Complex genetic predisposition in adult and juvenile rheumatoid arthritis

New discoveries in the genetics and genomics of systemic juvenile idiopathic arthritis

INTRODUCTION

Systemic juvenile idiopathic arthritis (sJIA) is a severe inflammatory condition with onset in childhood. It is sporadic, but elements of its stereotypical innate immune responses are likely genetically encoded by both common variants with small effect sizes and rare variants with larger effects.

AREAS COVERED

Genomic investigations have defined the unique genetic architecture of sJIA. Identification of the class II HLA locus as the strongest sJIA risk factor for the first time brought attention to T lymphocytes and adaptive immune mechanisms in sJIA. The importance of the human leukocyte antigen (HLA) locus was reinforced by recognition that HLA-DRB1*15 alleles are strongly associated with development of drug reactions and sJIA-associated lung disease (sJIA-LD). At the IL1RN locus, genetic variation relates to both risk of sJIA and may also predict non-response to anakinra. Finally, rare genetic variants may have critical roles in disease complications, such as homozygous LACC1 mutations in families with an sJIA-like illness, and hemophagocytic lymphohistiocytosis (HLH) gene variants in some children with macrophage activation syndrome (MAS).

EXPERT OPINION

Genetic and genomic analysis of sJIA holds great promise for both basic discovery of the course and complications of sJIA, and may help guide personalized medicine and therapeutic decision-making.

Survey of the association between polymorphisms of CTLA-4 exon 1 49 A/G genes with rheumatoid arthritis in Iran

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which suppresses T cell proliferation, is a promising candidate for the susceptibility genes to rheumatic arthritis diseases (RA). This study aims to examine the association between the polymorphisms of the CTLA-4 exon 1(+ 49) genes with RA in the Qazvin city of Iran population. The polymerase chain reaction of genomic DNA-restriction fragment length polymorphism (PCR-RFLP) was applied to genotype the CTLA-4 exon 1(+ 49) polymorphisms in 105 RA patients and 90 control subjects. Laboratory diagnostic tests were also measured for RA and control groups. Our results did not demonstrate a significant difference in allele and genotype frequencies of the CTLA-4 exon 1(+ 49) between RA patients and the control group (p < .0001). There was no significant difference in age at onset, CRP, RF value in patients with RA according to the CTLA-4 polymorphisms; just anti-CCP showed a significant difference. Our data declared that polymorphisms of CTLA-4 exon 1(+ 49) genes are not correlated with RA susceptibility and its clinical and paraclinical manifestations.

Association of MIF gene polymorphisms with pemphigus vulgaris: a case-control study with comprehensive review of the literature

BACKGROUND

Functional macrophage migration inhibitory factor (MIF) gene polymorphisms are associated with elevated serum levels of MIF and increased susceptibility to various autoimmune diseases. MIF levels in the sera of pemphigus vulgaris (PV) patients are increased; however, no definite association has been demonstrated between PV and MIF gene polymorphisms. The present study was conducted to ascertain any association between MIF-173*G-C and MIF-794*CATT_5-8 polymorphisms and PV.

METHODS

Seventy-five patients with PV and 252 healthy, unrelated, voluntary controls were enrolled randomly in the study. MIF-173*G-C polymorphism (rs755622) was genotyped using polymerase chain reaction (PCR) followed by restriction fragment length analysis, and MIF-794*CATT_5-8 (rs5844572) was genotyped using PCR followed by capillary gel electrophoresis. Subsequently, the allelic, genotype, and haplotype frequencies were determined and compared for both groups. Data were also analyzed with respect to sex, age at onset, type of disease, and duration of disease.

RESULTS

No significant association was observed in terms of allelic, genotype, and haplotype frequencies of MIF gene polymorphisms in PV patients. However, a significantly lower prevalence of the C allele (P=0.02) and CATT₇ allele (P=0.03) was seen in our patient population compared to healthy controls. Analysis of the effect of various factors such as gender, age at onset, type of disease, and disease duration revealed no significant association with the genetic variants.

CONCLUSIONS

MIF-173*G-C and -794*CATT_5-8 polymorphisms are not associated with PV.

Underlying CTLA4 Deficiency in a Patient With Juvenile Idiopathic Arthritis and Autoimmune Lymphoproliferative Syndrome Features Successfully Treated With Abatacept-A Case Report

BACKGROUND

Functional variants of the cytotoxic T-lymphocyte antigen-4 (CTLA4) could contribute to the pathogenesis of disorders characterized by abnormal T-cell responses.

CASE PRESENTATION

We report a case of a 13-year-old girl who first presented with polyarticular juvenile idiopathic arthritis poorly responsive to treatment. During the following years the patient developed cytopenias, chronic lymphoproliferation, high values of T-cell receptor αβ+ CD4- CD8- double-negative T cells and defective Fas-mediated T cells apoptosis. Autoimmune lymphoproliferative syndrome was diagnosed and therapy with mycophenolate mofetil was started, with good hematological control. Due to the persistence of active polyarthritis, mycophenolate mofetil was replaced with sirolimus. In the following months the patient developed hypogammaglobulinemia and started having severe diarrhea. Histologically, duodenitis and chronic gastritis were present. Using the next generation sequencing-based gene panel screening, a CTLA4 mutation was detected (p.Cys58Serfs*13). At the age of 21 the patient developed acute autoimmune hemolytic anemia; steroid treatment in combination with abatacept were started with clinical remission of all symptoms, even arthritis.

CONCLUSIONS

Targeted immunologic screening and appropriate genetic tests could help in the diagnosis of a specific genetically mediated immune dysregulation syndrome, allowing to select those patients who can take advantage of target therapy, as in the case of abatacept in CTLA4 deficiency.

Association between CTLA-4 gene polymorphism and risk of rheumatoid arthritis: a meta-analysis

Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) gene polymorphisms may be involved in the risk of Rheumatoid arthritis (RA). However, evidence for the association remains controversial. Therefore, we performed a meta-analysis to confirm the relationship between CTLA-4 gene polymorphisms and RA. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of association. Stratified analysis was conducted by ethnicity. In total, 66 case-control studies including 21681 cases and 23457 controls were obtained. For rs3087243 polymorphism, significant association was detected in Asians (A vs. G: OR=0.77, 95%CI=0.65-0.90, P=0.001; AA vs. GG: OR=0.67, 95%CI=0.48-0.94, P=0.02) and Caucasians (A vs. G: OR=0.89, 95%CI=0.86-0.93, P<0.00001; AA vs. GG: OR=0.81, 95%CI=0.75-0.88, P<0.00001). For rs231775 polymorphism, significant association was observed in the overall (G vs. A: OR =1.16, 95%CI=1.08-1.25, P<0.0001; GG vs. AA: OR=1.29, 95%CI=1.12-1.50, P=0.0006), and in Asians (G vs. A: OR=1.27, 95%CI=1.10-1.47, P=0.001; GG vs. AA: OR=1.58, 95%CI=1.24-2.01, P=0.0002), but not in Caucasians. However, there was no association between rs5742909 polymorphism and RA. This meta-analysis confirmed that rs3087243 and rs231775 polymorphism were associated with the risk of RA in both overall population and ethnic-specific analysis, but there was no association between rs5742909 polymorphism and RA risk.

Single-nucleotide polymorphism and haplotype analysis of macrophage migration inhibitory factor gene and its correlation with serum macrophage migration inhibitory factor levels in North Indian psoriatic patients with moderate disease severity: A cross-sectional study

BACKGROUND

Psoriasis is associated with significant morbidity and impaired quality of life. Identification of the host genes that influence disease susceptibility and can potentially guide future, targeted therapy is the need of the hour.

AIMS

The aim of the study was to investigate the associations of macrophage migration inhibitory factor (MIF) gene polymorphisms, that is, a 5-8-CATT tetra nucleotide repeats at -794 (-794*CATT5-8) and a single-nucleotide polymorphism at -173 (-173*G/C) with the risk of chronic plaque psoriasis and to observe the correlation, if any, of disease determinants with genetic functional variants and circulating MIF levels.

METHODS

Five hundred and seventeen individuals (265 psoriasis patients and 252 controls) were genotyped for MIF gene polymorphisms. Data were analyzed with respect to disease susceptibility, serum MIF levels, disease severity, age at onset, disease duration and presence of comorbidities.

RESULTS

The presence of co-morbidities was more frequently noted in patients with late onset disease (P = 0.01). No statistically significant differences were observed either in genotype (P = 0.680) or allele frequency (P = 0.69) with respect to distribution of MIF-173*G/C polymorphism between patients and controls. The frequencies of genotypes -794*CATT 5/7 and 7/7 were significantly lower in patients (P = 0.027* and 0.038*, respectively). CATT*5/MIF-173*C haplotype occurred at a higher frequency in patients (odds ratio 3.03, 95% confidence intervals 1.09-8.47, P = 0.02). The mean serum MIF levels were significantly higher in patients as compared to controls (P < 0.001). The presence of either extended MIF -794*CATT repeats or C allele did not reveal any significant association with serum MIF levels or age at onset. Analysis of effect of various disease determinants revealed no significant association with genetic variants and serum MIF levels.

LIMITATIONS

The lesional expression of MIF could not be studied.

CONCLUSION

Our results showed that CATT*5/MIF-173*C haplotype is associated with increased susceptibility to psoriasis vulgaris.

The role of the immune response mediator genes polymorphism in the predisposition to juvenile idiopathic arthritis

Objective ― The aim of the work was to study the contribution of the immune response mediator genes polymorphism (TNFA rs1800629, LTA rs909253, IL1B rs16944, IL2-IL21 rs6822844, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, MIF rs755622, CTLA4 rs3087243, NFKB1 rs28362491, PTPN22 rs2476601, PADI4 rs2240336) to the formation of the predisposition to juvenile idiopathic arthritis (JIA) and its clinical variants. Material and Methods ― The JIA group included 330 patients and the control group – 342 volunteers without autoimmune diseases from the Republic of Bashkortostan, Russia. Genotyping was conducted by the real-time polymerase chain reaction. Results ― Taking into account the differences by sex, it was established, that the alleles/genotypes of the TNFA rs1800629, LTA rs909253, IL2-IL21 rs6822844, PTPN22 rs2476601 polymorphic loci and the TNFA rs1800629*G – LTA rs909253*G haplotype are associated with the development of JIA as a whole (p<0.05); alleles/genotypes of the LTA rs909253, IL1B rs16944, IL2-IL21 rs6822844, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, MIF rs755622, CTLA4 rs3087243, NFKB1 rs28362491, PTPN22 rs2476601 polymorphic loci and the TNFA rs1800629*G – LTA rs909253*G haplotype – with some of JIA clinical variants (p<0.05). Conclusion ― In this work, the relationship of the alleles, genotypes and haplotypes of a number of the immune response mediator genes polymorphic loci with the risk of the development of JIA and its clinical variants was established. Specific associations were observed for girls and boys, which indicates the existence of sexual dimorphism in the JIA pathogenesis.

Association between interleukin-1, interleukin-6, and tumor necrosis factor-alpha polymorphisms and juvenile idiopathic arthritis: a meta-analysis

INTRODUCTION

In juvenile idiopathic arthritis (JIA), interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha (TNF-α) are associated with development and progression of JIA. We investigated whether IL-1, IL-6, and TNF-α polymorphisms were associated with susceptibility to JIA.

EVIDENCE ACQUISITION

A meta-analysis was conducted on the associations between IL-1α-899 C/T, IL-1β-511 C/T, IL-6-174 G/C, and TNF-α-308 G/A and -238 G/A polymorphisms, and JIA (PubMed and Embase).

EVIDENCE SYNTHESIS

A total of 27 studies involving 4678 JIA patients and 7634 controls were considered in the meta-analysis. There was no association between the IL-1α-899 C/T, IL-1β-511 C/T, IL-6-174 G/C, and TNF-α-308 G/A and -238 G/A polymorphisms, and JIA in allele contrast or any other genetic models. In subgroup analysis based on subtype, except for the dominant model of TNF-α-238 G/A, systemic JIA was not significantly associated with IL-6 and TNF-α polymorphisms. In Caucasians, the dominant and additive models of IL-1β-511 C/T were significantly associated with JIA (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.09-2.00, P=0.01; OR 1.46, 95% CI 1.05-2.03, P=0.02, respectively).

CONCLUSIONS

This meta-analysis showed no association between IL-1, IL-6, and TNF-α polymorphisms, and JIA, but the TT genotype of IL-1β -511 C/T was associated with higher prevalence of JIA in Caucasians.

The association between TNF-α 238A/G and 308A/G polymorphisms and juvenile idiopathic arthritis: An updated PRISMA-compliant meta-analysis

OBJECTIVE

A previous meta-analysis concluded that TNF-α 238A/G and TNF-α 308A/G polymorphisms were not associated with the risk of juvenile idiopathic arthritis (JIA) in the overall population or Caucasian subjects. With the publication of a fair number of studies on the association between TNF-α polymorphisms and JIA in recent years, we conducted this updated meta-analysis to make a more accurate evaluation of such relationship.

METHODS

We adopted PubMed, EMBASE, ISI Web of Science and CNKI to identify observational studies that addressed the association between TNF-α polymorphisms and risk for JIA. The allelic effect of variant A for the risk of JIA was expressed as odds ratio (OR) along with the associated 95% confidence interval (95% CI). Meta-analyses were performed by pooling ORs and 95%CI from included studies using RevMan 5.3 software. The stratified-analysis based on ethnicity was performed to confirm the ethnicity-dependent effect on the relationship.

RESULTS

A total of 15 case-control studies including 2845 patients in JIA groups and 4771 patients in control groups were included in our study. The findings indicated a statistically significant association between the A allele of the TNF-alpha 238A/G polymorphism and the decreased JIA risk in Caucasians (P = .0002). The study in Iranian showed similar results (P = .0002) whereas the studies in other ethnicities failed to replicate this finding: Han (P = .29), Mexican (P = .64) and Turkish population (P = .32). TNF-α 308A/G was not statistically associated with JIA in overall subjects or Caucasians.

CONCLUSION

Our study confirmed the protective role of the A allele in TNF-α 238A/G but not TNF-α 308A/G against the occurrence of JIA in the Caucasian population. To exactly validate the correlation between TNF-α polymorphisms and JIA in other ethnic backgrounds, additional studies are required.

Tumor necrosis factor (TNF) and TNFR1 polymorphisms are not risk factors for rheumatoid arthritis in a Mexican population

Tumor necrosis factor (TNF) plays an important role in the pathogenesis of rheumatoid arthritis (RA). Different genetic variants including the TNF -308G/A polymorphism are associated with RA susceptibility. However, these findings have not been replicated in all populations. The aim of this study was to determine whether the TNF -1031T/C (rs1799964), -376G/A (rs1800750), -308G/A (rs1800629) -238G/A (rs361525), and TNFR1 -609G/T polymorphisms are associated with RA susceptibility in a sample of Mexican patients. Our study included 499 patients with RA and 492 healthy controls. The genotypes of the TNF polymorphisms were obtained using TaqMan assay. The genotype and allele frequencies of the TNF -1031T/C, -376G/A, -308G/A, -238G/A, and TNFR1 -609G/T polymorphisms were similar among RA cases versus healthy controls, and no association with RA susceptibility was identified. Our results suggest that the TNF -1031T/C, -376G/A, -308G/A, -238G/A, and TNFR1 -609G/T polymorphisms are not associated with RA susceptibility in a sample of Mexican patients.

Tumor necrosis factor-α -308 A/G gene polymorphism in children with juvenile idiopathic arthritis: relation to disease activity, damage, and functional status

The study aims to evaluate the clinical significance of serum levels of tumor necrosis factor alpha (TNF-α) and -308 A/G promoter polymorphism in juvenile idiopathic arthritis (JIA) patients and find any association to the subsets, clinical and laboratory features, disease activity, and damage as well as functional disability. Forty-eight JIA children and 30 controls were included in the present study. Juvenile arthritis disease activity score in 27 joints (JADAS-27) was calculated, juvenile arthritis damage index (JADI) was assessed, and Childhood Health Assessment Questionnaire (CHAQ) measured the functional status. Serum TNF-α was assayed by ELISA and gene (-308) promoter polymorphism was determined by polymerase chain reaction. The 48 JIA children (mean age 11.5 ± 2.8 years) were 13 systemic, 17 oligoarticular, and 18 polyarticular onset. The serum TNF-α was significantly higher in patients (90.4 ± 6.3 ng/ml) compared to control (3.5 ± 2.6 ng/ml) (p < 0.0001) with a tendency to be higher in the polyarticular subtype. All controls had TNF-α -308 GG alleles. The frequency of GG genotype tended to be higher in systemic onset compared to oligoarticular and polyarticular subtypes. The serum TNF-α significantly correlated with JADAS-27 (r = 0.32, p = 0.03) and CHAQ (r = 0.37, p = 0.01) and negatively with the presence of GG alleles (r = -0.48, p = 0.001). The GG alleles were significantly negatively associated with C-reactive protein (r = -0.32, p = 0.03) with a tendency to negatively correlate with JADAS-27, CHAQ, and JADI-extrarticular (r = -0.28, p = 0.06; r = -0.25, p = 0.09 and r = -0.25, p = 0.09, respectively). There is evidence of a possible influence of the -308 SNP promoter position on the production of TNF-α, the severity of JIA which may consequently influence the response to anti-TNF-α treatment.

Association of macrophage migration inhibitory factor gene polymorphisms with chronic periodontitis in a South Eastern Iranian population

Background:

Macrophage migration inhibitory factor (MIF) is a key proinflammatory mediator. It plays a vital role in immune response against the oral disease. MIF is a regulator of innate immunity, and bacterial antigens can stimulate serum level of this protein. In experimental gingivitis, the expression level of MIF increases and this increment positively correlates with oral plaque index. The single nucleotide polymorphisms in the gene encoding the MIF protein can control the function of MIF. The aim of the present study was a clarification of the associations between MIF-173 G/C, MIF 95 bp, and 189 bp insertion/deletion (I/D) polymorphisms and chronic periodontitis (CP) compared with healthy controls.

Materials and Methods:

This case–control study was carried out on 210 CP patients and 100 normal subjects. MIF-173 G/C and MIF 95 bp and 189 bp I/D polymorphisms were genotyped, using polymerase chain reaction–restriction fragment-length polymorphism (PCR-RFLP) and PCR, respectively. Allele and genotype frequencies of the variants were compared between patients and controls using Chi-square. test. The value of P < 0.05 was considered statistically significant.

Results:

The study findings showed that MIF-173 G/C polymorphism, especially the C allele increased the risk of CP. The 95-bp I/D polymorphism was not associated with CP and the 185-bp I/D variant was not polymorphic in our population.

Conclusion:

Therefore, MIF-137 G/C variant increased the risk of CP in the South East of the Iranian population. In other words, polymorphisms in MIF gene influence clinical outcome of CP infection and influence the susceptibility to disease. Further studies with larger sample sizes and different ethnicities are required to validate our findings.

Association of Interleukin-2, but not Interferon-Gamma, single nucleotide polymorphisms with juvenile idiopathic arthritis

BACKGROUND

Cytokines, including interleukin-2 (IL-2) and interferon-gamma (IFN-γ), seem to play a role in the pathogenesis of juvenile idiopathic arthritis (JIA). The aim of this study was to investigate the associations of IL-2 and IFN-γ single nucleotide polymorphisms (SNPs) with susceptibility to JIA in an Iranian population.

METHODS

Genomic DNA of 54 Iranian patients with JIA and 139 healthy unrelated controls were typed for IL-2 (G/T at -330 and +166) as well as IFN-γ gene (A/T at +874), using polymerase chain reaction with sequence-specific primers method, and compared between patients and controls.

RESULTS

A significantly higher frequency of the IL-2 -330 GG genotype (p<0.01) was found in the JIA patients compared to the controls. However, the GT genotype at the same position was notably lower than in controls (p<0.01). Moreover, IL-2 (-330, +166) GT haplotype was more frequent in patients with JIA in comparison with controls. No significant differences was observed between the two groups of case and control for IL-2 (G/T at +166) and IFN-γ (A/T at +874) SNPs.

CONCLUSION

The results of the current study suggest that certain SNPs of IL-2 gene have association with individuals' susceptibility to JIA. However, further investigations are required to confirm the results of this study.

Rheumatoid Arthritis: The Stride from Research to Clinical Practice

Over 70 different genetic variants with a significant association with rheumatoid arthritis (RA) have been discovered. Anti-citrullination protein antibodies (ACPA)-positive RA variants are more well-defined than their ACPA-negative counterparts. The human leukocyte antigen, HLA-DRB1 locus remains the prime suspect in anti-citrullination protein antibodies (ACPA)—positive RA. Different HLA-DRB1 alleles are linked to RA susceptibility across different ethnicities. With evolving techniques, like genome-wide association studies (GWAS) and single nucleotide polymorphism (SNP) arrays, more non-HLA susceptibility loci have been identified for both types of RA. However, the functional significance of only a handful of these variants is known. Their roles include increasing susceptibility to RA or in determining the speed at which the disease progresses. Additionally, a couple of variations are associated with protection from RA. Defining such clear-cut biological functions can aid in the clinical diagnosis and treatment of RA. Recent research has focused on the implication of microRNAs, with miR-146a widely studied. In addition to disease susceptibility, genetic variations that influence the efficacy and toxicity of anti-RA agents have also been identified. Polymorphisms in the MTHFR gene influence the effectiveness of methotrexate, the first line of therapy in RA. Larger studies are, however, needed to identify potential biomarkers for early disease identification and monitoring disease progression.

Polymorphisms in the TNF-α, TNFR1 gene and risk of rheumatoid arthritis in Chinese Han population

Recent advances have highlighted a major genetic contribution to the pathogenesis of rheumatoid arthritis (RA).The aim of this study was to investigate whether polymorphisms of TNF-α (rs1800630, rs1800629) and TNFR1 (rs767455) were associated with susceptibility to and clinical outcome of RA in Chinese Han population. The target gene polymorphisms were genotyped in 256 patients with RA and 331 healthy controls using a high resolution melting (HRM) method. ESR, CRP, RF anti-CCP and anti-GPI level were also assayed and compared in genotypes of each polymorphism. Significant difference was observed in the genotype distributions and allele frequencies of TNF-α rs1800629 (P = 0.001, P < 0.001, respectively) between patients with RA and controls. There is no evidence to suggest an association between genotypes of the 3 SNPs according to age, gender, disease duration, DAS28 and serum level of autoantibodies. This study identifies a potentially important role for TNF-α rs1800629 polymorphisms in the susceptibility to RA.However, further studies in larger cohorts are required.

CD226 (DNAM-1) is associated with susceptibility to juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is considered a complex genetic autoimmune disease. We investigated the association of genetic variants previously implicated in JIA, autoimmunity and/or immunoregulation, with susceptibility to JIA.

METHODS

A genetic association study was performed in 639 JIA patients and 1613 healthy controls of northwest European descent. Ninety-three single nucleotide polymorphisms (SNP) were genotyped in a candidate gene approach. Results of the entire JIA patient group (all subtypes) were compared with results obtained, alternatively, with a clinically homogeneous patient group including only oligoarticular and rheumatoid factor (RF) negative polyarticular JIA patients (n=493). Meta-analyses were performed for all SNPs that have been typed in other Caucasian JIA cohorts before.

RESULTS

SNPs in or near PTPN22, VTCN1, the IL2-IL21 region, ANKRD55 and TNFA were confirmed to be associated with JIA (p<0.05), strengthening the evidence for involvement of these genes in JIA. In the majority of these replicated SNPs, effect sizes were larger when analysing a homogeneous patient cohort than when analysing all subtypes. We identified two novel associations with oligoarticular and RF-negative polyarticular JIA: CD226 rs763361 (OR 1.30, 95% CI 1.12 to 1.51, p=0.0006) and CD28 rs1980422 (OR 1.29, 95% CI 1.07 to 1.55, p=0.008). Meta-analyses including reported studies confirmed the association of both SNPs with susceptibility to JIA (OR 1.16, p=0.001 and OR 1.18, p=0.001, for rs763361 and rs1980422, respectively).

CONCLUSIONS

The CD226 gene has been identified as novel association with JIA, and a SNP near CD28 as a suggestive association. Both genes are probable candidate risk factors, since they are involved in costimulation of T cells.

The role of polymorphisms of genes CXCL12/CXCR4 and MIF in the risk development IBD the Polish population

Inflammatory bowel disease (IBD) are characterized recurrent inflammation of gastrointestinal tract. The etiology and pathogenesis this disease is currently unclear, but it has become evident that immune and genetic factors are involved in this process. The aim of this study was to determine whether gene polymorphisms: MIF-173 G/C; CXCL12-801 G/A and CXCR4 C/T exon 2 position of rs2228014 is associated with susceptibility to IBD. A total of 286 patients were examined with IBD, including 152 patients with ulcerative colitis and 134 with Crohn's disease (CD) and 220 healthy subjects were recruited from the Polish population. Genotyping for polymorphisms in CXCL12/CXCR4 and MIF was performed by RFLP-PCR. Statistical significance was found for polymorphisms CXCR4, a receptor gene for CXCL12 genotypes and alleles in CD and for genotype C/T and T allele in ulcerative colitis with respect to control. This confirms the effect of CXCL12 gene. The interplay between CXCL12 and its receptor CXCR4 affects homeostasis and inflammation in the intestinal mucosa. Three-gene analysis in CD confirmed the association of genotype GGGGCT. Statistical analysis of clinical data of patients with ulcerative colitis showed significant differences in the distribution of genotype C/T and T allele for CXCR4 in the left-side colitis. Having CXCR4/CXCL12 chemokine axis polymorphisms may predispose to the development of IBD. Activation can also be their defensive reaction to the long-lasting inflammation.

The role of MIF in type 1 and type 2 diabetes mellitus

Autoimmunity and chronic low-grade inflammation are hallmarks of diabetes mellitus type one (T1DM) and type two (T2DM), respectively. Both processes are orchestrated by inflammatory cytokines, including the macrophage migration inhibitory factor (MIF). To date, MIF has been implicated in both types of diabetes; therefore, understanding the role of MIF could affect our understanding of the autoimmune or inflammatory responses that influence diabetic pathology. This review highlights our current knowledge about the involvement of MIF in both types of diabetes in the clinical environment and in experimental disease models.

Meta-analysis confirms association between TNFA-G238A variant and JIA, and between PTPN22-C1858T variant and oligoarticular, RF-polyarticular and RF-positive polyarticular JIA

BACKGROUND

Although more than 100 non-HLA variants have been tested for associations with juvenile idiopathic arthritis (JIA) in candidate gene studies, only a few have been replicated. We sought to replicate reported associations of single nucleotide polymorphisms (SNPs) in the PTPN22, TNFA and MIF genes in a well-characterized cohort of children with JIA.

METHODS

We genotyped and analyzed 4 SNPs in 3 genes: PTPN22 C1858T (rs2476601), TNFA G-308A, G-238A (rs1800629, rs361525) and MIF G-173C (rs755622) in 647 JIA cases and 751 healthy controls. We tested for association between each variant and JIA as well as JIA subtypes. We adjusted for multiple testing using permutation procedures. We also performed a meta-analysis that combined our results with published results from JIA association studies.

RESULTS

While the PTPN22 variant showed only modest association with JIA (OR = 1.29, p = 0.0309), it demonstrated a stronger association with the RF-positive polyarticular JIA subtype (OR = 2.12, p = 0.0041). The MIF variant was not associated with the JIA as a whole or with any subtype. The TNFA-238A variant was associated with JIA as a whole (OR 0.66, p = 0.0265), and demonstrated a stronger association with oligoarticular JIA (OR 0.33, p = 0.0006) that was significant after correction for multiple testing. TNFA-308A was not associated with JIA, but was nominally associated with systemic JIA (OR = 0.33, p = 0.0089) and enthesitis-related JIA (OR = 0.40, p = 0.0144). Meta-analyses confirmed significant associations between JIA and PTPN22 (OR 1.44, p <0.0001) and TNFA-238A (OR 0.69, p < 0.0086) variants. Subtype meta-analyses of the PTPN22 variant revealed associations between RF-positive, RF-negative, and oligoarticular JIA, that remained significant after multiple hypothesis correction (p < 0.0005, p = 0.0007, and p < 0.0005, respectively).

CONCLUSIONS

We have confirmed associations between JIA and PTPN22 and TNFA G-308A. By performing subtype analyses, we discovered a statistically-significant association between the TNFA-238A variant and oligoarticular JIA. Our meta-analyses confirm the associations between TNFA-238A and JIA, and show that PTPN22 C1858T is associated with JIA as well as with RF-positive, RF-negative and oligoarticular JIA.

Macrophage migration inhibitory factor (MIF): genetic evidence for participation in early onset and early stage rheumatoid arthritis

Macrophage migration inhibitory factor (MIF) is an upstream pro-inflammatory cytokine that is associated with the pathogenesis of autoimmune inflammatory diseases including rheumatoid arthritis (RA). Two polymorphisms in the upstream region exist in the MIF gene and are associated with RA susceptibility or severity in different populations. In this case-control study, we investigated whether MIF polymorphisms are associated with RA susceptibility or activity in a western Mexican population .The relationship of MIF levels with clinical features of disease also was assessed. Genotyping of the -794 CATT5-8 (rs5844572) and the -173 G>C (rs755622) polymorphisms was performed by PCR and PCR-RFLP respectively on 226 RA patients and 210 healthy subjects. Serum MIF levels were determined by ELISA. We found a significant association between the -794 CATT5-8 6,7 MIF genotype with RA. Moreover, we detected an association between the -794 CATT7 allele with early onset RA. The -794 CATT7 and -173(*)C alleles, which are in linkage disequilibrium, were associated with high disease activity on RA patients. A positive correlation between circulating MIF levels and C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, anti-citrullinated protein/peptides antibodies and TNFα was detected. MIF levels appear to be associated with disease progression rather than disease activity, which is distinct from the established relationship between disease activity and TNFα levels. In conclusion, the MIF gene and protein are associated with RA in a western Mexican population, with a main contribution onto early onset and early stages of disease.

-174G/C interleukin-6 gene promoter polymorphism predicts therapeutic response to etanercept in rheumatoid arthritis

To examine whether -174G/C interleukin-6 (IL-6) gene polymorphism, previously reported to correlate with IL-6 level, influences response to etanercept therapy in patients with rheumatoid arthritis. Seventy-seven patients with active RA were studied, at baseline and 6- and 12-month follow-up after etanercept therapy. Treatment response was estimated according to the European League Against Rheumatism response criteria. RA patients were genotyped for -174G/C IL-6 gene polymorphism by the PCR-RFLP method, and influence of genotype at this polymorphism to clinical response to etanercept was assessed. After 12 months of treatment, the percentage of responders (patients who had DAS28 improvement >1.2) was significantly increased in patients carrying the IL-6 -174G/G genotype (95.7 %) compared with those with the G/C (75.6 %) or CC (44.4 %) genotype (p = 0.006 by Chi-square test). No significant difference in the mean values of DAS28 improvement was observed between groups with different genotype. RA patients with an IL-6 -174GG genotype respond to etanercept better than patients with GC or CC genotype. This finding, if confirmed in future studies, suggests that the -174G/C IL-6 polymorphism may be a genetic marker of responsiveness to tumor necrosis factor-alpha (TNF-α) blockers in RA.

TNF-α Polymorphisms in Juvenile Idiopathic Arthritis: Which Potential Clinical Implications?

Whether tumor necrosis factor alpha (TNF-α) gene polymorphisms (SNPs) influence disease susceptibility and treatment of patients with juvenile idiopathic arthritis (JIA) is presently uncertain. TNF-α is one of the most important cytokine involved in JIA pathogenesis. Several single nucleotide polymorphisms (SNPs) have been identified within the region of the TNF-α gene but only a very small minority have proven functional consequences and have been associated with susceptibility to JIA. An association between some TNF-α SNPs and adult rheumatoid arthritis (RA) susceptibility, severity and clinical response to anti-TNF-α treatment has been reported. The most frenquetly studied TNF-α SNP is located at -308 position, where a substitution of the G allele with the rare A allele has been found. The presence of the allele -308A is associated to JIA and to a poor prognosis. Besides, the -308G genotype has been associated with a better response to anti-TNF-α therapy in JIA patients, confirming adult data. Psoriatic and oligoarticular arthritis are significantly associated to the -238 SNP only in some works. Studies considering other SNPs are conflicting and inconclusive. Large scale studies are required to define the contribution of TNF-α gene products to disease pathogenesis and anti-TNF-α therapeutic efficacy in JIA.

TNF promoter -308 A/G and -238 A/G polymorphisms and juvenile idiopathic arthritis: a meta-analysis

The aim of this study was to determine whether the tumor necrosis factor (TNF) promoter polymorphisms confer susceptibility to juvenile idiopathic arthritis (JIA). A meta-analysis was conducted on the A allele of the TNF -308 A/G and -238 A/G polymorphisms. The nine comparison studies including 1,132 JIA patients and 1,663 controls were included in the meta-analysis and consisted of 7 European, 1 Mexican, and 1 Turkish population. No association was found between JIA and the TNF -308 A allele and the TNF -238 A allele (odds ratio [OR] = 1.211, 95 % confidence interval [CI] = 0.917-1.598, P = 0.177; OR = 1.135, 95 % CI = 0.603-1.861, P = 0.615, respectively). Stratification by ethnicity did not show the association of the TNF -308 and -238 polymorphisms with JIA in Europeans. Mexicans were found to have lower prevalences of A alleles (2.9, 4.1 %) of the TNF -308 A/G and -238 A/G polymorphisms than any other population studied, and the Turkish population the highest (31.2, 26.9 %). This meta-analysis shows no association between the A alleles of the TNF -308 A/G or -238 A/G polymorphisms and JIA in Europeans, but that the prevalences of these alleles are ethnicity dependent.

Contribution of the -173 G/C polymorphism of macrophage migration inhibitory factor gene to the risk of inflammatory bowel diseases

Inflammatory bowel disease (IBD) represents a heterogeneous group of chronic disorders characterized by inflammation of gastrointestinal tract, typically with a relapsing and remitting clinical course of unknown etiology. Presumably, IBD develops with response exogenous environmental factors only in persons with genetic predisposition. This predisposition was suggested to be associated with polymorphism and mutations in genes encoding proinflammatory immune system proteins. Enhanced production of macrophage migration inhibitory factor (MIF) was found in patients with inflammatory bowel disease (IBD) and mice with experimental colitis. These results suggest that MIF plays a critical role in etiology of the colitis.The aim of the study was determine whether the MIF -173 G/C gene polymorphism is associated with the susceptibility to inflammatory bowel disease (IBD).

MATERIAL AND METHODS

A total of 99 IBD patients, including 58 patients with ulcerative colitis (UC) and 41 with Crohn's disease (CD) and 436 healthy controls recruited from the Polish population, were genotyped for MIF polymorphisms. Genotyping of MIF gene polymorphism was performed by a RFLP-PCR.

RESULTS

We found an increased risk of UC for the C allele of the MIF-173 G/C polymorphism. The distribution of the genotypes was not significantly different in the CD group compared with the controls.

CONCLUSIONS

We demonstrated that the C allele is associated with an increased risk for development of UC. This suggests that the G/C polymorphism in the MIF gene promoter may be a potential risk factor for UC in Polish population.

The association between the functional PTPN22 1858 C/T and MIF -173 C/G polymorphisms and juvenile idiopathic arthritis: a meta-analysis

BACKGROUND

The aim of this study was to determine whether the protein tyrosine phosphatase nonreceptor 22 (PTPN22) 1858 C/T (rs2476601) and macrophage migration inhibitory factor (MIF) -173 C/G polymorphisms confer susceptibility to juvenile idiopathic arthritis (JIA).

METHODS

A meta-analysis was conducted on variant alleles versus common alleles of the PTPN22 1858 C/T and MIF -173 C/G polymorphisms across ten comparative studies, which containing 4,238 JIA patients and 6,012 normal control subjects.

RESULTS

Ten comparative studies, consisting of nine European, and one Turkish population, were included in his meta-analysis. Meta-analysis showed an association between the T allele of the PTPN22 1858 C/T polymorphism and JIA in Europeans [odds ratio (OR) 1.311, 95% confidence interval (CI) 1.205-1.427, P < 1 × 10(-8)]. In addition, meta-analysis revealed an association between the C allele of the MIF -173 C/G polymorphism and JIA in all subjects (OR 1.482, 95% CI 1.202-1.828, P = 2.3 × 10(-4)).

CONCLUSIONS

This meta-analysis confirms that the PTPN22 1858 C/T polymorphism is associated with JIA susceptibility in Europeans and shows that the MIF -173 C/G polymorphism may be associated with susceptibility to JIA.

Macrophage migration inhibitory factor (MIF): a key player in protozoan infections

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by the pituitary gland and multiple cell types, including macrophages (Mø), dendritic cells (DC) and T-cells. Upon releases MIF modulates the expression of several inflammatory molecules, such as TNF-α, nitric oxide and cyclooxygenase 2 (COX-2). These important MIF characteristics have prompted investigators to study its role in parasite infections. Several reports have demonstrated that MIF plays either a protective or deleterious role in the immune response to different pathogens. Here, we review the role of MIF in the host defense response to some important protozoan infections.

Selective IgA deficiency in autoimmune diseases

Selective immunoglobulin A deficiency (IgAD) is the most common primary immunodeficiency in Caucasians. It has previously been suggested to be associated with a variety of concomitant autoimmune diseases. In this review, we present data on the prevalence of IgAD in patients with Graves disease (GD), systemic lupus erythematosus (SLE), type 1 diabetes (T1D), celiac disease (CD), myasthenia gravis (MG) and rheumatoid arthritis (RA) on the basis of both our own recent large-scale screening results and literature data. Genetic factors are important for the development of both IgAD and various autoimmune disorders, including GD, SLE, T1D, CD, MG and RA, and a strong association with the major histocompatibility complex (MHC) region has been reported. In addition, non-MHC genes, such as interferon-induced helicase 1 (IFIH1) and c-type lectin domain family 16, member A (CLEC16A), are also associated with the development of IgAD and some of the above diseases. This indicates a possible common genetic background. In this review, we present suggestive evidence for a shared genetic predisposition between these disorders.

Association of tumour necrosis factor-alpha -308 G/A promoter polymorphism with susceptibility and disease profile of rheumatoid arthritis

The objective was to analyze the possible involvement of tumour necrosis factor-alpha (TNF-α) -308 G/A promoter polymorphism in the susceptibility and/or the disease profile of rheumatoid arthritis (RA) in Egyptian patients. TNF-α-308 G/promoter polymorphism detection by amplification refractory mutation system (ARMS) technique was carried out for 122 RA patients and 120 healthy controls. TNF-α-308 G allele/GG homozygous genotype were higher in patients with rheumatoid arthritis than those in control group (P < 0.001, respectively). A statistically significant association was found between the frequency of the A allele and presence of erosion (OR = 3.42, P = 0.015). No associations were found between the distribution of TNF-α-308 G/A alleles/genotypes and age of patients, disease duration, absence of remission, presence of deformity, clinical manifestations of the disease and presence or absence of rheumatoid factor. The positivity of rheumatoid factor was associated with occurrence of erosion (OR = 25.0, P < 0.001). The results of this study demonstrate the association of the TNF-α-308 G allele and GG homozygous genotype with susceptibility to RA and the A allele with the presence of erosion in the Egyptian patients.

CTLA4 exon1 A49G polymorphism in Slovak patients with rheumatoid arthritis and Hashimoto thyroiditis-results and the review of the literature

Autoimmune thyroid diseases frequently overlaps with rheumatoid arthritis (RA). Among genetic factors, the role of the HLA antigens and CTLA4 gene polymorphisms in the overlapping has been suggested. The aim of this study was to investigate the alleles and genotypes frequency of the CTLA4 exon1 A49G polymorphism in Slovak patients with RA, Hashimoto thyroiditis (HT), both (RA + HT) and in healthy controls. Fifty-seven unrelated adults with RA, 57 patients with HT, 34 patients with both (RA + HT), and 51 normal subjects were studied. All were ethnic Slovaks living in the same geographical area. The CTLA4 exon1 A49G polymorphism was genotyped by using small amplicon melting analysis after real-time PCR. The CTLA4 49GG genotype and G allele frequency in the group with RA was not significantly higher in comparison with controls (10.53% vs. 9.8%, p = 0.62, OR 1.39, 95% CI 0.35-5.74 and 39.47% vs. 34.31%, p = 0.43, OR 1.25, 95% CI 0.72-2.18). The frequency of GG genotype was slightly but not significantly higher in patients with HT as compared with control group (19.3% vs. 9.8%, p = 0.17, OR 2.27, 95% CI 0.67-8.45). However, the frequency of GG genotype and G allele in patients with both RA and HT was significantly higher than that in controls (29.41% vs. 9.8%, p = 0.02, OR 4.49, 95% CI 1.20-18.54 and 51.47% vs. 34.31%, p = 0.03, OR 2.02, 95% CI 1.08-3.81). The frequency of GG genotype of CTLA4 A49G gene polymorphism in Slovak patients with RA is not significantly higher in comparison to control group. However, carriers of GG genotype with RA may be susceptible to develop HT.

No association between transmembrane protein-tyrosine-phosphatase receptor type C (CD45) exon A 77C>G transversion and Hashimoto's thyroiditis in a German population

The CD45 77C>G transversion (rs17612648) in exon A of the CD45 gene has been reported to be associated with the development of various autoimmune diseases. Because Hashimoto's thyroiditis (HT) is a typical autoimmune disease, we performed a study to determine the association of the 77C>G transversion with susceptibility to HT. We enrolled 170 patients and 230 healthy individuals in the study. The 77C>G transversion was genotyped by polymerase chain reaction-allele specific restriction enzyme analysis (PCR-ASRA). We found four patients and six control individuals who carried the 77C>G transversion in a heterozygous form. No homozygous individual was detected in patients with HT or control population. The frequency of the 77G allele in patients was 1.2%, which did not significantly differ from 1.3% in controls (p = 0.871). Our data did not reveal any association between CD45 77C>G transversion and susceptibility to HT in a German population.

G to C transition at position -173 of MIF gene of the recipient is associated with reduced relapse rates after allogeneic stem cell transplantation

Pro-inflammatory and dendritic cell-activating properties of macrophage migration inhibitory factor (MIF) suggest a potentially important role for MIF in alloantigen-specific immune responses after allogeneic stem cell transplantation (allo-SCT). We tested whether MIF -173 G/C gene polymorphism of donor or patient had impacts on the outcomes after allo-SCT. Four hundred and fifty-four donor-patient pairs were genotyped and mortality, relapse, and development of complications were analyzed. Patient but not donor MIF -173 *C allele was associated with improved overall survival (OS) (5 years: 60.8% versus 46.3%, p=0.042) and disease free survival (DFS) (5 years: 55.4% versus 39.5%; p=0.014) due to a reduction in relapse (day 2000: 22.8% versus 42.0% p=0.006) but not due to decreased transplantation-related mortality (TRM) (p=0.44). Multivariate analysis proved patient -173 *C allele as an independent factor for reducing relapse after allo-SCT (p=0.023). Subgroup analysis showed a clear MIF -173 *C allele-related reduction in relapse for those patients who did not receive T cell depleted (TCD) SCT (p=0.01) in contrast to patients receiving TCD SCT (p=0.20). In summary, patient MIF -173 *C allele may be linked to specific, yet unrevealed functions in tumor biology and graft versus leukemia and lymphoma effects and potentially presents a novel prognostic marker for patient-tailored counseling and therapy in allo-SCT.

MIF (macrophage migration inhibitory factor) promoter polymorphisms and susceptibility to severe malarial anemia

BACKGROUND

Severe malarial anemia (SMA) resulting from Plasmodium falciparum infection is one of the leading causes of childhood mortality in sub-Saharan Africa. The innate immune mediator macrophage migration inhibitory factor (MIF) plays a critical role in the pathogenesis of SMA.

METHODS

To investigate the influence of MIF genetic variation on susceptibility to SMA, haplotypes of the MIF -173G/C and -794CATT5-8 polymorphisms were examined in a cohort of Kenyan children.

RESULTS

A statistically significant relationship between increasing frequencies of longer CATT repeats at -794 and increasing severity of malarial anemia was observed. In addition, there was a strong association between lower MIF concentrations and longer CATT repeats. Multivariate logistic regression analyses demonstrated that the 6G haplotype (ie, MIF -794CATT6/-173G) was associated with protection against SMA, whereas carriers of the 7C or 8C haplotype had increased risk of developing SMA. Furthermore, carriers of the 7C or 8C haplotype had reduced plasma MIF levels during acute disease.

CONCLUSIONS

The findings demonstrate that variation in the MIF promoter influences susceptibility to SMA and peripheral MIF production. However, the MIF -173 and -794 polymorphisms appear to have both independent and interactive effects on different measures of disease severity, suggesting that MIF plays a complex role in malarial pathogenesis.

TNF receptor I polymorphism is associated with persistent palindromic rheumatism

OBJECTIVES

To investigate the association between tumour necrosis factor-alpha (TNFalpha), TNF receptor superfamily member 1A (TNFRSF1A, also known as TNFRI), TNFRSF1B (TNFRII), and interleukin-1beta (IL-1beta) single nucleotide polymorphisms (SNPs) and the susceptibility to persistent palindromic rheumatism (PR).

METHODS

Fifty-six unrelated patients with persistent PR and 100 unrelated healthy controls were genotyped for TNFalpha -308G/A, -238G/A, and +488G/A, TNFRSF1A -609G/T and +36A/G, TNFRSF1B +676T/G and +1663G/A, and IL-1beta -511C/T, -31T/C, and +3954C/T using real-time polymerase chain reaction (RT-PCR).

RESULTS

The TNFRSF1A +36G allele [odds ratio (OR) = 3.94, p = 0.003, corrected p (p(c)) = 0.03] and the TNFRSF1A +36AG genotype (OR = 4.81, p = 0.002, p(c) = 0.04) were significantly associated with persistent PR. The frequency of TNFRSF1B +676T/+1663A was increased in PR patients (OR = 2.12, p = 0.01), but failed to reach statistical significance after Bonferroni correction. No correlation was observed between persistent PR and TNFalpha, TNFRSF1A -609G/T, or IL-1beta SNPs.

CONCLUSIONS

The results of this study provide evidence of an association between persistent PR and SNPs within the TNFRSF1A gene, and suggest that TNFRI is involved in the aetiopathogenesis of PR.

Susceptibility to JRA/JIA: complementing general autoimmune and arthritis traits

Juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA), includes the most common chronic autoimmune arthropathies of childhood. These two nomenclatures for classification include components representing the major subclasses of disease. The chromosomal regions and the genes involved in these complex genetic traits are being elucidated, with findings often specific for a particular disease subtype. With the advent of new SNP technologies, progress is being made at an ever-increasing pace. This review discusses the difficulties of deciphering the genetic components in complex disorders, while demonstrating the similarities that JRA shares with other autoimmune disorders. Particular emphasis has been placed on positive findings either for candidate genes that have been replicated independently in JRA/JIA, or findings in JRA for which consistent results have been reported in other forms of autoimmunity.

Tumor necrosis factor-alpha is a common genetic risk factor for asthma, juvenile rheumatoid arthritis, and systemic lupus erythematosus in a Mexican pediatric population

There is a great deal of evidence that points to the association of the tumor necrosis factor-alpha (TNF-alpha) gene as a common genetic factor in the pathogenesis of diseases that are caused by inflammatory and/or autoimmune etiologies. Two single nucleotide polymorphisms (SNPs) identified in the TNF-alpha promoter region have been associated with disease susceptibility and severity. We investigated whether -308G/A and -238G/A TNF-alpha polymorphisms were associated with asthma, systemic lupus erythematosus (SLE), and juvenile rheumatoid arthritis (JRA) in a pediatric Mexican population. In a case-control study of 725 patients (asthma: 226, JRA: 171, and SLE: 328) and 400 control subjects, the participants were analyzed using the allelic discrimination technique. The genotype distribution of both TNF-alpha polymorphisms was in Hardy-Weinberg equilibrium in each group. However, there were significant differences in the allele frequency of TNF-alpha-308A between the patients and the healthy controls. This allele was detected in 2.9% of the controls, 6.0% of asthmatic and JRA patients (p = 0.002 and p = 0.0086), and 6.7% of SLE patients (p = 0.00049); statistical significance was maintained after ancestry stratification (asthma: p = 0.0143, JRA: p = 0.0083, and SLE: p = 0.0026). Stratification by gender showed that the risk for the -308A allele in asthma and JRA was greater in females (OR = 4.16, p = 0.0008 and OR = 4.4, p = 0.0002, respectively). The TNF-alpha -238A allele showed an association only with JRA in males (OR = 2.89, p = 0.004). These results support the concept that the TNF-alpha gene is a genetic risk factor for asthma, SLE, and JRA in the pediatric Mexican population.

Tumor Necrosis Factor-α −308 Genotypes Influence Inflammatory Activity and TNF-α Serum Concentrations in Children with Juvenile Idiopathic Arthritis

Objective.

Considering the relevance of tumor necrosis factor-α (TNF-α) in the pathophysiology of juvenile idiopathic arthritis (JIA), it is likely that polymorphisms in its promoter area may be relevant in disease susceptibility and activity. We investigated if clinical measures of JIA activity and TNF-α serum concentrations were associated with TNF-α −308 genotypes.

Methods.

Portuguese patients with JIA in 5 pediatric rheumatology centers were recruited consecutively, along with a control group of healthy subjects. Demographic and clinical data and blood samples were collected from each patient. DNA was extracted for analysis of TNF-α gene promoter polymorphisms at position −308 by restriction fragment-length polymorphism.

Results.

One hundred fourteen patients and 117 controls were evaluated; 57% of patients presented the oligoarticular subtype, 25% the polyarticular subtype, 8% the systemic subtype, and 9% had enthesitis-related arthritis and 5% psoriatic arthritis. Twenty-four percent of the patients presented the −308 GA/AA genotypes and 76% the −308 GG genotype, similar to findings in controls. Patients with the −308 GA/AA genotype had higher degree of functional impairment, erythrocyte sedimentation rate, 100-mm visual analog scale score for disease activity, and TNF-α levels compared to those with the −308 GG genotype.

Conclusion.

TNF-α −308 GA/AA genotypes were found to be related to higher inflammatory activity and worse measures of disease activity in Portuguese patients with JIA. They were not associated with susceptibility to JIA.

Lack of association of functional CTLA4 polymorphisms with juvenile idiopathic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is an autoimmune disorder mediated by Th1 immune responses. CTLA-4, expressed on the T cell surface, plays a negative role in regulating T cell activation. Single-nucleotide polymorphisms (SNPs) in CTLA4 have been implicated in susceptibility to several autoimmune disorders, including JIA. This study was undertaken to test 3 functional CTLA4 variants for association with JIA.

METHODS

Families of 531 children with JIA were genotyped for SNPs located in the promoter region (C-318T), exon 1 (A49G), and the 3'-untranslated region (CT60) of CTLA4 by polymerase chain reaction amplification and digestion. Family Based Association Testing (FBAT) was used to test CTLA4 SNPs and haplotypes for association with JIA. A second independent cohort of >300 children with JIA and >500 controls were genotyped for case-control analyses. Case-control analyses of the combined cohorts, as well as meta-analyses of published association studies of CTLA4 and JIA, were performed.

RESULTS

There were no deviations of transmission of any of the CTLA4 variants to children with JIA, or JIA subtypes, determined by FBAT. No significant associations between CTLA4 C-318T or A49G SNPs and JIA were found in 650 JIA cases and 350 controls. Similarly, no significant associations with CT60 variants were found in >800 JIA cases and >500 controls. The meta-analysis also failed to confirm an association between JIA and CTLA4 variants.

CONCLUSION

These results suggest that C-318T, A49G, CT60, and haplotypes tagged by these CTLA4 SNPs are not associated with JIA or major JIA subtypes.

A comprehensive review of the genetics of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy of childhood which is believed to be influenced by both genetic and environmental factors. The progress in identifying genes underlying JIA susceptibility using candidate gene association studies has been slow. Several associations between JIA and variants in the genes encoding the human leukocyte antigens (HLA) have been confirmed and replicated in independent cohorts. However it is clear that genetic variants outside the HLA also influence susceptibility to JIA. While a large number of non-HLA candidate genes have been tested for associations, only a handful of reported associations such as PTPN22 have been validated. In this review we discuss the principles behind genetic studies of complex traits like JIA, and comprehensively catalogue non-HLA candidate-gene association studies performed in JIA to date and review several validated associations. Most candidate gene studies are underpowered and do not detect associations, and those that do are often not replicated. We also discuss the principles behind genome-wide association studies and discuss possible implications for identifying genes underlying JIA. Finally we discuss several genetic variants underlying multiple clinically distinct autoimmune phenotypes.

Macrophage migration inhibitory factor gene: influence on rheumatoid arthritis susceptibility

The macrophage inhibitory factor (MIF) is a cytokine that has been implicated in several inflammatory and autoimmune diseases, including rheumatoid arthritis, systemic lupus, glomerulonephritis, and multiple sclerosis. In rheumatoid arthritis (RA), results ranging from lack of association of MIF polymorphisms with RA, to involvement in either severity or susceptibility to the disease have been reported in the past. We aimed at investigating the role of this gene in RA in the Spanish population. Two well-known MIF promoter polymorphisms were tested in 606 adult RA patients and 886 healthy controls: a single nucleotide polymorphism at -173G/C and a tetranucleotide repeat (CATT)(5-8) located at -794. We found a significant association of the allele -173C with RA (p = 0.01; odds ratio [OR] = 1.31; 95% confidence interval [CI] = 1.06-1.62). The -173C risk allele, previously reported to be transmitted in excess in patients with juvenile idiopathic arthritis, was significantly more frequent in early-onset adult RA patients than in healthy controls (p = 0.003; OR = 1.57; 95% CI = 1.14-2.15), whereas late-onset patients were not significantly different to controls (p = 0.6; OR = 1.09; 95% CI = 0.77-1.55). In conclusion, the -173C allele in the MIF promoter region is associated with increased RA predisposition, mainly in early-onset patients.

Macrophage migration inhibitory factor: gene polymorphisms and susceptibility to inflammatory diseases

The cytokine macrophage migration inhibitory factor (MIF) is a constitutive element of the host antimicrobial defenses and stress response that promotes proinflammatory function of the innate and acquired immune systems. MIF plays an important role in the pathogenesis of acute and chronic inflammatory or autoimmune disorders, such as sepsis, acute respiratory distress syndrome, asthma, rheumatoid arthritis, and inflammatory bowel diseases. Polymorphisms of the human MIF gene (that is, guanine-to-cytosine transition at position -173 or CATT-tetranucleotide repeat at position -794) have been associated with increased susceptibility to or severity of juvenile idiopathic and adult rheumatoid arthritis, ulcerative colitis, atopy, or sarcoidosis. Whether these MIF polymorphisms affect the susceptibility to and outcome of sepsis has not yet been examined. Analyses of MIF genotypes in patients with sepsis may help to classify patients into risk categories and to identify those patients who may benefit from anti-MIF therapeutic strategies.

Gene polymorphism and requirement for vasopressor infusion after cardiac surgery

BACKGROUND

Genes in the class III region of the MHC, encoding proteins involved in inflammation and vascular regulation, were investigated for association with the occurrence of vasodilation and requirement for vasopressor infusion.

METHODS

A cohort of 236 elective cardiac surgical patients was studied. Hemodynamic and metabolic variables and dosage of vasopressor medications were recorded for the first 12 hours of intensive care unit admission after cardiac surgery on an electronic patient record. Demographic factors and operative details were recorded from other institutional databases. The DNA was extracted from peripheral blood mononuclear cells and genotyped for the presence of polymorphic alleles in genes coding for inflammation-related proteins.

RESULTS

Carriage of the dimethylarginine dimethylaminohydrolase II (DDAH II) -449 G allele and the lymphotoxin alpha +252 G allele was significantly less frequent in patients who required infusions of vasopressors after cardiac surgery. On multivariate analysis, prior myocardial infarction, prolonged bypass, and the homozygous carriage of the DDAH II C allele were associated with postoperative vasopressor requirement.

CONCLUSIONS

Vasopressor requirement after surgery may be related to an interaction of genotype, preoperative morbidity, and prolonged surgery.

Polymorphism of the promoter region and exon 1 of the CTLA4 gene in endemic pemphigus foliaceus (fogo selvagem)

Endemic pemphigus foliaceus (EPF) is an autoimmune bullous skin disease characterized by acantholysis and antibodies against a desmosomal protein, desmoglein 1. Genetic and environmental factors contribute to development of this multifactorial disease. HLA class II and some cytokine gene polymorphisms are the only genetic markers thus far known to be associated with susceptibility to or protection from EPF. The cytotoxic T-lymphocyte antigen-4 gene (CTLA4) encodes a key immunoreceptor molecule that regulates and inhibits T-cell proliferation. It participates in the regulatory process controlling autoreactivity and therefore has been considered a strong candidate gene in autoimmune diseases. In the search for genes that might influence EPF pathogenesis, we analyzed variants of the CTLA4 gene in a sample of 118 patients and 291 controls from a Brazilian population. This is the first study investigating the possible role of polymorphisms of the 2q33 chromosomal region in differential susceptibility to pemphigus foliaceus. Promoter region and exon 1 single nucleotide polymorphisms -318 (C,T) and 49 (A,G) were genotyped using sequence-specific oligonucleotide probes after amplification by the polymerase chain reaction. The allelic and genotypic frequencies did not differ significantly between the patient and the control groups (-318T: 9.8 and 10.9%, 49G: 33.0 and 35.2% were the allelic frequencies in patients and controls, respectively). In addition, no significant difference was found when the patient and control population samples were stratified by the presence of HLA-DRB1 alleles. We conclude that the CTLA4 -318 (C,T) and 49 (A,G) polymorphisms do not play a major role in EPF development.

Subtyping schizophrenia: implications for genetic research

Phenotypic variability and likely extensive genetic heterogeneity have been confounding the search for the causes of schizophrenia since the inception of the diagnostic category. The inconsistent results of genetic linkage and association studies using the diagnostic category as the sole schizophrenia phenotype suggest that the current broad concept of schizophrenia does not demarcate a homogeneous disease entity. Approaches involving subtyping and stratification by covariates to reduce heterogeneity have been successful in the genetic study of other complex disorders, but rarely applied in schizophrenia research. This article reviews past and present attempts at delineating schizophrenia subtypes based on clinical features, statistically derived measures, putative genetic indicators, and intermediate phenotypes, highlighting the potential utility of multidomain neurocognitive endophenotypes.

Genomic progress in pediatric arthritis: recent work and future goals

PURPOSE OF REVIEW

Pediatric arthritis is a heterogeneous group of chronic arthropathies that are influenced by complex genetic and perhaps environmental factors. Interacting genetic traits may one day be identified that provide the basis for predicting disease risk and other characteristics such as course, age of onset, and disease severity. The purpose of this review is to describe the recent progress towards identifying the multiple genes related to pediatric arthritis and understand how they relate to each other and to disease pathology.

RECENT FINDINGS

Candidate gene studies are by far the most widely reported type of genetic studies to date for juvenile arthritis with only one genome-wide screen for juvenile rheumatoid/idiopathic arthritis published. Particular attention is paid to studies of candidate genes with potential immunological roles and those associated with other forms of autoimmunity.

SUMMARY

Genomic studies may perhaps one day provide information to allow future classification systems of childhood arthritis to include molecular biomarkers as a complement to clinical observations, as well as understand how these genes or proteins relate to each other and to disease pathogenesis.