Influence of ethnic background on clinical and serologic features in patients with systemic sclerosis and anti-DNA topoisomerase I antibody

Therapeutic options for systemic sclerosis related interstitial lung diseases

Interstitial lung disease (ILD) is a common manifestation of systemic sclerosis (SSc) mainly encountered in patients with diffuse disease. Unlike idiopathic interstitial pneumonias (IIP), SSc associated ILD corresponds to non-specific interstitial pneumonia (NSIP) in most cases, whereas usual interstitial pneumonia (UIP) is encountered less frequently. This explains the better prognosis of SSc associated ILD compared to IIP. However, severe restrictive lung disease represents one of the two main causes of disease-related death in SSc patients. The treatment of SSc associated ILD is not very well established. Anti-fibrosing treatments have failed to demonstrate any benefit and cyclophosphamide, which has been used in the treatment of this condition for about 15 years, has recently been evaluated in two prospective randomised studies which showed a significant but modest effect on respiratory function. Since none of the patients included in retrospective or prospective studies were selected on the basis of progression of ILD, and since only a minority of SSc patients develop severe ILD, further studies should focus on the subgroup of SSc patients with worsening ILD. A subgroup of patients with rapidly progressive ILD might benefit from pulsed intravenous cyclophosphamide combined with prednisone 15 mg daily but this remains to be confirmed.

Stimulating autoantibodies against the angiotensin II type 1 receptor are not associated with preeclampsia in Mexican-Mestizo women

OBJECTIVE

Recent studies have demonstrated that stimulating autoantibodies against the angiotensin II type 1 receptor (AT1R-AA) are frequently detected in the sera from women with preeclampsia, suggesting that they may play an important role in the pathogenesis of this disease. Nevertheless, the real clinical significance of AT1R-AA in preeclampsia is still controversial due to the paucity of appropriate large comparative studies that require cumbersome, time-consuming, and expensive bioassays to detect AT1R-AA. At present, the prevalence of AT1R-AA in large populations of preeclamptic women is unknown. In an attempt to clarify this issue, we assessed the presence and potential clinical significance of AT1R-AA in a large population of Mexican-Mestizo women with preeclampsia.

METHODS

Using a cross-sectional design, we determined the presence of AT1R-AA in 525 pregnant women (99 healthy pregnant, 96 with mild preeclampsia, and 330 with severe preeclampsia) by a new bioassay that employs human embryonic kidney-293 cells stably expressing the recombinant rat AT1R and a 4x nuclear factor of activated T cells responsive luciferase construct as well as by the reference assay in Chinese hamster ovary (CHO) cells.

RESULTS

We found that IgG obtained from sera of healthy pregnant women and patients with preeclampsia were unable to induce luciferase activity in both HEK-293 and Chinese hamster ovary cells expressing functional angiotensin II receptor type 1. Therefore, the frequency of patients with AT1R-AA was zero.

CONCLUSION

We concluded that in Mexican-Mestizo women agonistic AT1R-AA cannot be invoked as a factor involved in the pathogenesis of preeclampsia. Whether these findings can be attributed to genetic or environmental factors remains unknown.

Gender and ethnicity differences in patients with diffuse systemic sclerosis--analysis from three large randomized clinical trials

OBJECTIVE

Although the incidence of dcSSc is higher in African-American and Hispanic populations compared with European Caucasian patients, it is not clear whether there are differences in subsequent disease course. Also, the potential impact of gender on the disease course of dcSSc is not well defined. Our objective was to assess the course of modified Rodnan skin score (MRSS), HAQ-disability index (HAQ-DI) and forced vital capacity per cent (FVC%) predicted between men vs women and three ethnic groups with dcSSc participating in three randomized clinical trials (RCTs).

METHOD

Data from RCTs (n = 495) were pooled and analysed. Baseline characteristics were compared in men vs women and among ethnic groups. A linear mixed effects model was used to assess the predictors of MRSS, HAQ-DI and FVC%. The primary independent variables were time-in-study and its interaction with gender and ethnicity. The models were adjusted for other covariates that were significant at baseline between gender and ethnicity analyses.

RESULTS

Men had lower HAQI-DI scores compared with women (P < 0.05). Among the three ethnic groups, Caucasians were older, African-Americans had lower FVC% predicted and Hispanics had greater tender joint counts (P < 0.05). The course of MRSS, HAQ-DI and FVC% predicted during the study period was not significantly different between gender and three ethnicities. Time-in-study was an independent predictor of improvement in MRSS and HAQ-DI.

CONCLUSION

Our analysis explores the influence of gender and ethnicity on disease course in RCTs. These findings are relevant to issues of future trial design.

Identification of myocardial damage in systemic sclerosis: a nuclear cardiology approach

Myocardial involvement is an important prognostic factor in patients with systemic sclerosis, and early diagnosis and staging of the disease have been sought after. Since myocardial damage is characterized by connective tissue disease, including fibrosis and diffuse vascular lesions or microcirculation, nuclear myocardial perfusion imaging has been a promising option for evaluating myocardial damages in early stages. In addition to the conventional stress-rest perfusion imaging, the current use of quantitative electrocardiographic gated imaging has contributed to more precise evaluation of cardiac perfusion, ventricular wall motion, and diastolic function, all of which have enhanced diagnostic ability of evaluating myocardial dysfunction. Abnormal sympathetic imaging with Iodine-123 metaiodobenzylguanidine might be another option for identifying myocardial damage. This paper deals with approaches from nuclear cardiology to detect perfusion and functional abnormality as an early sign of myocardial involvement as well as possible prognostic values in patients with abnormal imaging results. The role of nuclear cardiology in the era of multiple imaging modalities is discussed.

Interstitial lung disease in systemic sclerosis

Interstitial lung disease (ILD) is a common manifestation of systemic sclerosis (SSc) and mainly encountered in patients with diffuse disease and/or anti-topoisomerase 1 antibodies. ILD develops in up to 75% of patients with SSc overall. However, SSc-ILD evolves to end-stage respiratory insufficiency in only a few patients. Initial pulmonary function tests (PFT) with measurement of carbon monoxide diffusing capacity, together with high-resolution computed tomography, allows for early diagnosis of SSc-ILD, before the occurrence of dyspnea. Unlike idiopathic ILD, SSc-ILD corresponds to non-specific interstitial pneumonia in most cases, whereas usual interstitial pneumonia is less frequently encountered. Therefore, the prognosis of SSc-ILD is better than that for idiopathic ILD. Nevertheless, ILD represents one of the two main causes of death in SSc patients. To detect SSc-ILD early, PFT must be repeated regularly, every 6 months to 1 year, depending on disease worsening. Conversely, broncho-alveolar lavage is not needed to evaluate disease activity in SSc-ILD but may be of help in diagnosing opportunistic infection. The treatment of SSc-ILD is not well established. Cyclophosphamide, which has been used for 20 years, has recently been evaluated in two prospective randomized studies that failed to demonstrate a major benefit for lung function. Open studies reported mycophenolate mofetil, azathioprine and rituximab as alternatives to cyclophosphamide. On failure of immunosuppressive agent treatment, lung transplantation can be proposed in the absence of other major organ involvement or severe gastro-esophageal reflux.

Severe ankylosing spondylitis and diffuse systemic sclerosis: case report of a genetic trap

A rare association of ankylosing spondylitis (AS) and systemic sclerosis (SSc) is reported in a Brazilian Mestizo patient presenting a human leucocyte antigen (HLA) genotype that included HLA SSc-susceptibility genes previously reported in different ethnic groups and HLA-B27 associated with AS. The underlying genetic background supporting the full expression of both SSc- and AS-susceptibility alleles and the pertinent literature are discussed.

Major histocompatibility complex (MHC) class II alleles, haplotypes and epitopes which confer susceptibility or protection in systemic sclerosis: analyses in 1300 Caucasian, African-American and Hispanic cases and 1000 controls

Objective

To determine human leucocyte antigen-class II (HLA-class II) (DRB1, DQB1, DQA1 and DPB1) alleles, haplotypes and shared epitopes associated with scleroderma (systemic sclerosis (SSc)) and its subphenotypes in a large multi-ethnic US cohort by a case–control association study.

Patients and methods

1300 SSc cases (961 white, 178 black and 161 Hispanic subjects) characterised for clinical skin forms (limited vs diffuse), SSc-specific autoantibodies (anticentromere (ACA), anti-topoisomerase I (ATA), anti-RNA polymerase III (ARA), anti-U3 ribonucleoprotein (fibrillarin)) and others were studied using molecular genotyping. Statistical analyses in SSc itself by ethnicity, gender, skin type and autoantibodies were performed using exact logistic regression modelling for dominant, additive and recessive effects from HLA.

Results

The strongest positive class II associations with SSc in white and Hispanic subjects were the DRB1*1104, DQA1*0501, DQB1*0301 haplotype and DQB1 alleles encoding a non-leucine residue at position 26 (DQB1 26 epi), while the DRB1*0701, DQA1*0201, DQB1*0202 haplotype and DRB1*1501 haplotype were negatively correlated and possibly protective in dominant and recessive models, respectively. These associations did not discriminate between limited and diffuse SSc. SSc in black subjects was associated with DRB1*0804, DQA1*0501, DQB1*0301 alleles. DPB1*1301 showed the highest odds ratio for ATA (OR = 14). Moreover, it showed no linkage disequilibrium or gene interaction with DR/DQ. ACA was best explained by DQB1*0501 and DQB1*26 epi alleles and ARA by DRB1*0404, DRB1*11 and DQB1*03 alleles in white and Hispanic subjects but DRB1*08 in black subjects.

Conclusion

These data indicate unique and multiple HLA-class II effects in SSc, especially on autoantibody markers of different subphenotypes.

Diagnostic value of anti-topoisomerase I antibodies in a large monocentric cohort

Introduction

In the present study, the detection of anti-topoisomerase I (anti-topo I) autoantibodies was evaluated for diagnosis and risk assessment of systemic sclerosis (SSc) patients in a well characterized large monocentric cohort.

Methods

Sera from patients with SSc (diffuse n = 96, limited n = 113), from patients with overlap syndromes (n = 51), from patients with other diseases associated with SSc (n = 20), as well as from disease controls (n = 487) were analysed for the presence of anti-topo I antibodies by line immunoblot assay and ELISA. Assessment of organ manifestations was performed as proposed by the European Scleroderma Trial and Research network.

Results

The applied test systems for the detection of anti-topo I antibodies revealed a diagnostic sensitivity for SSc of approximately 24% and a diagnostic specificity of at least 99.6%. The sensitivity to identify patients with diffuse SSc amounted to 60%. Patients with anti-topo I antibodies showed a higher burden of skin and lung fibrosis, contractures, electrocardiogram changes, as well as digital ulcers and had more active disease than antibody-negative patients. Signal strengths correlated only weakly with disease activity, with modified Rodnan skin score, with predicted forced vital capacity, and with predicted diffusion capacity levels (P = 0.01, ρ = 0.234, ρ = 0.413, ρ = -0.215, ρ = -0.219). High signal intensities were associated with an increased mortality in diffuse SSc patients (P = 0.003).

Conclusions

Diagnosis and risk assessment of SSc patients can be supported by the detection of anti-topo I antibodies. Signal intensities as obtained by line immunoblot assay or ELISA can be used as a surrogate marker for fibrosis, active disease and worse prognosis.

Ethnic Influence on Disease Manifestations and Autoantibodies in Chinese-Descent Patients with Systemic Sclerosis

Objective.

To investigate ethnic influence on disease manifestations and autoantibody profile in patients of Chinese descent with systemic sclerosis (SSc).

Methods.

In a retrospective study of a multiethnic SSc cohort followed over a 17-year period, disease manifestations and autoantibody profile of patients of European and Chinese descent were compared.

Results.

There were 300 patients of European descent and 36 of Chinese descent, with similar proportions of women (81% and 72%, respectively) and patients with diffuse SSc (50% and 56%). Patients of Chinese descent [mean age ± standard deviation (SD) 52 ± 16 yrs; p = 0.05] were diagnosed at an older age compared to patients of European descent (mean ± SD 46 ± 12 yrs). Patients of Chinese descent compared to those of European descent had less frequent joint (69% vs 86%; p = 0.01) and gastrointestinal involvement (78% vs 94%; p = 0.004), but increased prevalence of myositis (17% vs 5%; p = 0.01). Patients of Chinese descent had less frequent digital ulceration (36% vs 55%; p = 0.04), and an absence of renal crisis. The frequency of cardiac and pulmonary involvement was similar in both groups. More patients of Chinese than of European descent were positive for anti-topoisomerase-I (47% vs 27%; p = 0.02), anti-Ro (36% vs 10%; p = 0.001), and anti-U1RNP (17% vs 5%; p = 0.03) antibodies. The observed differences for anti-topoisomerase-I, anti-Ro, and joint and gastrointestinal manifestations persisted in the subgroup analysis of patients matched for sex, disease subtype, and age at diagnosis.

Conclusion.

Patients of Chinese descent have milder SSc disease with less frequent joint and gastrointestinal manifestations, less severe vasculopathy, but increased prevalence of myositis and certain autoantibodies. Research is needed to identify determinants (genetic, environmental, and cultural factors) of the relationship between ethnicity and disease.

IgM, IgG, and IgA anti-DNA topoisomerase I antibodies in systemic sclerosis

BACKGROUND

Anti-DNA topoisomerase I (anti-topo I) antibodies have been broadly studied in systemic sclerosis (SSc). The use of different native and molecularly cloned antigens has shown a predominant IgG response, and a variable frequency of positive IgM and IgA tests. We report herein the serological findings of SSc using a recombinant topo I obtained through a standard bacterial system.

METHODS

Anti-topo I antibodies were studied in 45 SSc patients and 85 healthy controls through ELISA and western blot. Escherichia coli XL1-blue strain and pT7-7 vector were used to amplify a DNA topo I cDNA clone, and to obtain the recombinant polypeptide. The latter was purified by affinity chromatography, and the enzymatic and antigenic properties were evaluated through specific tests. A native antigen was included for comparison.

RESULTS

The SSc group disclosed positive IgM (20%), IgG (86.6%), and IgA (26.6%) anti-topo I tests with the recombinant polypeptide, and a purified calf thymus antigen yielded similar results. IgG autoantibodies were frequently associated with skin involvement, esophageal dysfunction, and restrictive lung disease. The recombinant protein showed a molecular weight of 86.6 kDa, a positive topo I activity using a supercoiled pBR322 DNA relaxation test, and its carboxyl terminus region was recognized by specific antibodies.

CONCLUSION

This report confirms that different immunoglobulin classes with anti-topo I activity may occur in SSc. IgG was the predominant serological feature with both, the recombinant and native antigens. The study also demonstrates the association between high levels of these autoantibodies and some clinical manifestations of SSc.

[Lower incidence of severe damage to target organs in mexican patients with systemic sclerosis and diffuse skin affection]

OBJECTIVE

To determine the cumulative incidence of severe organ involvement in Mexican patients with systemic sclerosis (SS) and diffuse scleroderma at 3 years from the onset of SS symptoms, and to compare itwith the cumulative incidence observed in a cohort of white patients with SS.

PATIENTS AND METHOD

Patients with SS and diffuse scleroderma were evaluated within the first 2 years from the onset of SS symptoms and were included. An estimation of the cumulative incidence of severe involvement to the skin, kidney, heart, lungs, and gastrointestinal track at 3 years from the onset of SS symptoms was carried out. This cumulative incidence was compared with that of white SS patients with diffuse scleroderma, using the one sample test for a binomial proportion.

RESULTS

Sixty-three patients were included. The cumulative incidence of severe involvement to the skin was 3.17% (2/63) (95% CI, 0.04%-11); kidney involvement in 4.17% (3/63) (95% CI, 0.99%-13.29%); heart involvement in 1.6% (1/63) (95% CI, 0.04%-8.5%); lung involvement in 11.11% (7/63) (95% IC, 4.5%-21.5%); and gastrointestinal involvement in 4.7% (3/63) (95% IC, 0.99%-13.3%). Mexican patients had a lower Reumatol Clin. 2008;4(1):3-7 3 02 ORIG 2582 (3-7).qxp 23/1/08 11:09 Página 4 Rojas-Serrano J et al. Incidencia de daño grave en pacientes mexicanos con esclerosis sistémica incidence of severe skin involvement (P=.0001), kidney involvement (P=.03) and heart involvement (P=.03) compared to white SS patients with diffuse scleroderma.

CONCLUSIONS

The cumulative incidence of severe organ involvement in SS Mexican patients with diffuse scleroderma was determined. The incidence of severe skin, kidney and heart involvement is lower than in white SS patients with diffuse scleroderma.

Changes in causes of death in systemic sclerosis, 1972-2002

BACKGROUND

Survival of scleroderma has changed since the renal crisis treatment has become possible.

AIMS

To document the changes in survival and organ system causes of mortality in systemic sclerosis (SSc) over the past 25 years in patients from a single medical centre.

METHODS

Consecutive patients evaluated at the University of Pittsburgh, Pittsburgh, Pennsylvania, USA between 1 January 1972 and 31 December 1996 were studied. Survival was determined in five 5-year time periods between 1972 and 1997. Causes of death included scleroderma-related (scleroderma renal crisis, pulmonary arterial hypertension, pulmonary fibrosis (PF), gastrointestinal (GI), heart and multiorgan failure) and non-scleroderma-related (cancer, atherosclerotic cardiovascular or cerebrovascular disease, infection, sudden death, other and unknown) causes.

RESULTS

The 10-year survival improved steadily from 54% to 66% during each of the time intervals. There was a significant improvement in survival for patients during 1982-91 compared with those during 1972-81 (p<0.001), even when patients with renal crisis were excluded (p<0.005). The frequency of deaths due to renal crisis significantly decreased over the 30-year time period, from 42% to 6% of scleroderma-related deaths (p<0.001), whereas the proportion of patients with scleroderma who died of PF increased from 6% to 33% (p<0.001). The frequency of pulmonary hypertension, independent of PF, also significantly increased during this time period (p<0.05). There were no changes in scleroderma GI- and heart-related deaths, nor in any of the non-scleroderma-related causes, although patients with scleroderma were less likely to die from scleroderma-related problems in the past 15 years.

CONCLUSION

The change in the pattern of scleroderma-related deaths over the past 30 years demonstrates that the lung (both pulmonary hypertension and PF) is the primary cause of scleroderma-related deaths today. It is important that aggressive searches continue to develop better therapies for these severe pulmonary complications of SSc.

[Epidemiology. Ethnic differences in systemic sclerosis]

To review the differences in the epidemiology, clinical manifestations, and severity of systemic sclerosis in different ethnic groups. This review considers only limited and diffuse forms of systemic sclerosis. The most relevant articles about ethnic differences in systemic sclerosis were selected. The information is presented in three sections: differences in the epidemiology of systemic sclerosis between ethnic groups; differences in clinical manifestations between ethnic group, and factors that may explain these differences. Of the different ethnic groups studied, whites have less incidence and prevalence of systemic sclerosis. Whites also have less frequency of inflammatory manifestations, and have a higher frequency of limited skin disease compared with other ethnic groups. These differences may result in the better survival of whites compared with no whites. The origin of these differences has not been discovered so far. Is probable that genetic and environmental factors may play a role in the expression of disease, producing the differences found among the ethnic groups.

Endothelin axis polymorphisms in patients with scleroderma

OBJECTIVE

To evaluate the distribution of polymorphisms in the endothelin 1 (EDN1), endothelin receptor A (EDNRA) and endothelin receptor B (EDNRB) genes in systemic sclerosis (SSc; scleroderma) and SSc subsets.

METHODS

Two hundred five patients with SSc and 255 healthy controls were screened for polymorphisms in EDN1, EDNRA, and EDNRB, using sequence-specific primer-polymerase chain reaction. The polymorphisms studied were at the following positions: for EDN1, -1370 (T-1370G) of the promoter, +138 of exon 1 (+138 A/-), +85 of exon 3 (E106E), and +23 of exon 5 (K198N); for EDNRA, -231 of exon 1 (G-231A), and +69(H323H) and +105 (E335E) of exon 6; for EDNRB, +2841 of exon 2 (EDNRB-3), -2547 of exon 3 (EDNRB-2), and -2446 of exon 3 (EDNRB-1).

RESULTS

No significant differences between the SSc group as a whole and control subjects were observed for any of the investigated polymorphisms in EDN1, EDNRA, and EDNRB. However, compared with patients with limited cutaneous SSc, patients with diffuse skin involvement had an increased frequency of allele carriage of EDNRB-1A (76.8% versus 54.4%; P = 0.002), EDNRB-2A (79.7% versus 60.2%; P = 0.006), and EDNRB-3G (79.7% versus 56.6%; P = 0.001). Significantly increased carriage frequencies for EDNRA alleles H323H/C and E335E/A were observed in SSc patients with anti-RNA polymerase (anti-RNAP) antibodies, compared with both anti-RNAP-negative SSc patients (P < 0.05) and control subjects (P < 0.005).

CONCLUSION

The finding of associations between endothelin receptors A and B and distinct clinical and immunologic SSc subsets supports the role of endothelin and its receptors in the pathogenesis of SSc. However, these findings and their functional significance need to be confirmed and investigated in future studies.

Anti-DNA topoisomerase II α autoantibodies in Japanese patients with systemic sclerosis

The pathogenesis and etiology of systemic sclerosis (SSc) remain unknown, but the presence of several autoantibodies is recognized as one of its prominent features. The clinical significance of anti-DNA topoisomerase II alpha antibody (anti-topo II alpha Ab) remains unknown in Japanese patients with SSc. To determine the prevalence and clinical correlation of anti-topo II alpha Ab in Japanese patients with SSc. Serum samples were obtained from 103 Japanese patients with SSc. Control serum samples were obtained from 43 healthy Japanese volunteers. Anti-topo II alpha Abs were determined by enzyme linked-immunosorbent assay.IgG anti-topo II alpha Ab levels were significantly increased in SSc patients (n=103) compared to normal controls (n=43; P<0.005). IgG or IgM anti-topo II alpha Ab was detected in 19% (20/103) of SSc patients when absorbance values higher than the mean+2SD of control serum samples were considered positive. By contrast, IgG or IgM anti-topo II alpha Ab was observed in only 7% (3/43) of healthy individuals. The presence of pulmonary fibrosis was more frequently detected in SSc patients with IgG anti-topo II alpha Ab than those without the Ab (P<0.05). Moreover, % DLco and % VC were significantly decreased in SSc patients with anti-topo II alpha Ab relative to those without the Ab (P<0.05 and P<0.01, respectively). The elevated levels of both erythrocyte sedimentation rate and C-reactive protein were also more frequently observed in SSc patients positive for IgG anti-topo II alpha Ab (P<0.005). The results of the present study indicate that anti-topo II alpha Ab represent one of the autoantibody specificities detected on SSc patients and may be regarded a serological marker of pulmonary fibrosis in Japanese patients with SSc.

Enzyme-linked immunosorbent assay for detection of anti-RNA polymerase III antibody: analytical accuracy and clinical associations in systemic sclerosis

OBJECTIVE

We have recently developed an enzyme-linked immunosorbent assay (ELISA) for detection of anti-RNA polymerase III (anti-RNAP III) antibody, using a recombinant fragment containing the immunodominant epitope as the antigen source. This study was conducted to assess the analytical accuracy and clinical associations of the anti-RNAP III ELISA in patients with systemic sclerosis (SSc).

METHODS

To evaluate analytical sensitivity and specificity of the ELISA, both immunoprecipitation tests and ELISA were used to detect anti-RNAP III antibody in 534 SSc sera from patients at 3 medical centers. Sera from 522 SSc patients and 516 controls, including patients with other connective tissue diseases and blood bank donors, were also evaluated to assess the clinical sensitivity and specificity of the ELISA. Clinical findings in anti-RNAP III antibody-positive SSc patients were compared between patient groups stratified according to anti-RNAP III antibody levels determined by the ELISA.

RESULTS

In SSc patients, our ELISA showed analytical sensitivity of 91% and analytical specificity of 99% compared with the immunoprecipitation assay (a gold standard for detection of anti-RNAP III antibody). The additional analysis using a large series of SSc and control sera showed that clinical sensitivity and specificity of the ELISA with respect to the diagnosis of SSc were 17% and 98%, respectively. A high level of anti-RNAP III antibody was associated with diffuse cutaneous SSc, higher maximum total skin score, and increased frequency of tendon friction rubs.

CONCLUSION

The anti-RNAP III ELISA is analytically accurate and clinically specific. With this assay, testing for anti-RNAP III antibody can be made routinely available.

Classification of systemic sclerosis. Visions and reality

Systemic sclerosis, scleroderma (SSc) is a disabling condition that shortens life expectancy. Disease heterogeneity and difficulties separating SSc from SSc-like conditions make classification an important issue. Limited cutaneous and diffuse cutaneous SSc, with different severity and survival, have been recognized for several years as distinct subsets. Some authors have suggested an intermediate cutaneous form with intermediate survival. This issue remains unsettled, however. The technique of capillaroscopy is helpful as an adjunct diagnostic tool to separate idiopathic Raynaud's phenomenon from SSc. Digitized video-capillaroscopy is developing as a powerful new method to assess individual capillaries over time. Using the simpler techniques of video-capillaroscopy, different patterns have been described and named 'early', 'active', 'late' and 'slow'. The value of nailfold video-capillaroscopy to distinguish different subsets or provide prognostic information for use in daily practice remains to be assessed. The features of CREST (calcinosis, Raynaud's, oesophagus dysmotility, sclerodactyly, telangiectasias) are not confined to single subsets of SSc. There is no convincing evidence of any advantage for distinguishing the limited, intermediate and diffuse forms of SSc rather than only the limited and diffuse forms.

Mortality in systemic sclerosis: an international meta-analysis of individual patient data

PURPOSE

Studies on mortality associated with systemic sclerosis have been limited by small sample sizes. We aimed to obtain large-scale evidence on survival outcomes and predictors for this disease.

METHODS

We performed a meta-analysis of individual patient data from cohorts recruited from seven medical centers in the United States, Europe, and Japan, using standardized definitions for disease subtype and organ system involvement. The primary outcome was all-cause mortality. Standardized mortality ratios and predictors of mortality were estimated. The main analysis was based only on patients enrolled at each center within 6 months of diagnosis (incident cases).

RESULTS

Among 1645 incident cases, 578 deaths occurred over 11,521 person-years of follow-up. Standardized mortality ratios varied by cohort (1.5 to 7.2). In multivariate analyses that adjusted for age and sex, renal (hazard ratio [HR] = 1.9; 95% confidence interval [CI]: 1.4 to 2.5), cardiac (HR = 2.8; 95% CI: 2.1 to 3.8), and pulmonary (HR = 1.6; 95% CI: 1.3 to 2.2) involvement, and anti-topoisomerase I antibodies (HR = 1.3; 95% CI: 1.0 to 1.6), increased mortality risk. Renal, cardiac, and pulmonary involvement tended to occur together (P <0.001). For patients without adverse predictors for 3 years after enrollment, the subsequent risk of death was not significantly different from that for the general population in three cohorts, but was significantly increased in three cohorts that comprised mostly referred patients. Analyses that included all cases in each center (n = 3311; total follow-up: 19,990 person-years) yielded largely similar results.

CONCLUSION

Systemic sclerosis confers a high mortality risk, but there is considerable heterogeneity across settings. Internal organ involvement and anti-topoisomerase I antibodies are important determinants of mortality.

Molecular Recognition Patterns of Serum Anti-DNA Topoisomerase I Antibody in Systemic Sclerosis

Autoreactive anti-DNA topoisomerase I (anti-Topo I) Abs are commonly detected in sera of systemic sclerosis (SSc) patients. Our studies have established a positive correlation between the levels of serum anti-Topo I Abs and both disease severity and activity of SSc. The molecular targets of anti-Topo I Ab on Topo I domains remain to be further defined. In this report, we studied the molecular recognition pattern of serum anti-Topo I Ab in 52 SSc patients. The highest reactivity of serum anti-Topo I Abs was against the core subdomains I and II (aa 207-441) and, to a lesser extent, against the core subdomain III (aa 433-636) of Topo I. The linker domain (aa 636-712) and the C-terminal domain (aa 713-765) had much less reactivity than the core domain (aa 207-636). Strikingly, very little reactivity was directed against the N-terminal domain (aa 1-213) by serum anti-Topo I Ab. This molecular recognition pattern was consistent among all SSc serum samples studied. Results from patients with serial serum samples indicated that this pattern remained unchanged over time. Interestingly, some naive B cells from healthy controls, upon transformation by EBV, produced IgM Abs against Topo I. These Abs had low affinity for Topo I and reacted equally to all domains of Topo I. The molecular recognition pattern of serum anti-Topo I Ab in SSc suggests the presence of a unique antigenic stimulation in vivo in this disease.

The diagnostic value of oesophageal transit scintigraphy for evaluating the severity of oesophageal complications in systemic sclerosis

BACKGROUND

Oesophageal complications are common in systemic sclerosis (SSc). However, the ability to determine the severity of oesophageal complications according to SSc type and skin lesion has not been evaluated.

METHODS

The study groups consisted of 35 patients with SSc who were classified into diffuse (n=20) and limited (n=15) cutaneous types, and 16 control subjects. An additional 26 consecutive patients were studied for an analysis of the reproducibility. The severity of a skin lesion was quantified by using a modification of Rodnan's total skin thickness scores. Oesophageal scans were performed after the subjects, in sitting and supine positions, had consumed potage soup. Condensed images of the dynamic study were classified into four patterns: normal, transient retention, slight retention and severe retention, in conjunction with parameters of retention fraction by analysing the time-activity curve.

RESULTS

The highest reproducibility was obtained using retention at 90 s (R90, r=0.93). Analysis of the condensed images showed that the SSc patients had a higher incidence of severe retention than did the control subjects. Groups with diffuse-type SSc or a high skin thickness score showed a higher incidence of severe retention (P=0.041 and 0.0048, respectively) compared with the control and less severe groups. The R90 in the supine position differed significantly among the controls, the limited-type and diffuse-type SSc groups (mean+/-SEM, 10+/-1%, 24+/-5%, 38+/-6%, respectively; P=0.0004)). The group with high skin scores (i.e. > or =10) showed a higher R90 (41+/-6%) than did either the group with low skin scores (R90=23+/-5%) or the control group (P=0.0001).

CONCLUSION

An oesophageal scan can detect both slight and severe types of oesophageal dysfunction, and can be used as a quantitative method that reflects functional abnormality in SSc.

Systemic sclerosis: the susceptible host (genetics and environment)

It is becoming evident that several genetic factors participate in modulating susceptibility to SSc and its clinical manifestations. Some genes that specifically affect ECM metabolism and vascular function may be unique to SSc and scleroderma-related disorders; others, such as those genes involved in regulating immune tolerance, are likely shared with other autoimmune diseases. The effect of genetic variations (or polymorphisms) that are found in most of these genes taken individually will likely have only a small or modest effect on disease risk; only a few genetic variations are expected to be highly penetrant. Moreover, genetic studies in SSc have to deal with the additional issues of heterogeneous phenotypes, low disease prevalence in the general population, and an even greater paucity of multiplex families that makes traditional linkage studies difficult, if not impossible. Alternative approaches include allelic association studies, but conventional case-controls designs may be subject to selection bias and will require large sample sizes if the genes that are under investigation confer only modest (OR = 1.5-2.0) disease risk (Fig. 2). The simultaneous examination of several genes that are biologically relevant to a specific disease process to attain higher aggregate ORs, is one approach that was used in several reports that were cited in this review. The use of family-based controls, such as in the transmission-disequilibrium test (based on assessment of the transmitted or nontransmitted alleles that are associated with disease from heterozygous parents to affected offspring), would provide more robustness to spurious associations from population stratification, but is actually less powerful and efficient than case-control designs. Furthermore, for many late adult-onset diseases the effort required to obtain samples from living parents are for a variety of reasons not trivial. The success of these allelic association-based approaches depends on the identification of likely candidate disease genes (or at least markers in disequilibrium with disease genes), careful definition/ascertainment of disease phenotypes to minimize genetic heterogeneity, and for case-control designs, strategies to account for population stratification or admixture. The identification of candidate genes will be aided by rapid progress in the Human Genome Project and other genome efforts that will eventually identify all human genetic variations. Although this will lead to better understanding of the genes that might be involved in complex diseases, much work is required to understand the basic biology of how disease genotypes become clinical phenotypes. This is especially daunting in complex diseases, such as SSc, where the phenotype (including disease susceptibility and clinical presentation) is influenced by dynamic interactions between genetic variations and environment. Multi-center collaborative efforts with research paradigms that integrate genetic and environmental factors (including sociodemographic variables) will be required to elucidate the contribution of environment and genetics in the pathogenesis of SSc.

Interstitial lung disease in scleroderma

Pulmonary fibrosis occurs most patients who have scleroderma. It progresses to severe restrictive lung disease in about 15% of patients and remains a major cause of death in this disease. Risks for developing pulmonary fibrosis include diffuse cutaneous scleroderma and anti-Scl-70 antibodies, and risks for developing progressive pulmonary fibrosis and death include low pulmonary function test results at presentation and lung inflammation. Early evaluation of the extent and severity of pulmonary fibrosis and the presence of lung inflammation is key, so that therapy can be given to patients who are at higher risk of progressive pulmonary fibrosis before they develop severe functional impairment occurs. Evaluation often includes pulmonary function tests, HRCT of the lungs, Doppler echocardiogram, and bronchoalveolar lavage. For patients who are unwilling or unable to participate in therapeutic trials that target pulmonary fibrosis in scleroderma, therapy with oral or intravenous cyclophosphamide is often given.

Ethnicity and race and systemic sclerosis: how it affects susceptibility, severity, antibody genetics, and clinical manifestations

Most studies have suggested that ethnic factors impact significantly on systemic sclerosis. Extensive epidemiologic studies have been carried out in white individuals, and limited data suggest that blacks are affected twice as frequently; Japanese patients have a lower prevalence than whites. This highest rate that has been described has been in Choctaw Native Americans. Blacks have a lower age at onset, as well as a higher frequency of diffuse skin involvement, pulmonary disease, and an overall worse prognosis than whites. Limited data in Hispanics and Native Americans suggest that they have more severe disease than whites. Whites have the highest frequency of anti-centromere antibodies (associated with limited skin involvement and less pulmonary fibrosis), whereas blacks have a higher frequency of anti-ribonucleoprotein and fibrillarin autoantibodies; the latter is a nucleolar antibody associated with a poorer prognosis. Ethnic differences are also seen for associations with non-major histocompatibility complex genes, such as FBN1 (fibrillin) genes, in Choctaws and Japanese and SPARC (osteonectin) in whites, Hispanics, and Choctaws. Although these facts do not entirely rule out socioeconomic factors associated with ethnicity, nevertheless ethnicity has an important impact on the pathogenesis of systemic sclerosis, perhaps because of genetic factors.

The prevalence and clinical significance of anti-U1 RNA antibodies in patients with systemic sclerosis

We studied the prevalence and clinical significance of anti-U1 RNA antibodies in patients with systemic sclerosis. The presence of anti-U1 RNA antibodies was determined using immunoprecipitation in systemic sclerosis patients with anti-U1 RNP antibodies (n=36), antitopoisomerase I antibodies (n=20), or anticentromere antibodies (n=20), mixed connective tissue disease patients (n=23), systemic lupus erythematosus patients with anti-U1 RNP antibodies (n=26), and normal controls (n=20). Moreover, antigen specificities for anti-U1 RNP antibodies were examined in patients with systemic sclerosis by immunoblotting and enzyme-linked immunosorbent assay. Anti-U1 RNA antibodies was detected in 22 of 36 systemic sclerosis patients (61%) with anti-U1 RNP antibodies, 14 of 23 patients (61%) with mixed connective tissue disease, and eight of 26 systemic lupus erythematosus patients (31%) with anti-U1 RNP antibodies. Anti-U1 RNA antibodies were not detected in other groups. As for systemic sclerosis patients, the frequencies of pulmonary fibrosis and reduced percentage diffusion capacity for carbon monoxide were significantly greater in patients with anti-U1 RNA antibodies than in those without (76%vs 18%, p<0.005; 82%vs 27%, p<0.005, respectively). Moreover, patients with anti-U1 RNA antibodies had significantly lower percentage diffusion capacity for carbon monoxide and percentage vital capacity values than those without (51.9+/-16.8 vs 79.4+/-16.4, p<0.01; 83.8+/-21.4 vs 101.4+/-12.9, p<0.05, respectively). Regarding the antigen specificities of anti-U1 RNP antibodies in systemic sclerosis patients, the frequency of anti-70 kDa antibodies determined by immunoblotting was significantly higher in patients with anti-U1 RNA antibodies than in those without (77%vs 43%, p<0.05). This finding was also confirmed by enzyme-linked immunosorbent assay for anti-70 kDa antibodies (86%vs 43%, p<0.05). These results indicate that anti-U1 RNA antibodies may be a serologic indicator for pulmonary fibrosis in systemic sclerosis patients with anti-U1 RNP antibodies.

[Immunological diagnosis of scleroderma]

Systemic sclerosis is characterized by a fibrosis and a microvascular injury. These vascular lesions can affect internal organs causing severe visceral damages. The pathogenesis of this disease is complex but some immunological disorders with a production of antinuclear auto-antibodies can be useful to the clinicians, especially for an early diagnosis and to distinguish the scleroderma/myositis overlap syndromes. This review presents the target antigens and the methods of detection of the different antinuclear auto-antibodies. Sensitivity, specificity and clinical association between the antinuclear auto-antibodies and the different subclasses of scleroderma are also presented in detail.

The genetics of systemic sclerosis

The etiopathogenesis of systemic sclerosis (SSc) is unclear. With no definitive evidence supporting an environmental cause, recent attention has focused on genetic factors. Familial clustering and ethnic influences have been demonstrated. Human leukocyte antigen (HLA) associations exist but are more related to the presence of particular autoantibodies rather than to the disease. In addition, no single major histocompatibility complex (MHC) allele predisposes to SSc in all ethnic groups. The role of microchimerism in SSc is a novel yet unproven hypothesis that may be related to intergenerational HLA compatibility. Recent studies investigating polymorphisms in genes coding for extracellular matrix proteins and cell-signaling molecules implicate non-MHC areas in SSc pathogenesis. The data reviewed suggest that SSc is a multigenic complex disorder.

Coexistence of antitopoisomerase I and anticentromere antibodies in patients with systemic sclerosis

BACKGROUND

Antibodies targeting DNA topoisomerase I (ATA) or centromere proteins (ACA) are associated with clinical subsets of patients with systemic sclerosis (SSc). The occurrence of those autoantibodies is considered to be mutually exclusive.

OBJECTIVE

To describe the clinical and immunogenetic data of three patients who are co-expressing both antibodies, and then review previous publications.

METHODS

Both antibodies were detected by different methods, including indirect immunofluorescence technique, enzyme linked immunosorbent assay, immunodiffusion, and immunoblot. Patients were HLA typed by serological and molecular genetic methods. Data were extracted from published reports for comparison. The search for published studies was through Medline and other database research programmes.

RESULTS

During routine laboratory diagnostics over several years three patients with scleroderma and coincidence of ATA and ACA were identified: patient 1 with diffuse SSc, Raynaud's phenomenon, puffy fingers and fingertip necrosis, contractures, and calcinosis; patient 2 with diffuse SSc, Raynaud's phenomenon, oedema of the hands, and interstitial calcinosis of hands, knees, and shoulders, and pulmonary fibrosis; patient 3 with scleroderma of hands, forearms, and face, Raynaud's phenomenon, puffy fingers, finger contractures, fingertip necrosis, and calcinosis. All three patients studied were carriers of HLA alleles known to be associated with these autoantibodies. In serial measurements the concentrations of the two antibodies showed independent or even reverse fluctuations. Screening of 100 patients with ACA for ATA and vice versa disclosed no further patients with coincidence of these antibodies. Twenty eight cases of ACA/ATA coexistence in 5423 patients (0.52%) with SSc or SSc associated symptoms were found in an analysis of published studies.

CONCLUSION

The expression of ATA and ACA is not totally mutually exclusive, but coincidence is rare (<1% of patients with SSc). Patients with both autoantibodies often have diffuse scleroderma and show immunogenetic features of both antibody defined subsets of SSc.

Systemic sclerosis (scleroderma): specific autoantigen genes are selectively overexpressed in scleroderma fibroblasts

The pathogenesis of systemic sclerosis (SSc) involves complex interactions between activated fibroblasts eventually leading to fibrosis, and impaired immune tolerance characterized by a variety of circulating SSc-specific autoantibodies. The expression of autoantigens in fibroblasts, a key target tissue in SSc, may play an important role in this process. To obtain a global view of this process, we examined gene expression profiles of SSc dermal fibroblasts using cDNA microarrays. The results show that dermal fibroblasts from SSc patients obtained from either affected or unaffected skin displayed a characteristic pattern of increased SSc autoantigen gene expression compared with that from normal controls. In particular, fibrillarin (p = 0.028), centromeric protein B (p = 0.01), centromeric autoantigen P27 (p = 0.042), and RNA polymerase II (220 kDa; p = 0.02) were significantly overexpressed in SSc fibroblasts. Quantitative RT-PCR confirmed overexpression of these autoantigens and also revealed increased levels of DNA topoisomerase I transcripts in SSc fibroblasts compared with normal control fibroblasts (p = 0.0318). The polymyositis/scleroderma autoantigen gene was overexpressed in some SSc patients (p = 0.09). To examine the specificity of these overexpressed autoantigen genes for SSc and its tissue specificity for fibroblasts, cDNA microarrays of dermal fibroblasts from patients with eosinophilic fasciitis and scleromyxedema were studied as well as PBMC and muscle biopsies from SSc patients. None of these tissues showed significant alterations in gene expression of SSc-specific autoantigens. Therefore, SSc-associated autoantigen genes are selectively overexpressed in SSc dermal fibroblasts, a major tissue involved in disease pathogenesis.

Autoantibody to DNA excision repair enzyme hMYH in a patient with rheumatic disease

We screened a human HepG2 cell cDNA expression library using serum from a patient with rheumatic disease. This serum had immunofluorescence reactivity to nuclei with a homogeneous staining pattern and to punctuate nuclear aggregates, chromosomal metaphase plate, midbody, and cytoplasmic bridge. YT1, the longest cDNA clone isolated, has sequence identity to hMYH, the human homologue of the Escherichia coli excision repair enzyme, DNA adenine glycosylase MutY. YT1 is a truncated cDNA of 1619 bp, encoding amino acids 22-535, and contains a full-length 3'-UTR sequence. We were unable to express a bacterial malE fusion protein incorporating amino acids 22 to 535 of hMYH. Consequently, we generated two additional malE fusion proteins of hMYH encoding amino acids 1-120 (pMAL-c2:hMYH(1-120)) and amino acids 121-535 (pMAL-c2:hMYH(121-535)). The patient serum immunoblotted only pMAL-c2:hMYH(1-120), suggesting that the autoepitope(s) is restricted to amino acids 22-120 of hMYH, and detected a protein of approximately 59-kDa in total HeLa and nuclear extracts consistent with reactivity to hMYH. Affinity-purified autoantibodies to pMAL-c2:hMYH(1-120) reacted by immunoblot to pMAL-c2:hMYH(1-120), with no reactivity to pMAL-c2:hMYH(121-535). By immunofluorescence, these antibodies displayed staining of nuclei. This is the first report of autoantibodies to hMYH in a patient with rheumatic disease. We were able to identify hMYH reactivity in relatively small cohorts of sera collected from rheumatoid factor-positive patients (6 of 18) and dsDNA-positive patients (1 of 18), with no reactivity detected in serum collected from 9 healthy subjects.

Systemic sclerosis in 3 US ethnic groups: a comparison of clinical, sociodemographic, serologic, and immunogenetic determinants

OBJECTIVE

To determine whether ethnic factors influence the presentation, serologic expression and immunogenetics of systemic sclerosis (SSc), patients from 3 ethnic groups were compared for clinical features, SSc-associated autoantibodies, and human leukocyte antigen (HLA) class II alleles.

METHODS

Fifty-four Hispanics, 28 African Americans, and 79 whites from Texas with recent-onset (less than 5 years) SSc enrolled in a prospective longitudinal study were assessed for sociodemographic, clinical, immunologic, immunogenetic, behavioral, and psychologic parameters using validated instruments and standard laboratory techniques. Serologic and immunogenetic characteristics from these patients and larger retrospective SSc cohorts of the same ethnic groups also were examined.

RESULTS

Hispanics and African Americans in the prospective cohort were more likely to have diffuse skin involvement, skin pigmentary changes, digital ulcers, pulmonary hypertension (African Americans), and an overall lower sociodemographic status than whites, who had more facial telangiectasia and hypothyroidism. In the larger combined prospective and retrospective groups of SSc patients, whites were likely to have more anticentromere antibodies (ACA) and African Americans more anti-U1-ribonucleoprotein (RNP) and anti-U3-RNP (fibrillarin) autoantibodies. HLA-DQB1*0301 was significantly associated with SSc per se in all 3 ethnic groups; HLA-DRB1*11 correlated with the anti-topoisomerase I antibody response, and HLA-DRB1*01, DRB1*04, and DQB1*0501 with ACA.

CONCLUSIONS

Important sociodemographic, clinical, and serologic differences exist between whites, African Americans, and Hispanics, despite shared genetic (HLA class II) predisposing factors. The impact of these differences on prognosis remain to be determined.

Autoantibodies to fibrillin 1 in systemic sclerosis: ethnic differences in antigen recognition and lack of correlation with specific clinical features or HLA alleles

OBJECTIVE

We previously reported the presence of autoantibodies to the extracellular matrix protein, fibrillin 1, in sera from patients with systemic sclerosis (SSc). These autoantibodies appeared to be highly disease-specific but had significantly different frequencies among ethnic groups. The aims of this study were 3-fold: 1) to determine whether sera from SSc patients of different ethnic backgrounds recognized different antigenic epitopes of fibrillin 1, 2) to determine whether sera from patients with polymyositis/dermatomyositis (PM/DM) with or without interstitial lung disease (ILD) also produced these antibodies, and 3) to determine any correlation of anti-fibrillin 1 antibodies with specific clinical features of SSc, other autoantibodies, or HLA class II alleles in a prospectively studied cohort of SSc patients with early (<5 years' duration) disease (the Genetics versus Environment In Scleroderma Outcome Study [GENISOS] cohort).

METHODS

Three recombinant peptides accounting for the N-terminal end, proline-rich C region, and epidermal growth factor-like calcium-binding (EGF-cb) domains of fibrillin 1 were used in a radioimmunoassay to screen sera from a large group of SSc and PM/DM patients and ethnically matched controls.

RESULTS

The majority of Choctaw American Indians, Japanese, and African Americans with SSc produced IgM and/or IgG autoantibodies to one or more recombinant fibrillin 1 proteins, while <50% of Caucasians with SSc showed seroreactivity. There were striking ethnic differences in fibrillin 1 antigenic epitope recognition among these ethnic groups. African American SSc sera recognized primarily the N-terminal end, and Caucasian sera mostly recognized the EGF-cb repeats and the proline-rich C region. In contrast, most Choctaw American Indian and Japanese SSc sera appeared to recognize 2 or 3 epitopes, respectively. PM/DM patient sera did not recognize any of the fibrillin 1 epitopes regardless of the presence of ILD. In the prospective, multiethnic GENISOS cohort, the presence of anti-fibrillin 1 antibodies did not correlate with any major clinical manifestations, other autoantibodies, or HLA class II alleles.

CONCLUSION

There are striking ethnic differences in antigenic epitope specificity of anti-fibrillin 1 antibodies in patients with SSc, and the majority of SSc patients, except for Caucasians, produce antibodies to fibrillin 1. The antifibrillin response thus far remains specific for scleroderma syndromes, but it does not correlate with any major clinical features, other autoantibodies, or HLA class II alleles.

Anti-topoisomerase II alpha autoantibodies in systemic sclerosis-association with pulmonary hypertension and HLA-B35

We have previously detected autoantibodies against topoisomerase II alpha (anti-topo II alpha) in sera from patients with idiopathic pulmonary fibrosis. To determine whether anti-topo II alpha is also present in systemic sclerosis (SSc) patients with pulmonary involvement, we screened sera from 92 patients and 34 healthy controls. Presence of anti-topo II alpha was investigated with respect to clinical and serological features, including the frequencies of HLA class I and II alleles. Anti-topo II alpha was detected in 20/92 (21.7%) patients. No association was found with either anti-topoisomerase I (Scl-70 or anti-topo I) or anti-centromere antibodies. However, anti-topo II alpha was associated with the presence of pulmonary hypertension (PHT) (as opposed to pulmonary fibrosis), and with a decrease of carbon monoxide diffusing capacity. Anti-topo II alpha was strongly associated with the presence of the class I antigen HLA-B35. No significant association was found with HLA class II antigens. HLA-B35 also turned out to be associated with the presence of PHT. These results indicate that in SSc patients, the presence of anti-topo II alpha is associated with PHT, and that the simultaneous presence of HLA-B35 seems to add to the risk of developing PHT.

Systemic scleroderma in Greece: low mortality and strong linkage with HLA-DRB1*1104 allele

OBJECTIVE

Description of Greek patients with scleroderma with reference to (a) major organ disease, (b) autoantibodies, (c) survival rate, and (d) HLA associations.

METHODS

The clinical files of 254 patients were analysed retrospectively and a standardised clinical chart was completed with age at disease onset, sex, date of first and last visit, clinical and serological findings, organs affected, reasons for death, and HLA class II alleles. HLA class II alleles (DRB1, DQA1, DQB1, DPB1) were determined by polymerase chain reaction amplification using oligopeptide probes. DNA was extracted from 98 patients and 130 Greek controls.

RESULTS

124 patients (49%) had limited systemic sclerosis (lSSc), 114 (45%) had diffuse systemic sclerosis (dSSc), and 16 (6%) had overlap syndromes. Patients with dSSc, compared with lSSc, were characterised by a higher prevalence of lung disease (p=0.0011), oesophageal, heart, and peripheral vessel disease (p=0.027, p=0.0025, and p=0.012, respectively). Anticentromere antibodies (ACA) occurred exclusively in lSSc (34%), whereas antibodies to topoisomerase I (anti-topo I) were associated with dSSc (p<0.0001). Anti-topo I were associated with interstitial pulmonary fibrosis, oesophageal and peripheral vessel disease (p=0.028, p=0.012, and p=0.01, respectively). The HLA-DRB1*1104 allele was associated with the disease (p<0.0001) and anti-topo I (p<0.001), whereas it was not associated with ACA serum reactivity (p<0.001). Renal disease occurred in 4% of patients with SSc. The estimated survival probability for this cohort of patients with SSc, four years after the first visit, is 94.8%.

CONCLUSION

SSc among Greek subjects has the same pattern of organ disease as in other white populations. However, the prevalence of kidney disease is low. The HLA class II DRB1*1104 allele is associated with the disease, with anti-topo I, and not associated with ACA serum reactivity.

Autoantibodies to the Extracellular Matrix Microfibrillar Protein, Fibrillin-1, in Patients with Scleroderma and Other Connective Tissue Diseases

A duplication in the fibrillin-1 gene has been implicated as the cause of the tight skin 1 (tsk1) phenotype, an animal model of scleroderma or systemic sclerosis (SSc). In addition to the production of abnormal fibrillin-1 protein, the tsk1 mouse also produces autoantibodies to fibrillin-1. Among a population of Choctaw Native Americans with the highest prevalence of SSc yet described, a chromosome 15q haplotype containing the fibrillin-1 gene has been strongly associated with SSc. With a recombinant human fibrillin-1 protein, autoantibodies to fibrillin-1 were detected in the sera of Native American SSc patients that correlated significantly with disease. Abs to fibrillin-1 also were detected in sera from Japanese, Caucasian, and African-American SSc patients. Compared with other ethnic groups, Japanese and Native American SSc patients had significantly higher frequencies of anti-fibrillin-1 Abs. Sera from patients with diffuse SSc, calcinosis, Raynaud’s, esophageal dysmotility, sclerodactyly, and telangiectasias syndrome and mixed connective tissue disease also had significantly higher frequencies of anti-fibrillin-1 Abs than sera from controls or patients with other non-SSc connective tissue diseases (lupus, rheumatoid arthritis, and Sjögren’s syndrome). Ab specificity for fibrillin-1 was demonstrated by the lack of binding to a panel of other purified autoantigens. The results presented demonstrate for the first time the presence of high levels of anti-fibrillin-1 Abs in a significant portion of patients with SSc.

An immunodominant epitope on DNA topoisomerase I is conformational in nature: heterogeneity in its recognition by systemic sclerosis sera

OBJECTIVE

To characterize an immunodominant epitope recognized by anti-DNA topoisomerase I (topo I) antibody, a major autoantibody in sera of patients with systemic sclerosis (SSc).

METHODS

Topo I fragments were generated as fusion proteins using a bacterial expression system as well as polypeptides translated in vitro using a eukaryotic expression system. Reactivities to the 2 preparations of recombinant topo I polypeptides in anti-topo I-positive sera from SSc patients of varied ethnic backgrounds were examined by immunoblotting, immunoprecipitation, and/or enzyme-linked immunosorbent assay.

RESULTS

The fragment encoding amino acids 489-573 of topo I was recognized by 98 of 100 anti-topo I-positive SSc sera. Both carboxyl- and amino-terminal deletion studies as well as competitive inhibition assays using topo I synthetic peptides showed that a region of > or =52 amino acids (512-563) was necessary for recognition by anti-topo I antibodies. The minimum epitope region and conformation required for this reactivity were variable among sera from Caucasian, African American, Japanese, and Choctaw SSc patients.

CONCLUSION

An immunodominant epitope recognized by anti-topo I autoantibody is located in the region of amino acids 489-573 of the topo I protein and is largely conformational in nature. The recognition pattern of this region by anti-topo I-positive sera is heterogeneous and is influenced by ethnic background.