The RUDY study platform - a novel approach to patient driven research in rare musculoskeletal diseases.

BACKGROUND: Research into rare diseases is becoming more common, with recognition of the significant diagnostic and therapeutic care gaps. Registries are considered a key research methodology to address rare diseases. This report describes the structure of the Rare UK Diseases Study (RUDY) platform that aims to improve research processes and address many of the challenges of carrying out rare musculoskeletal disease research. RUDY is an internet-based platform with online registration, initial verbal consent, online capture of patient reported outcome measures and events within a dynamic consent framework. The database structure, security and governance framework are described. RESULTS: There have been 380 participants recruited into RUDY with completed questionnaire rates in excess of 50 %. There has been one withdrawal and two participants have amended their consent options. CONCLUSIONS: The strengths of RUDY include low burden for the clinical team, low research administration costs with high participant recruitment and ease of data collection and access. This platform has the potential to be used as the model for other rare diseases globally.

A spectrum of susceptibility to rheumatoid arthritis within HLA-DRB1: stratification by autoantibody status in a large UK population.

Previously-proposed rheumatoid arthritis (RA) HLA-DRB1 susceptibility and protective models were compared, based on amino acids at positions 67-74 and autoantibody combinations. 3 657 RA patients and 1 357 controls were studied using logistic regression, with secondary stratification by anti-citrullinated peptide antibodies(ACPA) and rheumatoid factor(RF). Susceptibility models were based on previously defined HLA-DRB1 shared epitope(SE) subgroups. (70)DERAA(74), D(70) and I(67) protective models were compared, adjusting for HLA-DRB1 SE. A hierarchy of risk was observed within the HLA-DRB1 SE, particularly for ACPA-positive and RF-positive RA: HLA-DRB1(*)0401∼(*)0404>(*)0101∼(*)1001 ((*)0404>(*)0101: P=0.0003). HLA-DRB1(*)0401/(*)0404 compound heterozygosity conferred a risk similar to (*)0401 homozygosity (P=0.70). Protective effects of D(70) and I(67) were similar. Predictions of the D(70) model fitted the data better than those of the I(67) model. The protective effect of D(70) showed a gene-dose effect (OR 0.82, 95% CI 0.73-0.92, P=5.8 × 10(-4)), but was only seen in RA patients positive for RF or ACPA. HLA-DRB1 SE alleles were also associated with ACPA-negative, RF-positive RA (OR 1.42 (1.15-1.76), P=0.0012). In conclusion, HLA-DRB1 SE alleles show heterogeneity in RA susceptibility; their major effect appears to be mediated by ACPA positivity, but a significant association of HLA-DRB1 SE with RF-positive, ACPA-negative RA was also observed. D(70) specifically protected against antibody-positive RA.

The prevalence of obstructive sleep apnoea and its association with aortic dilatation in Marfan's syndrome.

BACKGROUND: Craniofacial abnormalities and increased pharyngeal collapsibility due to abnormal connective tissue suggest the possibility of an increased prevalence of obstructive sleep apnoea (OSA) in patients with Marfan's syndrome but the actual prevalence is uncertain. Aortic dilatation and dissection are life threatening manifestations of Marfan's syndrome and case reports have suggested a possible association with OSA but data from cohort studies are not available. METHODS: A sleep study was performed in 61 patients with Ghent criteria positive Marfan's syndrome (mean age 38.3 (SD 12.9) years; 37 females) and in 26 control subjects matched for age, gender, height and weight. OSA was defined using two conventional levels of apnoea-hypopnoea index (AHI), >5 and >15/h. In patients with Marfan's syndrome, aortic root diameter was measured by echocardiography. RESULTS: More patients with Marfan's syndrome than controls had OSA (AHI >5, 32.8% compared with 11.5%, mean difference +21.3%, 95% CI 4.2% to 38.3%, p = 0.04; AHI >15, 18.0% compared with 0%, mean difference +18.0%, 95% CI 8.4% to 27.7%, p = 0.02). AHI was correlated with aortic root diameter (r = 0.50, 95% CI 0.26 to 0.69, p = 0.0003), and mean aortic root diameter was significantly greater in patients with OSA (4.5 (SD 0.6) cm) compared with those without OSA (3.7 (0.6) cm) (mean difference 0.8 cm, 95% CI 0.4 to 1.2 cm, p<0.0001). CONCLUSIONS: In patients with Marfan's syndrome, the prevalence of OSA is considerably higher than in matched control subjects. OSA may be a risk factor for aortic root dilatation in Marfan's syndrome.

Association of HLA-DRB1*13 with susceptibility to uveitis in juvenile idiopathic arthritis in two independent data sets.

OBJECTIVES: Juvenile idiopathic arthritis (JIA) is the commonest rheumatic disease of childhood. Uveitis is the commonest eye complication of JIA, potentially leading to eye surgery and/or visual loss. JIA is a complex genetic trait with well-established HLA-DRB1 associations. The aim of this study was to investigate the involvement of HLA-DRB1 in JIA-associated uveitis. METHODS: A set of 130 UK Caucasian simplex families consisting of healthy parent(s) and a child affected with juvenile oligoarticular idiopathic arthritis (of which 31 had developed uveitis) had previously been screened for multiple markers in the major histocompatibility complex region. Associations with uveitis were investigated through haplotype pattern mining (HPM) and the extended transmission disequilibrium test (ETDT). A further set of 228 UK Caucasian patients with long-standing JIA were fully genotyped for HLA-DRB1 using PCR with sequence-specific primers. Associations of HLA-DRB1 alleles in patients with uveitis (n = 50) were examined individually using the chi 2 test. RESULTS: In the first cohort, HPM identified significant associations of HLA-DRB1*13 with uveitis in juvenile oligoarthritis (P = 0.002). The ETDT confirmed overtransmission of this allele in the families (empirical global P = 0.018). In the second cohort, the significant association of uveitis with HLA-DRB1*13 was replicated (P = 0.0002, odds ratio 3.4, 95% confidence interval 1.7-6.5). CONCLUSIONS: This study has established the HLA-DRB1*13 association with uveitis in JIA. Further work is necessary in order to explore the prognostic potential of this marker.

Activation/inactivation of the classical pathway of complement in non-lesional skin of patients with systemic lupus erythematosus.

BACKGROUND: The link between the lupus band and pathogenesis remains controversial, because immunoglobulins and complement components, including the membrane attack complex, can be found in both lesional and non-lesional skin of patients with systemic lupus erythematosus (SLE). The expression of proteins that regulate complement has not been previously investigated in the skin of patients with SLE. AIM: The aim of this study is to compare the expression of protectin (CD59), which demonstrates the activation of the classical pathway of complement, in non-lesional skin obtained from patients with SLE with its expression in normal skin. This may help us explain the link between the lupus band and pathogenesis of cutaneous lupus erythematosus. METHODS: An indirect immunofluorescence technique was performed in order to provide unequivocal evidence for the activation of complement via the classical pathway and to compare the expression of CD59 in non-lesional skin from patients with SLE with normal skin samples obtained from healthy people. RESULTS: The activation of the classical pathway of complement was demonstrated in non-lesional skin in more than 90% of SLE patients investigated in this study. Staining intensity of the complement regulatory protein CD59 was markedly increased in the majority of non-lesional skin samples obtained from patients with SLE, compared to that from normals. CONCLUSIONS: CD59 is overexpressed in non-lesional skin in which complement activation has occurred. It seems likely that an increased and continuous CD59 expression may be important for maintaining the integrity of the skin BMZ during inflammatory responses involving complement activation in SLE skin. Alahlafi A, Wordsworth P, Wojnarowska F. Activation/inactivation of the classical pathway of complement in non-lesional skin of patients with systemic lupus erythematosus.

The basement membrane zone in patients with systemic lupus erythematosus: immunofluorescence studies in the skin, kidney and amniochorion.

Histological studies suggest that the basement membrane zone (BMZ) is the main target of tissue pathology in cutaneous lupus erythematosus (LE). The BMZ is characteristically thickened and is the site of deposition of autoantibodies in LE. Alteration of some (BMZ) macromolecules is implicated in the pathology of several bullous skin diseases. A major component of BMZ is heparan sulphate proteoglycan (HSPG) which was found reduced in the skin of some patients with systemic lupus erythematosus (SLE) and in the kidney of mice with lupus nephritis. Similar to the skin, amnion is derived from the ectodermal germ layer during embryogenesis and expression of BMZ components of amniochorion was not previously studied in SLE. The aim of the present study was to investigate the expression of major BMZ macromolecules in the skin, kidney and amnioplacentae obtained from patients with SLE and compare these findings with organ biopsies from unaffected individuals. In addition, determining whether the differences in composition and distribution of BMZ macromolecules in these organs correlate with certain patterns of deposition of immunoreactants could contribute to our understanding of the mechanism of deposition of immunoreactants in SLE. In some patients with SLE, reduced expression of HSPG in nonlesional skin was reported previously. These changes of heparan sulphate might be important in the pathogenesis of LE. Therefore, the aims of this study are to confirm the previous finding and to compare HSPG expression between lesional and nonlesional LE skin. The unique features of each BMZ could contribute to the deposition or binding of positively charged immune complexes and explain the different patterns of immunofluorescence. Frozen sections of skin, kidney and amniochorion obtained from patients with SLE were investigated by indirect immunofluorescence technique using monoclonal antibodies (Moab) to determine the expression of major components of the BMZ. Heparan sulfate expression is reduced in the skin and, to a lesser extent, in the kidney in patients with SLE. There was no correlation between the kidney and skin heparan sulfate expression within the same patient. The BMZ composition in amniochorionic membrane ofplacentae from women with SLE was normal. Heparan sulfate may be one of the major targets for immunoglobulin deposition in the skin of patients with SLE. The processes of immunoglobulin deposition in SLE may be more complex in that there was no correlation between heparan sulfate expression in the skin and kidney of the same patient.

The distribution of IgG subclasses in the lupus band suggests disease-specific alteration in subclass switching rather than polyclonal B-cell activation.

Deposition of immunoglobulins in the skin of patients with lupus erythematosus (LE), demonstrable as a linear band 'lupus band' at the basement membrane zone (BMZ) by direct immunofluorescence, was first described in 1963. Four decades after the discovery of the lupus band, a basic question regarding the origin of immunoglobulins of the lupus band is still unanswered. Is the lupus band just a manifestation of polyclonal B-cell activation commonly seen in systemic LE (SLE)? The distribution of IgG subclasses deposited in the skin of patients with SLE was identified using immunohistochemistry. The relative restriction of IgG of the lupus band to the IgG3 subclass demonstrated in this study provides evidence against polyclonal B-cell activation as the only cause of the lupus band and suggests disease-specific alteration in subclass switching.

Human leukocyte antigen class II associations with systemic sclerosis in South Africans.

Human leukocyte antigen class II typing, using polymerase chain reaction-sequence-specific primers, was performed in 52 Black South Africans with systemic sclerosis (SSc) and 112 controls. Increased frequencies of DR2 in the overall SSc group (OR = 2.4), DRB1*0301 in the limited cutaneous SSc (lcSSc) subset (OR = 9.0), and DQB1*0301/4 in the diffuse cutaneous SSc (dcSSc) subset (OR = 9.0) were observed. Pulmonary fibrosis was associated with DRB1*11 and anti-topoisomerase I antibodies were associated with DPB1*1301 and DRB1*15. Patients with anti-fibrillarin antibodies (AFAs) had increased the frequencies of DRB1*1101 allele group (OR = 16) and DQB1*0603/14 (OR = 13.6). These findings provide new serological and immunogenetic data on a previously unreported population. The association of AFAs with class II alleles merits further investigation.

The lupus band: do the autoantibodies target collagen VII?

BACKGROUND: Circulating autoantibodies directed against basement membrane zone (BMZ) components from patients with bullous pemphigoid and epidermolysis bullosa acquisita have been used to identify their target antigen in the skin and to confirm pathogenicity. Although the pattern of immunofluorescence in those diseases is similar to the lupus band, little is known about the origin and pathogenesis of the lupus band. Identifying the binding sites of the lupus band could provide a clue to the nature of the autoantigen that stimulates autoantibody formation in the skin of patients with systemic lupus erythematosus (SLE) and might provide valuable insight into the factors that influence the localization and pathogenicity of the lupus band. OBJECTIVES: To investigate the relation between the lupus band and the main BMZ components and to identify the target epitopes of autoantibodies deposited in the skin of patients with SLE. METHODS: Colocalization of the main components of the skin BMZ in nonlesional SLE skin with the lupus band was investigated using conventional immunofluorescence and confocal laser scanning microscopy. The effect of collagenase and pepsin on the expression of the lupus band was correlated with the differential sensitivity of these proteases on the collagenous and noncollagenous (NC) domains of collagen VII. Reactivity of sera from patients with SLE to a complete recombinant human NC1 domain of type VII collagen was then investigated by enzyme-linked immunosorbent assay (ELISA). RESULTS: Near complete colocalization of the lupus band with collagen VII was found in this study, and chemical degradation of the skin attenuated the expression of the lupus band. Collectively, the NC1 domain of collagen VII was suggested as the target antigen of the lupus band, but none of the sera from patients with SLE reacted with recombinant NC1 domain-coated ELISA plates. Alternative explanations for the results of the colocalization of the lupus band with collagen VII are discussed. CONCLUSIONS: The lupus band colocalized with collagen type VII. The findings of this study ruled out the NC1 domain of collagen VII as a target antigen for circulating autoantibodies in SLE patients with no clinical evidence of blistering. Further studies are required to determine if other regions of collagen VII or another BMZ component is the target antigen for the immunoglobulins of the lupus band.

Development of rheumatoid arthritis is not associated with two polymorphisms in the Crohn's disease gene CARD15.

INTRODUCTION: It has been proposed that genetic susceptibility loci for rheumatoid arthritis (RA) may be shared with other autoimmune/inflammatory diseases. Recently, common variation in the CARD15 (NOD2) gene on chromosome 16q12 has been associated with Crohn's disease (CD) in several independent populations. CARD15 is an excellent functional and positional candidate gene for RA. METHODS: Genomic DNA was obtained from 392 RA cases and 471 ethnically matched healthy controls. All samples were genotyped for two polymorphisms in CARD15, 1007fs and R702W, using 5' nuclease reporter assays. Allele frequencies were compared between cases and controls using the chi(2) test. Estimated haplotype frequencies across the two mutations were determined using the EH program. RESULTS: The allele frequency of the 1007fs variant in RA cases was 1.8% compared with 1.6% in normal controls (not significant). The frequency of the R702W variant was 4.0% in both cases and controls. Haplotypes carrying either of the two mutations accounted for 5.6% of possible haplotypes. A haplotype carrying both mutations was rare, with estimated frequency <0.01%. This study provided high power to detect an association of similar magnitude to that in Crohn's disease. These data therefore exclude the possibility that the contribution of these mutations to RA is comparable to that seen in CD. CONCLUSION: Within defined statistical parameters, we excluded a role for the CARD15 1007fs and R702W variants in RA susceptibility. These data do not preclude a role for other polymorphisms in the CARD15 gene in RA susceptibility. Results from other autoimmune and inflammatory diseases will reveal whether the CARD15 gene is in fact a common autoimmune susceptibility locus.

Rheumatoid arthritis susceptibility and interleukin 10: a study of two ethnically diverse populations.

INTRODUCTION: IL-10 is an immunoregulatory cytokine which may modulate disease expression in rheumatoid arthritis (RA). The IL-10 gene is highly polymorphic with a number of single nucleotide polymorphisms in the promoter region and two microsatellite loci, IL10.R and IL10.G, 4 kb and 1.1 kb 5' of the transcription initiation site. It has been reported that allele 2 of the IL10.R microsatellite (IL10.R2) is associated with increased IL-10 secretion and IL10.R3 with reduced secretion. Subsequently, over-representation of IL10.R2 and under-representation of IL10.R3 in three independent RA groups has been reported. The aim of the current study is to determine whether there is an association between the IL10.R2 allele and RA in two ethnically distinct populations. METHODS: IL10.R genotypes were determined by semi-automated DNA sequencing technology in 186 UK Caucasians and 138 South Africans of Zulu or Sotho origin, fulfilling the 1987 American College of Rheumatology (ACR) criteria for RA. The Caucasian patients had relatively severe disease and comprised 75 patients with RA vasculitis, 22 with Felty's syndrome and 89 who had undergone a joint replacement (hip or knee) within 15 years of the onset of disease. Allele frequencies were compared with 296 Caucasians and/or 73 South Africans. RESULTS: The frequency of the IL10.R2 allele was significantly greater in the South Africans (RA and controls) than in the Caucasians (0.78 vs 0.66, P=1 x 10(-6)), while the frequency of IL10.R3 was less common (0.16 vs 0.3, P=1 x 10(-8)). No differences were observed in either IL10.R2 or IL10.R3 frequencies between patients and controls in either population. CONCLUSIONS: We were unable to confirm any association between IL10.R alleles and RA in this study. However, significant differences were demonstrated in the frequency of IL10.R2 and IL10.R3 between the two ethnic groups. The relatively high frequency of IL10.R2 in the South African population (0.78) would have reduced the power to detect an association with RA.

Suggestive evidence for association of human chromosome 18q12-q21 and its orthologue on rat and mouse chromosome 18 with several autoimmune diseases.

Some immune system disorders, such as type 1 diabetes, multiple sclerosis (MS), and rheumatoid arthritis (RA), share common features: the presence of autoantibodies and self-reactive T-cells, and a genetic association with the major histocompatibility complex. We have previously published evidence, from 1,708 families, for linkage and association of a haplotype of three markers in the D18S487 region of chromosome 18q21 with type 1 diabetes. Here, the three markers were typed in an independent set of 627 families and, although there was evidence for linkage (maximum logarithm of odds score [MLS] = 1.2; P = 0.02), no association was detected. Further linkage analysis revealed suggestive evidence for linkage of chromosome 18q21 to type 1 diabetes in 882 multiplex families (MLS = 2.2; lambdas = 1.2; P = 0.001), and by meta-analysis the orthologous region (also on chromosome 18) is linked to diabetes in rodents (P = 9 x 10(-4)). By meta-analysis, both human chromosome 18q12-q21 and the rodent orthologous region show positive evidence for linkage to an autoimmune phenotype (P = 0.004 and 2 x 10(-8), respectively, empirical P = 0.01 and 2 x 10(-4), respectively). In the diabetes-linked region of chromosome 18q12-q21, a candidate gene, deleted in colorectal carcinoma (DCC), was tested for association with human autoimmunity in 3,380 families with type 1 diabetes, MS, and RA. A haplotype ("2-10") of two newly characterized microsatellite markers within DCC showed evidence for association with autoimmunity (P = 5 x 10(-6)). Collectively, these data suggest that a locus (or loci) exists on human chromosome 18q12-q21 that influences multiple autoimmune diseases and that this association might be conserved between species.