Variation in interleukin 7 receptor alpha chain (IL7R) influences risk of multiple sclerosis.

Multiple sclerosis is a chronic, often disabling, disease of the central nervous system affecting more than 1 in 1,000 people in most western countries. The inflammatory lesions typical of multiple sclerosis show autoimmune features and depend partly on genetic factors. Of these genetic factors, only the HLA gene complex has been repeatedly confirmed to be associated with multiple sclerosis, despite considerable efforts. Polymorphisms in a number of non-HLA genes have been reported to be associated with multiple sclerosis, but so far confirmation has been difficult. Here, we report compelling evidence that polymorphisms in IL7R, which encodes the interleukin 7 receptor alpha chain (IL7Ralpha), indeed contribute to the non-HLA genetic risk in multiple sclerosis, demonstrating a role for this pathway in the pathophysiology of this disease. In addition, we report altered expression of the genes encoding IL7Ralpha and its ligand, IL7, in the cerebrospinal fluid compartment of individuals with multiple sclerosis.

Vitamin D receptor genotypes, ultraviolet radiation exposure, and risk of non-Hodgkin lymphoma.

Ultraviolet radiation (UVR) exposure may influence risk of non-Hodgkin lymphoma (NHL) through vitamin D, with antineoplastic effects mediated through the vitamin D receptor (VDR). To explore the role of vitamin D in NHL risk and the potential interaction with UVR, the authors genotyped 10 VDR polymorphisms in 2,448 NHL patients and 1,981 controls from Denmark and Sweden who were recruited in 1999-2002. Odds ratios and 95% confidence intervals were computed with logistic regression. P values were 2-sided. Most VDR variants (e.g., rs731236/TaqI, rs15444410/BsmI) were not associated with overall risk of NHL, but there was some evidence of a positive association between rs4760655 and follicular lymphoma risk (nominal P(trend) = 0.004, corrected P(trend) = 0.24). There was no support for an effect of interaction between VDR variants and UVR exposure on risk of overall NHL or B-cell lymphoma subtypes. However, there was some evidence that rs731236 altered associations between UVR and T-cell NHL risk; while increasing UVR frequency lowered T-cell NHL risk among rs731236 TT carriers, an elevated risk was observed among rs731236 CC carriers (nominal P(interaction) ≤ 0.008, corrected P(interaction) ≥ 0.12). VDR does not appear to harbor major determinants of NHL risk, except perhaps for follicular lymphoma. Possible heterogeneity in effects of UVR exposure on T-cell lymphoma risk by VDR rs731236 genotype merits further investigation.

Gene expression profiling in multiple sclerosis: a disease of the central nervous system, but with relapses triggered in the periphery?

The aetiology of multiple sclerosis (MS), an autoimmune demyelinating disease of the central nervous system (CNS), includes both genetic and environmental factors, but the pathogenesis is still incompletely known. We performed gene expression profiling on paired cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMCs) samples from 26 MS patients without immunomodulatory treatment, sampled in relapse or remission, and 18 controls using Human Genome U133 plus 2.0 arrays (Affymetrix). In the CSF, 939 probe sets detected differential expression in MS patients compared to controls, but none in PBMCs, confirming that CSF cells might mirror the disease processes. The regulation of selected transcripts in CSF of MS patients was confirmed by quantitative PCR. Unexpectedly however, when comparing MS patients in relapse to those in remission, 266 probe sets detected differential expression in PBMCs, but not in CSF cells, indicating the importance of events outside of the CNS in the triggering of relapse.

Genetic variation in chromosomal translocation breakpoint and immune function genes and risk of non-Hodgkin lymphoma.

BACKGROUND: Tumor necrosis factor (TNF) and interleukin 10 (IL10) are promising candidate susceptibility genes for non-Hodgkin lymphoma (NHL). Chromosomal translocation breakpoint genes are of interest, given their documented involvement in lymphoma progression. METHODS: We analyzed 11 polymorphisms in BCL2, CCND1, MYC, TNF, and IL10 in a large, population-based, Danish-Swedish case-control study including 2,449 NHL cases and 1,980 controls. Relative risk of NHL was computed as odds ratios (OR). RESULTS: There was no clear evidence of associations between variants in BCL2, CCND1, and MYC and risk of NHL overall or subtypes. TNF rs1800629 was associated with risk of NHL (OR 1.53, 95% confidence interval, CI, 1.06-2.19 for minor allele homozygosity), T-cell lymphoma (OR 2.54, CI 1.27-5.09) and mantle cell lymphoma (OR 2.84, CI 1.38-5.87). IL10 rs1800890 was associated with risk of diffuse large B-cell lymphoma (OR 1.41, CI 1.08-1.85 for minor allele homozygosity) and mantle cell lymphoma (OR 1.77, CI 1.04-3.00). We did not replicate a previously reported interaction with autoimmunity. CONCLUSIONS: We found no support for a role of the studied variants in BCL2, CCND1, or MYC in risk of NHL or subtypes, but we provide further evidence of putative susceptibility loci in TNF and IL10 for specific NHL subtypes.

Genetic association analysis of the interleukin 7 gene (IL7) in multiple sclerosis.

IL7 is a nonredundant cytokine, essential for T cell survival and development in humans. We genotyped nine tagging single nucleotide polymorphisms (SNP), representing all parts of the IL7 gene, in 1,210 Swedish multiple sclerosis (MS) patients and 1,234 healthy controls. None of the SNPs showed a significantly different distribution in MS, and haplotype analysis also failed to reveal differences between patients and controls. We conclude that the IL7 gene is very unlikely to influence the genetic susceptibility to MS in this population.

Gene and protein expression profiling of the microvascular compartment in experimental autoimmune encephalomyelitis in C57Bl/6 and SJL mice.

Dysfunction of the blood-brain barrier (BBB) is a hallmark of inflammatory diseases of the central nervous system (CNS) such as multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). The molecular mechanisms leading to BBB breakdown are not well understood. In order to find molecules involved in this process, we used oligonucleotide microarrays and proteomics to analyze gene and protein expression of the microvascular compartment isolated from brains of C57Bl/6 and SJL/N mice afflicted with EAE and the microvascular compartment isolated from healthy controls. Out of the 6500 known genes and expressed sequence tags (ESTs) studied, expression of 288 genes was found to be changed. Of these genes 128 were altered in the microvascular compartment in both EAE models. Six proteins were identified to be present at altered levels. In addition to the expected increased expression of genes coding for molecules involved in leukocyte recruitment, genes not yet ascribed to EAE pathogenesis were identified. Thus, proteomics and gene array screens of the microvascular compartment are valid approaches, that can be used to define novel candidate molecules involved in EAE pathogenesis at the level of the BBB.

Increased levels of APRIL (a proliferation-inducing ligand) mRNA in multiple sclerosis.

B cells play an indispensable, yet indeterminate, role in the pathogenesis of multiple sclerosis (MS). We measured mRNA of APRIL-a promotor of B-cell survival-in peripheral blood and quantified protein levels in plasma and cerebrospinal fluid in MS patients and controls. APRIL mRNA levels in monocytes and T cells were significantly higher in MS patients than in controls. Levels of soluble APRIL in plasma were higher in patients with chronic progressive MS than in patients with relapsing-remitting MS, albeit not significantly. MS may thus be associated with increased transcription in peripheral blood of factors promoting B-cell survival, including APRIL.

Gene and protein expression profiling of human cerebral endothelial cells activated with tumor necrosis factor-alpha.

An increase in permeability of the blood-brain barrier is a critical event in the pathophysiological process of multiple sclerosis and other neurodegenerative diseases. Tumor necrosis factor alpha (TNFalpha) is known to play a crucial role in this process and is a powerful activator of endothelial cell inflammatory responses. Although many reports describe effects of TNFalpha activation in endothelial cells, the molecular mechanisms specific for activation of cerebral endothelial cells remains unclear. The objective of this study was to identify potential pharmaceutical targets for the treatment of multiple sclerosis using molecular profiling techniques. Gene expression measurements (Affymetrix Hu6800 oligonucleotide arrays) and proteomics (two-dimensional gel electrophoresis and mass spectrometry) were applied to analyze early alterations in human cerebral endothelial cells (HCEC) activated by TNFalpha. Human umbilical vein endothelial cells (HUVEC) were used as the reference system. The results presented show that HCEC and HUVEC respond similarly with respect to cell adhesion molecules, chemotaxis, apoptosis and oxidative stress molecules. However, nuclear factors NFkB1 and NFkB2, plasminogen activator inhibitor 1 and cofilin 1 are examples of cerebral specific responses. Our results indicate involvements of the urokinase plasminogen activator system and cytoskeletal rearrangements unique to TNFalpha activation of cerebral endothelial cells.

HIV-1 exposed uninfected men who have sex with men have increased levels of salivary CC-chemokines associated with sexual behavior.

OBJECTIVES: To determine whether soluble molecules with known anti-HIV-1 activity are increased in saliva of HIV-1 exposed uninfected individuals of discordant couples of men who have sex with men (MSM), and whether the levels of these molecules are associated with genetic polymorphisms, sexual behavior and/or HIV-1 neutralizing capacity. METHODS: Saliva and PBMC were collected from exposed uninfected individuals (n=25), and low-risk controls (n=22). Levels of CCL2, CCL3, CCL4, CCL5 and CCL11 were detected by Luminex, and SLPI, LL-37, alpha-defensins and IgA2 were detected by ELISA. Single nucleotide polymorphisms (SNPs) were investigated using mass spectrometry or PCR-sequencing. HIV-1 neutralizing activity was assessed using PBMCbased neutralization assays. Self-reported questionnaires described sexual behavior. RESULTS: Exposed uninfected individuals had significantly higher levels of salivary CCL2, CCL4, CCL5 and CCL11 as compared with controls although genetic polymorphisms within the corresponding regions were equally distributed. IgA2 was also increased in exposed uninfected individuals, whereas neither CCL3, SLPI, LL-37 nor alpha-defensins differed between exposed uninfected individuals and controls. The HIV-1 neutralizing capacity of saliva was associated with higher levels of CC-chemokines (but not SLPI, LL-37, alpha-defensins or IgA2) in both exposed uninfected individuals and controls. The increased levels of CC-chemokines were associated with a higher frequency of unprotected oral sex and/or additional casual sex partners. CONCLUSION: HIV-1 exposed uninfected MSM had higher levels of salivary CC-chemokines compared with controls, this finding associated with sexual behavior rather than with genetic polymorphisms. The increased levels of CC-chemokines associated with HIV-1 neutralizing capacity in saliva.

Two HLA class I genes independently associated with multiple sclerosis.

OBJECTIVE: The risk of multiple sclerosis (MS) is influenced by HLA-DRB1, while protective effects have been proposed for HLA-A*02 and HLA-C*05. Our aim was to further understand the role of HLA class I in MS through a comprehensive investigation. METHODS: 1529 MS patients and 1814 controls from Sweden and Norway were genotyped for HLA-DRB1, HLA-A, and HLA-C. Simultaneous analysis of all alleles while adjusting for confounding was achieved using logistic regression. RESULTS: We observed independent effects of all three genes. We confirm the HLA-A*02 (OR=0.73, p=9.2 x 10(-4)) association and report a novel effect of HLA-C*08 (OR=1.85, p=0.0093). CONCLUSIONS: The HLA class I region contains two factors modulating MS risk, characterized by independent associations with HLA-A and HLA-C.

HLA-A confers an HLA-DRB1 independent influence on the risk of multiple sclerosis.

A recent high-density linkage screen confirmed that the HLA complex contains the strongest genetic factor for the risk of multiple sclerosis (MS). In parallel, a linkage disequilibrium analysis using 650 single nucleotide polymorphisms (SNP) markers of the HLA complex mapped the entire genetic effect to the HLA-DR-DQ subregion, reflected by the well-established risk haplotype HLA-DRB1*15,DQB1*06. Contrary to this, in a cohort of 1,084 MS patients and 1,347 controls, we show that the HLA-A gene confers an HLA-DRB1 independent influence on the risk of MS (P = 8.4x10(-10)). This supports the opposing view, that genes in the HLA class I region indeed exert an additional influence on the risk of MS, and confirms that the class I allele HLA-A*02 is negatively associated with the risk of MS (OR = 0.63, P = 7x10(-12)) not explained by linkage disequilibrium with class II. The combination of HLA-A and HLA-DRB1 alleles, as represented by HLA-A*02 and HLA-DRB1*15, was found to influence the risk of MS 23-fold. These findings imply complex autoimmune mechanisms involving both the regulatory and the effector arms of the immune system in the triggering of MS.

Gene expression profiling in cluster headache: a pilot microarray study.

BACKGROUND: Cluster headache (CH) is a primary neurovascular headache disorder characterized by attacks of excruciating pain accompanied by ipsilateral autonomic symptoms. CH pathophysiology is presumed to involve an activation of hypothalamic and trigeminovascular systems, but inflammation and immunological mechanisms have also been hypothesized to be of importance. OBJECTIVE: To identify differentially expressed genes during different clinical phases of CH, assuming that changes of pathophysiological importance would also be seen in peripheral venous blood. METHODS: Blood samples were drawn at 3 consecutive occasions from 3 episodic CH patients: during attacks, between attacks and in remission, and at 1 occasion from 3 matched controls. Global gene expression was analyzed with microarray tehnology using the Affymetrix Human Genome U133 2.0 Plus GeneChip Set, covering more than 54,000 gene transcripts, corresponding to almost 22,000 genes. Quantitative RT-PCR on S100P gene expression was analyzed in 6 patients and 14 controls. RESULTS: Overall, quite small differences were seen intraindividually and large differences interindividually. However, pairwise comparisons of signal values showed upregulation of several S100 calcium binding proteins; S100A8 (calgranulin A), S100A12 (calgranulin C), and S100P during active phase of the disease compared to remission. Also, annexin A3 (calcium-binding) and ICAM3 showed upregulation. BIRC1 (neuronal apoptosis inhibitory protein), CREB5, HLA-DQA1, and HLA-DQB1 were upregulated in patients compared to controls. The upregulation of S100P during attack versus remission was confirmed by quantitative RT-PCR analysis. CONCLUSIONS: The S100A8 and S100A12 proteins are considered markers of non-infectious inflammatory disease, while the function of S100P is still largely unknown. Furthermore, upregulation of HLA-DQ genes in CH patients may also indicate an inflammatory response. Upregulation of these pro-inflammatory genes during the active phase of CH has not formerly been reported. Data from this pilot microarray study provide a basis for further studies in CH.

Genetically determined susceptibility to neurodegeneration is associated with expression of inflammatory genes.

Axonal damage, a core feature of neurological diseases, induces a retrograde reaction in neurons and surrounding glia. We determined transcriptional profiles of this reaction using Affymetrix oligonucleotide arrays. Gene expression was examined in spinal cord tissue prior to injury and following ventral root avulsion in two inbred rat strains, where the degree of neurodegeneration differs. Stringent statistical analysis revealed 278 regulated genes, whereof 245 were regulated by the injury and 68 differed between strains. Principal component analysis disclosed a common injury response pattern significantly modified by genetic background. Notably, inflammatory genes comprised the largest group of genes induced by injury and these transcripts prevailed in the strain most susceptible to neurodegeneration. In addition, levels of the strain regulated genes C1qb and Timp1 correlated with degree of neurodegeneration in a cohort of genetically heterogeneous animals. These results suggest a link between the inflammatory response elicited by nerve injury and subsequent neurodegeneration.