Two single‐nucleotide polymorphisms in the 5′ and 3′ ends of the osteopontin gene contribute to susceptibility to systemic lupus erythematosus

Objective

To test the association of osteopontin (OPN) polymorphisms with systemic lupus erythematosus (SLE).

Methods

The coding 5′ and 3′ flanking regions of the OPN gene were scanned for polymorphisms by denaturing high‐performance liquid chromatography. A case–control association study was performed in 394 Italian SLE patients and 479 matched controls. OPN serum levels were determined by enzyme‐linked immunosorbent assay in 40 patients and 124 controls, and the mean levels were compared between the different OPN genotypes.

Results

Among the 13 detected single‐nucleotide polymorphisms (SNPs), alleles −156G (frequency 0.714 versus 0.651; P = 0.006, corrected P [P_corr] = 0.036) and +1239C (0.377 versus 0.297; P = 0.00094, P_corr = 0.0056) were significantly increased in the SLE patients compared with the controls. The presence of the associated allele in single or double dose conferred an odds ratio (OR) of 2.35 (95% confidence interval [95% CI] 1.38–4.02) for SNP −156 and an OR of 1.57 (95% CI 1.16–2.13) for SNP +1239. These effects were independent of each other, i.e., not a consequence of linkage disequilibrium between the 2 alleles. The risk associated with a double dose of susceptibility alleles at both SNPs was 3.8‐fold higher (95% CI 2.0–7.4) relative to the complete absence of susceptibility alleles. With regard to individual clinical and immunologic features, a significant association was seen between lymphadenopathy and −156 genotypes (overall P = 0.0011, P_corr = 0.046). A significantly increased OPN serum level was detected in healthy individuals carrying +1239C (P = 0.002), which is indicative of an association between the SLE susceptibility allele and OPN levels.

Conclusion

These data suggest the independent effect of a promoter (−156) and a 3′‐untranslated region (+1239) SNP in SLE susceptibility. We can speculate that these sequence variants (or others in perfect linkage disequilibrium) create a predisposition to high production of OPN, and that this in turn may confer susceptibility to SLE.

     

Association of the CT60 marker of the CTLA4 gene with systemic lupus erythematosus

OBJECTIVE: To investigate the possible association of the CT60A/G marker with systemic lupus erythematosus (SLE) in Spanish patients, and to identify the possible CTLA4 haplotype responsible for the association, taking into account other polymorphisms described at positions -1722T/C, -319C/T, +49A/G, and the microsatellite (AT)(n) in the 3'-untranslated region (3'-UTR) of the CTLA4 gene. METHODS: Genotyping of CT60 was performed in 395 patients with SLE and 293 healthy controls using polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis. Genotyping of the rest of the dimorphisms has been previously reported. Genotyping of microsatellite polymorphism (AT)(n) in the 3'-UTR was performed using PCR with a fluorescence-labeled primer. RESULTS: With regard to CT60A/G, the frequency of the AA genotype was significantly decreased among the SLE patients (18.7% versus 28.3% in the control group; P = 0.003, corrected P [P(corr)] = 0.009, odds ratio [OR] = 0.58, 95% confidence interval [95% CI] 0.40-0.85). In other words, the frequency of individuals bearing the G phenotype was increased in the patient group compared with the control group (81.2% versus 71.7%; P = 0.003, P(corr) = 0.006, OR = 1.71, 95% CI 1.18-2.49). The distribution of allele frequency was also significantly different between patients and controls (P = 0.01, P(corr) = 0.02, OR [for allele G] = 1.32, 95% CI 1.06-1.65). After combining the data on the different polymorphisms, 2 neutral haplotypes were found: +49A;(AT)(7);CT60A and +49G;(AT)(8-19);CT60G. In addition, a susceptibility haplotype was found: +49A;(AT)(>19);CT60G. CONCLUSION: The 3'-UTR of the CTLA4 gene is involved in susceptibility to SLE.     

Variants in Intron 4 of PD-1 Gene are Associated with the Susceptibility to SLE in an Iranian Population

Background: Programmed cell death protein 1 (PD-1) is a negative costimulatory molecule with immunomodulatory properties. Recently, PD-1 gene defects have attracted attention in the pathogenesis of SLE. Objective: Here, we assessed the association of PD-1 gene polymorphisms in intron 4 and haplotypes with the susceptibility to SLE. Method: Seventy-six SLE patients and 159 healthy controls were included. We screened the polymorphisms by amplifying the intron 4 of the PD-1 gene with the specific primers followed by sequencing. Results: Two distinct SNPs were identified (rs6705653 and rs41386439) within the intron 4 of the PD-1 gene. The AA genotype of +7499 (G/A) SNP was associated with the higher risk of SLE [OR=3.31, 95% CI (1.25-8.76), p-value=0.045], while A allele was identified as a risk allele [OR=1.75, 95% CI (1.10-2.76), p-value=0.015]. However, no significant association was observed between the allele and the genotype frequencies of +7209 (C/T) polymorphic region of the PD-1 gene and susceptibility to SLE. Haplotype analysis showed the significantly higher presence of H2 haplotype (AC; +7499/+7209) [OR=1.70, 95% CI (1.24-2.33), p-value=0.0012] in SLE patients. Conclusion: To the best of our knowledge, this is the first report of the significant association of PD-1 +7499 (G/A) SNP with the SLE susceptibility and the first detection of both polymorphic loci in a population from Iran. However, more investigations are necessary to confirm these findings.     

A new haplotype of PDCD1 is associated with rheumatoid arthritis in Hong Kong Chinese

OBJECTIVE: The programmed death 1 (PD-1) molecule is a negative regulator of T cells, and a genetic association between PD-1 and systemic lupus erythematosus and rheumatoid arthritis (RA) in Caucasians has been reported. The aim of this study was to investigate the association of PDCD1 polymorphisms and haplotypes with RA in the Chinese population. METHODS: Three single-nucleotide polymorphisms (SNPs), PD-1.1 G/A, PD-1.3 G/A, and PD-1.5 C/T, were genotyped in 180 patients with RA and 647 healthy controls in a case-control association study. Analyses of the association of genotypes and alleles with disease, haplotype construction, and linkage disequilibrium (LD) were performed. RESULTS: We constructed haplotypes with the alleles of markers PD-1.1 G/A and PD-1.5 C/T and found that the GT haplotype was overrepresented in patients with RA (31%) compared with controls (23%) (P = 0.001, odds ratio [OR] 1.54, 95% confidence interval [95% CI] 1.18-1.99). Among GT double homozygotes the risk of RA was increased even further (OR 2.31, 95% CI 1.31-4.08, P = 0.006). We also observed that the AA genotype of SNP PD-1.1 was associated with a decreased risk for developing RA (OR 0.38, 95% CI 0.15-0.99, P = 0.034). No association for SNP PD-1.5 in RA was found, and SNP PD-1.3 was nonpolymorphic in the Chinese population. CONCLUSION: Our results support the involvement of PDCD1 as a susceptibility gene for RA in the Chinese population.     

Analysis of single-nucleotide polymorphisms in Japanese rheumatoid arthritis patients shows additional susceptibility markers besides the classic shared epitope susceptibility sequences

OBJECTIVE: To examine the entire HLA region for loci (other than the DRB1 locus) associated with rheumatoid arthritis (RA) susceptibility, by typing HLA-DRB1 alleles and multiple single-nucleotide polymorphisms (SNPs) in the Japanese population. METHODS: The HLA-DRB1 alleles and 88 SNPs distributed over the HLA gene complex were genotyped, for 828 patients with RA and 1,032 control subjects. The data were evaluated for linkage disequilibrium, and case-control associations were analyzed in 2 ways, in the presence or absence of the disease-susceptibility DRB1 allele, to detect loci independent of the DRB1 allele. RESULTS: HLA-DRB1 alleles *0405, *0401, *0901, *0101, *1401, *1602, *0403, and *1405 were significantly associated with RA in the Japanese population. The smallest P value (P = 1.4 x 10(-27)) was observed in association with an intronic SNP of the NOTCH4 gene, which was due to strong linkage disequilibrium with the HLA-DRB1 allele. A strong association that was independent of HLA-DRB1 shared epitope alleles was observed in 2 SNPs: one in the intron of the MICA gene, the other in the intron of the HLA-DQB2 gene. Their association with RA, independent of HLA-DRB1 shared epitope alleles, was suggestive (P = 0.0024 [corrected P (P(corr)) = 0.068, and P = 0.00037 [P(corr) = 0.012], respectively). CONCLUSION: These findings suggest that 1 or more other loci besides the HLA-DRB1 or other DRB1 (non-shared epitope, non-*0901) alleles are involved in RA susceptibility/protection.     

p21 gene polymorphisms in systemic lupus erythematosus

OBJECTIVE: Cyclin-dependent kinase inhibitor 1A (p21) is a negative regulator in the cell cycle. Development of sex-linked lupus-like syndrome in p21-/- mice and reduced p21 gene expression in patients with systemic lupus erythematosus (SLE) compared with those in healthy controls suggested that p21 is a susceptibility gene of SLE. We investigated the same by a case-control association study. METHODS: Six single nucleotide polymorphisms, p21US G/A, p21DS C/A, p21-1022 G/A, p21C31 C/A, p21In2 G/C and p21UTR T/C, were genotyped in 516 SLE patients and 693 healthy controls. Association of genotypes and alleles with disease, disease phenotypes, haplotypes construction, linkage disequilibrium analysis and p21 mRNA expression were performed. RESULTS: We found a significant association of p21US A allele (OR = 0.23, 95% CI: 0.14-0.38, P < 0.001) and p21-1022 A allele (OR = 1.95, 95% CI: 1.37-2.78, P < 0.001) with SLE. We identified significant differences in the frequencies of haplotypes ht1-ACACCC, which contains p21US A allele, and ht2-GCACCC, which contains p21-1022 A allele, between SLE patients and controls (P < 0.0001). Besides, the p21US GA was associated with SLE patients suffering from arthritis (P = 0.003). We also observed differential p21 mRNA expressions among different genotypes of p21US and p21-1022 which were statistically significant. CONCLUSION: Our results suggested that the p21US A allele and p21-1022 A allele were both associated with the development of SLE, and the p21US A allele was associated with arthritis in SLE patients.     

Cyclooxygenase-2 polymorphisms and susceptibility to gastric carcinoma: a meta-analysis

AIM: To investigate the association of the cyclooxygenases-2 (COX-2) polymorphisms and susceptibility to gastric cancer (GC) by means of meta-analysis. METHODS: Publications addressing the association between polymorphisms of COX-2 and susceptibility to GC were selected from the MEDLINE, EMBASE and CBMdisc databases. Data was extracted from the studies by 2 independent reviewers. The meta-analyses were performed by RevMan 5.0.23. From these data, odds ratio (OR) with 95% confidence interval (CI) was calculated.RESULTS: Ten studies were retrieved reporting a total of 11 COX-2 polymorphisms. Carriers of -765C, -1195A, -1290G, *2430T alleles and *429TT genotype revealed increased risk for GC (OR = 1.71, 95% CI: 1.01-2.90, P = 0.05; OR = 1.58, 95% CI: 1.05-2.38, P = 0.03; OR = 1.55, 95% CI: 1.01-2.39, P = 0.05; OR = 2.62, 95% CI: 1.20-5.73, P = 0.02 and OR = 0.74, 95% CI: 0.59-0.95, P = 0.02, respectively). CONCLUSION: The -765C, -1195A, -1290G, *2430T alleles and *429TT genotype of COX-2 polymorphisms were determined a significant association with susceptibility to GC.     

Wnt-1-inducible signaling pathway protein 3 and susceptibility to juvenile idiopathic arthritis

OBJECTIVE: To determine whether Wnt-1-inducible signaling pathway protein 3 (WISP3) polymorphisms are associated with susceptibility to juvenile idiopathic arthritis (JIA). METHODS: The exons and the intron/exon boundaries of the WISP3 gene were mutation-screened by denaturing high-performance liquid chromatography in 86 patients with polyarticular-course JIA (>/=5 joints affected) and 15 controls. Seven single-nucleotide polymorphisms (SNPs) were genotyped, using allelic discrimination, in a case-control study. Initially, 159 patients with polyarticular-course JIA and 263 controls were studied, followed by study of a replication cohort of 181 patients with polyarticular-course JIA and 355 controls. Available parents of patients with polyarticular-course JIA were also genotyped. Finally, other JIA subgroups were studied (initial cohort, n = 218; replication cohort, n = 213). Single-point and haplotype analysis was carried out. RESULTS: Positive association with SNP WISP3*G84A was observed and replicated in 2 cohorts of patients with polyarticular-course JIA. Specifically, homozygosity of the mutant allele (WISP3*84AA) conferred a 2-fold increased risk of disease susceptibility (for the initial cohort, odds ratio [OR] 2.1, 95% confidence interval [95% CI] 1.1-4.2, P = 0.03; for the replication cohort, OR 2.0, 95% CI 1.0-4.3, P = 0.05). Strong linkage disequilibrium was observed between SNPs; however, no haplotypic effect of an order of magnitude greater than the single-point WISP3*G84A association was observed. Using the transmission disequilibrium test, a trend toward overtransmission of the WISP3*84A allele was observed in patients with polyarticular-course JIA. No association of any WISP3 polymorphism was observed in the other JIA subgroups. CONCLUSION: Association and replication of a polymorphism within the first intron of the WISP3 gene have been shown in patients with polyarticular-course JIA. The functional significance of the WISP3*G84A SNP is being determined.     

IL13RA2 gene polymorphisms are associated with systemic sclerosis

OBJECTIVE: To investigate the influence of genetic variability on the phenotypic expression of systemic sclerosis (SSc), by testing possible associations between single nucleotide polymorphisms (SNP) in IL13RA1 and IL13RA2 genes and SSc in a Caucasian population. METHODS: As IL13RA1 and IL13RA2 are located on the X chromosome and SSc occurs far more frequently in women than in men, only women were genotyped. The study group comprised 97 women with SSc, 36 with diffuse (dcSSc) and 61 with limited (lcSSc) cutaneous forms of disease, and 109 healthy controls. Patients and controls were Caucasian. We investigated 4 SNP in IL13RA1 and 3 in IL13RA2 by polymerase chain reaction amplifications and enzymatic digestion or primer extension reactions and denaturing high-performance liquid chromatography. RESULTS: We detected an association between IL13RA2 rs638376 and patients with SSc [p = 0.004, odds ratio (OR) = 1.85, confidence interval (CI) 1.22-2.74, p corr = 0.02], as well as with dcSSc in that subgroup of patients (p = 0.01, OR 2.22, 95% CI 1.27-3.89, p corr = 0.05). The IL13RA2 rs638376G allele frequency was higher in patients with SSc (51.6%) than in controls (36.4%, p = 0.003, OR 1.86, 95% CI 1.24-2.79, p corr = 0.015) and in the subgroup with dcSSc (57.6%) than in controls (36.4%, p = 0.003, OR 2.37, 95% CI 1.35-4.15, p corr = 0.015). One other IL13RA2 SNP was only associated with the dcSSc subgroup: the IL13RA2 rs5946040G allele was more common in patients with dcSSc (33.8%) than in controls (17%, p = 0.004, OR 2.5, 95% CI 1.36-4.60, p corr = 0.02). CONCLUSION: Our data suggest that IL13RA2 gene polymorphisms may be involved in susceptibility to SSc. Further studies are under way to show that they contribute to disease.     

No primary association of MICA polymorphism with systemic lupus erythematosus

OBJECTIVE: To replicate the described association between MHC class I chain-related A (MICA) gene polymorphism and susceptibility to systemic lupus erythematosus (SLE). METHODS: MICA transmembrane microsatellite polymorphism was genotyped using a polymerase chain reaction (PCR)-based method. Genotyping of HLA-B* and DRB1* was performed using PCR and detection with a reverse sequence-specific oligonucleotide (SSO) probe system. Combined data for these three loci (HLA-B*, DRB1* and MICA) were obtained from a total of 333 patients and 361 healthy controls. RESULTS: Significant association with B*08 [P < 10(-7), odds ratio (OR) 3.17, 95% confidence interval (CI) 2.02-5.00], DRB1*0301 (P < 10(-7), OR 2.07, 95% CI 1.59-2.68) and MICA5.1 (P = 0.01, OR 1.23, 95% CI 1.04-1.46) was observed. The combinations DRB1*0301-MICA5.1-B8 and HLA-DRB1*0301-B*08-positive and MICA5-1-negative were more frequent among SLE patients (11.4 vs 3.3% in healthy controls, P = 3.9 x 10(-5), OR 3.76, 95% CI 1.85-7.73, and 6.9 vs 1.7%, P = 0.0007, OR 4.32, 95% CI 1.68-13.10, respectively). Additionally, individuals who were HLA-DRB1*0301-B*08-negative and MICA5-1-positive were less frequent among patients (22.2 vs 31.3% in healthy controls, P = 0.007, OR 0.63, 95% CI 0.44-0.89) and the magnitude of the OR was similar to that obtained in individuals negative for all the three factors (OR 0.69, 95% CI 050-0.94). Further analysis performed to detect independent association strongly suggested that the association between MICA5.1 and SLE is secondary to the linkage disequilibrium of this allele with B*08. CONCLUSIONS: Our results do not support an independent association of MICA gene polymorphism with susceptibility to SLE.     

Association of interferon regulatory factor 5 haplotypes, similar to that found in systemic lupus erythematosus, in a large subgroup of patients with rheumatoid arthritis

OBJECTIVE: Previous studies have shown either a lack of effect of IRF5 polymorphisms or an association of the IRF5 gene in only a minor subset of rheumatoid arthritis (RA) patients in whom anti-citrullinated protein antibodies (ACPAs) are absent. The present study was undertaken to investigate the role of genetic variation in IRF5 in susceptibility to RA. METHODS: Nine IRF5 single-nucleotide polymorphisms (SNPs) were studied in 1,338 patients with RA and 1,342 control subjects in analyses of exploratory and replication sample collections, with stratification according to sex and by the presence or absence of ACPAs, rheumatoid factor, the shared epitope, the 620W PTPN22 allele, and erosions. A meta-analysis that included results from previous studies was also carried out. RESULTS: Our findings together with those from previous studies, in a total of 4,620 RA patients and 3,741 controls, showed a significant association of the rs2004640 IRF5 SNP in RA patients as a whole (odds ratio [OR] 0.88, 95% confidence interval [95% CI] 0.83-0.94; P = 6.5 x 10(-5) versus controls). This association was stronger in ACPA- patients, but was also present in ACPA+ patients (from 3 sample collections). Further analysis of our exploratory sample collection showed that only patients in the ACPA+ and SE- group lacked an association with IRF5 SNPs. All of the remaining RA patients (ACPA- or SE+) showed a strong association with IRF5 SNPs, which followed a complex pattern of opposing effects mediated by independent haplotypes. The susceptibility haplotype showed an OR of 1.8 (95% CI 1.4-2.3; P = 1.2 x 10(-6) versus controls), whereas the protective haplotype showed an OR of 0.76 (95% CI 0.6-0.98; P = 0.046 versus controls). CONCLUSION: IRF5 polymorphisms seem to influence RA susceptibility in a large subgroup of patients, following a pattern of association very similar to that described in patients with systemic lupus erythematosus.     

The adiponectin gene SNP+45 is associated with coronary artery disease in Type 2 (non-insulin-dependent) diabetes mellitus.

BACKGROUND: The ACRP30/adiponectin gene on chromosome 3q27, a region linked to the metabolic syndrome, encodes for the abundant adipocyte-specific secreted protein. Consistent rodent and human studies suggested that this adipokine may be a molecular link between metabolic and cardiovascular diseases. AIMS: In order to investigate the role of single nucleotide polymorphisms (SNPs) within the APM1 gene in the susceptibility to coronary artery disease (CAD), we performed a case-control study on Caucasian Type 2 (non-insulin-dependent) diabetic patients, a population at high-risk for CAD. METHODS: Five APM1 SNPs were genotyped in 162 Type 2 diabetic French and Swiss subjects with CAD and in 315 Type 2 diabetic French and Swiss subjects without CAD. RESULTS: In univariate analysis, SNP+45 T>G was associated with CAD (OR 1.9 95% CI 1.2-2.9 P = 0.0036). In multivariate analysis, SNP+45 T>G remained associated with CAD (OR 1.2 95% CI 0.8-1.9 P = 0.017), independently of classical cardiovascular risk factors including components of the metabolic syndrome. SNP haplotype analyses revealed a CAD protective combination of all SNP wild-type alleles (OR 0.5 95% CI 0.3-0.7 P = 0.0006). CONCLUSIONS: Our study, performed in diabetic subjects, revealed an association between individual SNP+45 in the APM1 gene and CAD. Furthermore, the susceptibility for CAD due to SNP+45 was independent of classic cardiovascular risk factors. Further studies will be necessary to confirm the role of SNP+45 in the development of CAD. However, ACRP30/adiponectin may contribute to atherosclerosis susceptibility in high-risk populations such as Type 2 diabetic subjects.     

HO-1 promoter polymorphism associated with rheumatoid arthritis

OBJECTIVE: To investigate the role of the HO-1 gene as a novel functional candidate gene for rheumatoid arthritis (RA). METHODS: We performed a case-control study including 736 RA patients and 846 healthy controls of Spanish Caucasian origin. Two putative functional HO-1 promoter polymorphisms, a (GT)(n) microsatellite and a -413 A/T single-nucleotide polymorphism (SNP), were selected as genetic markers and genotyped using polymerase chain reaction-based methods. In addition, the intracellular expression of heme oxygenase 1 (HO-1) was determined in healthy individuals with different (GT)(n) genotypes. RESULTS: The distribution of HO-1 (GT)(n) short (S) alleles (< or =25 GT repeats) and long (L) alleles (>25 GT repeats) revealed a significant protective effect of S (GT)(n) alleles (P = 0.019) (odds ratio [OR] 0.8, 95% confidence interval [95% CI] 0.7-0.9) and the SS (GT)(n) genotype (P = 0.002) (OR 0.6, 95% CI 0.4-0.9). In contrast, the -413 HO-1 promoter SNP did not yield any statistically significant deviation between RA patients and controls, considering either allele or genotype frequencies. The haplotype analysis showed a strong protective effect of the S/A haplotype (P = 7 x 10(-7), corrected P [P(corr)] = 3 x 10(-6)) (OR 0.4, 95% CI 0.3-0.6), whereas the L/A haplotype showed the opposite tendency (P = 0.008, P(corr) = 0.03) (OR 1.2, 95% CI 1.0-1.4). In addition, we demonstrated that monocytes from individuals carrying the SS (GT)(n) genotype showed a significantly higher percentage of HO-1 expression than did cells from LL homozygous individuals (P = 0.0003). CONCLUSION: In this study, we identified the HO-1 (GT)(n) microsatellite as a new genetic marker involved in RA genetics in our population.     

Association of the PD-1.3A allele of the PDCD1 gene in patients with rheumatoid arthritis negative for rheumatoid factor and the shared epitope

OBJECTIVE: To study the frequency of allele A of polymorphism PD-1.3 of the PDCD1 gene in patients with rheumatoid arthritis (RA) and its subsets, based on the presence of rheumatoid factor (RF) and the shared epitope (SE) alleles. METHODS: A total of 1,175 patients with RA and 3,404 controls were genotyped for the PD-1.3 A/G polymorphism, which previously was identified as being involved in susceptibility to systemic lupus erythematosus (SLE) in patients of European descent. RESULTS: We first detected a trend for association of allele A of the single-nucleotide polymorphism PD-1.3 with RA (P = 0.053, odds ratio [OR] 1.18, 95% confidence interval [95% CI] 0.99-1.41). To further clarify the nature of this association, patients with RA were divided into 4 groups according to the presence of RF and the SE alleles. Association was found only in the group of patients negative for both RF and the SE alleles (P = 0.0054 [corrected P = 0.015], OR 1.75, 95% CI 1.15-2.65). CONCLUSION: Patients negative for both RF and the SE alleles showed association with the same allele that we previously identified as being involved in susceptibility to SLE. These results provide the first evidence of the involvement of the human PDCD1 gene in arthritis.     

Interleukin-10 gene polymorphisms are associated with the SLICC/ACR Damage Index in systemic lupus erythematosus

OBJECTIVE: Overproduction of interleukin-10 (IL-10) is a pivotal feature in the pathophysiology of systemic lupus erythematosus (SLE). We examined the IL10 genotype of Korean patients with SLE and normal controls to determine whether associations exist between the pattern of inherited IL10 genes and SLE susceptibility or the SLICC/ACR Damage Index (SDI). METHODS: A total of 350 Korean SLE patients and 330 healthy subjects were enrolled. Direct DNA sequencing and primer extension procedures were employed. Logistic regression analyses were performed to examine the genetic association with SLE and SDI. RESULTS: Eight sequence variants were identified by direct DNA sequencing in 24 Korean individuals. Five of the polymorphisms were selected for larger scale genotyping (n = 680) by considering their allele frequencies, haplotype-tagging status and linkage disequilibrium coefficients among polymorphisms. Haplotypes and allele distributions of the IL10 polymorphisms did not differ significantly between SLE patients and controls. Among identified SNPs, the rare C allele of IL10-592A-->C was significantly associated with the SDI among SLE patients in the following three alternative models: codominant (P = 0.007, odds ratio = 1.70), dominant (P = 0.02, odds ratio = 1.85) and recessive (P = 0.05, odds ratio = 2.25). Similarly, IL10+955T-->G and IL10-ht2 were significantly associated with the SDI in the codominant and dominant models. CONCLUSION: IL10 polymorphisms are not associated with disease susceptibility in Korean patients with SLE. However, IL10-592A-->C, IL10+955T-->G and IL10-ht2 are significantly associated with the SDI, suggesting that IL10-592C, IL10+955G and IL10-ht2 accelerate the damage induced by SLE.     

Genetic linkage and association of Fcgamma receptor IIIA (CD16A) on chromosome 1q23 with human systemic lupus erythematosus

OBJECTIVE: Although low-affinity alleles of human Fcgamma receptor types IIA and IIIA (FcgammaRIIA and FcgammaRIIIA, respectively) polymorphisms have been associated with systemic lupus erythematosus (SLE) in case-control studies, the relative contribution of these genes to SLE susceptibility has not been resolved. METHODS: We analyzed the distribution of alleles of FcgammaRIIA, FcgammaRIIIA, and FcgammaRIIIB in 126 multiplex-SLE pedigrees and FcgammaRIIA and FcgammaRIIIA in a case-control replication study, using allele-specific polymerase chain reaction and direct sequencing of genomic DNA. Statistical tests of association were performed to detect evidence of linkage between the single nucleotide polymorphisms and SLE. RESULTS: We found evidence for linkage at both the FcgammaRIIIA (single-point nonparametric linkage [NPL] 1.8, P = 0.038; multipoint NPL 2.7, P = 0.004) and the FcgammaRIIA (single-point NPL 2.0, P = 0.021; multipoint NPL 2.6, P = 0.006) loci, but not the FcgammaRIIIB locus. Family-based tests of association demonstrated increased transmission of the low-affinity F176 allele at the FcgammaRIIIA locus (odds ratio [OR] 2.18, P = 0.0005 by transmission disequilibrium test and P = 0.002, by pedigree disequilibrium test [PDT]), but little evidence of preferential transmission of alleles at FcgammaRIIA (P = 0.089 by PDT). Stratification by ethnicity showed preferential transmission of the associated FcgammaRIIIA allele both in families of African American ancestry and in those of European American ancestry. Despite significant linkage disequilibrium between these genes, 2- and 3-locus haplotype analysis of the extended Fcgamma receptor cluster did not reveal any significant association beyond that observed with FcgammaRIIIA alone. In a large case-control replication study of 438 patients with SLE and 219 controls, FcgammaRIIIA provided the strongest evidence of an FcgammaR-SLE association (additive model: V/V 176 versus V/F 176 OR 1.51, V/V 176 versus F/F 176 OR 1.98, P = 0.007). CONCLUSION: To our knowledge, these data are the first to demonstrate linkage and both family-based and case-control-based association of FcgammaRIIIA with SLE. These data provide genetic evidence supporting a role for the physiologically relevant single nucleotide polymorphism of the FcgammaRIIIA gene in the pathophysiology of this complex genetic disease.     

Influence of VEGF gene polymorphisms on the severity of ankylosing spondylitis

OBJECTIVES: To investigate the role of polymorphisms of the vascular endothelial growth factor (VEGF) gene in susceptibility to ankylosing spondylitis (AS), and their relationship to clinical features and radiographic severity. METHODS: This study included 157 patients with AS and 140 healthy unrelated controls. Polymorphisms of the VEGF gene were analysed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism assay and amplification refractory mutation system-PCR. Haplotypes were reconstructed using the Bayesian algorithm. Radiographic severity was assessed by the Bath Ankylosing Spondylitis Radiological Index (BASRI). RESULTS: The genotype frequencies of the polymorphisms were in Hardy-Weinberg equilibrium. The distributions of genotypes and alleles did not differ between AS patients and controls. Among the six haplotypes reconstructed based on the tight linkage disequilibrium at positions -2578, -1154 and -634 (pairwise linkage disequilibrium coefficient, r = 0.361-0.706), no haplotype was associated with susceptibility to AS. Clinical features were analysed for the four haplotypes (CGC, CGG, AAG, AGG) which were prevalent. In carriers of the AGG haplotype, the frequency of cervical spine involvement was significantly higher (P = 0.002, P(corr) = 0.036) and that of patients showing a BASRI score >6 was also higher (P = 0.025, P(corr) = 0.45). CONCLUSIONS: This study demonstrates that polymorphisms of the VEGF gene may contribute to disease severity in AS.     

Contribution of MHC class I region to genetic susceptibility for giant cell arteritis

OBJECTIVE: The aim of this study was to assess the potential contribution of HLA-class I MICA and HLA-B gene polymorphisms towards the pathogenesis of giant cell arteritis (GCA). METHODS: Ninety-eight biopsy-proven GCA patients and 225 ethnically matched controls from Lugo, Northwest Spain, were genotyped for the MICA-TM microsatellite polymorphism using a polymerase chain reaction (PCR)-based method. Genotyping of HLA-B was performed using PCR and detection with a reverse sequence-specific oligonucleotide (SSO) probes system. RESULTS: A significant difference in the distribution of the alleles of MICA between patient and control groups (P = 0.005) was found. This was due to an increased frequency of the MICA A5 allele in GCA patients compared with controls (26 vs 13.6%; P = 0.0001; P(C) = 0.0005; OR 2.2, 95% CI 1.4-3.4). In addition, the HLA-B*15 allele showed a higher frequency in GCA patients compared with controls (P = 0.004; P(C) = 0.04; OR 2.7, 95% CI 1.3-5.7). Interestingly, the association observed with the MICA A5 allele seems to be independent of linkage disequilibrium with HLA-B, as well as independent of that previously described with HLA-DRB1*04. Remarkably, simultaneous presence of MICA A5 and HLA-B*15 or HLA-DRB1*04 genetic markers leads to an increase in the OR obtained for each individual genetic marker (MICA A5 + B*15 OR 3.2; MICA A5 + DRB1*04 OR 5.8). CONCLUSIONS: Our results provide the first evidence that the MICA and HLA-B genes are independently associated with the genetic susceptibility to GCA, and suggest that several genes within the MHC might have independent effects in the susceptibility to this systemic vasculitis.     

Single nucleotide polymorphisms of CD244 gene predispose to renal and neuropsychiatric manifestations with systemic lupus erythematosus

Abstract

The objective of this study was to explore the association of single nucleotide polymorphisms (SNPs) of the CD244 gene with several clinical features of systemic lupus erythematosus (SLE). Two hundred and forty-three patients with SLE and 369 healthy controls were enrolled. Two SNPs (rs6682654 and rs3766379) in the CD244 gene were determined by allelic discrimination using a specific TaqMan probe. Only SNP rs3766379 was significantly associated with susceptibility to SLE [P = 0.009; odds ratio (OR) 1.28; 95% confidence interval (CI) 1.04–1.57]. The association was preferentially observed in subsets of SLE patients with nephritis and neuropsychiatric lupus. The frequency of the rs6682654 C allele was strongly associated with nephritis and neuropsychiatric lupus (P = 0.00065; OR 1.99; 95% CI 1.34–2.95, and P = 1.6 × 10^?7; OR 3.47; 95% CI 2.12–5.70, respectively), as was the frequency of the rs3766379 T allele (P = 0.0014; OR 1.86; 95% CI 1.27–2.71, and P = 2.6 × 10^?7; OR 3.15; 95% CI 2.00–4.96, respectively). In this study, an SNP of the CD244 gene was associated with susceptibility to SLE. There was a strikingly strong association in SLE patients with nephritis and neuropsychiatric lupus, suggesting that this genetic marker could predict involvement of those severe complications.     

MERTK polymorphisms associated with risk of haematological disorders among Korean SLE patients

OBJECTIVE: The MER receptor tyrosine kinase (MERTK) gene is critical for the efficient clearance of apoptotic cells and has implications for inflammation and autoimmune diseases such as systemic lupus erythematosus (SLE). We investigated the genetic polymorphisms in MERTK to evaluate it as a potential candidate gene for a host genetic study of SLE and clinical manifestations in patients with SLE. METHODS: By resequencing the coding and flanking regions of the MERTK gene in 24 unrelated Koreans, 37 polymorphisms were identified. Based on gene position, minor allele frequency and inter-single-nucleotide polymorphism (SNP) linkage disequilibrium, six of these polymorphisms were selected for subsequent genotyping and association analysis with the risk of SLE and haematological disorders in 350 Korean SLE patients and 330 controls. RESULTS: Although no significant associations with the risk of SLE were found, logistic regression analyses revealed that variants +465C > G (P = 0.05) and +130215insdelT (P = 0.0005) were significantly associated with decreased risk of leucopenia in SLE patients. Further, +465C > G, +95616G > A, +123157A > G and the haplotype ht1 also showed significant associations (P = 0.006-0.05) with a decreased risk of lymphopenia in SLE patients. CONCLUSION: Our findings suggest that polymorphisms in MERTK might be one of the genetic risk factors for presenting leucopenia and lymphopenia in SLE patients.