Polymorphism in the LMP2 gene influences susceptibility to extraspinal disease in HLA-B27 positive individuals with ankylosing spondylitis.

OBJECTIVE--To investigate the potential influence of the HLA-linked LMP2 gene on disease susceptibility in HLA-B27 individuals with ankylosing spondylitis (AS). METHODS--A polymorphic CfoI restriction enzyme site in the coding region of the LMP2 gene was evaluated in genomic DNA samples from 193 white and 49 Chinese B27 individuals with well documented AS, 97 of whom had had acute anterior uveitis (AAU) and 97 peripheral arthritis; 42 samples from normal, white, B27 positive blood donors in whom AS was excluded were also evaluated. RESULTS--Analysis of B27 white AS individuals with AAU, peripheral arthritis, or both, revealed significant differences in genotypic distribution of this bi-allelic locus compared with B27 AS patients without extraspinal manifestations (p < 0.005) or B27 controls (p < 0.01). Furthermore, homozygosity for one LMP2 gene allele was significantly more prevalent in AS patients with AAU (71.3%) (p < 0.01) or peripheral arthritis (68.3%) (p < 0.02) than in B27 controls (45.2%). A similar genotypic distribution was noted in B27 Chinese AS individuals with extraspinal manifestations compared with those with axial disease alone. CONCLUSIONS--These findings support the involvement of the HLA linked LMP2 gene in the expression of disease in B27 individuals and represent a novel finding in rheumatic disease.     

LMP2与LMP7基因多态性与强直性脊柱炎并发虹睫炎易感性关系的研究

目的研究ＬＭＰ基因多态性与强直性脊柱炎并发虹睫炎发病的关系。方法应用ＰＣＲ对正常人和病人进行ＨＬＡＢ２７检测以及ＬＭＰ２和ＬＭＰ７扩增。ＣｆｏＩ进行限制性酶切图谱分析。结果强直性脊柱炎有虹睫炎（ＡＳ＋ＡＡＵ）病史以及单纯虹睫炎（ＡＡＵ）患者ＬＭＰ２基因ＢＢ纯合型较正常人以及强直性脊柱炎（ＡＳ）患者明显增高（Ｐ＜００５）,ＡＳ＋ＡＡＵ患者ＢＢ型ＯＲ＝３６,ＡＡＵ患者ＢＢ型ＯＲ＝５８３。ＬＭＰ７基因多态性无明显差别。结论在我国汉人中,ＬＭＰ２基因多态性与ＡＳ＋ＡＡＵ以及ＡＡＵ发病存在明显相关关系。     

Two distinctive HLA haplotypes harbor the B27 alleles negatively or positively associated with ankylosing spondylitis in Sardinia: implications for disease pathogenesis

OBJECTIVE: To compare haplotype distribution in HLA-B27-positive patients with ankylosing spondylitis (AS) and healthy control subjects possessing either AS-associated HLA-B27 alleles or the non-AS-associated HLA-B*2709 allele. METHODS: DNA samples from 47 HLA-B27-positive patients with AS and 76 HLA-B27-positive healthy controls (19 positive and 57 negative for B*2709) living in different areas of Sardinia were collected and typed for HLA class I and class II alleles. The third exon of the B27 gene was analyzed for the presence of Asp(116) or His(116), which differentiates B*2709 from the other two B27 subtypes (B*2705 and B*2702) that are mostly found in Sardinia. The parents of 6 subjects positive for B*2709 were also typed for HLA class I and class II alleles. Statistical analysis was performed by Fisher's exact test. RESULTS: In Sardinia, the B27 alleles conferring susceptibility to AS appear to be more frequently carried by a haplotype (A2;B27;Cw2;DR16) that reaches its highest frequency in patients with AS (A2 80.8%, B27 100%, Cw2 83%, and DR16 74.5%). Conversely, the non-AS-associated B*2709 allele is more frequently found together with other HLA alleles whose frequencies are inversely correlated with the disease (A32 or A30, Cw1, and DR12). Familial analysis of 6 subjects positive for HLA-B*2709 confirmed the existence of a "Sardinian" haplotype that is not associated with AS (A32;B*2709;Cw1;DR12). CONCLUSION: In Sardinia, 2 distinct haplotypes harbor the non-AS-associated HLA-B*2709 allele or the AS-associated B27 alleles. Our findings are compatible with the hypothesis that other genes within the HLA region besides HLA-B27 may play some role in conferring susceptibility to AS.     

Finnish HLA studies confirm the increased risk conferred by HLA-B27 homozygosity in ankylosing spondylitis

OBJECTIVE: To determine the influence of HLA-B27 homozygosity and HLA-DRB1 alleles in the susceptibility to, and severity of, ankylosing spondylitis in a Finnish population. METHODS: 673 individuals from 261 families with ankylosing spondylitis were genotyped for HLA-DRB1 alleles and HLA-B27 heterozygosity/homozygosity. The frequencies of HLA-B27 homozygotes in probands from these families were compared with the expected number of HLA-B27 homozygotes in controls under Hardy-Weinberg equilibrium (HWE). The effect of HLA-DRB1 alleles was assessed using a logistic regression procedure conditioned on HLA-B27 and case-control analysis. RESULTS: HLA-B27 was detected in 93% of cases of ankylosing spondylitis. An overrepresentation of HLA-B27 homozygotes was noted in ankylosing spondylitis (11%) compared with the expected number of HLA-B27 homozygotes under HWE (4%) (odds ratio (OR) = 3.3 (95% confidence interval, 1.6 to 6.8), p = 0.002). HLA-B27 homozygosity was marginally associated with reduced BASDAI (HLA-B27 homozygotes, 4.5 (1.6); HLA-B27 heterozygotes, 5.4 (1.8) (mean (SD)), p = 0.05). Acute anterior uveitis (AAU) was present in significantly more HLA-B27 positive cases (50%) than HLA-B27 negative cases (16%) (OR = 5.4 (1.7 to 17), p<0.004). HLA-B27 positive cases had a lower average age of symptom onset (26.7 (8.0) years) compared with HLA-B27 negative cases (35.7 (11.2) years) (p<0.0001). CONCLUSIONS: HLA-B27 homozygosity is associated with a moderately increased risk of ankylosing spondylitis compared with HLA-B27 heterozygosity. HLA-B27 positive cases had an earlier age of onset of ankylosing spondylitis than HLA-B27 negative cases and were more likely to develop AAU. HLA-DRB1 alleles may influence the age of symptom onset of ankylosing spondylitis.     

LMP2 polymorphism is associated with extraspinal disease in HLA-B27 negative Caucasian and Mexican Mestizo patients with ankylosing spondylitis

OBJECTIVE: To determine the effects of HLA Class II genes, particularly LMP2 and previously implicated Class I genes, on susceptibility and disease expression in HLA-B27 negative ankylosing spondylitis (AS). METHODS: Patients included 41 HLA-B27 negative Caucasians from a total AS population of 546 and 17 HLA-B27 negative Mexican Mestizo. Controls included 4352 random HLA-B27 negative Caucasians. LMP2 genotype assignments were made on all patients and 282 random Caucasian controls by polymerase chain reaction-restriction fragment length polymorphism with the Cfo I restriction enzyme while HLA typing was performed on patients and controls using microcytotoxicity assays for Class I, and sequence specific probe-PCR for HLA-B60, B39, B38, and DR. RESULTS: The LMP2BB genotype was significantly decreased in Caucasian AS patients without extraspinal (ES) disease (25%) compared to AS patients with ES (64.7%) (p = 0.01) and random Caucasian controls (53.9%) (p = 0.007), even when those with colitis and psoriasis were excluded from analysis (ES+ 55.6% versus ES- 22.2%). This finding remained significant after stratification by HLA-DR. Similar trends were noted in the Mexican population. A potential role for HLA-DR8 and DR2 in susceptibility to disease was observed in Caucasian patients, although this observation requires confirmation. We could not confirm reported associations with HLA-B60 or B39. Peripheral arthritis was significantly more commonly observed in those who had had acute anterior uveitis (AAU) (75%) than in those who had not developed AAU (27.3%) (p = 0.04). CONCLUSION: HLA Class II encoded genes may have effects on disease susceptibility and/or phenotype in HLA-B27 negative individuals similar to those noted in HLA-B27 positive AS. Eccentric and axial phenotypes of disease may be immunogenetically determined.     

The -308.1 polymorphism in the promoter region of the tumor necrosis factor gene is associated with ankylosing spondylitis independent of HLA-B27.

OBJECTIVE: To investigate the allele frequencies of 6 polymorphic sites spanning the region of the genome close to the tumor necrosis factor (TNF) gene in a group of HLA-B27 positive patients with ankylosing spondylitis (AS) in the West of Scotland. METHODS: One hundred sixty-seven patients with AS, 93 healthy controls, and 88 HLA-B27 positive healthy controls, all from the West of Scotland, were typed by polymerase chain reaction (PCR) for 3 restriction fragment length polymorphisms (RFLP) and 3 microsatellite polymorphic sites spanning the TNF gene cluster. The distribution of these alleles was correlated with the presence of extraspinal manifestations such as peripheral joint disease and uveitis. RESULTS: The frequency of the Nco-1.2 allele was significantly reduced in patients compared to the genetically unselected control population (p < 0.05), but was no different from the HLA-B27 positive controls. However, the -308.1 allele was significantly increased in the patients compared to the HLA-B27 positive controls (p < 0.03). CONCLUSION: This study confirms the importance of correct matching in genetic analysis in disease association studies, and provides further evidence supporting the involvement of genes other than the MHC class I locus in the pathogenesis and features of AS.     

HLA class I associations of ankylosing spondylitis in the white population in the United Kingdom.

OBJECTIVE: To investigate the HLA class I associations of ankylosing spondylitis (AS) in the white population, with particular reference to HLA-B27 subtypes. METHODS: HLA-B27 and -B60 typing was performed in 284 white patients with AS. Allele frequencies of HLA-B27 and HLA-B60 from 5926 white bone marrow donors were used for comparison. HLA-B27 subtyping was performed by single strand conformation polymorphism (SSCP) in all HLA-B27 positive AS patients, and 154 HLA-B27 positive ethnically matched blood donors. RESULTS: The strong association of HLA-B27 and AS was confirmed (odds ratio (OR) 171, 95% confidence interval (CI) 135 to 218; p < 10(-99)). The association of HLA-B60 with AS was confirmed in HLA-B27 positive cases (OR 3.6, 95% CI 2.1 to 6.3; p < 5 x 10(-5)), and a similar association was demonstrated in HLA-B27 negative AS (OR 3.5, 95% CI 1.1 to 11.4; p < 0.05). No significant difference was observed in the frequencies of HLA-B27 allelic subtypes in patients and controls (HLA-B*2702, three of 172 patients v five of 154 controls; HLA-B*2705, 169 of 172 patients v 147 of 154 controls; HLA-B*2708, none of 172 patients v two of 154 controls), and no novel HLA-B27 alleles were detected. CONCLUSION: HLA-B27 and -B60 are associated with susceptibility to AS, but differences in HLA-B27 subtype do not affect susceptibility to AS in this white population.     

The LMP2 polymorphism is associated with susceptibility to acute anterior uveitis in HLA-B27 positive juvenile and adult Mexican subjects with ankylosing spondylitis

INTRODUCTION—An association between polymorphism of the HLA linked LMP2 locus and the development of acute anterior uveitis (AAU) has previously been described in B27 positive white subjects with ankylosing spondylitis (AS). This study evaluated LMP2 alleles in two HLA-B27 positive Mexican populations of patients with spondyloarthropathy known to have a different clinical spectrum of disease from white people.
PATIENTS AND METHODS—The study populations consisted of 90 AS patients from Guadalajara with predominantly adult onset disease and 80 AS patients from Mexico City with predominantly juvenile onset disease. LMP2-CfoI amplified fragment length polymorphisms were determined after polymerase chain reaction amplification and digestion with CfoI restriction enzyme.
RESULTS—There was an increased LMP2A allelic frequency in patients who had had AAU in both Guadalajara (31.8%) and Mexico City (33.3%) when compared with non-AAU patients (15.2% and 17.7% of Guadalajara and Mexico City populations, respectively). The odds ratio relating LMP2A allelic frequency and AAU for the combined population, stratified by age at onset of disease, was 2.51 (p=0.01). LMP2 alleles did not influence the age at onset of disease or the development of peripheral arthritis.
CONCLUSIONS—These data support the view that polymorphism at the LMP2 locus is associated with the development of AAU in B27 positive subjects with AS. The requirement for both the less common LMP2 allele and HLA-B27 is consistent with the low prevalence of AAU in Mexican patients with spondyloarthritis.

     

Restriction fragment length polymorphism of the tumor necrosis factor region in patients with ankylosing spondylitis.

Although ankylosing spondylitis (AS) is known to be strongly associated with the class I major histocompatibility complex antigen HLA-B27, B27 is probably not the only genetic factor involved in the pathogenesis of AS. Because of the involvement of tumor necrosis factor (TNF) in cartilage damage and the localization of the TNF genes in the proximity of the HLA-B locus, we investigated the association between AS and TNF alleles. The frequencies of the restriction fragment length polymorphisms linked to the TNF genes were determined in 73 AS patients and 81 controls. No differences were observed between AS patients and controls with respect to the frequencies of the TNF restriction fragment length polymorphisms.     

Association of ankylosing spondylitis with HLA-B*1403 in a West African population

OBJECTIVE: To investigate the contribution of HLA class I alleles in the susceptibility to primary ankylosing spondylitis (AS) in West African patients living in Togo. METHODS: A large epidemiologic analysis of 9,065 West African rheumatology patients living in Togo was performed in order to identify those who had AS. Eight Togolese patients with AS were identified. HLA was typed by polymerase chain reaction using sequence-specific oligonucleotide probes. DNA typing was also performed on a control population of 85 healthy subjects matched for ethnic background. RESULTS: A significant association between AS and B*14 was identified. This allele was found in 62.5% of the AS patients (odds ratio 69), but was carried by only 2% of the healthy controls. Analysis for B14 subtypes showed that B*1403 was the predominant allele in AS patients (odds ratio 171), and that this allele was absent in healthy controls. B27 was virtually absent, being observed in only 1 AS patient (B*2705). CONCLUSION: HLA-B*1403 shows the B27 "supertype" motif and may exert an effect on AS susceptibility according to the arthritogenic peptide model. The association of B*1403 with AS has not previously been reported in either population.     

HLA class II antigens (DR, DQ loci) and peripheral arthritis in ankylosing spondylitis.

Fifty one patients with ankylosing spondylitis (AS) were typed for HLA-A, B, C, DR, and DQ antigens. The antigen frequencies were compared with those of a normal population and with a B27 positive control group. All but one of the patients with AS were HLA-B27 positive. A positive linkage disequilibrium between Cw1, Cw2, DR1, and the B27 antigen was observed. Patients with AS showed a significant increase in DQw2 antigen compared with the B27 positive control group. No differences in antigenic frequencies were observed in patients having peripheral arthritis and patients with only axial involvement. Seven out of nine patients (78%) with an erosive peripheral arthritis were DR7 positive, suggesting that DR7 or genes closely linked could be related with a more aggressive peripheral joint involvement in patients with AS.     

Relationship between genotype for the cytochrome P450 CYP2D6 and susceptibility to ankylosing spondylitis and rheumatoid arthritis.

OBJECTIVES--To determine whether particular genotypes for the cytochrome P450 enzyme CYP2D6, a polymorphic enzyme, are associated with susceptibility to ankylosing spondylitis (AS) and rheumatoid arthritis (RA), or linked with any specific clinical or familial features of the two conditions. METHODS--CYP2D6 genotypes were determined in 54 patients with AS, 53 patients with RA, and 662 healthy controls. Leucocyte DNA was analysed for the presence of mutations by restriction fragment length polymorphism analysis with the restriction enzyme Xbal and by two separate polymerase chain reaction assays. RESULTS--On the basis of odds ratio (OR), individuals with two inactive CYP2D6 alleles were more susceptible to AS than controls (OR 2.71, 95% confidence interval (CI) 1.04 to 7.08), with a stronger effect for the CYP2D6B allele (OR 4.11, 95% CI 1.54 to 11.0). No significant differences in the distribution of overall genotypes and allele frequencies were observed between RA and controls. No significant relationships were found between the skeletal, extraskeletal or familial features of AS or RA (iritis, psoriasis, inflammatory enteropathy and rheumatoid nodules, kerato-conjunctivitis sicca, pleuritis, rheumatoid and antinuclear factors) and the overall genotype. CONCLUSIONS--Our findings suggest a modest association between homozygosity for inactive CYP2D6 alleles, particularly CYP2D6B alleles, and susceptibility to AS. However, our results fail to demonstrate a genetic link between CYP2D6 genotype and RA.     

<Emphasis Type="Italic">IL1RN*2</Emphasis> allele of IL-1receptor antagonist VNTR polymorphism is associated with susceptibility to anklyosing spondylitis in Indian patients

Despite strong linkage of ankylosing spondylitis (AS) with human leukocyte antigen (HLA) B27, its contribution to disease susceptibility is only 15%, and additional genetic factors are likely to be involved in AS. Interleukin (IL)-1 locus has been linked to AS in European population. Thus, we studied IL-1 receptor antagonist polymorphism in Indian patients with AS. One hundred and sixty-two patients with AS and ethnically matched healthy controls were included. IL-1Ra variable number tandem repeat polymorphism was studied by polymerase chain reaction (PCR). HLA B27 was done by amplification refractory mutation system PCR. Clinical details regarding severity of articular disease, presence of peripheral arthritis, and extra-articular manifestations were collected. The mean age of these 162 patients was 35 years, and the mean duration of disease was 10.8 years. Of these162 patients, 137 were HLA B27 positive. The commoner alleles—IL-1RN*1 and IL-1RN*2—together accounted for 99.5% of the IL-1RN alleles in the control population and 98.5% of the cases. The allele frequency as well as the carriage rate of allele IL-1RN*2 were significantly higher in patients with AS than the control populations (26.3 vs 16.2% and 41.97 vs 22.5%, respectively; p = 0.015 and 0.0002). The IL-1RN*2 allele was not associated with any difference in clinical disease expression. The IL-1RN*2 allele is a susceptibility marker for AS in the Indian population but does not influence disease phenotype.     

A polymorphism within the interleukin 1 receptor antagonist (IL-1Ra) gene is associated with ankylosing spondylitis.

OBJECTIVE: Genetic factors that predispose individuals to ankylosing spondylitis (AS) are not fully understood, but are unlikely to be restricted to HLA-B27. Proinflammatory cytokines are implicated in the development of sacroiliitis. We have examined the allele frequencies of three polymorphic sites in the interleukin (IL)-1 genes in AS patients to investigate whether genetic regulation of IL-1 production could be implicated in AS pathogenesis. METHODS: DNA from 188 AS patients, 115 healthy controls and 81 HLA-B27-positive healthy controls, all from the West of Scotland, were examined with the polymerase chain reaction in a case-controlled study. Polymorphic sites in genes of the IL-1 family were examined, including the 86-base pair variable number tandem repeat within intron 2 of the IL-1Ra gene, and the restriction fragment length polymorphisms at positions -889 in the IL-1alpha gene and -511 in the IL-1beta gene. RESULTS: No significant differences were seen at the polymorphic alleles in the IL-1alpha and IL-1beta genes, but there was a significant increase in the carriage of allele 2 in the IL-1Ra in the AS patients compared with local controls (16 vs 8%, odds ratio 2.3, 95% confidence interval 1.2-4.4, P=0.01). CONCLUSION: This report of an association with a polymorphic site within the IL-1 locus and AS suggests that genes other than B27 may well be involved in the pathogenesis of AS.     

?383 A/C tumor necrosis factor receptor 1 polymorphism and ankylosing spondylitis in Mexicans: a preliminary study

The objective of this study was to evaluate the differences in allele and genotype frequencies of ?383 tumor necrosis factor receptor 1 (TNFR1) polymorphism between ankylosing spondylitis (AS) and controls. Mexican Mestizos with AS were matched by gender, age, and ethnicity with healthy controls and compared in allele and genotype frequencies of the ?383 TNFR1 polymorphism. Polymorphisms were genotyped using PCR–RFLP. The AA genotype occurred at a higher frequency in the AS group (92%) compared with controls (79%, P?=?0.03). A allele was increased in AS (96% vs. 88%, P?=?0.015) and was associated with genetic susceptibility for AS (odds ratio?=?3.48, 95% CI?=?1.23–10.61). This preliminary study is the first assessing the association of the ?383 A/C TNFR1 polymorphism with AS, although it has the limitation of a small sample size. These data are of interest for the genetic epidemiology of AS in the Mexican population, requiring further investigation in other countries.     

Usefulness of human leucocyte antigen-B27 subtypes in predicting ankylosing spondylitis: Taiwan experience

Background: Genetic factors are clearly attributed to the susceptibility of ankylosing spondylitis (AS). The human leucocyte antigen (HLA)‐B27 proved to be the very useful marker for diagnosing AS. The aim of this study was to determine the prevalence of HLA‐B27 subtypes in Taiwan and to investigate whether these subtypes may be of help in predicting the diagnosis of AS. Methods: A total of 314 patients with AS and a control group of 71 subjects positive for HLA‐B27 detected by flow cytometry analysis were recruited for the study. HLA‐B27 subtypes were confirmed by the polymerase chain reaction‐sequence‐specific primers and sequence‐specific oligonucleotide probing. Results: Four B27 alleles were identified: B*2704, B*2705, B*2706 and B*2707. HLA‐B*2704 was the predominant allele. There were significant differences in the distribution of HLA‐B27 subtypes between patients with AS and controls. Five of them who were homozygous for the B*2704 allele were solely found in AS group but not in controls. Statistical analysis showed that B*2704 was positively associated with AS, which suggested an increased possibility of having AS. Other HLA‐B27 subtypes showed no strong correlation with AS. Conclusion: In the Taiwanese population, susceptibility to AS was determined by the presence of HLA‐B*2704. Although B*2706 was reported to have a negative association with AS in Taiwanese, Thai and Chinese Singaporean populations, we report, in our study, two AS patients with B*2706 (0.6%). Disease heterogeneity suggests that other than genetic background, many pathogenic factors could be associated with AS. This may need to be investigated with a larger group of patients with AS and controls.     

Undifferentiated spondyloarthropathies in Brazilians: importance of HLA-B27 and the B7-CREG alleles in characterization and disease progression

OBJECTIVE: To analyze the profile of the HLA-B27 and B7 cross-reactive group (CREG) alleles and the role of these markers in disease characterization and progression in patients with undifferentiated spondyloarthropathies (uSpA). METHODS: A total of 80 patients with a diagnosis of uSpA (40 HLA-B27 positive and 40 HLA-B27 negative) were prospectively studied for 2 years. The control group consisted of 66 HLA-B27 positive and 112 HLA-B27 negative individuals without a history of seronegative SpA. HLA-B alleles were typed at low (B7-CREG alleles, i.e., B*7, B*54, B*55, B*56, B*40, B*42) or high resolution (B*27 alleles) using polymerase chain reaction-amplified DNA hybridized with sequence-specific oligonucleotide probes. RESULTS: HLA-B*2705 was the most frequent allele, observed in 92.5% of the patients and in 77% of the controls, followed by the HLA-B*2702, observed in 5% of the patients and in 12% of the controls. HLA-B*2704 was observed in only one patient (2.5%), and was absent in the control population. HLA-B*2703 (6%) and HLA-B*2707 (5%) alleles were observed only in controls. No associations between HLA-B*27 alleles or B7-CREG alleles and any specific manifestation of uSpA were observed. HLA-B27 positive patients more frequently presented juvenile onset SpA (p = 0.002) and progression to ankylosing spondylitis (AS) (p = 0.03) than did HLA-B27 negative patients. The B7-CREG alleles were observed in 5% of the HLA-B27 positive uSpA group, in 25% of the HLA-B27 negative uSpA group, in 7% of the HLA-B27 positive controls, and in 13% of the HLA-B27 negative controls; a significant association was observed between the presence of the B7-CREG and the HLA-B27 negative uSpA group (p = 0.012). CONCLUSION: The frequency of the HLA-B*2705 allele among the B27 positive uSpA patients of this series was closely similar to that reported for patients with ankylosing spondylitis (AS). The presence of HLA-B*27 alleles was associated with the progression to AS, and the presence of B7-CREG was associated with uSpA in the HLA-B27 negative group.     

Analysis of LMP and TAP polymorphisms by polymerase chain reaction-restriction fragment length polymorphism in rheumatoid arthritis

OBJECTIVE—The aim of this study was to investigate the relation between the polymorphism of large molecular weight proteasome (LMP) (LMP2-LMP7) and transporter associated with antigen processing (TAP) (TAP1-TAP2) genes and rheumatoid arthritis (RA).
METHODS—Sixty RA patients and 102 ethnically matched unrelated healthy subjects were typed for LMP, TAP, and disease associated HLA-DRB1 alleles by using a new strategy based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with amplification created restriction sites.
RESULTS—The polymorphism of LMP (LMP2-LMP7) and TAP (TAP1-TAP2) genes was examined in shared epitope positive and negative RA patients and controls. No significant differences in the LMP or TAP allele frequencies were observed between the total patient and control groups or the patients and controls positive or negative for the shared epitope.
CONCLUSION—The data suggest that the polymorphisms of LMP and TAP genes do not have an important influence in the pathogenesis of RA, although larger studies will be needed to provide more conclusive evidence on the role of these genes in RA. A new, highly reliable strategy for typing LMP alleles is also described.

Keywords: large molecular weight proteasome; transporter assoicated with antigen processing; rheumatoid arthritis     

TLR4 mutations (Asp299Gly and Thr399Ile) are not associated with ankylosing spondylitis

BACKGROUND: Immunoregulatory genes and Gram negative gut bacteria are thought to be important in disease expression in ankylosing spondylitis (AS). OBJECTIVE: To compare the frequency of two common and functional TLR4 mutations (Asp299Gly, and Thr399Ile) between patients with AS and HLA-B27 healthy controls. METHODS: The TLR4 genotypes of patients and healthy HLA-B27 controls were determined using allele-specific PCR and restriction fragment length polymorphism analysis. Asp299Gly genotype was determined in 193 patients and 125 HLA-B27 positive controls and Thr399Ile genotype in 184 patients and 113 HLA-B27 controls. Allele frequencies were compared using a chi(2) test of association. RESULTS: 29/193 (15%) patients with AS had a polymorphism in the Asp299 site compared with 18/125 (14.4%) healthy HLA-B27 controls. Of the patients genotyped for the Thr399Ile allele, 29/184 (15.8%) carried the polymorphism compared with 19/113 (16.8%) HLA-B27 controls. No significant difference between the frequencies of the Asp299Gly genotype or the Thr399Ile genotype between patients with AS and healthy HLA-B27 controls was found. No significant difference in allele frequency was found at either site. CONCLUSION: Two common TLR4 polymorphisms, which cause a functional deficiency in host immune response to Gram negative bacteria, are not overrepresented in patients with AS.     

Susceptibility to reiter's syndrome is associated with alleles of tap genes

Objective. Although HLA–B27 is strongly associated with susceptibility to Reiter's syndrome (RS), recent data suggest that an additional modifying or susceptibility gene(s) acts in concert with HLA–B27 to contribute to disease pathogenesis. The recently described TAP genes (transporters associated with antigen processing) are potential candidates because they are polymorphic and their function is to transport antigenic peptides to be loaded in HLA class I molecules. Methods. TAP1 and TAP2 alleles were determined for 34 patients with RS (28 HLA–B27 positive, 6 HLA–B27 negative), and their frequencies were compared with those observed for 52 HLA–B27 positive and 80 random disease-free control subjects. Results. The allele frequency of TAP1C was greater in patients with RS (8 of 62, 13%) than in random controls (5 of 160, 3%) (P = 0.009). The frequency of TAP2A was greater in RS patients (51 of 66,77%) than in random controls (88 of 160, 55%) (P = 0.002); likewise, the frequency was greater in HLA–B27 positive RS patients (41 of 54, 76%) than in HLA–B27 positive disease-free controls (49 of 94, 52%) (P = 0.004). Furthermore, the TAP2A allele was present in all RS patients (100%), whereas TAP2A was present in 79% (63 of 80) of the random controls (P = 0.003). Conclusion. The association observed between TAP alleles and RS is independent of the presence of HLA–B27, and despite the physical proximity of TAP and HLA class II genes, linkage disequilibrium does not account for the observed associations between TAP and RS. Thus, TAP genes are genetically separated but functionally linked to class I genes, and both contribute to susceptibility to RS.