Influence of variations across the MMP-1 and -3 genes on the serum levels of MMP-1 and -3 and disease activity in rheumatoid arthritis.

Matrix metalloproteinases (MMPs) are involved in joint destruction in rheumatoid arthritis (RA), and are strongly associated with levels of inflammation. To understand the relationship between MMP-1 and -3 variants and MMP levels in RA, we investigated the genotypic and haplotypic relationships of the MMP-1 and -3 genes with circulating levels of these MMPs. The genotypes of single-nucleotide polymorphisms (SNPs) rs1799750 (1G/2G, MMP-1 promoter), rs495366 (G/A, intergene), rs679620 (A/G, MMP-3 coding region) and rs3025058 (5A/6A, MMP-3 promoter) were determined in 430 RA patients. Each polymorphism was associated with serum levels of MMP-1 (P trend <0.0001 for each SNP), with haplotype 1G-G-A-5A associated with the highest level. The intergenic and MMP-3 SNPs were associated with MMP-1 levels independent of the MMP-1 promoter SNP. The MMP-3 SNPs were associated with serum MMP-3 level (P trend <0.0001 for each SNP), and were each associated with mean time-averaged disease activity (DAS28) in patients followed up for 2 years (P=0.003). Our findings indicate that several closely linked polymorphisms in the MMP-1-MMP-3 loci have an important role in determining the circulating levels of these MMPs in RA, and that MMP-3 polymorphism is associated with the level of disease activity over time.

Antinuclear antibodies are associated with tumor necrosis factor receptor I gene polymorphism in patients with rheumatoid arthritis.

OBJECTIVES: Antinuclear antibodies (ANA) are a common feature of autoimmune diseases such as rheumatoid arthritis (RA). Herein, we investigate the relationship between ANA and polymorphism in the tumour necrosis factor receptor (TNFR) genes. METHODS: Serum titers of ANA at diagnosis were measured in 267 patients with RA and a single nucleotide polymorphism (SNP) in each of the TNFR-I (36A/G) and TNFR-II (676T/G) genes was genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. Circulating levels of soluble TNFR (sTNFR) and TNF-α were also measured in some patients. RESULTS: Our initial analyses revealed the presence of ANA was associated with the TNFR-I 36A/G SNP, with a trend of increasing ANA frequency with G allele dosage (p=0.004). ANA status was also associated with lower sTNFR-I levels and a raised sTNFR-II/sTNFR-I ratio. The TNFR-II 676T/G SNP and circulating levels of sTNFR-II and TNF-α were not associated with ANA status. In an adjusted multivariate regression model the TNFR-I 36 GG genotype (OR 7.8, p=0.008) and levels of sTNFR-I (p=0.018) were independently associated with ANA status. CONCLUSIONS: Our findings suggest a possible link between the production of ANA and the TNF-α/TNFR-I signalling system, which may be related to the apoptosis-inducing ability of this cytokine.

The overall status in rheumatoid arthritis (OSRA) measure--further evidence to support its use in clinical practice.

OBJECTIVES: The overall status in rheumatoid arthritis (OSRA) instrument is a simple summary of health status, including disease activity (OSRA-A) and damage (OSRA-D) scores. Despite evidence of the validity of the OSRA, uptake has been low. This study aimed to assess the responsiveness and re-examine the validity of the OSRA using the measures from the British Rheumatoid Outcome Study Group (BROSG) randomized controlled trial of aggressive vs symptomatic treatment of rheumatoid arthritis (RA) patients. METHODS: 466 patients were recruited. Outcome measures included the OSRA, the OMERACT core set and the DAS28, and were collected at baseline and annually for the 3 yrs of the trial. X-rays of the hands and feet were taken at baseline and 3 yrs. Patients were assigned a Townsend score (a measure of social deprivation) according to area of residence. Construct validity was assessed by correlating the OSRA with a range of outcome measures, and testing for the known inequality in RA outcome between patients classified by social deprivation. Responsiveness to change was assessed against self-reported change over the first year of the trial. RESULTS: The OSRA-A and OSRA-D measures demonstrated construct validity, performing as hypothesized. The OSRA-A was the most responsive measure in the BROSG trial in detecting patient reported improvement and deterioration. The OSRA-D demonstrated similar responsiveness to alternative measures. CONCLUSIONS: Our results demonstrate the validity and responsiveness of the OSRA, and its potential for inclusion in clinical trials. More important, as the OSRA is quick and easily calculated, uses routinely collected information, and provides useful quantitative information about a patient's status and progress it is suitable for use in the routine clinic.

Association between cigarette smoking and release of tumour necrosis factor alpha and its soluble receptors by peripheral blood mononuclear cells in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the relationship between cigarette smoking and release of TNF-alpha and its soluble receptors (sTNFRI and sTNFRII) by peripheral blood mononuclear cells (PBMCs) from RA patients. METHODS: We studied 71 RA patients with established disease (mean duration 10.6 yr). Smoking history was established by questionnaire. T lymphocytes and monocytes were isolated from peripheral blood and incubated with or without stimulation (phytohaemagglutinin and lipopolysaccharide, respectively). Release of TNF-alpha and sTNFR into culture medium was measured by enzyme-linked immunosorbent assay. RESULTS: TNF-alpha release by stimulated T lymphocytes was significantly higher in patients with a history of smoking than in those who had never smoked (1416.0 vs 767.4 pg/ml, P = 0.04), and showed a relationship with smoking duration and intensity (P for trend < or =0.009). Monocyte TNF-alpha release was not associated with smoking status. Release of sTNFR showed no clear relationships with extent of smoking, although release by stimulated T lymphocytes was higher in past smokers than in those who had never smoked (P < or = 0.03). The ratio of TNF-alpha/sTNFR released from T lymphocytes was higher in past and current smokers, and was associated with extent of smoking. No relationship was found between smoking and plasma TNF-alpha levels, but levels of both receptors were higher in past smokers. CONCLUSION: In RA patients who smoke there is an alteration in the ratio of TNF-alpha/sTNFR released by stimulated T cells that might favour increased TNF-alpha activity. The increased TNF-alpha/sTNFR ratio is associated with extent of smoking, and remains elevated after smoking cessation.

Self-referral of symptoms (SOS) follow-up system of appointments for patients with uncertain diagnoses in rheumatology out-patients.

OBJECTIVE: Clinical features in rheumatological conditions often fluctuate with time and this may cause difficulty when evaluating patients whose symptoms or signs do not coincide with their initial rheumatology visit. The aim of this study was to evaluate the outcome of a follow-up system whereby patients with uncertain rheumatological diagnoses at their initial assessment are given easy and rapid access to a rheumatology review. METHOD: We studied the outcome of SOS (self-referral of symptoms) appointments offered to patients over a 44-month period in one consultant's clinic at the Staffordshire Rheumatology Centre. The reattendance rates and diagnoses at the initial and subsequent visits were evaluated over a mean period of 26.3 months (range 7-64 months). RESULTS: Thirty-seven patients (23 males, 14 females) were offered SOS appointments during the period studied. At the initial assessment, a provisional diagnosis was recorded for 29 patients (78.4%), whereas the diagnosis was unclear for the other eight patients. At the end of the study period, 10 patients (27%) had requested specialist review via the SOS system after a mean period of 6.8 months (1-19 months). The diagnosis remained unchanged in 8 of the 10 reattenders, whereas the diagnosis was revised in two patients. None of these patients, however, developed an inflammatory arthritis. CONCLUSION: We suggest that an SOS system of appointments may be a feasible and practical method to follow up patients who have uncertain rheumatological diagnoses at their initial visit. This follow-up system may not easily fit into the current out-patient reforms being implemented in the National Health Service, yet this form of specialist follow-up seems clinically essential for some forms of disease management. The requirements necessary to operate such a system as well as the envisaged pros and cons for the patient and for the rheumatologist are discussed.

Patient-assessed health in ankylosing spondylitis: a structured review.

OBJECTIVE: To review evidence relating to the measurement properties for all disease-specific, multi-item, patient-assessed health instruments in patients with ankylosing spondylitis (AS). METHODS: Systematic literature searches were made to identify instruments, using predefined criteria relating to reliability, validity, responsiveness and precision. RESULTS: Twelve AS-specific and three arthritis-specific instruments met the inclusion criteria. Three AS-specific instruments that measure health-related quality of life (HRQL) were reviewed. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Dougados Functional Index (DFI) had the greatest amount of evidence for reliability, validity and responsiveness across a range of settings. Four instruments lacked evidence for test-retest or internal consistency reliability. Most were assessed for validity through comparisons with other instruments, global judgements of health, mobility or clinical and sociodemographic variables. Most were assessed for responsiveness through mean score changes. Three instruments lacked evidence of responsiveness. CONCLUSION: This review provides a contribution to AS assessment. AS-specific multi-item measures specific to the assessment of pain, stiffness, fatigue and global health were not identified; where assessed, these domains were largely measured with single-item visual analogue scales. Single items may provide a limited reflection of these important domains. The BASFI and DFI remain the instruments of choice for functional assessment. HRQL is recommended as a core assessment domain. Further concurrent evaluation is recommended.

Association of polymorphism in the transforming growth factor {beta}1 gene with disease outcome and mortality in rheumatoid arthritis.

OBJECTIVE: To investigate whether polymorphism in the transforming growth factor beta1 (TGFbeta1) gene is associated with disease outcome in rheumatoid arthritis. METHODS: 208 patients with established rheumatoid arthritis were genotyped for the TGFbeta1 T869C polymorphism using an amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method. Disease severity was assessed by measuring radiographic damage by Larsen score and functional outcome by the health assessment questionnaire (HAQ). Patients were tracked on the NHS central register for notification of death, and the relation between TGFbeta1 polymorphism and mortality was analysed using Cox proportional hazards regression. RESULTS: Patients carrying a TGFbeta1 T allele had a higher mean HAQ score than those without this allele (1.60 v 1.22, p = 0.04). The T allele was also associated with higher five year mean area under the curve (MAUC) erythrocyte sedimentation rate (ESR), and nodular disease. Larsen score was higher in patients with the TT genotype compared with CC + CT genotypes, although this was not significant after correction for disease duration. There was a trend of increasing mortality risk with T allele dose after adjustment for age, sex, and disease duration (hazard ratio = 1.6 (95% confidence interval, 1.1 to 2.4), p = 0.01). CONCLUSIONS: TGFbeta1 T869C gene polymorphism is associated with disease outcome in rheumatoid arthritis. Carriage of the T allele (putatively associated with decreased TGFbeta1 production) was associated with increased inflammatory activity and poor functional outcome, while increasing T allele dose was associated with worse survival.

Spinal mobility in ankylosing spondylitis: reliability, validity and responsiveness.

OBJECTIVE: To evaluate the measurement properties of an evidence-based selection of measures of spinal mobility in patients with ankylosing spondylitis (AS). METHODS: Measurements of spinal mobility were taken by trained observers within a UK rheumatology centre. Inter-observer reliability was assessed. Intra-observer reliability was assessed in patients reporting no change in AS-specific health at 2 weeks. Validity was assessed and scores were correlated with responses to health transition questions. Responsiveness was evaluated for patients reporting change in health at 6 months. RESULTS: Reliability estimates support the use of all measures in individual evaluation (intraclass correlation>0.90). Correlations between measures of spinal mobility were in the hypothesized direction; the largest was between the modified Schober index (15 cm) (MSI) and the other measures. As hypothesized, small to moderate levels of correlation were found between mobility measures and patient-assessed health status. There was no significant linear relationship between mobility measures and self-reported health transition. Fingertip-to-floor distance following trunk forward flexion (FFD) was the most responsive mobility measure but was not as responsive as two AS-specific patient-assessed instruments, the Ankylosing Spondylitis Quality of Life Questionnaire (ASQoL) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The MSI and cervical rotation (Crot) also had evidence of responsiveness. Low levels of responsiveness were found for the remaining measures. CONCLUSION: All mobility measures had adequate levels of reliability and validity. The MSI had a strong relationship with all mobility measures, and the FFD and Crot were the most responsive to self-perceived changes in health at 6 months. The MSI, FFD and Crot are recommended for clinical practice and research.

Increased levels of antibodies to cytokeratin 18 in patients with rheumatoid arthritis and ischaemic heart disease.

OBJECTIVE: To determine whether raised levels of antibodies to CK18 in patients with RA are associated with ischaemic heart disease (IHD). METHODS: IgA, IgG, and IgM antibodies to CK18 were measured by enzyme linked immunosorbent assay (ELISA) in patients with RA with (n = 34) or without (n = 28) IHD. The relationship between CK18 antibody levels and markers of inflammatory and/or cardiovascular disease was examined. RESULTS: Initial analysis showed that IgG antibody levels to CK18 were higher in patients with RA with IHD than in those without (50.1 v 34.5 AU, p = 0.047), although significance was lost after correction for multiple comparisons. Further analysis showed a significant difference (p = 0.015) between patients with IHD and a positive family history, and patients without IHD and a negative family history (53.7 v 29.0 AU, Kruskal-Wallis multiple comparison Z value test). There was also a significant trend of increasing 10 year cardiovascular risk with increasing CK18 IgG antibody levels (p = 0.01). No association was found between CK18 antibody levels and conventional markers of inflammation or cardiovascular disease, but an association was found between levels of CK18 IgG and IgG antibodies to cytomegalovirus (CMV) (Spearman's r(s) = 0.379, p(corr) = 0.04). No evidence for cross reactivity of CK18 antibodies with CMV antigens was found. CONCLUSION: Levels of IgG antibodies to CK18 are raised in patients with RA with IHD, particularly if they also have a positive family history. This may reflect damage to CK18 containing cells in the cardiac vasculature and/or in atherosclerotic plaques, and may be a useful additional marker for the identification of patients with, or likely to develop, IHD.

Association of matrix metalloproteinase 3 promoter genotype with disease outcome in rheumatoid arthritis.

Matrix metalloproteinases (MMPs) are implicated in joint destruction in rheumatoid arthritis (RA). We investigated whether the 5A/6A polymorphism within the MMP-3 (stromelysin-1) gene promoter region is associated with disease outcome in 254 patients with established RA. Patients homozygous for the MMP-3 6A allele had more radiographic damage (measured by Larsen score) than those with other genotypes (109.8 vs 91.1, P=0.04). Patients with the 6A/6A genotype also had more functional impairment and higher serum proMMP-3 levels, although only the latter was significant (P=0.002). A possible association was found between homozygosity for the 6A allele and carriage of the RA-associated HLA-DRB1 shared epitope (SE). Combination of these factors was associated with more severe disease than the SE alone. The data suggest that the MMP-3 6A/6A genotype is associated with worse RA outcome, and that this genotype may have an additive effect with the SE on disease severity.

Control perceptions in patients with rheumatoid arthritis: the role of social support.

OBJECTIVE: To identify factors that patients perceive as influencing control in living with rheumatoid arthritis. METHOD: A sample of 40 patients with rheumatoid arthritis were randomly recruited from an outpatient population and partook in an in depth, qualitative interview by one researcher to identify control perceptions. The data were analysed utilizing Colaizzi's procedural steps. RESULTS: Four major categories were identified that positively influenced control perceptions: The reduction of physical symptoms. Social support matching perceived need. The provision of information. The nature of the clinical consultation. Three components were identified in relation to social support: Remaining involved in family activities. Ongoing support from family members. Achieving a balance between support needs and support provision. CONCLUSION: The categories identified can be influenced by practitioners enabling patients with RA to obtain perceived control over their condition.

Generic measures of health-related quality of life in ankylosing spondylitis: reliability, validity and responsiveness.

OBJECTIVE: To assess the acceptability and measurement properties of two generic measures of health-related quality of life (HRQL): the EuroQol and the Short Form 12-item Health Survey Questionnaire (SF-12) in ankylosing spondylitis (AS). METHODS: Instruments were administered by means of a self-completed questionnaire to AS patients recruited from across the United Kingdom. Instruments were assessed for data quality and scaling assumptions. Test-retest reliability was assessed in those patients reporting no change in general health at 2 weeks. The convergent validity of both instruments was assessed and scores were correlated with responses to health transition questions. Responsiveness was assessed for patients reporting change in health at 6 months. RESULTS: The instruments had high completion rates. Although slightly skewed towards better levels of health, scores covered the available range for both sections of the EuroQol [EQ-5D and EQ-visual analogue scale (EQ-VAS)]. Score distributions approximated normality for the SF-12. Test-retest reliability estimates support the use of both instruments in group evaluation and the SF-12 Physical Component Summary score (PCS) in individual evaluation (>0.90). Correlations between instruments were in the hypothesized direction and were of a moderate level. The EQ-VAS had the strongest linear relationship, with responses to both specific and general health transition questions (P<0.01). The EQ-VAS and SF-12 PCS were the most responsive instruments. The EQ-5D was the least responsive instrument. CONCLUSION: The instruments have undergone a comprehensive comparative evaluation to assess the measurement properties required for patient-assessed measures of health outcome in AS. Adequate levels of acceptability, reliability and validity were found for both instruments. Although evidence supporting instrument responsiveness was strong for the EQ-VAS and SF-12 PCS, it was very weak for the EQ-5D and SF-12 Mental Component Summary Scale (MCS). The EQ-VAS and SF-12 PCS can both be recommended for use in group evaluation, and the SF-12 PCS is recommended in routine practice or research. However, the lower reliability of the SF-12 MCS and the limited ability of both the EQ-5D and SF-12 MCS to detect change in health may restrict these roles.

Disease-specific, patient-assessed measures of health outcome in ankylosing spondylitis: reliability, validity and responsiveness.

OBJECTIVE: To assess the acceptability and measurement properties of four ankylosing spondylitis (AS)-specific, patient-assessed measures of health outcome: AS Quality of Life Questionnaire (ASQoL), Bath AS Disease Activity Index (BASDAI), the Body Chart and the Revised Leeds Disability Questionnaire (RLDQ). METHODS: Instruments were administered by means of a self-completed questionnaire to patients recruited from across the United Kingdom (UK). Instruments were assessed for data quality and scaling assumptions. Where appropriate, dimensionality was assessed using principle component analysis (PCA). Internal consistency reliability was tested using Cronbach's alpha. Test-retest reliability was assessed in those patients reporting no change in AS-specific health at 2 weeks. The convergent validity of the instruments was assessed and scores were correlated with responses to the health transition questions. Responsiveness was assessed for patients reporting change in health at 6 months. RESULTS: The BASDAI and Body Chart have low self-completion rates. Item responses for the RLDQ were skewed towards higher levels of functional ability. PCA supported instrument unidimensionality. Cronbach's alpha ranged from 0.87 (BASDAI) to 0.93 (RLDQ). Test-retest reliability estimates support the use of the ASQoL and RLDQ in individual evaluation (>0.90). Correlations between instruments were in the hypothesized direction; the largest was between the ASQoL and BASDAI (0.79). The BASDAI had the strongest linear relationship, with responses to both specific and general health transition questions (P<0.01). With the exception of the Body Chart, instruments had a stronger relationship with general health transition. The BASDAI was the most responsive instrument. The Body Chart and RLDQ had low levels of responsiveness. CONCLUSION: The instruments have undergone a comprehensive comparative evaluation to assess the measurement properties required for patient-assessed measures of health outcome. Adequate levels of reliability and validity were found for all instruments. The BASDAI and the ASQoL were the most responsive to self-perceived change in health, but the BASDAI had low levels of self-completion.

The mechanical joint score: a new clinical index of joint damage in rheumatoid arthritis.

OBJECTIVES: To evaluate the mechanical joint score (MJS) in terms of its reliability between observers and over time, its ease of use and its relationship with conventional measures of rheumatoid arthritis (RA) disease activity, severity and functional outcome. METHODS: The MJS was evaluated in 103 patients with reference to the following joints: total proximal interphalangeal (PIP) joints, total metacarpophalangeal (MCP) joints, wrists, elbows, shoulders, hips, knees, ankles and total metatarsophalangeal (MTP) joints. The score was based on the appearance of the joints on a scale of 0-3, 0 representing no abnormality and 3 severe abnormality or previous surgery. The MJS was evaluated in terms of its intra- and inter-observer variability and its content, construct and criterion validities. A subset of 29 patients were re-evaluated after 5 yr to examine change in MJS over time. RESULTS: The MJS performed well in terms of inter-observer and intra-observer reliability. The MJS showed strong correlation with the Larsen X-ray score of hands and feet (Spearman correlation coefficient 0.74) and with the modified Health Assessment Questionnaire (Spearman correlation coefficient 0.56) and only weak correlation with indices of disease activity, such as the Ritchie index and erythrocyte sedimentation rate. The MJS showed highly significant positive change over time. CONCLUSION: The MJS is a reliable clinical index of joint damage and may be a useful new outcome measure in RA.

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-DRBI, 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.

Mortality in rheumatoid arthritis: relationship to single and composite measures of disease activity.

BACKGROUND: Rheumatoid arthritis (RA) is a heterogeneous disease characterized by a variable course of remissions and relapses. Single measures of disease activity at only one point in time may not reflect the overall control of disease activity. OBJECTIVE: The aim was to determine (i) the predictive value of 20 baseline demographic and disease variables on mortality, and (ii) the relationship between serial measures of the Stoke index (SI; a validated index of disease activity in RA) and mortality in RA. METHODS: Mortality in 309 RA patients followed up for a median of 14 yr was analysed retrospectively. The standardized mortality ratio (SMR) was calculated for all causes of death. The predictive values of baseline and time-integrated variables were assessed using multivariate Cox proportional hazards regression analysis. RESULTS: The SMR was 1.65. At baseline, only nodules, erosions, RA latex titre, white cell count and globulin level were predictive of mortality after correction for age, sex and disease duration. Using a stepwise Cox proportional hazards regression model, the most powerful predictors of mortality were age, nodules and RA latex titre. Individual measures of disease activity and the SI at baseline were not predictive of mortality. However, the mean level of the SI over 12 months was related to mortality (P=0.039). CONCLUSIONS: At baseline, the demographic and disease variables most significantly related to mortality in RA are age, nodules and RA latex titre. Individual measures of disease activity at a single point in time are poor predictors of mortality in RA. However, measurement of the mean level of disease activity over time using the composite SI has a significant relationship with mortality. A high level of sustained inflammation appears to be an important predictor of premature death.

HLA-DRB1 alleles encoding an aspartic acid at position 70 protect against development of rheumatoid arthritis.

OBJECTIVE: To determine whether the association between rheumatoid arthritis (RA) and HLA-DRB1 is influenced by the amino acid residue encoded at position 70 (beta70) of the third hypervariable region (HVR3) of the HLA-DRbeta chain. METHODS: The frequencies of HLA-DRB1 alleles encoding different amino acid residues at beta70 were compared between patients with RA and controls in a population from the UK and in a confirmatory population from northwestern Spain. HLA-DRB1 typing was done by polymerase chain reaction methods on 476 clinic based patients with RA and 180 healthy controls from Staffordshire and Cheshire in the UK, and on 179 clinic patients and 145 controls from Lugo, Spain. Associations were investigated using chi-square analyses and regression analyses. The extended Mantel-Haenszel procedure was used for trend analysis. RESULTS: Carriage of 2 shared epitope (SE)+ alleles encoding a glutamine at beta70 (Q70SE+/Q70SE+) was associated with the greatest risk of RA in the UK and Spanish population (odds ratios 7.93 and 4.66, respectively), while possession of 2 SE- alleles encoding an aspartic acid at beta70 (D70SE-D70SE-) was associated with the lowest risk (OR 0.23 and 0.34, respectively). In individuals carrying one SE+ allele and an accompanying D70SE- allele there was no increased risk of developing RA [OR 0.93 (UK) and 1.30 (Spain)]. Possession of D70SE- was more strongly protective than possession of Q70SE. Analysis of trend indicated that the strength of association of different DRB1 genotypes with RA could be ranked in order (from Q70SE+/Q70SE+ to D70SE-/D70SE-) according to which amino acid residues were encoded at beta70, and whether or not they formed part of a SE sequence. The severity of radiographic damage could not be ranked in the same fashion. CONCLUSION: The amino acid residue at position 70 of the HVR3 in HLA-DRbeta molecules influences susceptibility to RA. The strength of the association of DRB1 genotypes with RA is dependent not only on SE status, but also on which amino acid residues are encoded at beta70 of the DRB1 alleles. Presence of an aspartic acid residue at beta70 protects against development of RA. However, the severity of erosive damage does not appear to be associated with the amino acid substitution at 1370.