Low prevalence of anti-RNA polymerase III antibodies in a French scleroderma population: anti-RNA polymerase III scleroderma

Characteristics of Systemic Sclerosis patients with positive anti-Th/To antibodies: About 6 patients and literature review

Among the antibodies described in Systemic Sclerosis (SSc), anti-Th/To antibodies (anti-Th/To) are rare and have been poorly studied. Thus, little is known about the profile of anti-Th/To positive patients. From our local Biobank (Marseille, France), we retrospectively selected data for 6 patients positive for anti-Th/To with an Immunodot assay. All of them suffered from SSc, sharing clinical and biological common features such as a limited cutaneous form of SSc, a decreased lung diffusing capacity and a speckled nuclear nucleolar immunofluorescence pattern of antinuclear antibodies screening on HEp-2 cells. In order to further characterize patients positive for anti-Th/To, we performed a thorough literature review. From 402 studied patients positive for anti-Th/To, we confirmed that these antibodies are associated with the limited cutaneous form of the disease (88% of the patients), and with an SSc related-pulmonary involvement (50%). The review analysis pointed out the rarity of the anti-Th/To with an estimated mean frequency of 3.4% of all SSc patients worldwide, their usual exclusivity with respect to the specific antibodies of scleroderma, and their high specificity (around 98%) for the diagnosis of SSc.

TNFA -308G>A and -238G>A polymorphisms and risk to systemic sclerosis: impact on TNF-α serum levels, TNFA mRNA expression, and autoantibodies

Systemic sclerosis (SSc) is a rare autoimmune disease with high mortality, characterized by chronic inflammation and fibrosis, which are processes associated with higher serum tumor necrosis factor-α (sTNF-α) levels. TNFA -308G>A and -238G>A polymorphisms have been associated with higher sTNF-α levels. In this study, we genotyped the TNFA -308G>A and -238G>A polymorphisms in 53 SSc patients and 115 unrelated control subjects (CS) from southern Mexico. The TNFA mRNA expression and sTNF-α levels were also quantified by qPCR and enzyme-linked immunosorbent assays, respectively. TNFA -308GA genotype was associated with disease susceptibility according to a codominant genetic model (OR = 3.2, 95% CI 1.05-9.75, p = 0.03), and with higher anti-fibrillarin antibodies (p = 0.01), and higher skin thickening (p = 0.006). TNFA -238GA was not associated with SSc risk. TNFA mRNA expression and sTNF-α levels were similar between SSc patients and CS and were not statistically associated with the TNFA polymorphisms; however, a correlation (rho = 0.362, p = 0.009) between sTNF-α levels with anti-RNA polymerase III antibodies was observed in the SSc patients. In conclusion, the -308G>A polymorphism is a genetic marker of SSc susceptibility in population from southern Mexico, and it is associated with skin thickening and anti-fibrillarin antibodies. In addition, sTNF-α levels correlate positively with the anti-RNA pol III antibodies levels.

Prevalence of anti-RNA polymerase III antibodies in systemic sclerosis: New data from a French cohort and a systematic review and meta-analysis

OBJECTIVE

Studies assessing the prevalence of anti-RNA polymerase III (anti-RNAP III) antibodies in systemic sclerosis (SSc) have yielded a wide range of results. The aim of the present study was to describe a new SSc cohort tested for presence of anti-RNAP III and perform a systematic review and meta-analysis to assess the prevalence of anti-RNAP III in patients worldwide and the potential factors of variability.

METHODS

Seropositivity for anti-RNAP III was evaluated in a French cohort of SSc patients. A systematic review of the literature was carried out in PubMed and EMBase. Meta-analysis was performed using available data on prevalence, clinical characteristics of SSc patients, and the types of assays used for anti-RNAP III testing.

RESULTS

One hundred thirty-three French SSc patients were tested for anti-RNAP III, and a prevalence of 6-9% was found in these patients. Thirty studies representing a total population of 8,437 SSc patients were included in the meta-analysis. Prevalence of anti-RNAP III in this population was highly variable (range 0-41%). The overall pooled prevalence of anti-RNAP III was 11% (95% confidence interval 8-14), but heterogeneity was high among studies (I(2) = 93%, P < 0.0001). Geographic factors such as continent or country of study origin partially explained this heterogeneity and correlated with the prevalence. No other baseline SSc characteristics were significantly correlated with the prevalence of anti-RNAP III.

CONCLUSION

Data on our new cohort and our meta-analysis of the literature confirmed that anti-RNAP III prevalence in SSc varies among centers. Geographic factors were significantly associated with prevalence, which underscores the probable implication that genetic background and environmental factors play a role. Heterogeneity among studies remained largely unexplained.

Systemic sclerosis--challenges for clinical practice

The management of patients with systemic sclerosis (SSc) can be challenging because disease-associated damage is often difficult to reverse and curative therapies are not yet available. Early identification and appropriate monitoring of patients with SSc is, therefore, critical so that active disease can be controlled and tissue damage prevented or delayed. However, early diagnosis of SSc is often difficult because the early clinical stages of the disease can be very similar to that of other autoimmune conditions. Screening for major organ manifestations of SSc, particularly interstitial lung disease, pulmonary hypertension, renal involvement and cardiac disease is a priority because involvement of these organs is associated with shorter life expectancies and early intervention might prevent disease progression. The prevention and management of digital ischaemia is also important as appropriate therapy often prevents substantial morbidity and functional loss. Treating gastrointestinal dysmotility can usually be managed using proton pump inhibitors and promotility agents, although in severe cases total parenteral nutrition is required. Calcinosis in patients with SSc is another common challenge that requires appropriate disease management and pain control. Each of these topics, which are relevant to both physicians and patients with SSc, are reviewed in further detail herein.

Prevalence, correlates and clinical usefulness of antibodies to RNA polymerase III in systemic sclerosis: a cross-sectional analysis of data from an Australian cohort

INTRODUCTION

The prevalence of antibodies to RNA polymerase III (anti-RNAP) differs among systemic sclerosis (SSc) cohorts worldwide. Previously reported associations of anti-RNAP include diffuse cutaneous disease, tendon friction rubs and renal crisis, with recent reports suggesting a close temporal association between malignancy and SSc disease onset among patients with anti-RNAP.

METHODS

Patients with SSc were tested for the presence of anti-RNAP at recruitment into the Australian Scleroderma Cohort Study. We used univariate and multivariable methods to identify and quantify clinical and laboratory correlates of anti-RNAP in SSc. Diagnostic testing procedures were used to determine the usefulness of these antibodies in estimating the likelihood of clinically important outcomes.

RESULTS

There were 451 patients with mean ± standard deviation age and disease duration at recruitment of 58.1 ± 12.4 and 11.6 ± 10.0 years, respectively; 151 (33.5%) patients were recruited within 5 years of diagnosis of SSc. Overall, 69 (15.3%) patients had anti-RNAP. Univariate associations of anti-RNAP were diffuse disease (75.4% vs. 20.9%, P < 0.0001), joint contractures (73.9% vs. 30.1%, P < 0.0001), greater highest-recorded modified Rodnan skin score (20.6 ± 12.4 vs. 10.1 ± 7.9, P < 0.0001), synovitis (31.9% vs. 19.9%, P = 0.03), myositis (2.9% vs. 0.5%, P = 0.05), systemic hypertension (59.4% vs. 39.7%, P = 0.002), renal crisis (24.6% vs. 1.8%, P < 0.0001) and malignancy diagnosed within 5 years of onset of SSc skin disease (13.3% vs. 3.9%, P = 0.01). In multiple regression analysis, after adjustment for other covariates, anti-RNAP were independently associated with renal crisis (odds ratio (OR) 3.8, 95% confidence interval (CI) 1.2 to 11.5, P = 0.02; positive predictive value (PPV) 24.6%, negative predictive value (NPV) 98.2%), diffuse disease (OR 6.4, 95% CI 2.9 to 13.8, P < 0.0001; PPV 75.4%, NPV 20.9%), joint contractures (OR 2.5, 95% CI 1.2 to 5.3, P = 0.02; PPV 73.9%, NPV 69.9%) and malignancy diagnosed within 5 years of onset of SSc skin disease (OR 4.2, 95% CI 1.3 to 13.4, P = 0.01; PPV 13.3%, NPV 96.1%).

CONCLUSIONS

Anti-RNAP status is a clinically useful prognostic marker in SSc and enables clinicians to identify patients at high risk of developing renal crisis, synovitis, myositis and joint contractures. Patients with anti-RNAP also have an increased risk of malignancy within a 5-year timeframe before or after onset of SSc skin changes.

Scleroderma renal crisis in a Swedish systemic sclerosis cohort: survival, renal outcome, and RNA polymerase III antibodies as a risk factor

OBJECTIVES

To study survival, renal outcome, and RNA polymerase III antibodies (RNAP Abs) as a risk factor for scleroderma renal crisis (SRC) in a Swedish cohort of systemic sclerosis (SSc) patients.

METHODS

SRC was diagnosed in 16 SSc patients during the period from 1982 to 2010. For comparison, 112 (seven for each SRC patient) SSc patients without SRC were included. RNAP Abs were detected by a fully automated fluoroenzyme immunoassay (EliA). Values greater than 15 μg/L were considered positive. Frozen serum samples from the time of diagnosis of SSc were used.

RESULTS

The 5- and 10-year survival rates were, respectively, 58% and 40% for SRC patients and 90% and 76% for patients without SRC (p < 0.001). The odds ratio (OR) for mortality was 4.39 [95% confidence interval (CI) 2.10-9.16, p < 0.001] in patients with SRC compared to those without SRC. Renal outcome was good in three patients. Haemodialysis was started in 10 patients and peritoneal dialysis in three. Renal function improved in three patients and dialysis was terminated. Four patients underwent renal transplantation. Seven SRC patients and nine without SRC were positive for RNAP Abs. Anti-RNAP Abs was a strong predictor of SRC. The sensitivity and specificity for development of SRC were 0.44 and 0.92, respectively. The OR for development of SRC was 8.90 (95% CI 2.68-29.6, p = 0.001) in RNAP-positive patients.

CONCLUSIONS

RNAP positivity is a strong risk factor for SRC. Renal outcome was variable and survival is still notably decreased.

Gender and ethnicity differences in the prevalence of scleroderma-related autoantibodies

Autoantibodies to topoisomerase I (topo I), RNA polymerase III (RNAPIII), centromere, U3RNP/fibrillarin, Th, PM-Scl, and U1RNP found in scleroderma (SSc) are associated with unique clinical subsets. The effects of race and gender on autoantibody prevalence and clinical manifestations were examined. Autoantibodies in sera from 105 SSc (include 75 Caucasian, 24 African-American, 6 others; 89 females and 16 males) were analyzed by immunofluorescence and immunoprecipitation. Clinical information was from database. SSc-related autoantibodies seldom coexist except for anti-topo I and anti-U1RNP. Anti-topo I (35% vs 15%), anti-U3RNP (30% vs 3%, p = 0.0005), and anti-U1RNP (30% vs 13%) were more common in African-Americans vs Caucasians. Anti-centromere (17%) and anti-PM-Scl (only in 8% of female) were found only in Caucasians. In race/gender combination, all three African-American males had anti-topo I (p = 0.04). Anti-U3RNP (35% vs 3%, p = 0.0005) and anti-U1RNP were common in African-American females. In African-American, all nucleolar dominant staining sera had anti-U3RNP; nuclear pattern was topo I (50%), U1RNP (19%), and RNAPIII (13%). In Caucasian, nucleolar was anti-Th (43%) and PM-Scl (29%); nuclear pattern was RNAPIII (29%), topo I (24%), and U1RNP (18%). Anti-topo I, anti-RNAPIII, and anti-U3RNP were associated with diffuse SSc while anti-centromere, anti-Th, and anti-U1 with limited disease. Proximal scleroderma was less common in African-American with anti-topo I (38% vs 91% in Caucasian, p = 0.04). The production of SSc-related autoantibodies is gender and race dependent, and this can be highly relevant in understanding their clinical significance.