Genetic association studies of tumour necrosis factor alpha and beta and tumour necrosis factor receptor 1 and 2 polymorphisms across the clinical spectrum of multiple sclerosis

Do the Physical and Histologic Features and Time Course in Acute Generalized Exanthematous Pustulosis Reflect a Pattern of Cytokine Dysregulation?

Background:

Acute generalized exanthematous pustulosis (AGEP) is characterized by fever and an indurated erythematous eruption early, with the development of nonfollicular pinhead sterile pustules on an erythematous background. The eruption progresses and resolves relatively rapidly. Although drugs are believed to be the major etiologic agents, other immune modulators, including infections, heavy metals, and radiation, have been implicated.

Objective:

The purpose of this study was to document underlying diseases in patients with AGEP and to determine if this data and the histologic features suggested an underlying pattern of immune dysregulation.

Methods:

Twenty-one patients with new or recurrent episodes of AGEP were questioned concerning underlying diseases. The histopathologic features seen in the biopsy sections and the approximate time of biopsy during the course of their eruptions were recorded.

Results:

Two patients had a history of psoriasis and one patient had a family history of psoriasis, two patients had diagnoses of sarcoid, two patients had inflammatory bowel disease, one had autoimmune thyroiditis, and one patient had multiple sclerosis. Biopsies done at the onset of the eruption showed marked to moderate papillary dermal edema and a mixed dermal inflammatory infiltrate. Shortly thereafter, biopsies showed spongiform pustules within the epidermis and occasional dyskeratotic cells with residual perivascular dermal edema. Although no definitive vasculitis was seen, there was leukocytoclasis within the dermal infiltrate in the majority of biopsy specimens performed more than 48 hours after the onset of the eruption.

Conclusion:

The histologic features seen in AGEP and the disease associations suggest that patients who develop this eruption may have an underlying tendency for development of a pattern of immune dysregulation characterized by a T helper-1 cytokine pattern.

Sulfoglucuronosyl paragloboside is a ligand for T cell adhesion: regulation of sulfoglucuronosyl paragloboside expression via nuclear factor kappaB signaling

Inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta stimulate glucuronosyltransferase genes (S and P) in endothelial cells (ECs) and up-regulate sulfoglucuronosyl paragloboside (SGPG) expression, which serves as a ligand for T cell adhesion. However, the mechanism of cytokine-mediated gene up-regulation has not been elucidated. To evaluate the precise mechanism of SGPG up-regulation, we have specifically inhibited the SGPG synthesis in the cerebromicrovascular EC line (SV-HCECs), a transformed brain ECs of human origin. SV-HCECs were transfected with small interfering RNA designed to mimic the human natural killer epitope-1 sulfotransferase (HNK-1ST), the ultimate enzyme that transfers the sulfate group to glucuronic acid for SGPG synthesis. An inhibition of SGPG expression along with a reduction of human CD4(+) cell adhesion was observed in siRNA HNK-1ST (siHNK-1)-transfected cells after TNFalpha stimulation. A thorough screening of the signaling system confirmed that TNFalpha/IL-1beta stimulation up-regulated nuclear factor kappaB (NFkappaB) signaling in SV-HCECs. siHNK-1 transfection interfered with the SGPG up-regulation after TNFalpha/IL-1beta stimulation in transfected cells and reduced the T cell adhesion. Hence, our study indicates that T cell-SGPG adhesion in SV-HCECs may proceed through NFkappaB activation. In addition, siHNK-1 transfection reduced the NFkappaB activity compared with cells that were transfected with scrambled siRNA, before and after TNFalpha/IL-1beta stimulation. This is the first report indicating that NFkappaB signaling is involved in SGPG gene expression in brain ECs by an unknown mechanism. Its down-regulation by inhibiting HNK-1ST expression may have a potential use in preventing the T cell invasion and consequently nerve damage during inflammation.

The genetics of clinical outcome in multiple sclerosis

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system (CNS), the clinical course of which varies considerably between patients. Genetic complexity and interactions with as yet unknown environmental factors have hindered researchers from fully elucidating the aetiology of the disease. In addition to influencing disease susceptibility, epidemiological evidence suggests that genetic factors may affect phenotypic expression of the disease. Genes that affect clinical outcome may be more effective therapeutic targets than those which determine susceptibility. We present in this review a comprehensive survey of the genes (both MHC- and non-MHC-related) that have been investigated for their role in disease outcome in MS. Recent studies implicating the role of the genotype and epistatic interactions in the MHC in determining outcome are highlighted.

Tumor necrosis factor-alpha up-regulates glucuronosyltransferase gene expression in human brain endothelial cells and promotes T-cell adhesion

Stimulation of human brain microvascular endothelial cells (SV-HCECs) with tumor necrosis factor-alpha (TNF-alpha) up-regulates sulfoglucuronosyl paragloboside (SGPG) synthesis in a dose- and time-dependent manner. After TNF-alpha exposure at a concentration of 50 ng/ml for 24 hr, we observed a seven- to tenfold elevation of SGPG concentration. Interleukin-1beta (IL-1beta) at a concentration of 10 ng/ml and the combined doses of TNF-alpha and IL-1beta were less effective than TNF-alpha alone. TNF-alpha also stimulated T-cell (Jurkat) adhesion with SV-HCECs via SGPG-L-selectin recognition: this was determined by double-label immunofluorescent staining with SGPG and L-selectin antibodies. The number of T cells bound to SV-HCECs after different cytokine stimulations was proportional to the SGPG concentration, and the cell attachment was inhibited by anti-SGPG and anti-L-selectin antibodies, respectively. Our data unequivocally establish that inflammatory cytokines, particularly TNF-alpha, stimulate the glucuronosyltransferse, GlcAT-P, and GlcAT-S, gene expression in brain endothelial cells and promote T-cell adhesion via SGPG-L-selectin recognition, a preliminary step for onset of neuroinflammation.

Interferon-beta1b treatment modulates cytokines in patients with primary progressive multiple sclerosis

OBJECTIVES

It is unknown whether the immunological effects of beta-interferon (IFN-beta) differ in primary progressive multiple sclerosis (PPMS) when compared with relapsing-remitting multiple sclerosis (RRMS). Therefore, we investigated the effects of IFN-beta1b treatment in PPMS on proliferation and cytokine pattern of peripheral blood mononuclear cells (PBMC) and interleukin-10 (IL-10) serum level.

METHODS

Eighteen patients were treated with IFN-beta1b for 12 months in an open-label trial. Serum and PBMC were collected longitudinally.

RESULTS

Interleukin-10 serum levels increased (P = 0.02) during treatment. Tumor necrosis factor-alpha was increased in anti CD3 (OKT3) antibody stimulated PBMC during treatment (P = 0.04), whereas secretion of IL-10 was decreased in OKT3 (P = 0.04), but increased in concavalin A stimulated PBMC (P = 0.02).

CONCLUSIONS

Interleukin-10 serum levels rose in IFN-beta1b-treated patients as has been observed in RRMS. The changes in cytokine patterns secreted by T-lymphocytes of PPMS patients, however, differ from effects observed in RRMS supporting the hypothesis that PPMS differs in some immunological aspects from RRMS.

Mapping candidate non-MHC susceptibility regions to multiple sclerosis

Understanding the genetic basis of multiple sclerosis (MS) remains a major challenge, despite decades of intensive research. In order to identify candidate non-MHC susceptibility regions to MS, the results of whole genome screens for linkage or association and follow-up studies in 18 different populations were superimposed together in a combined genomic map. Analysis of this map led to the prediction of at least 38 potential susceptibility regions, each showing linkage and/or association in several populations. Among these, 17 regions were the most reproducibly reported in these studies, thus representing top predicted candidates for MS. This non-formal approach to meta-analysis demonstrated the ability to verify results and retrieve lost information in an association study. Assessment of the map in a Northern Irish refined screen (n=415 cases, n=490 controls) revealed association in 15 regions (P<0.05), including 10 promising candidates on chromosomes 1p13, 2p13, 2q14, 3p23, 7q21, 13q14, 15q13, 17p13, 18q21 and 20p12 (P<0.0025). Seven of these regions were previously overlooked in the Northern Irish whole genome association study. Collating results from numerous studies, this draft map represents a tool that should facilitate the analysis of the genetic backgrounds of MS in many populations.

Positive and negative associations of human leukocyte antigen variants with the onset and prognosis of adult glioblastoma multiforme

Associations of genetic factors with malignant gliomas have been modest. We examined the relationships of human leukocyte antigen (HLA) and related polymorphisms to glioblastoma multiforme in adult Caucasians (non-Hispanic Whites) from the San Francisco Bay area. For 155 glioblastoma multiforme patients and 157 control subjects closely matched by ethnicity, age, and gender, PCR-based techniques resolved alleles at HLA-A, -B, -C, and -DRB1 loci along with short tandem repeat polymorphisms of MICA exon 5 and TNFb. By multivariable logistic regression, B*13 and the B*07-Cw*07 haplotype were positively associated with glioblastoma multiforme (P=0.01 and <0.001, respectively), whereas Cw*01 was the only variant showing a negative association (P=0.05). Among glioblastoma multiforme patients, progression to death after diagnosis was slower in those with A*32 (relative hazard, 0.45; P<0.01) and faster in those with B*55 (relative hazard, 2.27; P<0.01). Thus, both the occurrence and the prognosis of glioblastoma multiforme could be associated with specific but different HLA genotypes. B*07 and the B*07-Cw*07 haplotype are much more common in Caucasians than other ethnic groups in the U.S., which may partially explain the higher incidence of glioblastoma multiforme in Caucasians.

Molecular typing of human leukocyte antigen and related polymorphisms following whole genome amplification

Reliable, high-resolution genotyping of human leukocyte antigen (HLA) polymorphisms is often compromised by DNA samples of suboptimal quality or limited quantity. We tested the feasibility of molecular typing for variants at HLA and neighboring loci using whole genome amplification (WGA) strategy facilitated by the Phi29 DNA polymerase. With little (5-100 ng) starting genomic DNA of varying quality and source materials, WGA was deemed successful in 167 of 169 DNA from 47 cell lines, 100 European Americans, and 22 native Africans. The Phi29-processed DNA provided adequate templates for polymerase chain reaction (PCR)-based analyses of several HLA (A, B, C, DRB1, and DQB1) and related loci (HFE, MICA, and 10 microsatellites) in the 6p24.3-6p21.3 region, with PCR amplicons ranging from 92 to 2200 bp. Five different genotyping techniques resolved and confirmed 364 genotypes when both original and Phi29-processed DNA worked in PCRs. General population genetic analyses provided additional evidence that WGA may represent a reliable and simple approach to securing ample genomic DNA for typing HLA, MICA, and related variants.

A NOTCH4 association with multiple sclerosis is secondary to HLA-DR*1501

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) with supposedly autoimmune features known to be associated with a specific HLA DR-DQ haplotype (DR15, DQ6, or HLDRB1*1501,DRB5*0101,DQA1*0102,DQB1*0602). We have previously reported that the associated haplotype extends to HLA-B and described an independent association with HLA-A alleles in MS. Owing to a complex situation with extensive linkage disequilibria, it is still unclear whether classical HLA genes are responsible or whether associations may be due to other genes in this region. Here, we analyzed an association in MS with the NOTCH4 and TNFalpha (tumor necrosis factor-alpha) genes, located between the HLA-DRB1 gene and the HLA-A gene. For NOTCH4, located 0.4 Mb telomeric to HLA-DRB1, an SNP at position -25 and a trinucleotide repeat were investigated in 181 MS patients, and 180 controls also typed P = 0.027 for HLA-DRB and HLA-A. A modest association was observed (OR = 3.44) with the C-25 allele. However, two-locus analysis revealed that this association was secondary to the classical association with HLA-DRB1. For TNF, located 0.7 Mb telomeric of NOTCH4, SNPs at positions -308 and -238 were studied in the same dataset. We found no association between these TNFalpha gene polymorphisms and MS in this dataset, although there was linkage disequilibrium (LD) between DRB1 and TNF and between HLA-A and TNF. We conclude that alleles of the NOTCH4 and TNFalpha genes are unlikely to be of importance for the susceptibility to MS, although specific alleles of these genes are often carried on the same haplotype as DR15, DQ6.

Genetic variants in the tumor necrosis factor receptor II gene in patients with multiple sclerosis

Common genetic variants have been shown to influence disease susceptibility, disease course, or both in multiple sclerosis (MS). Several studies have suggested a role for tumor necrosis factor-alpha (TNF-alpha) in the pathogenesis of MS. Recently, it has been reported that the TNF receptor (TNFR) II plays an essential role in the pathology and progression of experimental autoimmune encephalomyelitis, an animal model of MS. To investigate whether TNFR II polymorphisms influence susceptibility and/or clinical progression of MS, genomic DNA of 321 samples of the Austrian Genetics in MS study group and DNA of 174 platelet donors, who served as healthy controls, were genotyped for five polymorphic sites in the TNFR II gene: exon 6 nucleotide (nt) 676*T-->G, exon 6 nt 783*G-->A (both are associated with non-conserved amino acid substitution), exon 10 nt 1663*G-->A, exon 10 nt 1668*T-->G, and exon 10 nt 1690*T-->C (all of which are located in the 3' non-coding region of the gene). We found a significant association between exon 10 nt 1668*T-->G polymorphism and susceptibility to MS. The other investigated nucleotide substitutions were not associated with susceptibility to or clinical parameters in MS.

A genome wide scan for association with multiple sclerosis in a N. Irish case control population

In order to screen the genome for linkage disequilibrium (LD) in multiple sclerosis (MS), we typed 2537 microsatellite markers in separately pooled DNA from 200 cases and 200 controls from N. Ireland. Twenty two markers showing significant evidence of association were identified including three from the HLA region on chromosome 6p21. Putative candidate genes mapping close to the 19 novel markers include the IL10RA and CD3E genes on 11q23 (which both lie close to the marker D11S1998). Individual typing of the marker D11S1998 confirmed its association.

Discrimination of suballeles present at the TNFd microsatellite locus using induced heteroduplex analysis

Polymorphism at the TNFd locus has been implicated in a number of disease association studies. The TNFd locus consists of three regions of (GA)(n) repeats separated by an imperfect repeat of two guanine bases. TNFd alleles are genotyped by the number of repeats in the first (GA)(n) repeat region, and until now the second repeat region had been thought to be nonpolymorphic. We report the existence of suballeles present within the TNFd microsatellite locus, detected using induced heteroduplex generator (IHG) technology. These alleles cannot be detected using conventional typing strategies as they represent altered distribution of the (GA)(n) repeats or sequence variation within the repeat. The suballeles affect the frequencies of the conventional d3 and d4 alleles leading to significantly altered allele frequencies. Some studies have associated the d3 and d4 alleles with disease outcome. We re-analysed one such study cohort using IHG technology and demonstrated a high proportion of incorrectly assigned TNFd3 alleles.

Primary progressive multiple sclerosis: increasing clarity but many unanswered questions

Heterogeneity in the clinical course of multiple sclerosis (MS) is well recognised and patients following a primary progressive course, 10-15% of the MS population, have a distinct clinical and paraclinical phenotype. This review examines recent advances in our understanding of this subgroup of patients and examines the new criteria to be applied in diagnosis. It also highlights developments in genetic, immunological, magnetic resonance and pathological aspects of the disease, whilst also outlining the results of recent therapeutic trials.

Multiple sclerosis in the tropics: genetic association to STR's loci spanning the HLA and TNF

Clear evidence has been presented correlating gene polymorphisms at 6p21.3-21.4 (containing HLA and TNF) and the predisposition to acquire multiple sclerosis (MS). In a previous study, we found that polymorphisms at HLA DQAI were associated with being or not being predisposed to MS in individuals inhabiting the tropics, where the prevalence of MS is significantly lower than in subtropical areas. Here, we tested the hypothesis that polymorphisms at D6S276, D6S265, D6S273 and D6S291 microsatellite loci are in strong linkage disequilibrium with a major genetic factor predisposing to MS. These microsatellites span the 6p21.3 region with intervals of 5 cM establishing particular landmarks for the HLA and TNF loci. Thirty-five MS patients and 35 controls, age, sex, social, ethnically and geographically matched healthy individuals, were studied. After testing the fit of gene frequencies to the normal distribution and performing the correlation for multiple comparisons, we found significant differences among the case and the control frequencies for the allele 202 belonging to the marker D6S276 (Pc=0.00455) and for the allele 114 belonging to the marker D6S265 (Pc=0.0084). For these two alleles at different loci, we found higher frequencies in the cases than in the controls. A nonsignificant p value was found in testing the existence of linkage disequilibrium among the studied loci in the cases and in the controls. In conclusion, the current study adds evidence to the established association among polymorphisms of genes located at 6p21.3-21.4 and MS. Furthermore, because of the distribution of the tested microsatellite loci, the more probable critical region could be correlated with the TNF neighborhood.

Tumor necrosis factor gene polymorphism in migraine

OBJECTIVE

To better define the involvement of human leukocyte antigen region (HLA) genes in migraine via an association study of the tumor necrosis factor (TNF) genes, located in the HLA class III region, with migraine with and without aura.

BACKGROUND

Migraine without aura and migraine with aura are disorders involving multiple factors-environmental and genetic. In a previous study, we hypothesized a protective role for the HLA-DR2 antigen, providing additional basis for the proposed genetic heterogeneity between migraine without aura and migraine with aura. The cytokines produced by TNF genes are polypeptide effectors of inflammatory reaction and endothelial function.

METHODS

Tumor necrosis factor (TNF)-308 (TNF-308A and TNF-308G alleles) and lymphotoxin alpha (TNFB*1 and TNFB*2 alleles) polymorphisms were analyzed by the NcoI-cleaved polymerase chain reaction-amplified fragments in 47 patients with migraine without aura, 32 patients with migraine with aura, and 101 migraine-free controls.

RESULTS

The frequency of TNFB*2 allele was significantly increased in our patients with migraine without aura as compared with the control group (78.72% versus 61.4%, Pc =.004), but no significant differences were found between patients with migraine with aura and controls. Additionally, there was a significant decrease of TNFB*1 homozygotes in patients with migraine without aura compared with the control group (2.13% versus 16.8%, Pc =.0201). Carriage of the TNFB*2 allele confers a high risk for the development of migraine without aura. No significant association was found at TNF-308 polymorphism.

CONCLUSION

These data support the hypothesis that lymphotoxin alpha could be a susceptibility gene in migraine without aura and confirm previous data indicating that migraine with and without aura are distinct entities with different genetic backgrounds.

Identifying disease modifying genes in multiple sclerosis

Evidence is mounting that genetic variation influences not only susceptibility to multiple sclerosis (MS), but also its course and severity. Identification of disease modifying genes, however, poses unique challenges, especially on how to classify the course and outcome of the disease in ways that may be relevant to analysis of biological factors that might be influenced by genes. The power of the statistical approaches to detect small effects of individual genes in complex disorders such as MS is problematic, and approaches to estimate power must be appropriate for the data. Nonetheless, using contemporary schemes of classification, genetic variants that influence disease course have been found; in fact, a small number have been confirmed to influence disease course in two or more independent studies. This review addresses strategies relevant to identification of disease modifying genes in MS, and summarizes and critically evaluates the current state of knowledge in this area.

Tumor necrosis factor allelic polymorphism with diabetic retinopathy in India

The association of tumor necrosis factor (TNF) with diabetic retinopathy (DR) has been described previously. A total of 207 Asian Indian patients of 15-year duration of type 2 diabetes were identified. This group included (i) 100 patients with DR and (ii) 107 patients without retinopathy (DNR). In this study, we correlated the length of the (GT)n microsatellite di-nucleotide repeat upstream to the promoter region of TNF gene with susceptibility for the development of retinopathy. The microsatellite was polymerase chain reaction amplified and electrophoresed on polyacrylamide gel and silver stained. In our study population, there were 18 alleles ranging from 97 to 131 base pairs (bp). Allele 4 (103 bp) had a higher prevalence (9.81%) in the DNR group compared to that (2.5%) in the DR group (P=0.002). Patients with retinopathy and allele 8 (111 bp) had a tendency to develop proliferative diabetic retinopathy (PDR). In this study of Indian subjects, it is suggested that allele 4 is a low risk allele for developing retinopathy and allele 8 (111 bp) shows an association with PDR.

Inter-individual differences in cytokine release in patients undergoing cardiac surgery with cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass (CPB) leads to a systemic inflammatory response with secretion of cytokines (e.g. IL-6, TNF-alpha, IL-1 beta and sIL-2R). The objective of the following study was to investigate in vitro and in vivo cytokine responses and white blood cell counts (WBC) of patients with high versus low cytokine secretion after a coronary artery bypass grafting (CABG) procedure. Twenty male patients undergoing elective CABG surgery with CPB under general anaesthesia were enrolled in the study. On the day of surgery (postoperatively), serum levels of TNF-alpha and IL-1 beta were significantly higher in patients of the high IL-6 level group compared to the respective values in the patient group with low IL-6 levels. The inter-individual differences in IL-6 release in patients undergoing CABG surgery with CPB were accompanied by differences in the release of other cytokines, such as TNF-alpha, IL-1 beta and sIL-2R. To understand whether genetic background plays a role in influencing cytokine plasma levels under surgical stress, we examined the distribution of polymorphic elements within the promoter regions of the TNF-alpha and IL-6 genes, and determined their genotype regarding the BAT2 gene and TNF-beta intron polymorphisms. Our preliminary data suggests that regulatory polymorphisms in or near the TNF locus, more precisely the allele set 140/150 of the BAT2 microsatellite marker combined with the G allele at -308 of the TNF-alpha gene, could be one of the genetic constructions providing for a less sensitive response to various stimuli. Our results suggest: (1) close relationships between cytokine release in the postoperative period, and (2) inter-individually varying patterns of cytokine release in patients undergoing CABG surgery with CPB.

Mapping and identification of autoimmunity genes

Over the past several years, intense effort has been made to map the chromosomal locations of genes involved in the susceptibility to autoimmune diseases. The first phase of this mapping effort-performed in most cases by using microsatellite markers to scan the genome for loci that are linked with disease-has generated first-draft maps for numerous autoimmune diseases in humans, mice and rats, pointing to as many as 20 different loci in some diseases. The second phase is now beginning, with efforts focused on narrowing the loci sufficiently to allow the positional cloning of disease-associated alleles. From these mapping data it is clear that some of these loci overlap between various autoimmune diseases and preliminary results suggest that indeed there is a sharing of 'autoimmunity genes' between various autoimmune diseases.