key: cord-0959817-5iqkh85d authors: Dettogni, Raquel Spinassé; Sá, Ricardo Tristão; Tovar, Thaís Tristão; Louro, Iúri Drumond title: Polymorphic genetic variation in immune system genes: a study of two populations of Espirito Santo, Brazil date: 2013-05-11 journal: Mol Biol Rep DOI: 10.1007/s11033-013-2582-7 sha: 3e9144ca167c83ee3c303358ea414bd010ae636d doc_id: 959817 cord_uid: 5iqkh85d Mapping single nucleotide polymorphisms (SNPs) in genes potentially involved in immune responses may help understand the pathophysiology of infectious diseases in specific geographical regions. In this context, we have aimed to analyze the frequency of immunogenetic markers, focusing on genes CD209 (SNP -336A/G), FCγRIIa (SNP -131H/R), TNF-α (SNP -308A/G) and VDR (SNP Taq I) in two populations of the Espirito Santo State (ES), Brazil: general and Pomeranian populations. Peripheral blood genomic DNA was extracted from one hundred healthy individuals of the general population and from 59 Pomeranians. Polymorphic variant identification was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP). SNP genotype frequencies were in Hardy–Weinberg Equilibrium. There was no statistically significant difference in allelic and genotypic distributions between the two populations studied. Statistically significant differences were observed for SNP genotype distribution in genes CD209, TNF-α and VDR when comparing the ES populations with other Brazilian populations. This is the first report of CD209, FcγRIIa, TNF-α and VDR allelic frequencies for the general and Pomeranian populations of ES. Small genetic variations such as SNPs can influence gene expression and change protein structure or function. SNPs located in the promoter or other regulatory regions may affect gene transcription and alter variability in the immune response. The presence of certain alleles may contribute to the susceptibility or host resistance for different infectious diseases caused by viruses [1] , bacteria [2] and protozoa [3] [4] [5] . SNPs in genes CD209, FccRIIa, TNF-a and VDR affect the immune response for various infections [1, [6] [7] [8] . Gene and protein nomenclature are shown in Table 1 . Dendritic cell-specific ICAM-3 grabbing non-integrin (DC-SING, encoded by CD209) is mainly expressed in dendritic cells (DC) and plays an important role in some infectious diseases [9] [10] [11] . DCs can be targets for pathogens, in an attempt to impair the initial immune response in early infection [12] . Among SNPs in the CD209, the guanine (G) to adenine (A) transition at position 2336 within the CD209 gene promoter (SNP -336 A/G) has been suggested to affect transcriptional activity of DC-SIGN [8] . Association studies have been performed between CD209 gene polymorphisms and pathogens: viruses such as human immunodeficiency virus-1 (HIV-1), hepatitis C virus (HCV), cytomegalovirus, Ebola virus and SARS-coV; bacteria such as Mycobacterium tuberculosis and parasites such as Leishmania and Schistosoma mansoni [13] [14] [15] [16] [17] . SNP -336A/ G has been associated with the susceptibility to HIV [18] , M. tuberculosis [19] , HCV [20] , and dengue [8] . Fcc leukocyte receptors are essential for the immune defense against pathogens. Antibody binding to the Fc-receptors causes important biological consequences, e.g. antibody dependent cell-mediated cytotoxicity or inhibition and phagocytosis [21] . FccRIIa has two co-dominantly expressed alleles, R131 (G at position 494) and H131 (A at position 494), which differ in their ability to bind immunoglobulin G (IgG) subclasses. Cells expressing H131 bind more efficiently to IgG2 and IgG3 than those expressing the R131 variant [22] . This SNP has been associated with susceptibility and severity of some infectious disease such as meningococcal disease, Streptococcus pneumoniae infections, dengue fever and HIV infection [1, [23] [24] [25] . RR genotype seems to be associated with protection against intracellular pathogen infections [2, 26, 27] . TNF-a is a pleiotropic pro-inflammatory cytokine, with effects on apoptosis and activation of target cells involved in the amplification of immunological cellular processes [28] . Among several TNF-a gene polymorphisms, the SNP located at nucleotide position 308 (G or A) has been shown to directly affect TNF-a expression [29] . The AA genotype has been significantly associated with higher TNF-a production and in some cases with increased morbidity and mortality in sepsis, malaria, chronic obstructive pulmonary disease (COPD), leishmaniosis, systemic lupus erythematosus (SLE), type 1 autoimmune hepatitis and other immune mediated disorders (asthma and contact dermatitis) [30] [31] [32] [33] [34] . The vitamin D receptor (VDR) mediates the immunoregulatory effects of the hormonal form of vitamin D, which includes activating monocytes, stimulating cellular immune responses, suppressing immunoglobulin production and lymphocyte proliferation [35] . The TT genotype of VDR Taq I SNP (substitution of a thymine (T) for a cytosine (C) at position 352) [36] has been recently associated with tuberculoid leprosy, enhanced clearance of hepatitis B infection and resistance to pulmonary tuberculosis [37, 38] . Allele A-150 bp [8] FccRIIa Allele R-322 bp [39] TNF-a -308 A/G (rs1800629) This study was approved by the Research Ethics Committee of the Federal University of ES and all patients signed an informed consent (Protocol n°190/11). Five milliliters (ml) of peripheral blood were collected from 100 healthy volunteers of the ES general population. As for the 59 healthy Pomeranian volunteers of Santa Maria de Jetibá, ES, 3-5 peripheral blood drops were collected on FTA Ò Elute Cards (Whatman, USA). Genomic DNA was isolated using phenol/chloroform extraction or following FTA Ò Elute Card manufacturer's recommendations (Whatman, USA). CD209, FccRIIa, TNF-a and VDR alleles were detected by PCR-RFLP. Table 2 . Statistical analysis SNP allele and genotype frequencies were determined by direct counting. P values .05 were considered statistically significant. Chi square test was used to determine whether a genotype was at HWE, using Chi square HWE equilibrium test calculator for biallelic markers (http:// www.genes.org.uk/software/hardy-weinberg.shtml). Fisher's exact test was performed using Graphpad Prism Ò version 5.0 (www.graphpad.com). Representative genotyping results are shown in Figs. 1, 2, 3 and 4. SNP allele and genotype frequencies for genes CD209, FccRIIa, TNF-a and VDR in the Pomeranian and general populations of ES are given in Table 3 . All polymorphisms were at HWE equilibrium among Pomeranian and non-Pomeranian individuals (p [ 0.05, Table 4 ). Genotype and allele frequencies were not significantly different between the two populations (p [ 0.05, Table 5 ). This study aimed to characterize the general and Pomeranian populations of ES, Brazil as for 4 SNPs in genes important for the immune response to infections. Allelic frequencies for all SNPs were in HWE equilibrium. There was no statistically significant difference in allelic and genotypic distributions between the two populations. This result confirms data of Stur et al. [42] which reported gene flow between the general and Pomeranian populations of ES. (14) 11.9 (7) Numbers in parenthesis represents allele or genotype counts For each SNP, we analyzed the difference in genotype distribution among ES populations and two other populations of different ethnic groups randomly selected and a population of southeast Brazil (Table 6) . CD209 gene SNP showed a significant difference in genotype distribution between the ES populations separately, as well as when they were compared with the population of Taiwan and South Africa. Moreover, the GG genotype had a significant difference in distribution between the general ES and Sao Paulo populations. FccRIIa SNP genotype distribution was not different among ES populations and other populations analyzed. Comparing TNF-a SNP genotype frequencies among ES populations and other 3 populations, there was a statistically significant difference in homozygous genotypes distribution between the general ES population and Italians. VDR SNPs showed a significant difference in genotype distribution among ES populations and populations of Rio de Janeiro and Vietnam. These variations indicate the need to characterize specific populations for SNP composition in genes important for the immune system in various regions of the world. The ES state, as well as the entire southeastern Brazil, presents high prevalence of many infectious diseases. Thus, assessing the genetic diversity of immune system components may generate knowledge relevant to the understanding of how the population responds to infectious diseases such as dengue, tuberculosis, hepatitis, malaria, HIV and others. Susceptibility to dengue hemorrhagic fever in Vietnam: evidence of an association with variation in the vitamin D receptor and Fcc receptor IIA genes Association between FccRIIa-R131 allotype and bacteremic pneumococcal pneumonia High immunoglobulin G2 (IgG2) and low IgG4 levels are associated with human resistance to Plasmodium falciparum malaria Fcc receptor IIA and IIIB polymorphisms are associated with susceptibility to cerebral malaria Fcg receptor IIa (CD32) polymorphism is associated with protection of infants against high-density Plasmodium falciparum infection Association between G308A tumor necrosis factor alpha gene polymorphism and schizophrenia Asymptomatic dengue infection in a Cuban population confirms the protective role of the RR variant of the FcgammaRIIa polymorphism A variant in the CD209 promoter is associated with severity of dengue disease The C type lectin DC-SIGN (CD209) is an antigen-uptake receptor for Candida albicans on dendritic cells DCSIGN is a receptor for human herpes virus 8 on dendritic cells and macrophages DC-SIGN (CD209) mediates dengue virus infection of human dendritic cells Virus infection of dendritic cells: portal for host invasion and host defense Human cytomegalovirus binding to DC-SIGN is required for dendritic cell infection and target cell trans infection DC-SIGN and L-SIGN can act as attachment receptors for alphaviruses and distinguish between mosquito cell and mammalian cell-derived viruses DC-SIGN is the major Mycobacterium tuberculosis receptor on human dendritic cells A fatal attraction: mycobacterium tuberculosis and HIV-1 target DC-SIGN to escape immune surveillance pH-dependent entry of severe acute respiratory syndrome coronavirus is mediated by the spike glycoprotein and enhanced by dendritic cell transfer through DCSIGN Association of DC-SIGN promoter polymorphism with increased risk for parenteral, but not mucosal, acquisition of human immunodeficiency virus type 1 infection Promoter variation in the DC-SIGN-encoding gene CD209 is associated with tuberculosis Variant in CD209 promoter is associated with severity of liver disease in chronic hepatitis C virus infection IgG receptor polymorphisms: risk factors for disease FccRIIa polymorphism: a susceptibility factor for immune complex-mediated lupus nephritis in Brazilian patients Polymorphism of Fc receptor IIa for IgG in infants is associated with susceptibility to perinatal HIV-1 infection Association of human Fc gamma RIIa (CD32) polymorphism with susceptibility to and severity of meningococcal disease FcgammaRIIA polymorphisms in Streptococcus pneumoniae infection Coexistence of (partial) immune defects and risk of recurrent respiratory infections Association of Fcgamma receptor IIa (CD32) polymorphism with severe Malaria in West Africa K-related kinase involved in NF-kappaB induction by TNF, CD95 and IL-1 Effects of a polymorphism in the human tumor necrosis factor alpha promoter on transcriptional activation Cytokine polymorphisms associated with clinical features and treatment outcome in type 1 autoimmune hepatitis A polymorphism that affects OCT-1 binding to the TNF promoter region is associated with severe malaria Association between -308 tumor necrosis factor promoter polymorphism and bronchial hyper reactivity in asthma Association of TNF2, a TNF-alpha promoter polymorphism, with septic shock susceptibility and mortality: a multicenter study TNF-308A and HLA-DR3 alleles contribute independently to susceptibility to systemic lupus erythematous New insight into the structure and functions of the vitamin D receptor Vitamin D receptor genotypes and intestinal calcium absorption in postmenopausal women Tuberculosis and chronic hepatitis virus infection in Africans and variation in the vitamin D receptor gene Association of vitamin D receptor genotype with leprosy type Rapid detection of the Fc gamma RIIA-H/R 131 ligand-binding polymorphism using an allele-specific restriction enzyme digestion (ASRED) Single base polymorphism in the human tumor necrosis factor alpha (TNF alpha) gene detectable by Ncol restriction of PCR product Association of a vitamin D receptor gene polymorphism with localized earlyonset periodontal diseases Polymorphism Analysis of MTHFR, Factor II and Factor V genes in the Pomeranian population of Espirito Santo-Brazil DC-SIGN (CD209) Promoter 2336 A/G Polymorphism Is Associated with Dengue Hemorrhagic Fever and Correlated to DC-SIGN Expression and Immune Augmentation DC-SIGN (CD209) gene promoter polymorphisms in a Brazilian population and their association with human T-cell lymphotropic virus type 1 infection Variant genotypes of the low affinity Fc gamma Receptors in two control populations and a review of low affinity receptor polymorphisms in control and disease population Relation between tumor necrosis factor polymorphism TNFa-308 and risk of asthma TNFA and IL10 gene polymorphisms are not associated with periodontitis in brazilians Frequency of fokI and taqI polymorphism of vitamin D receptor gene in Indian population and its association with 25 hydroxyvitamin D levels Bone mass and breast milk calcium concentration are associated with vitamin D Acknowledgments RSD was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Amparo à Pesquisa do Espírito Santo (FAPES) scholarships. This work was supported by FAPES.