Genotypes of CCR2 and CCR5 chemokine receptors in human myasthenia gravis

The aim of this study was to examine the association of human autoimmune myasthenia gravis (MG) with two DNA polymorphisms of the chemokine receptors CCR5-Delta 32 and CCR2-64I. CCR2 and CCR5 interact primarily with the human CC family ligands CCL2 (formerly called monocyte chemoattractant protein; MCP-1), CCL3 and CCL4 (macrophage inflammatory protein-1 alpha and -1 beta; MIP-1 alpha/beta), and their main function is to recruit leukocytes from circulation into the tissues, thus playing an important role in human inflammatory disorders. A PCR-based genotyping method was used to determine the genetic variation at the CCR5 gene and an automated real-time Pyrosequencing technology was employed for the analysis of G right curved arrow A point mutation at the CCR2 gene. Results obtained from 158 patients and 272 healthy controls demonstrate no evidence of association between genetic variants of CCR2 and CCR5 with MG and its clinical manifestations. CCR2-64I and CCR5-Delta 32 genotypes are thus unlikely to be involved in protection or predisposition to MG.     

Immunosuppressive therapy for kidney transplant prevents vaso-occlusive crisis in a haemoglobin SC disease patient

Although the molecular basis of sickle cell disease (SCD) is well established, the wide variability in clinical manifestations still puzzles haematologists and clinicians. Recently, SCD started to be considered by different groups as a chronic inflammatory condition, where the inflammatory tendency of each individual could drive more or less severe clinical features. Here we describe a haemoglobin SC disease patient (heterozygous to both HbS and HbC variants) that experienced several vaso-occlusive crises before underwent a successful kidney transplantation. Since then (16 years ago), she is on uninterruped immunosuppressive therapy, and do not experienced any severe vaso-occlusive crisis. Considering SCD associated morbidity as a result of exacerbated immune responses, we suggest that the immunosuppressive therapy directed to the kidney graft maintenance is actually also helping in the control of the chronic inflammatory responses associated to SCD.     

Genetic polymorphism of the mannose-binding protein gene in children with sickle cell disease: identification of three new variant alleles and relationship to infections.

Mannose-binding protein (MBP) is a serum lectin that participates in the innate immune response. MBP deficiency may constitute a risk factor in the development of infections. Three MBP structural variants have been identified with a dominant effect on MBP serum concentration. Similarly, polymorphisms in the promoter of the corresponding gene (HSMBP1B) have been related to variations of MBP concentration in serum. Children with sickle cell disease (SCD) have an increased susceptibility to infections with encapsulated organisms resulting in meningitis, septicaemia, and osteomyelitis. We have investigated the HSMBP1B genotype in 242 children with SCD living in Paris. Apart from the known variant alleles, we identified three novel ones and report their distribution in our sample population. In addition, we found rather unexpectedly an increased frequency of the variant alleles in patients who had not suffered severe infections.     

Immunological studies in sickle cell disease: comparison of homozygote mild and severe variants

Cellular and humoral immune functions in patients suffering from severe and mild forms of homozygous sickle cell disease (SCD) were compared with those of healthy control subjects. Random neutrophil migration, chemotactic activity, and lymphocyte transformation index were all defective in individuals with severe variants of SCD when compared with individuals with mild disease or healthy controls. In contrast, serum opsonization activity was significantly reduced in both severe and mild variants of SCD. There were no statistical differences between serum immunoglobulin (IgA, IgG, and IgM) or complement C3 levels in any of the three groups. These results demonstrate that even though individuals with the mild variant of SCD possess two S genes, their immune functions are generally normal and in parallel with their clinical and hematological status. The one area of impaired immune function is their defective serum opsonization activity and this may explain their sensitivity to certain infections.     

Genetic variants in the chemokines and chemokine receptors in Chagas disease

Clinical symptoms of Chagas' disease occur in 30% of the individuals infected with Trypanosoma cruzi and are characterised by heart inflammation and dysfunction. Chemokines and chemokine receptors control the migration of leukocytes during the inflammatory process and are involved in the modulation of Th1 or Th2 responses. To determine their influence, we investigated the possible role of CCL5/RANTES and CXCL8/IL8 chemokines, and CCR2 and CCR5 chemokines receptors cluster gene polymorphisms with the development of chagasic cardiomyopathy. Our study included 260 Chagas seropositive individuals (asymptomatic, n=130; cardiomyopathic, n=130) from an endemic area of Colombia. Genotyping was performed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and TaqMan SNP genotyping assay. We found statistically significant differences in the distribution of the CCR5 human haplogroup (HH)-A (p=0.027; OR=3.78, 95% CI=1.04-13.72). Moreover, we found that the CCR5-2733 G and CCR5-2554 T alleles are associated, respectively, with a reduced risk of susceptibility and severity to develop chagasic cardiomyopathy. No other associations were found to be significant for the other polymorphisms analysed in the CCR5, CCR2, CCL5/RANTES and CXCL8/IL8 genes. Our data suggest that the analysed chemokines and chemokine receptor genetic variants have a weak but important association with the development of chagasic cardiomyopathy in the population under study.     

The 844ins68 cystathionine beta-synthase and C677T MTHFR gene polymorphism and the vaso-occlusive event risk in sickle cell disease

Introduction

Sickle cell disease (SCD) is an inflammatory condition with an increase in the adhesion of sickled erythrocytes, and it is a potential cause of vaso-occlusive episodes, an event related to clinical manifestations, morbidity and mortality. The cystathionine beta-synthase enzyme gene (CBS) and the methylenetetrahydrofolate reductase enzyme gene (MTHFR) are risk factors for thromboembolic disorders. This study evaluated the frequency of the 844ins68 CBS and C677T MTHFR gene polymorphisms and their possibility to be risk factors for vaso-occlusive crises.

Material and methods

In total 91 blood samples from SCD patients were studied by PCR-RFLP and PCR-allele-specific, for the SCD genotype confirmation and polymorphism identification.

Results

The presence of clinical manifestations related to vaso-occlusive crises were more frequent among patients with the Hb SS genotype (p = 0.007). The CBS enzyme gene was three times more frequent (p = 0.011) among patients with vaso-occlusive complications. The MTHFR gene mutation frequency showed no increased risk for vaso-occlusive crises in SCD patients (p = 0.193). The interaction between the two polymorphisms was evaluated in 12.08% of the SCD patients and doubled the vaso-occlusive disease risk (relative risk: 2.16).

Conclusions

We conclude that the presence of 844ins68 CBS and C677T MTHFR gene polymorphism was a risk factor for vaso-occlusive episodes in the SCD patients evaluated.     

No allelic association or interaction of three known functional polymorphisms with bipolar disorder in a northern Swedish isolated population

Most genetic association studies in bipolar disorder have focussed on genes involved in major neurotransmitter systems or brain development. Functional polymorphisms in the serotonin transporter (5-HTTLPR), catechol-O-methyltransferase (Val158Met) and dopamine D3 receptor (Ser9Gly) genes have all been associated with bipolar disorder. We aimed at investigating whether these functional variants contribute to the genetic etiology of bipolar disorder in a northern Swedish isolated population. Moreover, we wanted to gain information about the synergistic contribution of these functional variants. Neither of these functional polymorphisms was associated with bipolar disorder in the northern Swedish patient-control sample nor did we find evidence of gene-gene interaction. Together, our data suggest that these functional variants are not involved in the etiology of bipolar disorder in the northern Swedish population nor did gene-gene interaction analysis support a central role of these variants in bipolar disorder.     

Genetic variants in the CCR gene cluster and spontaneous viral elimination in hepatitis C-infected patients

Hepatitis C virus (HCV) infection results in chronic hepatitis in more than 80% of infected patients while 10-20% of patients recover spontaneously. Host genetic factors may influence the ability to clear the virus after infection. Six single nucleotide polymorphisms and a 32 bp deletion in the genes coding for CCR3, CCR2 and CCR5 (which are all located in a cluster on chromosome 3) were investigated in 465 consecutively recruited patients infected with HCV and 370 matched controls. Genetic variants were tested for association with spontaneous viral elimination and, in the chronically infected patients, stage of fibrosis and response to antiviral therapy. The G190A polymorphism (variant allele Ile64) in the first transmembrane domain of CCR2 was under-represented in the 29 patients who had cleared the hepatitis C virus spontaneously (P = 0.018). None of the other variants in the CCR gene cluster showed association with the natural course of the infection, stage of fibrosis or response to therapy.     

PKDB: Polycystic Kidney Disease Mutation Database--a gene variant database for autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) arises from mutations in the PKD1 and PKD2 genes. The Polycystic Kidney Disease Mutation Database (PKDB) is an internet-accessible relational database containing comprehensive information about germline and somatic disease-causing variants within these two genes, as well as polymorphisms and variants of indeterminate pathogenicity. The PKDB database structure incorporates an interface between these gene variant data and any associated patient clinical data. An initiative of the Polycystic Kidney Disease Foundation, PKDB is a publicly accessible database that aims to streamline the evaluation of PKD1 and PKD2 gene variants detected in samples from those with ADPKD, as well as to assist ongoing clinical and molecular research in the field. As the accurate reporting of nucleotide variants is essential for ensuring the quality of data within PKDB, a mutation checker has been mounted on the PKDB server allowing contributors to assess the accuracy of their PKD1 and PKD2 variant reports. Researchers and clinicians may submit their PKD1/PKD2 gene variants and any associated deidentified clinical data via standardized downloadable data entry forms accessible through the PKDB site. PKDB has been launched with the full details of PKD1 and PKD2 gene variant reports published in 73 peer-reviewed articles. Through a series of user-friendly advanced search facilities, users are able to query the database as required. The PKDB server is accessible at http://pkdb.mayo.edu.     

Influence of NKG2C gene deletion and CCR5Δ32 in Pre‐eclampsia—Approaching the effect of innate immune gene variants in pregnancy

Pre‐eclampsia (PE) is a hypertensive disorder that affects an important number of pregnant women worldwide. The exact causes of PE remain poorly understood. However, inflammation and deregulation of innate immune cells, such as natural killer (NK) cells, contribute to PE pathogenesis. Besides, the mother's genetic background also impacts on PE susceptibility. Thus, genetic variants that potentially modify the behaviour of inflammatory cells may help us to understand the causes of PE. Variants of genes encoding NKG2C (expressed in NK cells) and C–C chemokine receptor type 5 (CCR5) (expressed mainly in leucocytes) are important targets in the study of gestational disorders. In this context, we evaluated the impact of both NKGC2 gene deletion and CCR5Δ32 gene variant on PE susceptibility in a population sample from central‐southeast Brazil composed by 369 women (156 with PE and 213 healthy pregnant women). No statistically significant association between the NKG2C gene deletion and susceptibility to PE was observed. However, taking into consideration the important role of NK cells in pregnancy, the influence of NKG2C gene deletion on PE pathogenesis should not be ruled out and deserves further studies in populations with different genetic/ethnic backgrounds. In addition, our results regarding CCR5Δ32 corroborate previous data from our group approaching a distinct cohort and reinforce CCR5Δ32 as a protective factor against PE development (p < 0.05).     

Analysis of polymorphic sites in the promoter of the nitric oxide synthase 2 gene in Brazilian patients with leprosy

Leprosy is one of the most neglected infectious tropical diseases of the skin and the nerves caused by the intracellular pathogen Mycobacterium leprae. The inducible NOS isoform encoded by NOS2A plays a vital role in host defence against bacterial infections. The functional promoter polymorphisms in NOS2A are associated with various autoimmune and infectious diseases. We investigated the association of NOS2A variants with progression of leprosy in a Brazilian cohort including 221 clinically classified patients and 103 unrelated healthy controls. We observed a novel variant ss528838018A/G in the promoter region at position ?6558. The other functional variants were observed with low frequency of minor allele (<0.005). NOS2A promoter variant (?954G/C) was not observed in Brazilian populations, and the new observed promoter variant (ss528838018A/G) as well as other promoter variants were not associated with any clinical forms of leprosy in the Brazilian populations.     

Auto-immune disorders in a child with PIK3CD variant and 22q13 deletion

22q13 deletion syndrome is a genetic disorder caused by the deletion or disruption of the segment of the long arm of chromosome 22. The characteristic clinical features of this syndrome include delayed expressive speech, autistic behavior and hypotonia, and clinically severe complications associated with autoimmunity are rarely reported. We herein report a girl with 22q13 deletion syndrome complicated with multiple inflammatory and autoimmune diseases during early childhood. We performed whole-exome sequencing to identify the genes responsible for her autoimmune diseases and identified the de novo variant p.R512W in the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) gene. We suspected it to be the disease-causing variant at the conserved residue in PIK(3)C p110δ. Alternatively, haplo-insufficiency of SHANK3 or other genes by 22q13 deletion and the PIK3CD variant might have synergistically contributed to the onset of the distinctive clinical manifestations in this patient.     

Identification of the CCR5-Delta32 HIV resistance allele and new mutations of the CCR5 gene in different Tunisian populations

Polymorphisms in some chemokine receptor genes are associated with susceptibility to and progression of human immunodeficiency virus–1 (HIV-1) infection. Most mutations detected in the CC-chemokine receptor 5 (CCR5) gene are specific to different populations. In this study, we focused on polymorphisms of the CCR5 coding region in three healthy populations from Tunisia, corresponding to a cosmopolitan population from Tunis, and two isolated Berber populations. In addition to the CCR5-Δ32 deletion, eleven single nucleotide polymorphisms were detected. Some of these point mutations were associated with the same genotype and even the same haplotype. The (L55Q-C101X), I124, V131F, T143N, A159V, I237, T239A and G301R alleles have not been described previously, whereas the CCR5-Δ32, L55Q, A335V and Y339F variants have already been reported in the literature. The distribution and frequency of these variants were different among the three groups studied, a result in agreement with the mosaic genetic structure of the Tunisian population.

To determine whether these alleles affect HIV-1 transmission, we compared allele frequencies between healthy and HIV-1 infected individuals from Tunis. The frequency of the CCR5-Δ32 variant was significantly different between the two groups, leading us to conclude that this mutation might confer protection against HIV infection in Tunisian populations.     

不同病理类型局灶节段性肾小球硬化症的临床病理分析

目的探讨不同病理类型局灶节段性肾小球硬化症（FSGS）的临床病理特征及其与临床表现的关系。方法对北京大学第一医院2000年1月—2005年12月收集的102例特发性FSGS进行回顾性病理阅片及分型,并对其活动性及慢性化病理改变进行定量评估,分析不同病理类型FSGS的病理变化及其临床表现的特征。结果102例FSGS中,非特殊型占55．9％,门部型占6．9％,细胞型占25．5％,顶端型占4．8％,塌陷型占6．9％。细胞型和顶端型FSGS的尿蛋白水平较非特殊型明显增高,塌陷型和顶端型FSGS的肾病综合征比例较其他三型明显升高（x^2=12．23,P＜0．05）,细胞型和塌陷型FSGS的病理活动性积分较其他3型明显增高（P＜0．05）;门部型FSGS的病程较其他4组患者明显增高,其病理慢性化积分较顶端型和非特殊型明显增高（P＜0．05）;顶端型FSGS的病理总积分最少,明显低于细胞型和塌陷型（P＜0．05）;其慢性化积分较非特殊型和门部型明显降低（P＜0．05）。结论非特殊型FSGS是特发性FSGS的主要病理类型;塌陷型和细胞型FSGS是病变处于活动性阶段的病理类型,门部型FSGS为病理改变呈慢性化的病理类型,顶端型FSGS是病理改变最轻的病理类型。     

RettBASE: Rett syndrome database update

Rett syndrome (RTT) is an X‐linked progressive neurodevelopmental disorder that primarily affects females. Mutations in the MECP2 gene have been attributed as the major genetic cause of RTT. Recently, mutations in CDKL5 and FOXG1 genes have also been suggested to give rise to RTT, although subsequent more extensive studies suggest that diseases resulting from mutations in these two genes should be considered as distinct clinical entities. While the genetic basis for the RTT has been recognized, so far there is no effective cure for the disease and the treatments available are mainly aimed at ameliorating clinical problems associated with the disorder. The swift identification of the mutations in children is crucial for pursuing the best therapeutic care. RettBASE was created in 2002 as a MECP2 variant database and has grown to become a comprehensive variant database for RTT and related clinical phenotypes, containing a curated collection of variants for MECP2, CDKL5, and FOXG1 genes. Here, we describe the development and growth of RettBASE after its inception in 2001. Currently, RettBASE holds a total of 4,668 variants in MECP2, 498 variants in CDKL5, and 64 variants in FOXG1.     

Analysis of the involvement of CCR5-Delta32 and CCR2-V64I variants in the development of endometriosis

Several arguments support the proposal that the cytokine network plays a critical role in the aetiology of endometriosis. Among various chemokines, regulated-on-activation, normal-T-cell-expressed and -secreted (RANTES) and monocyte chemotactic protein 1 (MCP-1) concentrations have been shown to be increased in the peritoneal fluid of women with endometriosis. Some studies have demonstrated that, in the context of endometriosis, these chemokines are involved in apoptosis, angiogenesis and/or chemotaxis. Since the chemokines exert their effects by binding to their receptors, it would be plausible that factors affecting such interactions might play a role in the pathogenesis of endometriosis. Thus we postulated that the genes encoding CCR5 and CCR2, which are the receptors for RANTES and MCP-1 respectively, could be good candidate genes for the disease. We have used real-time PCR and FRET technologies to genotype and evaluate the variants CCR5-Delta32 and CCR2-V64I, as susceptibility factors in a cohort of Spanish women with endometriosis. No differences have been found in the frequencies of the two polymorphisms nor in the haplotype/genotype distribution between cases and controls. These data would suggest the lack of association between these polymorphisms and endometriosis in our population, although they do not permit us to discard completely a possible role of other variants within CCR5 and CCR2 genes in this pathology.