Validation of an Algorithm to Detect Multiple Sclerosis Cases in Administrative Health Databases in Piedmont (Italy): An Application to the Estimate of Prevalence by Age and Urbanization Level.

INTRODUCTION: Italy is considered a high-risk country for multiple sclerosis (MS). Exploiting electronic health archives (EHAs) is highly useful to continuously monitoring the prevalence of the disease, as well as the care delivered to patients and its outcomes. The aim of this study was to validate an EHA-based algorithm to identify MS patients, suitable for epidemiological purposes, and to estimate MS prevalence in Piedmont (North Italy). METHODS: MS cases were identified, in the period between January 1, 2012 and December 31, 2017, linking data from 4 different sources: hospital discharges, drug prescriptions, exemptions from co-payment to health care, and long-term care facilities. Sensitivity of the algorithm was tested through record linkage with a cohort of 656 neurologist-confirmed MS cases; specificity was tested with a cohort of 2,966,293 residents presumably not affected by MS. Undercount was estimated by a capture-recapture method. We calculated crude, and age- and gender-specific prevalence. We also calculated age-adjusted prevalence by level of urbanization of the municipality of residence. RESULTS: On December 31, 2017, the algorithm identified 8,850 MS cases. Sensitivity was 95.9%, specificity was 99.97%, and the estimated completeness of ascertainment was 91.9%. The overall prevalence, adjusted for undercount, was 152 per 100,000 among men and 286 among women; it increased with increasing age and reached its peak value in the 45- to 54-year class, followed by a progressive reduction. The age-adjusted prevalence of residents in cities was 15% higher than in those living in the countryside. DISCUSSION/CONCLUSION: We validated an algorithm based on EHAs to identify cases of MS for epidemiological use. The prevalence of MS, adjusted for undercount, was among the highest in Italy. We also found that the prevalence was higher in highly urbanized areas.

Overexpression of the Cytokine BAFF and Autoimmunity Risk.

BACKGROUND: Genomewide association studies of autoimmune diseases have mapped hundreds of susceptibility regions in the genome. However, only for a few association signals has the causal gene been identified, and for even fewer have the causal variant and underlying mechanism been defined. Coincident associations of DNA variants affecting both the risk of autoimmune disease and quantitative immune variables provide an informative route to explore disease mechanisms and drug-targetable pathways. METHODS: Using case-control samples from Sardinia, Italy, we performed a genomewide association study in multiple sclerosis followed by TNFSF13B locus-specific association testing in systemic lupus erythematosus (SLE). Extensive phenotyping of quantitative immune variables, sequence-based fine mapping, cross-population and cross-phenotype analyses, and gene-expression studies were used to identify the causal variant and elucidate its mechanism of action. Signatures of positive selection were also investigated. RESULTS: A variant in TNFSF13B, encoding the cytokine and drug target B-cell activating factor (BAFF), was associated with multiple sclerosis as well as SLE. The disease-risk allele was also associated with up-regulated humoral immunity through increased levels of soluble BAFF, B lymphocytes, and immunoglobulins. The causal variant was identified: an insertion-deletion variant, GCTGT→A (in which A is the risk allele), yielded a shorter transcript that escaped microRNA inhibition and increased production of soluble BAFF, which in turn up-regulated humoral immunity. Population genetic signatures indicated that this autoimmunity variant has been evolutionarily advantageous, most likely by augmenting resistance to malaria. CONCLUSIONS: A TNFSF13B variant was associated with multiple sclerosis and SLE, and its effects were clarified at the population, cellular, and molecular levels. (Funded by the Italian Foundation for Multiple Sclerosis and others.).

Analysis of the GCG repeat length in NIPA1 gene in C9orf72-mediated ALS in a large Italian ALS cohort.

Amyotrophic lateral sclerosis (ALS) is characterized by degeneration of upper and lower motor neurons. The hexanucleotide repeat expansion in C9orf72 gene (C9orf72-HRE) is the most frequent genetic cause of ALS. Since many ALS pedigrees showed incomplete penetrance, several genes have been analyzed as possible modifiers. Length of the GCG repeat tract in NIPA1 (non-imprinted in Prader-Willi/Angelman syndrome 1) gene has been recently investigated as a possible modifier factor for C9orf72-HRE patients with contrasting findings. To disclose the possible role of NIPA1 GCG repeat length as modifier of the disease risk in C9orf72-HRE carriers, we analyzed a large cohort of 532 Italian ALS cases enriched in C9orf72-HRE carriers (172 cases) and 483 Italian controls. This sample size is powered (92% power, p = 0.05) to replicate the modifier effect observed in literature. We did not observe higher frequency of NIPA1 long alleles (> 8 GCG) in C9orf72-HRE carriers (3.5%) compared with C9orf72-HRE negative patients (4.1%) and healthy controls (5%). For the latter comparison, we meta-analyzed our data with currently available literature data, and no statistically significant effect was observed (p = 0.118). In conclusion, we did not confirm a role of NIPA1 repeat length as a modifier of the C9orf72 ALS disease risk.

HLA alleles modulate EBV viral load in multiple sclerosis.

BACKGROUND: The etiopathology of multiple sclerosis (MS) is believed to include genetic and environmental factors. Human leukocyte antigen (HLA) alleles, in particular,  are associated with disease susceptibility, whereas Epstein Barr Virus (EBV) infection has long been suspected to play a role in disease pathogenesis. The aim of the present study is to evaluate correlations between HLA alleles and EBV infection in MS. METHODS: HLA alleles, EBV viral load (VL) and serum anti-EBV antibody titers were evaluated in EBV-seropositive MS patients (N = 117) and age- and sex-matched healthy controls (HC; N = 89). RESULTS: Significantly higher DNA viral loads (p = 0.048) and EBNA-1 antibody titer (p = 0.0004) were seen in MS compared to HC. EBV VL was higher in HLA-B*07+ (p = 0.02) and HLA-DRB1*15+ (p = 0.02) MS patients, whereas it was lower in HLA-A*02+ (p = 0.04) subjects. EBV VL was highest in HLA-A*02-/B*07+/DRB1*15+ patients and lowest in HLA-A*A02+/B*07-/DRB1*15- individuals (p < 0.0001). HLA-B*07 resulted the most associated allele to EBV VL after multiple regression analysis considering altogether the three alleles, (p = 0.0001). No differences were observed in anti-EBV antibody titers in relationship with HLA distribution. CONCLUSIONS: Host HLA-B*07 allele influence EBV VL in MS. As HLA-class I molecules present antigens to T lymphocytes and initiate immune response against viruses, these results could support a role for EBV in MS.

Variations in the high-mobility group-A2 gene (HMGA2) are associated with idiopathic short stature.

BACKGROUND: Several association studies confirmed high-mobility group-A2 gene (HMGA2) polymorphisms as the most relevant variants contributing to height variability. Animal models and deletions in humans suggest that alterations of HMGA2 might be relevant in causing short stature. Together, these observations led us to investigate the involvement of HMGA2 in idiopathic short stature (ISS) through an association study and a mutation screening. METHODS: We conducted an association study (155 ISS patients and 318 normal stature controls) with three HMGA2 single-nucleotide polymorphisms (SNPs) (SNPs rs1042725, rs7968682, and rs7968902) using a TaqMan-based assay. The patients were then analyzed by direct sequencing and multiplex ligation-dependent probe amplification (MLPA) to detect point mutations and genomic micro-rearrangements. RESULTS: Considering a recessive model, an OR value >1 was observed for genotypes rs7968682 TT (Odds ratio (OR) = 1.72, confidence interval (CI): 1.14-2.58) and rs1042725 TT (OR = 1.51, CI: 1.00-2.28) in accordance to the effect exhibited by the single alleles in the general population. None of the patients carried possibly causative HMGA2 mutations. CONCLUSION: Besides the already known role in determining variability in human height, HMGA2 polymorphisms also contribute to susceptibility to ISS. Moreover, we here report the first mutation screening performed in ISS concluding that HMGA2 has not a significant impact on the monogenic form of ISS.

Genetic variants are major determinants of CSF antibody levels in multiple sclerosis.

Immunological hallmarks of multiple sclerosis include the production of antibodies in the central nervous system, expressed as presence of oligoclonal bands and/or an increased immunoglobulin G index-the level of immunoglobulin G in the cerebrospinal fluid compared to serum. However, the underlying differences between oligoclonal band-positive and -negative patients with multiple sclerosis and reasons for variability in immunoglobulin G index are not known. To identify genetic factors influencing the variation in the antibody levels in the cerebrospinal fluid in multiple sclerosis, we have performed a genome-wide association screen in patients collected from nine countries for two traits, presence or absence of oligoclonal bands (n = 3026) and immunoglobulin G index levels (n = 938), followed by a replication in 3891 additional patients. We replicate previously suggested association signals for oligoclonal band status in the major histocompatibility complex region for the rs9271640*A-rs6457617*G haplotype, correlated with HLA-DRB1*1501, and rs34083746*G, correlated with HLA-DQA1*0301 (P comparing two haplotypes = 8.88 × 10(-16)). Furthermore, we identify a novel association signal of rs9807334, near the ELAC1/SMAD4 genes, for oligoclonal band status (P = 8.45 × 10(-7)). The previously reported association of the immunoglobulin heavy chain locus with immunoglobulin G index reaches strong evidence for association in this data set (P = 3.79 × 10(-37)). We identify two novel associations in the major histocompatibility complex region with immunoglobulin G index: the rs9271640*A-rs6457617*G haplotype (P = 1.59 × 10(-22)), shared with oligoclonal band status, and an additional independent effect of rs6457617*G (P = 3.68 × 10(-6)). Variants identified in this study account for up to 2-fold differences in the odds of being oligoclonal band positive and 7.75% of the variation in immunoglobulin G index. Both traits are associated with clinical features of disease such as female gender, age at onset and severity. This is the largest study population so far investigated for the genetic influence on antibody levels in the cerebrospinal fluid in multiple sclerosis, including 6950 patients. We confirm that genetic factors underlie these antibody levels and identify both the major histocompatibility complex and immunoglobulin heavy chain region as major determinants.

Inverse correlation of genetic risk score with age at onset in bout-onset and progressive-onset multiple sclerosis.

We correlated the weighted genetic risk score measured using 107 established susceptibility variants for multiple sclerosis (MS) with the age at onset in bout-onset (BOMS, n=906) and progressive-onset MS Italian patients (PrMS) (n=544). We observed an opposite relationship in the two disease courses: a higher weighted genetic risk score was associated with an earlier age at onset in BOMS (rho= -0.1; p=5 × 10(-3)) and a later age at onset in PrMS cases (rho=0.07; p=0.15) (p of difference of regression=1.4 × 10(-2)). These findings suggest that established MS risk variants anticipate the onset of the inflammatory phase, while they have no impact on, or even delay, the onset of the progressive phase.

The burden of multiple sclerosis variants in continental Italians and Sardinians.

BACKGROUND: Recent studies identified > 100 non-HLA (human leukocyte antigen) multiple sclerosis (MS) susceptibility variants in Northern European populations, but their role in Southern Europeans is largely unexplored. OBJECTIVE: We aimed to investigate the cumulative impact of those variants in two Mediterranean populations: Continental Italians and Sardinians. METHODS: We calculated four weighted Genetic Risk Scores (wGRS), using up to 102 non-HLA MS risk variants and 5 HLA MS susceptibility markers in 1691 patients and 2194 controls from continental Italy; and 2861 patients and 3034 controls from Sardinia. We then assessed the differences between populations using Nagelkerke's R(2) and the area under the Receiver Operating Characteristic (ROC) curves. RESULTS: As expected, the genetic burden (mean wGRS value) was significantly higher in MS patients than in controls, in both populations. Of note, the burden was significantly higher in Sardinians. Conversely, the proportion of variability explained and the predictive power were significantly higher in continental Italians. Notably, within the Sardinian patients, we also observed a significantly higher burden of non-HLA variants in individuals who do not carry HLA risk alleles. CONCLUSIONS: The observed differences in MS genetic burden between the two Mediterranean populations highlight the need for more genetic studies in South Europeans, to further expand the knowledge of MS genetics.

No evidence for a role of rare CYP27B1 functional variations in multiple sclerosis.

Association studies have implicated common variants in the 12q14.1 region containing CYP27B1 in multiple sclerosis (MS). Rare CYP27B1 mutations cause autosomal recessive vitamin D-dependent rickets type 1, and it has recently been reported that heterozygous CYP27B1 mutations are associated with increased MS susceptibility and lower active vitamin D levels. By sequencing CYP27B1 in 134 multiplex families and genotyping the most common variant R389H in 2,608 MS patients and 1,987 controls from Italy and Belgium (a total of 4,729 individuals), we were unable to replicate these observations. These results provide evidence against a major role for CYP27B1 mutations in MS.

Genetic burden of common variants in progressive and bout-onset multiple sclerosis.

BACKGROUND: The contribution of genetic variants underlying the susceptibility to different clinical courses of multiple sclerosis (MS) is still unclear. OBJECTIVE: The aim of the study is to evaluate and compare the proportion of liability explained by common SNPs and the genetic burden of MS-associated SNPs in progressive onset (PrMS) and bout-onset (BOMS) cases. METHODS: We estimated the proportion of variance in disease liability explained by 296,391 autosomal SNPs in cohorts of Italian PrMS and BOMS patients using the genome-wide complex trait analysis (GCTA) tool, and we calculated a weighted genetic risk score (wGRS) based on the known MS-associated loci. RESULTS: Our results identified that common SNPs explain a greater proportion of phenotypic variance in BOMS (36.5%±10.1%) than PrMS (20.8%±6.0%) cases, and a trend of decrease was observed when testing primary progressive (PPMS) without brain MRI inflammatory activity (p = 7.9 × 10(-3)). Similarly, the wGRS and the variance explained by MS-associated SNPs were higher in BOMS than PPMS in males (wGRS: 6.63 vs 6.51, p = 0.04; explained variance: 4.8%±1.5% vs 1.7%±0.6%; p = 0.05). CONCLUSIONS: Our results suggest that the liability of disease is better captured by common genetic variants in BOMS than PrMS cases. The absence of inflammatory activity and male gender further raise the difference between clinical courses.

The role of eight polymorphisms in three candidate genes in determining the susceptibility, phenotype, and response to anti-TNF therapy in patients with rheumatoid arthritis.

OBJECTIVES: Several single nucleotide polymorphisms (SNPs) have been associated with rheumatoid arthritis (RA) such as peptidylarginine deiminase-4 (PADI4), osteopontin (OPN), and perforin (PRF1) genes. Thus, we aimed at analysing the influence of eight SNPs in these candidate genes on RA susceptibility and their association with laboratory and clinical features in terms of response to anti-TNF therapy. METHODS: We performed a case-control study on 377 Caucasian RA patients and 391 healthy, ethnicity-matched, population-based controls. All subjects were genotyped for PADI4_89/94, PADI4_92, PADI4_104, PADI4_100 in PADI4; -156G/GG and +1239A/C in OPN and A91V and N252S in PRF1 genes. The patients were stratified for shared epitope (SE) HLA-DRB1. rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) were analysed. The patients started anti-TNF treatment and they were evaluated at baseline and after 12 weeks. Disease activity was evaluated with DAS28 and response to treatment with EULAR criteria. RESULTS: A statistically significant association between RA and OPN -156G/GG was found (p=0.023). SE was firmly confirmed to be associated with RA (OR=3.68; p<10-10). No other statistically significant association with clinical and laboratory features were observed. CONCLUSIONS: For the first time, in an Italian cohort, we report the association between -156G/GG in OPN gene and RA susceptibility. Short-term response to anti-TNF therapy was not influenced by the genetic variants studied.

The impact of osteopontin gene variations on multiple sclerosis development and progression.

Osteopontin is a proinflammatory molecule, modulating TH1 and TH17 responses. Several reports suggest its involvement in multiple sclerosis (MS) pathogenesis. We previously reported that OPN gene variations at the 3' end are a predisposing factor for MS development and evolution. In this paper, we extended our analysis to a gene variation at the 5' end on the -156G > GG single nucleotide polymorphism (SNP) and replicated our previous findings at the 3' end on the +1239A > C SNP. We found that only +1239A > C SNP displayed a statistically significant association with MS development, but both +1239A > C and -156G > GG had an influence on MS progression, since patients homozygous for both +1239A and -156GG alleles displayed slower progression of disability and slower switch to secondary progression than those carrying +1239C and/or -156G and those homozygous for +1239A only. Moreover, patients homozygous for +1239A also displayed a significantly lower relapse rate than those carrying +1239C, which is in line with the established role of OPN in MS relapses.

Association of the CBLB gene with multiple sclerosis: new evidence from a replication study in an Italian population.

BACKGROUND: The T allele of rs9657904 within the CBLB gene was recently found to be significantly associated with multiple sclerosis (MS) in a genome-wide association study in Sardinia. OBJECTIVE: To replicate this association in an independent population with a different genetic background. METHODS: The rs9657904 variant was typed in a sample of 1435 cases and 1466 controls from the Italian mainland. RESULTS: It was found that in this sample also, the common allele T of rs9657904 is significantly positively associated (one-tailed p=7.35 × 10(-5)) and with a comparable effect size with MS (OR=1.31, 95% CI 1.14 to 1.52). CONCLUSION: These data provide further evidence of the association of MS disease with variation within CBLB.

Association of HLA class I markers with multiple sclerosis in the Italian and UK population: evidence of two independent protective effects.

BACKGROUND: The association of HLA A*02 with multiple sclerosis (MS) was recently confirmed by the authors, and it was observed that the combined presence of HLA Cw*05 significantly enhanced (threefold) the protective effect of HLA A*02. OBJECTIVES AND METHODS: Since A*02-Cw*05 is carried by two HLA extended haplotypes characterised by the B*4402 and B*1801 alleles, respectively, the association analysis was extended to HLA B*44 and B*18 in an Italian sample (1445 MS cases and 973 controls) and these associations were verified in a UK cohort (721 MS cases, 408 controls and 480 family trios). RESULTS: A strong protective effect, independent of DR15, of the A*02-Cw*05 combination carrying B*44 (OR 0.27, p=3.3×10(-5)) was seen in the Italian samples and confirmed in UK family trios (OR 0.33, p=5.5×10(-4)) and in a combined cohort of UK families and case-controls (OR 0.53, p=0.044). This protective effect was significantly stronger than that mediated by A*02 alone. Logistic regression showed that A*02-Cw*05 maintained a significant protection when adjusted for B alleles (Italy: OR 0.38, p=6.5×10(-7); UK: OR 0.60, p=0.0029), indicating that it was not secondary to linkage disequilibrium with B*44. Different from A*02, the other HLA class I tested markers individually showed no significant (Cw*05, B*18) or a modest (B*44) protection when adjusted for the remaining markers. CONCLUSIONS: This study identified at least two independent protective effects which are tagged by A*02-Cw*05 and A*02, respectively. Further studies are needed to elucidate whether this protective effect is due to the presence of an unanalysed factor characterising the HLA extended haplotype(s) carrying A*02 and Cw*05 or to a direct interaction between these alleles.

Influence of Sex on the Microbiota of the Human Face.

The role of the microbiota in health and disease has long been recognized and, so far, the cutaneous microbiota in humans has been widely investigated. The research regarded mainly the microbiota variations between body districts and disease skin states (i.e., atopic dermatitis, psoriasis, acne). In fact, relatively little information is available about the composition of the healthy skin microbiota. The cosmetic industry is especially interested in developing products that maintain and/or improve a healthy skin microbiota. Therefore, in the present work, the authors chose to investigate in detail the structure and composition of the basal bacterial community of the face. Ninety-six cheek samples (48 women and 48 men) were collected in the same season and the same location in central northern Italy. Bacterial DNA was extracted, the 16S rDNA gene was amplified by PCR, the obtained amplicons were subjected to next generation sequencing. The principal members of the community were identified at the genus level, and statistical analyses showed significant variations between the two sexes. This study identified abundant members of the facial skin microbiota that were rarely reported before in the literature and demonstrated the differences between male and female microbiota in terms of both community structure and composition.

A Scoping Review on Body Fluid Biomarkers for Prognosis and Disease Activity in Patients with Multiple Sclerosis.

Multiple sclerosis (MS) is a complex demyelinating disease of the central nervous system, presenting with different clinical forms, including clinically isolated syndrome (CIS), which is a first clinical episode suggestive of demyelination. Several molecules have been proposed as prognostic biomarkers in MS. We aimed to perform a scoping review of the potential use of prognostic biomarkers in MS clinical practice. We searched MEDLINE up to 25 November 2021 for review articles assessing body fluid biomarkers for prognostic purposes, including any type of biomarkers, cell types and tissues. Original articles were obtained to confirm and detail the data reported by the review authors. We evaluated the reliability of the biomarkers based on the sample size used by various studies. Fifty-two review articles were included. We identified 110 molecules proposed as prognostic biomarkers. Only six studies had an adequate sample size to explore the risk of conversion from CIS to MS. These confirm the role of oligoclonal bands, immunoglobulin free light chain and chitinase CHI3L1 in CSF and of serum vitamin D in the prediction of conversion from CIS to clinically definite MS. Other prognostic markers are not yet explored in adequately powered samples. Serum and CSF levels of neurofilaments represent a promising biomarker.

The impact of lifetime coffee and tea loads on Multiple Sclerosis severity.

BACKGROUND AND AIMS: The association between lifestyle factors and Multiple Sclerosis (MS) disease severity and progression has been investigated to a lesser extent compared with susceptibility to the disease. We aimed to assess the impact of lifetime coffee and tea consumption on MS severity. METHODS: Design: cross-sectional study. Two hundred and eight patients (139 females and 69 males) consecutively recruited at the Department of Neurology in Novara, Italy were asked about their lifetime consumption of coffee and tea. The lifetime intensity of consumption (cups/day) was estimated as the weighted sum of the mean number of standard cups drunk per day at different ages. A measure of cumulative lifetime load of the exposure was expressed in terms of cup-years. Disease severity was estimated by the Multiple Sclerosis Severity Score (MSSS). HLA-DRB1∗15 and HLA-A∗02 genotyping was performed in 167 patients. RESULTS: The MSSS was not associated with the status of coffee or tea consumer, or the amount of cups/day or cup-years. The Odds Ratios (OR) for falling in the upper tertile of the MSSS distribution was 1.30 (95% Confidence Interval (CI): 0.47-3.58) for coffee consumers of 1-3 cups/day and 1.14 (95%CI: 0.33-3.95) for 4-8 cups/day vs. non-consumers. The OR was 0.69 (95%CI: 0.35-1.34) for tea consumers vs. non-consumers. However, heavy consumers of coffee (4-8 cups/day) more frequently had a progressive form than small consumers (1-3 cups/day) and non-consumers (19% vs. 14% vs. 0%), and had a significantly higher age at MS onset (36.6 ± 10.3; 31.5 ± 9.5; 28.6 ± 8.1 years, p = 0.001). Although not reaching statistical significance, coffee consumers positive for HLA-A∗02 had a six-fold risk of being in the worst tertile compared to never consumers, whereas the risk was only 1.3 for coffee consumers negative for the same allele. CONCLUSIONS: Coffee or tea intake is not associated with different severity of MS. However, we cannot exclude a possible effect of higher doses of coffee for the subgroup of progressive patients.

A multi-step genomic approach prioritized TBKBP1 gene as relevant for multiple sclerosis susceptibility.

BACKGROUND: Over 200 genetic loci have been associated with multiple sclerosis (MS) explaining ~ 50% of its heritability, suggesting that additional mechanisms may account for the "missing heritability" phenomenon. OBJECTIVE: To analyze a large cohort of Italian individuals to identify markers associated with MS with potential functional impact in the disease. METHODS: We studied 2571 MS and 3234 healthy controls (HC) of continental Italian origin. Discovery phase included a genome wide association study (1727 MS, 2258 HC), with SNPs selected according to their association in the Italian cohort only or in a meta-analysis of signals with a cohort of European ancestry (4088 MS, 7144 HC). Top associated loci were then tested in two Italian cohorts through array-based genotyping (903 MS, 884 HC) and pool-based target sequencing (588 MS, 408 HC). Finally, functional prioritization through conditional eQTL and mQTL has been performed. RESULTS: Top associated signals overlap with already known MS loci on chromosomes 3 and 17. Three SNPs (rs4267364, rs8070463, rs67919208), all involved in the regulation of TBKBP1, were prioritized to be functionally relevant. CONCLUSIONS: No evidence of novel signal of association with MS specific for the Italian continental population has been found; nevertheless, two MS loci seems to play a relevant role, raising the interest to further investigations for TBKBP1 gene.

Vitamin D receptor (VDR) gene SNPs influence VDR expression and modulate protection from multiple sclerosis in HLA-DRB1*15-positive individuals.

Multiple sclerosis (MS) is an autoimmune disease with a multifactorial etiology. The HLA-DRB1*15 allele, is the main genetic risk factor for MS in Caucasians; recent findings showed that the transcription of this molecule is regulated by the vitamin D/vitamin D receptor (VDR) complex. We analyzed SNPs within the VDR gene in association with the HLA-DRB1 locus in 641 MS patients diagnosed according to McDonald criteria and 558 age- and sex-matched healthy controls, to verify possible correlations between the vitamin D/VDR complex, HLA-DRB1, and susceptibility to MS. Results confirmed that HLA-DRB1*15 is a strong predisposing allele (p<1×10(-7); OR: 3.04; 95% CI: 2.02-4.60) for MS. Cosegregation analyses of VDR SNPs with HLA-DRB1*15 indicated a reduction of risk for MS given by the presence of the -DRB1*15-rs731236 T VDR haplotype (p=9.5×10(-5); OR: 2.52; 95% CI: 1.56-4.06) and, conversely, an augmented risk for disease associated with the -DRB1*15-rs731236 C VDR haplotype. Analyses performed on HLA-DRB1*15-positive MS patients and HC alone confirmed the protective role of rs731236 TT VDR genotype (p(y)=0.004; OR: 0.53; 95% CI: 0.33-0.83); notably, FACS, PCR, and confocal microscopy analyses showed that rs731236 TT genotype is associated with an augmented VDR expression in MBP-stimulated PBMC from patients. In conclusion, rs731236 TT VDR genotype modulates VDR expression and confers protection against MS in HLA-DRB1*15-positive individuals. Results herein offer a model justifying the interaction between the major genetic (HLA-DRB*15) and environmental (vitamin D) factors associated with MS onset.

Genetic association and altered gene expression of mir-155 in multiple sclerosis patients.

Multiple sclerosis (MS) is a complex autoimmune disease of the central nervous system characterized by chronic inflammation, demyelination, and axonal damage. As microRNA (miRNA)-dependent alterations in gene expression in hematopoietic cells are critical for mounting an appropriate immune response, miRNA deregulation may result in defects in immune tolerance. In this frame, we sought to explore the possible involvement of miRNAs in MS pathogenesis by monitoring the differential expression of 22 immunity-related miRNAs in peripheral blood mononuclear cells of MS patients and healthy controls, by using a microbead-based technology. Three miRNAs resulted >2 folds up-regulated in MS vs controls, whereas none resulted down-regulated. Interestingly, the most up-regulated miRNA (mir-155; fold change = 3.30; P = 0.013) was previously reported to be up-regulated also in MS brain lesions. Mir-155 up-regulation was confirmed by qPCR experiments. The role of mir-155 in MS susceptibility was also investigated by genotyping four single nucleotide polymorphisms (SNPs) mapping in the mir-155 genomic region. A haplotype of three SNPs, corresponding to a 12-kb region encompassing the last exon of BIC (the B-cell Integration Cluster non-coding RNA, from which mir-155 is processed), resulted associated with the disease status (P = 0.035; OR = 1.36, 95% CI = 1.05-1.77), suggesting that this locus strongly deserves further investigations.