Regulation of Mertk Surface Expression via ADAM17 and γ-Secretase Proteolytic Processing.

Mertk, a type I receptor tyrosine kinase and member of the TAM family of receptors, has important functions in promoting efferocytosis and resolving inflammation under physiological conditions. In recent years, Mertk has also been linked to pathophysiological roles in cancer, whereby, in several cancer types, including solid cancers and leukemia/lymphomas. Mertk contributes to oncogenic features of proliferation and cell survival as an oncogenic tyrosine kinase. In addition, Mertk expressed on macrophages, including tumor-associated macrophages, promotes immune evasion in cancer and is suggested to act akin to a myeloid checkpoint inhibitor that skews macrophages towards inhibitory phenotypes that suppress host T-cell anti-tumor immunity. In the present study, to better understand the post-translational regulation mechanisms controlling Mertk expression in monocytes/macrophages, we used a PMA-differentiated THP-1 cell model to interrogate the regulation of Mertk expression and developed a novel Mertk reporter cell line to study the intracellular trafficking of Mertk. We show that PMA treatment potently up-regulates Mertk as well as components of the ectodomain proteolytic processing platform ADAM17, whereas PMA differentially regulates the canonical Mertk ligands Gas6 and Pros1 (Gas6 is down-regulated and Pros1 is up-regulated). Under non-stimulated homeostatic conditions, Mertk in PMA-differentiated THP1 cells shows active constitutive proteolytic cleavage by the sequential activities of ADAM17 and the Presenilin/γ-secretase complex, indicating that Mertk is cleaved homeostatically by the combined sequential action of ADAM17 and γ-secretase, after which the cleaved intracellular fragment of Mertk is degraded in a proteasome-dependent mechanism. Using chimeric Flag-Mertk-EGFP-Myc reporter receptors, we confirm that inhibitors of γ-secretase and MG132, which inhibits the 26S proteasome, stabilize the intracellular fragment of Mertk without evidence of nuclear translocation. Finally, the treatment of cells with active γ-carboxylated Gas6, but not inactive Warfarin-treated non-γ-carboxylated Gas6, regulates a distinct proteolytic itinerary-involved receptor clearance and lysosomal proteolysis. Together, these results indicate that pleotropic and complex proteolytic activities regulate Mertk ectodomain cleavage as a homeostatic negative regulatory event to safeguard against the overactivation of Mertk.

A cytokine gene screen uncovers SOCS1 as genetic risk factor for multiple sclerosis.

Cytokine and cytokine receptor genes, including IL2RA, IL7R and IL12A, are known risk factors for multiple sclerosis (MS). Excitotoxic oligodendroglial death mediated by glutamate receptors contributes to demyelinating reactions. In the present study, we screened 368 single-nucleotide polymorphisms (SNPs) in 55 genes or gene clusters coding for cytokines, cytokine receptors, suppressors of cytokine signaling (SOCS), complement factors and glutamate receptors for association with MS in a Spanish-Basque resident population. Top-scoring SNPs were found within or nearby the genes coding for SOCS-1 (P=0.0005), interleukin-28 receptor, alpha chain (P=0.0008), oncostatin M receptor (P=0.002) and interleukin-22 receptor, alpha 2 (IL22RA2; P=0.003). The SOCS1 rs243324 variant was validated as risk factor for MS in a separate cohort of 3919 MS patients and 4003 controls (combined Cochran-Mantel-Haenszel P=0.00006; odds ratio (OR)=1.13; 95% confidence interval (CI)=1.07-1.20). In addition, the T allele of rs243324 was consistently increased in relapsing-remitting/secondary progressive versus primary-progressive MS patients, in each of the six data sets used in this study (P(CMH)=0.0096; OR=1.24; 95% CI 1.05-1.46). The association with SOCS1 appears independent from the chr16MS risk locus CLEC16A.

ANKRD55 and DHCR7 are novel multiple sclerosis risk loci.

Multiple sclerosis (MS) shares some risk genes with other disorders hallmarked by an autoimmune pathogenesis, most notably IL2RA and CLEC16A. We analyzed 10 single-nucleotide polymorphisms (SNPs) in nine risk genes, which recently emerged from a series of non-MS genome-wide association studies (GWAS), in a Spanish cohort comprising 2895 MS patients and 2942 controls. We identified two SNPs associated with MS. The first SNP, rs6859219, located in ANKRD55 (Chr5), was recently discovered in a meta-analysis of GWAS on rheumatoid arthritis (RA), and emerged from this study with genome-wide significance (odds ratio (OR) = 1.35; P = 2.3 × 10(-9)). The second SNP, rs12785878, is located near DHCR7 (Chr11), a genetic determinant of vitamin D insufficiency, and showed a size effect in MS similar to that recently observed in Type 1 diabetes (T1D; OR = 1.10; P = 0.009). ANKRD55 is a gene of unknown function, and is flanked proximally by the IL6ST-IL31RA gene cluster. However, rs6859219 did not show correlation with a series of haplotype-tagging SNPs covering IL6ST-IL31RA, analyzed in a subset of our dataset (D'< 0.31; r(2)< 0.011). Our results expand the number of risk genes shared between MS, RA and T1D.

NR2F1 Is a Barrier to Dissemination of Early-Stage Breast Cancer Cells.

Cancer cells can disseminate during very early and sometimes asymptomatic stages of tumor progression. Though biological barriers to tumorigenesis have been identified and characterized, the mechanisms that limit early dissemination remain largely unknown. We report here that the orphan nuclear receptor nuclear receptor subfamily 2, group F, member 1 (NR2F1)/COUP-TF1 serves as a barrier to early dissemination. NR2F1 expression was decreased in patient ductal carcinoma in situ (DCIS) samples. High-resolution intravital imaging of HER2+ early-stage cancer cells revealed that loss of function of NR2F1 increased in vivo dissemination and was accompanied by decreased E-cadherin expression, activation of wingless-type MMTV integration site family, member 1 (WNT)-dependent ß-catenin signaling, disorganized laminin 5 deposition, and increased expression of epithelial-mesenchymal transition (EMT) genes such as twist basic helix-loop-helix transcription factor 1 (TWIST1), zinc finger E-box binding homeobox 1 (ZEB1), and paired related homeobox 1 (PRRX1). Furthermore, downregulation of NR2F1 promoted a hybrid luminal/basal phenotype. NR2F1 expression was positively regulated by p38α signaling and repressed by HER2 and WNT4 pathways. Finally, early cancer cells with NR2F1LOW/PRRX1HIGH staining were observed in DCIS samples. Together, these findings reveal the existence of an inhibitory mechanism of dissemination regulated by NR2F1 in early-stage breast cancer cells. SIGNIFICANCE: During early stages of breast cancer progression, HER2-mediated suppression of NR2F1 promotes dissemination by inducing EMT and a hybrid luminal/basal-like program.

Members 6B and 14 of the TNF receptor superfamily in multiple sclerosis predisposition.

TNFRSF6B and TNFRSF14 genes were recently associated with Crohn's disease and rheumatoid arthritis. TNFRSF14 is known as herpes virus entry mediator (HVEM), and herpes viruses have been involved in the aetiology of multiple sclerosis (MS). MS patients present human herpes virus 6 (HHV6) in active plaques and increased antibody responses to HHV6. We aimed to ascertain the role of these genes in MS susceptibility and to investigate the relationship of the gene encoding the widely expressed HVEM receptor with the active replication of HHV6 found in some MS patients. Genotyping of 1370 Spanish MS patients and 1715 ethnically matched controls was performed. HHV6A DNA levels (surrogate of active viral replication) were analysed in serum of MS patients during a 2-year follow-up. Both polymorphisms were associated with MS predisposition, with stronger effect in patients with HHV6 active replication-TNFRSF6B-rs4809330(*)A: P=0.028, OR=1.13; TNFRSF14-rs6684865(*)A: overall P=0.0008, OR=1.2; and HHV6-positive patients vs controls: P=0.017, OR=1.69.

Replication of top markers of a genome-wide association study in multiple sclerosis in Spain.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with presumed autoimmune origin, triggered by genetic and environmental risk factors. A recent genome-wide association study conducted on MS identified new biallelic markers outside the HLA (human leucocyte antigen) region involved in disease susceptibility: rs1109670 (DDEF2); rs1458175 (PDZRN4); rs1529316 and rs2049306 (CSMD1); rs16914086 (TBC1D2); rs1755289 (SH3GL2); rs1841770 (ZIC1); rs651477 (EN1); rs7607490 (TRIB2); rs397020 (C20orf46); rs908821 (SLC25A36); rs7672826 (MGC45800) and rs9523762 (GPC5). We aimed at replicating these top association signals in a Spanish cohort of 2863 MS patients and 2930 sex- and age-matched controls. Only rs9523762 mapping in the GPC5 gene was significantly associated (G allele, P=1.6 × 10(-5); odds ratio (95% confidence interval)=1.23 (1.12-1.36)), supporting a role for this proteoglycan in MS predisposition. The independent replication of association signals to validate data generated by genome-wide association scans is a first step in the effort to improve patient care.

STAT3 locus in inflammatory bowel disease and multiple sclerosis susceptibility.

STAT3 (signal transducer and activator of transcription 3) signaling is a critical component of Th17-dependent autoimmune processes. Genome-wide association studies (GWAS) have revealed the role of the STAT3 gene in inflammatory bowel disease (IBD) susceptibility, although confirmation in clinical subphenotypes is warranted. Mice with targeted deletion of Stat3 in T cells are resistant to experimental autoimmune encephalomyelitis, which is a multiple sclerosis (MS) model. Moreover, increased phosphorylated STAT3 was reported in T cells of patients evolving from clinically isolated syndrome to defined MS and in relapsing patients. These evidences led us to analyze the role of STAT3 in Crohn's disease (CD), ulcerative colitis (UC) and MS risk. Polymorphisms in the STAT3 region (rs3809758/rs744166/rs1026916/rs12948909) were genotyped and the inferred haplotypes were subsequently analyzed in 860 IBD and 1540 MS Spanish patients and 1720 ethnically matched controls. The haplotype conformed by the risk alleles of each polymorphism was significantly associated with both clinical phenotypes of IBD (CD: P=0.005, odds ratio 1.25, 95% confidence interval 1.06-1.46; and UC: P=0.002, odds ratio 1.19, 95% confidence interval 1.02-1.38). No evidence of association was detected for MS. The originally described association of IBD with STAT3 polymorphisms is corroborated for the two clinical phenotypes, CD and UC, in an independent population. A major role of this gene in MS seems unlikely.

The autoimmune disease-associated KIF5A, CD226 and SH2B3 gene variants confer susceptibility for multiple sclerosis.

Genome-wide association studies (GWAS) have revealed that different diseases share susceptibility variants. Twelve single-nucleotide polymorphisms (SNPs) previously associated with different immune-mediated diseases in GWAS were genotyped in a Caucasian Spanish population of 2864 multiple sclerosis (MS) patients and 2930 controls. Three SNPs were found to be associated with MS: rs1678542 in KIF5A (P=0.001, odds ratio (OR)=1.13, 95% confidence interval (CI)=1.05-1.23); rs3184504 in SH2B3 (P=0.00001, OR=1.19, 95% CI=1.10-1.27) and rs763361 in CD226 (P=0.00007, OR=1.16, 95%CI=1.08-1.25). These variants have previously been associated with rheumatoid arthritis and type 1 diabetes. The SH2B3 polymorphism has additionally been associated with systemic lupus erythematosus. Our results, in addition to validating some of these loci as risk factors for MS, are consistent with shared genetic mechanisms underlying different immune-mediated diseases. These data may help to shape the contribution of each pathway to different disorders.

A Trypanosoma cruzi membrane protein shares an epitope with a lymphocyte activation antigen and induces crossreactive antibodies.

Chagas' disease results from the infection of the protozoan parasite Trypanosoma cruzi and affects several million people in South America. Several alterations of the immune response have been described in this disease, such as severe immunosuppression of both cellular and humoral responses and massive polyclonal stimulation with the generation of autoantibodies crossreacting with host cells and tissues. We have obtained monoclonal antibodies (mAbs) from T. cruzi-infected mice that recognized a 50/55-kD antigen (GP50/55) on the T. cruzi membrane, but not in other parasites of the family Trypanosomatidae. One of these GP50/55-specific mAbs (C10) crossreacts with a 28-kD antigen (p28) expressed on the membrane of greater than 85% of activated mouse T and B lymphocytes, after in vitro activation with concanavalin A, Salmonella typhosa lipopolysaccharide, phorbol dibutyrate ester, or antigen, and on several murine T and B lymphocyte cell lines. Human T and B lymphocytes also express upon activation with phytohemagglutinin or Staphylococcus aureus Cowan I (SAC) a similar antigen recognized by mAb C10, although in a lower proportion of cells (30-40%). Furthermore, this mAb was able to suppress mouse and human T and B cell proliferation to any of those stimuli. In addition, sera from chagasic patients and T. cruzi-infected mice, but not from control patients or littermates, contain antibodies that recognize a similar p28 antigen on B lymphocytes. Furthermore, the immunoglobulin fractions of some chagasic sera also suppress the proliferation of human T lymphocytes. These results suggest a possible pathological role of autoantibodies as an alternative mechanism for T. cruzi-associated immunosuppression.

Multiple sclerosis association study with the TENR-IL2-IL21 region in a Spanish population.

Polymorphisms from the TENR-IL2-IL21 block in the 4q27 chromosome were recently associated with type 1 diabetes, celiac disease, rheumatoid arthritis and psoriasis. We undertook this study to investigate the potential role of polymorphisms rs3136534, rs6822844 and rs2069762 (-330 T/G IL2) in multiple sclerosis (MS) (805 patients of Spanish Caucasian origin and 952 health controls). We did not find evidence for association with any single nucleotide polymorphisms (SNPs) tested. Allele and genotype frequencies of the SNPs, which were studied, were similar in DRB1*15-positive or DRB1*15-negative patients. After stratification of MS patients by clinical course, a weak association was observed with rs2069762 G allele and haplotype bearing this allele with secondary progressive MS, although these cases represent 22% of the MS cases. Our results did not show major influence of TENR-IL2-IL21 locus on susceptibility or disease progression in MS. However, we could not exclude completely the effect in MS for this region. Additional studies, using much larger sample sizes and analysis of additional polymorphisms in the gene and its flanking region, will be required to ascertain their contributions to MS susceptibility.

Interferon regulatory factor 5 (IRF5) gene variants are associated with multiple sclerosis in three distinct populations.

BACKGROUND: IRF5 is a transcription factor involved both in the type I interferon and the toll-like receptor signalling pathways. Previously, IRF5 has been found to be associated with systemic lupus erythematosus, rheumatoid arthritis and inflammatory bowel diseases. Here we investigated whether polymorphisms in the IRF5 gene would be associated with yet another disease with features of autoimmunity, multiple sclerosis (MS). METHODS: We genotyped nine single nucleotide polymorphisms and one insertion-deletion polymorphism in the IRF5 gene in a collection of 2337 patients with MS and 2813 controls from three populations: two case-control cohorts from Spain and Sweden, and a set of MS trio families from Finland. RESULTS: Two single nucleotide polymorphism (SNPs) (rs4728142, rs3807306), and a 5 bp insertion-deletion polymorphism located in the promoter and first intron of the IRF5 gene, showed association signals with values of p<0.001 when the data from all cohorts were combined. The predisposing alleles were present on the same common haplotype in all populations. Using electrophoretic mobility shift assays we observed allele specific differences in protein binding for the SNP rs4728142 and the 5 bp indel, and by a proximity ligation assay we demonstrated increased binding of the transcription factor SP1 to the risk allele of the 5 bp indel. CONCLUSION: These findings add IRF5 to the short list of genes shown to be associated with MS in more than one population. Our study adds to the evidence that there might be genes or pathways that are common in multiple autoimmune diseases, and that the type I interferon system is likely to be involved in the development of these diseases.

Chemotropic signaling by BMP7 requires selective interaction at a key residue in ActRIIA.

BMP7 evokes acute chemotropic PI3K-dependent responses, such as growth cone collapse and monocyte chemotaxis, as well as classical Smad-dependent gene transcription. That these divergent responses can be activated in the same cell raises the question of how the BMP-dependent signaling apparatus is manipulated to produce chemotropic and transcriptional signals. RNA interference and site-directed mutagenesis were used to explore functional and structural BMP receptor requirements for BMP7-evoked chemotropic activity. We show that specific type II BMP receptor subunits, ActRIIA and BMPR2, are required for BMP7-induced growth cone collapse in developing spinal neurons and for chemotaxis of monocytes. Reintroduction of wild-type ActRIIA into monocytic cells lacking endogenous ActRIIA restores BMP7-evoked chemotaxis, whereas expression of an ActRIIA K76A receptor variant fails to rescue. BMP7-evoked Smad-dependent signaling is unaffected by either ActRIIA knockdown or expression of the ActRIIA K76A variant. In contrast, BMP7-evoked PI3K-dependent signaling is significantly disturbed in the presence of ActRIIA K76A. These results support a model for selective engagement of chemotropic BMPs with type II BMP receptors, through specific residues, that results in strict regulation of PI3K-dependent signal transduction.This article has an associated First Person interview with the first author of the paper.

A new cDNA sequence for the murine interleukin-2 gene.

We have amplified by PCR and sequenced the first exon of the interleukin 2 gene from the RF/J mouse strain DNA. When we compared the RF/J first exon sequence with the one reported previously, we found several differences. These differences are also reflected in the deduced amino acid sequence and they have been localized in the first 23 amino acids of the mature polypeptide. The finding of this new IL-2 sequence shows that there is more than one allele for the mouse IL-2 molecule and raises the possibility of functional differences between alleles.

The cloning and expression of Pfacs1, a Plasmodium falciparum fatty acyl coenzyme A synthetase-1 targeted to the host erythrocyte cytoplasm.

Plasmodium is unable to carry out de novo fatty acid synthesis and has to obtain these compounds from their host for subsequent activation by thioesterification with coenzyme A. This activity is catalyzed by a fatty acyl-CoA synthetase enzyme (EC 6.2.1.3). Here, we describe a novel gene from P. falciparum whose recombinant purified product from baculovirus-transfected insect cell line had the enzymatic activity of a long-chain fatty acyl-CoA synthetase. It was named pf acs1, since it belongs to a multi-member gene family as revealed by the sequence of several clones and a multi-band pattern in Southern blots. The sequence specifies a product of 820 amino acid residues. It was transcribed and expressed in infected erythrocytes having an apparent molecular mass of 100 kDa. Immuno-labeling of infected erythrocytes with a specific antibody against the carboxy-terminal part of the PfACS1 localized the product early after the erythrocyte invasion in vesicle-like structures budding off the parasitoforous membrane toward the red cell cytoplasm. Its unique carboxy- terminal structure of 70 extra amino acid residues, longer than any other reported acyl-CoA synthetase, is probably related to its localization in the cytoplasm of the host erythrocyte. The phylogenetic relationship among other AMP-forming enzymes, placed PfACS1 closer to Saccharomyces cerevisiae, sharing significant amino acid identities, especially in the conserved signature motif that modulates fatty acid substrate specificity and ATP/AMP-binding domains. Taking into account the importance of this enzymatic activity for the parasite, its extra-cellular location inside the infected erythrocyte, and the divergence with respect to the homologous human enzymes, it may be an important protein as a potential target candidate for chemotherapeutic antimalaria drugs.

A colorimetric assay based on cell viability for the indirect detection of intracellular replication and killing of Trypanosoma cruzi.

We have developed an 'in vitro' colorimetric assay for the detection of replication and/or destruction of the intracellular amastigote form of Trypanosoma cruzi. The assay can be applied to other intracellular parasites having lytic effects on the infected cells. The assay is based on the relationship between the content of the lysosomal enzyme hexosaminidase and the number of viable cells. The level of this enzyme can be detected by a simple and sensitive procedure in microtiter wells using a p-nitrophenol derivative as enzyme substrate and scanning the absorbance at 405 nm. Macrophages or other suitable host cells which support T. cruzi intracellular replication have detectable levels of this enzyme whereas the protozoan parasites do not. The assay exhibited a good inverse correlation between the number of amastigotes released and the amount of enzyme in the infected cultures. Furthermore, the method was used for the detection of macrophage-activating factors and gave results similar to those obtained by microscopical examination of the cells. The advantages of the procedure are objectivity, sensitivity and simplicity.

A tubulin-related 55 kilodalton surface antigen recognized by different Trypanosoma cruzi stage-specific monoclonal antibodies from infected mice.

Thirteen monoclonal antibodies (MAbs) specific for the membrane of live Trypanosoma cruzi have been obtained from BALB/c infected mice. Most of them had greater avidity for intact than for disrupted parasites. According to the staining by indirect immunofluorescence of the different live developmental stages of the parasite the MAbs could be divided into several groups. Three of them were trypomastigote specific, one amastigote-specific and two epimastigote-specific. The rest reacted with either all stage forms or with various combinations of the different stages. However, despite the fact that they seemed to correspond to stage-specific antibodies, ten of them reacted with the same 55/50 kDa antigen by immunoblotting. Similarly, a 55 kDa protein was immunoprecipitated from these MAbs. By contrast, a single band or a dimer of about 25 kDa was the predominant antigen(s) immunoprecipitated by the same MAbs in absence of protease inhibitors. This smaller protein may arise from proteolysis of the 55 kDa band. This protein is related to tubulin since tubulin (a 55 kDa protein) but not other cytoskeleton proteins blocked the binding of these MAbs to T. cruzi, and some MAbs react with pig alpha-tubulin by immunoblotting.

Stimulation of the trypanocidal and endoribonuclease activities by the interferon induced (2'-5') oligoadenylates.

Interferon or 2'-5' oligoadenylates (2'-5' An) activated the microbicidal activity of primary cultures of rat glia cells and of the mouse macrophage transformed cell line J774 against infection by Trypanosoma cruzi. Pretreatment with gamma-interferon (gamma-IFN) or 2'-5' A3 of rat glia cells or direct addition of these compounds during the incubation with the parasite enhanced the uptake of metacyclic trypanosomes by the cells. Furthermore, glia cells treated with gamma-IFN or 2'-5' A3 were able to restrict the growth and to eventually destroy intracellular amastigotes. Bacterial lipopolysaccharide (LPS) synergized with gamma-IFN as well as with 2'-5' A3 and 2'-5' A4, but not with dephosphorylated 'core' molecules or ATP, to induce a partial trypanocidal activity in J774 cells. In addition, those treatments with gamma-IFN or 2'-5' A3 activated to a similar extent an endoribonuclease, which degraded ribosomal RNA, in rat glia cells, suggesting a role of this enzyme in the mechanism of the trypanocidal activity of gamma-IFN.

Allelic expression and interleukin-2 polymorphisms in multiple sclerosis.

We have investigated the association of two single nucleotide polymorphisms (SNPs) at positions -384 and 114 in the human interleukin-2 (hIL-2) with multiple sclerosis (MS). For two of the -384 genotypes (G/T, T/T), we observed an association with the susceptibility to secondary progressive (SP) course of MS (P=0.005 and P=0.013, respectively). Expression level differences of the IL-2 alleles (between one- and three-fold) were not attributable to the -384 promoter polymorphism. These data indicate for the first time the relevance of the il-2 gene locus in human MS and its possible involvement in other autoimmune diseases.

The -174/-597 promoter polymorphisms in the interleukin-6 gene are not associated with susceptibility to multiple sclerosis.

Interleukin-6 (IL-6) has been implicated in the etiology of experimental autoimmune encephalomyelitis (EAE) in transgenic animals and contributes to neuropathology in humans. A single nucleotide polymorphism (SNP) at position -174 in the IL-6 gene promoter (IL-6pr) appears to influence IL-6 expression. Complete linkage disequilibrium was observed between the -174 and the -597 alleles. The aim of this study was to investigate the possible influence of -174/-597 IL-6pr polymorphisms on susceptibility to multiple sclerosis (MS). Genotyping of the -597 variant was performed by an RFLP method in 131 MS patients [88 relapsing-remitting (RR-MS), 43 secondary progressive (SP-MS)] and 157 healthy subjects. No differences were found between MS patients and controls with respect to the distribution of -597 IL-6pr genotypes. Neither was found when genotypes were analyzed according to the clinical course of the disease (RR-MS or SP-MS). Future studies focusing on complex transcriptional interactions between the IL-6pr and 3' flanking region polymorphic sites will be necessary to determine the IL-6 haplotype influence on susceptibility to MS.

The T244I variant of the interleukin-7 receptor-alpha gene and multiple sclerosis.

Several but not all studies have provided evidence for the association between multiple sclerosis (MS) and the T244I variant of the interleukin-7 receptor-alpha gene (IL7RA), rs6897932. We performed a new replication case-control study in 599 MS patients and 594 healthy controls, all Caucasians from the south of Spain. The genotype and allele frequencies differed between MS cases and controls. The IL7RA rs6897932 C allele and the CC genotype were found to be factors for disease susceptibility [per allele odds ratio (OR) 1.32, 95% CI 1.1-1.6, P=0.0031; per CC genotype vs TT + TC genotypes, OR 1.5, 95% CI 1.18-1.87, P=0.0007]. The combined data analysis included 3324 cases and 5032 controls of Europeans and Americans of European origin resulting in stronger association with similar OR (P=1.9 x 10E-9). These findings in our sample support previous reported association studies between IL7RA rs6897932 and MS.