Independent association of rheumatoid factor and the HLA–DRB1 shared epitope with radiographic outcome in rheumatoid arthritis

Objective

Findings of a recent study suggested that HLA–DRB1 alleles encoding the rheumatoid arthritis (RA) “shared epitope” (SE) were not predictive of erosive damage at 2 years in patients with early inflammatory arthritis who were rheumatoid factor (RF) positive, but were predictive in those who were RF negative. The present study was undertaken to determine whether RF status was also important in the association between the SE and radiographic outcome in patients with longstanding RA.

Methods

The association between radiographic outcome, HLA–DRB1, and RF status was examined in 299 RA patients with established disease (5–30 years). Radiographic outcome was measured by scoring radiographs of the hands and feet using the standard radiographs of Larsen. HLA–DRB1 typing was performed using polymerase chain reaction methodology. Results were stratified by RF status and analyzed by multiple regression.

Results

An association between radiographic severity and the SE was found in RF−, but not RF+, patients. RF− patients carrying an SE allele had higher Larsen scores than RF− patients lacking the SE, although there was no association with SE dosage. The mean Larsen score was significantly higher in RF+ patients than in RF− patients, but there were no differences between RF+ patients with 0, 1, or 2 SE alleles. Multiple regression analysis confirmed independent associations of RF and SE positivity with radiographic outcome. No significant associations were found between RF and the SE, or RF and individual SE alleles.

Conclusion

Our data indicate that RF and the SE are independently associated with radiographic outcome in RA. In RF+ patients with longstanding RA, there is no apparent association between the presence of the SE and radiographic damage. However, in RF− patients, although radiographic outcome is generally less severe, there is an association between severity and presence of the SE.

     

Relationship among the HLA-DRB1 shared epitope,smoking, and rheumatoid factor production in rheumatoid arthritis

OBJECTIVE: Rheumatoid factor (RF) production in rheumatoid arthritis (RA) is generally associated with more severe disease. In some studies, RF production has been associated with carriage of HLA-DRB1 alleles encoding the RA-associated shared epitope (SE). Patients who smoke are also more likely to be RF positive. In this study, we investigated whether the association between RF production and smoking was influenced by carriage of the SE. METHODS: The smoking histories of 371 RA patients attending a hospital clinic were recorded. RF levels and SE status were determined for every patient, and the associations between the SE, smoking, and RF production were examined. HLA-DRB1 typing was performed using polymerase chain reaction. Results were analyzed using chi-square tests and logistic regression analysis. RESULTS: Patients who had ever smoked were significantly more likely to be RF positive than nonsmokers (odds ratio 2.2, P < 0.0001). This remained significant (P = 0.003) after correction for age, sex, and disease duration in a logistic regression model. An association was also found between RF positivity and carriage of the SE (P = 0.03, after correction for age, sex, and disease duration), but significance was reduced or lost after correction for previous or current smoking (P = 0.05 and 0.09, respectively). Examination of the major SE phenotypes in this RA population by multivariate logistic regression analysis revealed that only DRB1*0401 was associated with RF positivity, and that this was independent of the influence of smoking. CONCLUSION: Our data confirm that RF production in RA patients is associated with smoking. This does not appear to depend on an HLA-DR-restricted immune response. The association of the SE with RF positivity is primarily due to HLA-DRB1*0401. This appears to be independent of the association with smoking, although smoking further increases the likelihood of RF production in DRB1*0401 patients.     

Interaction between tumor necrosis factor microsatellite polymorphisms and the HLA-DRB1 shared epitope in rheumatoid arthritis: influence on disease outcome

OBJECTIVE: To investigate whether interactions between tumor necrosis factor (TNF) microsatellite polymorphisms and the HLA-DRB1 shared epitope (SE) are associated with disease severity in rheumatoid arthritis (RA), and to determine if such associations are the same in male and female patients. METHODS: Genotyping for the TNFa microsatellite and HLA-DRB1 was carried out on 157 RA patients with established disease (duration >5 years). Disease severity measures included radiographic damage (the Larsen method), functional assessment by the Health Assessment Questionnaire, history of joint surgery, and global appraisal of outcome by means of a visual analog scale score. The association of severity measures with TNFa microsatellite polymorphisms stratified by SE status, and the interaction between TNFa and the SE, were investigated using stratified analyses and multiple or logistic regression analyses. RESULTS: No significant associations were observed between any single TNFa microsatellite polymorphism and disease severity, although preliminary evidence for an interaction between TNFa6 and TNFa11 was obtained. In the presence of the SE, a significantly worse outcome was associated with individuals carrying TNFa6, and a significant interaction (P = 0.04-0.006) was found between these alleles for all the outcome measures examined except history of joint surgery. In the absence of the SE, the TNFa6 allele was associated with significantly better outcome scores. When examined by sex, significant associations between the TNFa6/SE haplotype and disease outcome measures were found only in females. No statistically significant interactions were found in males, although the TNFa6/SE haplotype was still associated with the worst outcome scores. CONCLUSION: The association of the SE with disease severity in RA is influenced by an interaction with the TNFa6 microsatellite polymorphism. This interaction appears to be acting predominantly in female patients, although the trend is similar in the smaller percentage of males carrying the TNFa6/SE haplotype.     

The Influence of the HLA-DRB1 rheumatoid arthritis shared epitope on the clinical characteristics and radiological outcome of psoriatic arthritis

OBJECTIVE: To investigate the associations of the HLA-DRB1 rheumatoid arthritis shared epitope (SE) with clinical characteristics and radiological outcome in patients with psoriatic arthritis (PsA). METHODS: One hundred fifty-eight patients with well documented PsA and 250 controls were typed for HLA-DRB1 alleles including the SE by polymerase chain reaction. Clinical data collected on the patient group included disease subset, swollen and tender joint counts, the psoriasis area severity index (PASI), and the presence of radiological erosions. Clinical and radiological associations with HLA-DRB1 and SE alleles were determined. RESULTS: There was an increased frequency of HLA-DR7 (41 vs 25%; puncorr = 0.001, OR 2.02, pcorr = 0.01) and a decreased frequency of HLA-DR2 (19 vs 28%; puncorr = 0.03, OR 0.59, pcorr = 0.3) in the patient population compared with controls. There was no significant difference in the frequency of HLA-DR1 and HLA-DR4 between patient and control populations. There was no significant difference in the prevalence of SE alleles between the patient and control populations (48 vs 54%). There was no increase in the prevalence of the SE in the polyarthritis subgroup, but there was a marginal decrease in those who remained in the oligoarthritis subgroup. There were no differences with respect to sex, age of onset of disease, family history, Health Assessment Questionnaire score, joint score, skin score, or nail score between those patients who were SE positive and those who were SE negative. However, significantly more patients who were SE positive developed radiological erosions (60 vs 43%; p = 0.03, OR 2.11). CONCLUSION: Overall, the prevalence of the SE in patients with PsA did not differ from our control population. However, it was overrepresented in those who developed radiological erosions. It is possible that the SE does have a role in the clinical severity of PsA.     

Mode of inheritance of HLA-DRB1 shared epitope in Japanese familial rheumatoid arthritis

OBJECTIVE: To clarify the mode of genetic contribution of the HLA-DR shared epitope (SE) to the pathogenesis of familial cases of Japanese rheumatoid arthritis (RA). METHODS: Fifty-three unrelated Japanese RA families that had more than 2 affected sibs were selected. The HLA-DR shared epitope typing was carried out by the PCR method and PCR-SSCP (single stranded DNA conformation polymorphism) method. Affected sib pair analysis was carried out using the MAPMAKER/SIB 2.0 program. The mode of inheritance was also calculated based on the sharing of genes identical by descent (IBD) between siblings in each of the 53 affected sib-pairs (propositus and the 2nd affected sib). RESULTS: The maximum LOD score of HLA-DR was 0.437, and the sharing of 2 IBDs, 1 IBD, and no IBDs between affected sibs were 0.330, 0.500, and 0.170, respectively. The sharing distribution of IBD was confirmed to be compatible with the dominant or additive mode since the observed gene frequency of SE was 0.255. CONCLUSION: The HLA-DR shared epitope participated in the pathogenesis of familial cases of Japanese RA. The SE contributes to this pathogenesis in either the dominant or additive mode of inheritance.     

山东地区类风湿关节炎与HLA-DRB1基因共同表位的关联性研究

目的　探讨山东地区汉族人群类风湿关节炎 (RA)与HLA DRB1基因共同表位 (SE)的关联性。方法　采用特异性引物聚合酶链反应 (PCR SSP)方法对山东地区人群 1 32例RA患者及1 30名正常健康者的HLA DRB1 0 1、 0 4、 1 0的 1 7个等位基因进行检测。结果　山东地区RA患者中携带有SE的基因频率显著高于正常对照组 (5 0 0 %∶2 2 3% ,P <0 0 1 ) ,HLA DR4亚型 0 4 0 5是主要的易感基因 (2 2 8%∶1 0 0 % ,P <0 0 0 5 )。其他亚型包括DRB1 0 1 0 1 (3 8%∶3 1 % ) , 0 1 0 2 (2 3%∶2 3% ) , 0 1 0 3(3 8%∶3 1 % ) , 0 1 0 4 (3 0 %∶2 3% ) , 0 4 0 1 (1 0 6 %∶4 6 % ) , 0 4 0 4 (9 1 %∶4 6 % ) , 0 4 0 7(8 3%∶9 2 % ) , 0 4 0 3(6 8%∶3 1 % ) , 0 4 0 2 (6 8%∶4 6 % ) , 0 4 0 8(5 3%∶1 5 % ) , 0 4 0 9(2 3%∶0 ) , 0 4 0 6 (1 5 %∶0 ) , 0 4 1 0 (0 8%∶0 ) , 0 4 1 1 (0 8%∶0 )和 1 0 0 1 (1 1 4 %∶6 9% )的差别均无统计学意义。Logistic回归分析表明 :SE纯合子对RA的危害性要比其杂合子大 (P <0 0 0 1 )。结论　SE与山东地区汉族RA易感性及疾病严重性有关联     

Value of the HLA-DRB1 shared epitope for predicting radiographic damage in rheumatoid arthritis depends on the individual patient risk profile

OBJECTIVE: To investigate the influence of individual patient risk profiles on the value of the HLA-DRB1 shared epitope (SE) as a predictor of severe erosive damage in rheumatoid arthritis (RA). METHODS: Patient characteristics, clinical signs and symptoms, rheumatoid factor (RF) status, and HLA-DRB1 genotypes were available for 154 Caucasian women with RA. Risk profiles were defined by non-genetic factors that predict severe erosive disease. The additional value of the SE was defined by the likelihood ratios (LR) of SE presence and absence, which were calculated at the individual patient level. RESULTS: In the total population, the LR of SE presence was 1.42 and the LR of SE absence was 0.37, corresponding to an odds ratio of 3.9, indicating a substantially higher risk of severe erosive disease in those with the SE compared to those without. The LR of SE presence and absence varied depending on the risk profile of the women, from 1.01 to 2.25 for SE presence and 0.22 to 0.49 for SE absence. Considering all the patient characteristics, SE status was most significantly related to RF status. Consequently, the LR of SE presence and absence were higher for RF-negative women compared to RF-positive women (SE presence 1.77 vs 1.40, p < 0.001 and SE absence 0.38 vs 0.30, p < 0.001). CONCLUSION: The additional value of SE testing for predicting severe erosive disease varies according to patient risk profiles. Given the likely availability of genetic and other novel tests in the future, information about the additional value of test results is needed to ensure the optimal use of such testing in the management of RA.     

The presence of the HLA-DRB1 shared epitope correlates with erosive disease in Chilean patients with rheumatoid arthritis

OBJECTIVE: To assess the contribution of the HLA-DRB1 shared epitope (SE) to the radiological outcome of rheumatoid arthritis (RA) after 6 yr of follow-up in a reported series of 129 Chilean patients with established disease. METHODS: A prospective study was conducted between 1992 and 1998 using hand radiographs to assess disease outcome in a published series of patients in whom two doses of the SE were present in 20%, one dose was present in 34% and the SE was absent in 46%. At study entry, 29 of the 92 patients with hand radiographs were at Steinbrocker stages I or II (non-erosive), with a median disease duration of 2.8 yr (0.4-17). RESULTS: In 1998, 113 (87%) of the patients were alive. One hundred and eight patients underwent complete clinical evaluation. Their median age was 57 yr (range 30-81) and the median disease duration was 15 yr (6-50). We were able to study 25 of the 29 patients who had non-erosive disease at study entry in 1992. We found that 10 of 11 patients having one or two doses of the SE developed erosive disease compared with three of 14 without the SE (Yates' corrected P=0.0023, relative risk 4.24, 95% confidence interval 1.53-11.77). CONCLUSIONS: These observations support and extend the notion that the presence of the SE in one or two doses can predict the development of erosions even in RA populations in whom the SE is not as prevalent as in Caucasians.     

Lack of association of the HLA-DRB1 shared epitope with rheumatoid nodules: an individual patient data meta-analysis of 3,272 Caucasian patients with rheumatoid arthritis

OBJECTIVE: The objective of this individual patient data (IPD) meta-analysis was to examine the relationship of rheumatoid nodules to the HLA-DRB1 shared epitope (SE) and to individual SE genotypes. METHODS: English-language studies that enrolled adult non-Hispanic Caucasian patients with rheumatoid arthritis (RA) were identified by searches of Medline and Embase, and by manual searches of medical journals. All authors were contacted for IPD. Meta-analysis was performed to assess the association of SE presence, dose, and genotype with rheumatoid nodules. Meta-analyses adjusted for disease duration and cumulative meta-analyses were also performed to assess the influence of RA duration and year of study publication on the results. RESULTS: A total of 24 studies and 3,272 patients were available for analysis. IPD were obtained for 22 of the studies. There was a nonsignificant association between the presence of the SE (i.e., 1 or 2 alleles versus 0 alleles) and rheumatoid nodules (summary odds ratio [OR] 1.3, 95% confidence interval [95% CI] 0.97-1.6). Analysis by SE genotype, however, demonstrated a weak relationship with inheritance of a single DRB1*0401 SE allele (OR 1.4, 95% CI 1.1-1.8). No other genotypes achieved statistical significance in the adjusted or unadjusted analyses. CONCLUSION: The presence of the HLA-DRB1 SE does not appear to significantly increase the risk of rheumatoid nodules among Caucasian patients with RA. Analysis by DRB1 SE genotype was uninformative, suggesting only a potential (and at most modest) role of the DRB1*0401 SE allele. Results from this IPD meta-analysis implicate other genetic, stochastic, and/or environmental factors in the susceptibility to rheumatoid nodules.     

Influence of HLA-DRB1 genes and the shared epitope on genetic susceptibility to rheumatoid arthritis in Taiwanese

OBJECTIVE:To investigate the association of predisposing and protective HLA-DRB1 alleles with rheumatoid arthritis (RA) and its clinical markers in a Taiwanese population. METHODS: A total of 273 patients with RA and 480 healthy controls, all of Taiwanese origin, were genotyped for HLA-DRB1 alleles by polymerase chain reaction and sequence-based typing assays. The associations between RA and HLA-DRB1 alleles and genotypes were investigated by chi-squared test. RESULTS: The DRB1*0405 and *1001 phenotypes showed the most significant associations with RA (OR 4.04, 95% CI 2.84-5.77, pc = 3.2 10(-14); OR 5.25, 95% CI 2.10-13.06, pc = 3.0 10(-3), respectively). Individuals carrying single or double doses of the shared epitope (SE/non-SE or SE/SE) had higher risks of RA. The compound heterozygote of DRB1*0405/*1001 showed the largest increase in RA risk (OR 15.8, 95% CI 2.48-100.7, pc = 0.004). Single or double doses of SE alleles were significantly associated with a higher bone erosion rate. Rheumatoid factor positivity and bone erosion were more frequent in patients with at least one copy of DRB1*0405. CONCLUSION: Our results show that SE-encoding HLA-DRB1*0405 and *1001 are associated with RA in a Taiwanese population; this is the first time DRB1*1001 has been described in persons of Asian ethnicity. Heterozygotes of DRB1*0405 and *1001 predicted the strongest susceptibility to RA, suggesting that this genotype enhances susceptibility to RA in Taiwanese.     

内蒙古地区汉族类风湿关节炎与HLA-DRB1基因共同表位的相关性研究

目的探讨内蒙古地区汉族人群类风湿关节炎(RA)与HLA-DRB1基因共同表位(SE)的关联性。方法采用特异性引物聚合酶链反应(PCR-SSP)方法对内蒙古地区汉族人群80例RA患者及110名正常健康者的HLA-DRB1*01、*04、*10的17个等位基因进行检测。结果内蒙古地区RA患者中携带有SE的基因频率显著高于正常对照组(48．8％：20％,P＜0．01),HLA-DR4亚型*0405是主要的易感基因(28．8％：12％,P＜0．01),其他亚型包括DRB1*0101(2．5％：0．9％),*0102(2．5％：0),*0103(1．25％：0．9％),*0104(2．5％：0％),*0401(6．25％：1．8％),*0402(3．75％：0．9％),*0403(1．25％：1．8％),*0404(2．5％：1．8％),*0406(2．5％：2．7％),*0407(1．25％：0．9％),*0408(3．75％：0．9％),*0409(1．25％：0),*0410(2．5％：0．9％),*0411(0：0)和*001(8．75％：4．5％)的差异均无统计学意义。Logistic回归分析表明：SE纯合子对RA的危害性要比杂合子大(P＜0．01)。在RA患者中。SE纯合子和SE杂合子的病程、关节肿痛数、关节压痛数、血沉(ESR),C反应蛋白(CRP)、类风湿因子(RF)、X线(Ⅲ期 Ⅳ期)与SE阴性组比较,差异有统计学意义。SE纯合子与SE杂合子相比较,各观察指标差异均无统计学意义。结论SE与内蒙古地区汉族RA易感性及疾病严重性有关。     

Particular HLA-DRB1 shared epitope genotypes are strongly associated with rheumatoid vasculitis

OBJECTIVE: To examine the relationship of the HLA-DRB1 shared epitope (SE) to rheumatoid vasculitis, using individual patient data (IPD) meta-analytic methods. METHODS: Published studies that enrolled adult patients with rheumatoid arthritis (RA) were identified by searches of Medline and Embase, and by manual searches of medical journals. All authors were contacted for IPD. Meta-analyses were performed to assess the association of SE presence, dose, and genotype with rheumatoid vasculitis. RESULTS: A total of 14 studies and 1,568 patients (129 with vasculitis) were included in the analysis. RA patients with vasculitis were significantly more likely to have rheumatoid nodules (odds ratio [OR] 2.5, 95% confidence interval [95% CI] 1.5-3.9], but there was no significant association with male sex, rheumatoid factor positivity, or erosive disease. No significant association was observed between the presence of the SE (i.e., 1 or 2 alleles versus 0 alleles) and rheumatoid vasculitis (summary OR 1.4, 95% CI 0.7-2.7). Analysis by SE genotype, however, demonstrated a striking relationship of vasculitis to 3 genotypes containing a double dose of the SE, specifically HLA-DRB1*0401/*0401 (OR 6.2, 95% CI 1.01-37.9), *0401/*0404 (OR 4.1, 95% CI 1.1-16.2), and *0101/*0401 (OR 4.0, 95% CI 1.4-11.6). CONCLUSION: The HLA-DRB1 SE genotypes *0401/*0401, *0401/*0404, and *0101/*0401 may be of particular importance to rheumatoid vasculitis. It is hoped that additional investigation of these and other SE genotypes will lead to improved insight into the mechanisms influencing the clinical expression of RA.     

Use of monoclonal antibodies to detect disease associated HLA-DRB1 alleles and the shared epitope in rheumatoid arthritis

OBJECTIVE—To use a panel of monoclonal antibodies (Mab) which recognise HLA class II alleles associated with rheumatoid arthritis for fluorescence activated cell sorter (FACS) analysis of peripheral blood mononuclear cells (PBMNC) from patients with early and established rheumatoid arthritis and to compare these results against DNA oligotyping of HLA class II molecules in the same patients.
METHODS—27 patients (18 from an early arthritis clinic, nine with established rheumatoid arthritis) were studied using both techniques. PBMNC were stained with Mab which recognise the shared epitope, the HLA-DRB1*04 molecule and its *0401, *0404 subtypes in the presence of bound peptide. Mab stained cells were analysed by FACS. Genomic DNA was prepared from PBMNC and used for DNA oligotyping and sequencing by standard methods.
RESULTS—FACS analysis of Mab stained PBMNC gave identical results to those obtained by DNA oligotyping in 26/27 patients. The antibodies identified the shared epitope in 14/14 cases and the presence of an HLA-DRB1*04 molecule in 12/12 cases. HLA-DRB1*0404 was identified in 4/4 cases. HLA-DRB1*0401 was identified in 5/6 cases. One patient oligotyped as HLA-DRB1*0401, but consistently failed to react with the *0401 Mab. DNA sequencing of the second exon of the HLA-DRB1*0401 allele in this patient confirmed a normal HLA-DRB1*0401 genotype.
CONCLUSIONS—FACS analysis of PBMNC stained with Mab recognising the shared epitope and rheumatoid arthritis associated HLA susceptibility molecules provides a rapid, reliable, and more accessible alternative to DNA oligotyping. The apparent discordance between phenotypic and genetic analysis of HLA-DRB1*0401 in one patient, may reflect variability in HLA-DRB1*0401 gene expression or in class II peptide presentation.

     

Smoking is a risk factor for anti-CCP antibodies only in rheumatoid arthritis patients who carry HLA-DRB1 shared epitope alleles

OBJECTIVES: To study the gene-environment interaction of tobacco exposure and shared epitope on autoantibodies in patients with rheumatoid arthritis and undifferentiated arthritis. METHODS: From incident cases of arthritis (n = 1305), patients who did not fulfil any classification criteria (undifferentiated arthritis (n = 486)) and those who fulfilled the American College of Rheumatology criteria for rheumatoid arthritis (n = 407) were identified. IgM rheumatoid factor (RF), anti-cyclic-citrullinated peptide (CCP) antibodies, and HLA-DRB1 alleles were determined. RESULTS: In rheumatoid arthritis, an interaction was found between tobacco exposure and shared epitope for the presence of anti-CCP antibodies, as the odds ratio for anti-CCP antibodies in patients having both tobacco exposure (TE) and shared epitope (SE) was higher than the summed odds ratios of patients having only tobacco exposure or shared epitope (odds ratios: TE+/SE-, 1.07; TE-/SE+, 2.49; and TE+/SE+, 5.27-all relative to TE-/SE-). A similar effect was found for RF, but stratification showed that the interaction primarily associated with the anti-CCP antibody response. In patients with undifferentiated arthritis at two weeks, or with persistent undifferentiated arthritis after one year, no interaction between tobacco exposure and shared epitope was observed for the presence of autoantibodies. CONCLUSIONS: Tobacco exposure increases the risk factor for anti-CCP antibodies only in shared epitope positive patients with rheumatoid arthritis. The gene-environment interaction between smoking and shared epitope leading to autoantibodies is specific for rheumatoid arthritis and is not observed in undifferentiated arthritis.     

HLA-DRB1 association in Saudi rheumatoid arthritis patients

Association between HLA-DRB1 alleles and rheumatoid arthritis (RA) has been known for more than three decades. However, the strength of these links varies between ethnic groups. This study examines the frequency of HLA-DRB1 alleles amongst Saudi RA patients. The DRB1 region of major histocompatibility complex was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) in a total of 140 subjects including 70 RA patients and 70 matched healthy controls. HLA-DRB1 *04 was found to be the most frequent allele associated with RA followed by DRB1 *08 and DRB1 *10. On the other hand, the frequency of DRB1*06 was found to be decreased in RA patients as compared to controls. Molecular sub typing of the most prevalent allele DRB1 *04 revealed a statistically significant association between RA and DRB1 *0405. We conclude that an improved understanding about the influence of HLA on RA might help in predicting the susceptibility or protection against disease.