odds ratio [OR] per H-allele, 1.8; 95% confidence interval [CI], 1.1-2.9). This association persisted in 29 patients with high titer inhibitors (OR per H-allele, 1.9; 95% CI, 1.2-3.2) and in 44 patients with the F8 intron 22 inversion (OR per H-allele, 2.6; 95% CI, 1.1-6.6). Hemophilia A patients with the HH genotype of the FCGR2A polymorphism 131R > H have a more than 3-fold increased risk of inhibitor development compared with patients with the RR genotype.