Clinical subsets, skin thickness progression rate, and serum antibody levels in systemic sclerosis patients with anti-topoisomerase I antibody

OBJECTIVE: To describe the clinical and laboratory features and natural history of the disease in systemic sclerosis (SSc; scleroderma) patients with anti-topoisomerase I (anti-topo I) antibody who have different skin thickness progression rates (STPRs). METHODS: SSc patients (n = 212) who were anti-topo I antibody positive were divided into 5 subgroups based on STPRs. Skin thickness was measured using the modified Rodnan skin thickness score (MRSS). Anti-topo I IgG antibody levels were determined. RESULTS: Sixty patients who were anti-topo I antibody positive had diffuse cutaneous SSc (dcSSc) with rapid progression, 82 had dcSSC with intermediate progression, and 29 had dcSSc with slow progression, 14 had limited cutaneous SSc (lcSSc) that became dcSSc, and 27 had lcSSc that did not change throughout. Patients beginning with lcSSc were younger at disease onset and had longer disease duration when diagnosed as having SSc. Interstitial lung disease was common and was equally distributed across the subgroups. Renal crisis occurred most often in patients with rapid progression (22%) and was absent in lcSSc patients. Cardiac involvement was most frequent in the dcSSc subgroups. Both kidney and heart disease occurred most often within 3 years after the onset of skin thickening. The 10-year cumulative survival rate was <40% for patients with rapid and intermediate progression. Renal and cardiac causes of death were disproportionately frequent in these 2 subgroups. Anti-topo I antibody levels correlated with the STPR and the MRSS. CONCLUSION: Anti-topo I antibody-positive patients with SSc with a rapid STPR have reduced survival rates, primarily due to early and often fatal renal and cardiac involvement. Anti-topo I antibody levels parallel the MRSS at the first visit and the STPR. This information is important for managing physicians and researchers planning clinical trials involving patients with early dcSSc.     

Correlation of serum anti‐DNA topoisomerase I antibody levels with disease severity and activity in systemic sclerosis

Objective

To investigate correlations between serum levels of topoisomerase I–specific antibody (anti–topo I) and clinical features of systemic sclerosis (SSc), including disease severity (the total skin score [TSS]) and disease activity.

Methods

Using highly sensitive enzyme‐linked immunosorbent assays, we measured the levels of anti–topo I antibody, including total IgG, individual IgG subclasses, and IgA, and analyzed their correlations with the TSS in 59 patients with SSc, all of whom had diffuse cutaneous involvement. Serial serum samples were obtained from 11 of these patients.

Results

The titers of anti–topo I antibody, including IgG and IgA, were positively correlated with the TSS, a measure of SSc disease severity. In 8 of the 11 patients from whom serial serum samples were obtained, changes in the levels of both IgG and IgA, when detectable, paralleled changes in the TSS. In 3 patients, an increasing anti–topo I IgG level preceded an increase in the TSS. The level of each IgG subclass also correlated with and tended to parallel the TSS. The patients with very active disease had higher mean IgG (P < 0.001) and IgA (P < 0.05) titers than did those with inactive disease.

Conclusion

Serum levels of anti–topo I antibody correlate positively with disease severity and disease activity in SSc.

     

Correlation of serum anti-DNA topoisomerase I antibody levels with disease severity and activity in systemic sclerosis

OBJECTIVE: To investigate correlations between serum levels of topoisomerase I-specific antibody (anti-topo I) and clinical features of systemic sclerosis (SSc), including disease severity (the total skin score [TSS]) and disease activity. METHODS: Using highly sensitive enzyme-linked immunosorbent assays, we measured the levels of anti-topo I antibody, including total IgG, individual IgG subclasses, and IgA, and analyzed their correlations with the TSS in 59 patients with SSc, all of whom had diffuse cutaneous involvement. Serial serum samples were obtained from 11 of these patients. RESULTS: The titers of anti-topo I antibody, including IgG and IgA, were positively correlated with the TSS, a measure of SSc disease severity. In 8 of the 11 patients from whom serial serum samples were obtained, changes in the levels of both IgG and IgA, when detectable, paralleled changes in the TSS. In 3 patients, an increasing anti-topo I IgG level preceded an increase in the TSS. The level of each IgG subclass also correlated with and tended to parallel the TSS. The patients with very active disease had higher mean IgG (P < 0.001) and IgA (P < 0.05) titers than did those with inactive disease. CONCLUSION: Serum levels of anti-topo I antibody correlate positively with disease severity and disease activity in SSc.     

DNA topoisomerase I binding to fibroblasts induces monocyte adhesion and activation in the presence of anti–topoisomerase I autoantibodies from systemic sclerosis patients

Objective

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis due to excessive and dysregulated collagen production by fibroblasts. Previously, we reported that anti–DNA topoisomerase I (anti–topo I) antibodies bound specifically to fibroblast surfaces; however, we had not identified their antigenic target. We undertook this study to characterize the target of anti–topo I antibodies on fibroblasts and the effects of their binding.

Methods

Purified topo I or topo I released from apoptotic cells was tested for surface binding to a number of human cell types by cell‐based enzyme‐linked immunosorbent assay, flow cytometry, and indirect immunofluorescence. Antibodies purified from SSc patient and normal control sera were used to detect topo I binding. The consequences of topo I and anti–topo I binding to fibroblasts were assessed by coculture with THP‐1 monocytes.

Results

The autoantigen topo I itself was found to bind specifically to fibroblasts in a dose‐dependent and saturable manner, where it was recognized by anti–topo I from SSc patients. The binding of anti–topo I subsequently stimulated adhesion and activation of cocultured monocytes. Topo I released from apoptotic endothelial cells was also found to bind specifically to fibroblasts.

Conclusion

The findings of this study thus confirm and extend the findings of our previous study by showing that topo I binding to fibroblast surfaces is both necessary and sufficient for anti–topo I binding. Second, topo I–anti–topo I complex binding can then trigger the adhesion and activation of monocytes, thus providing a plausible model for the amplification of the fibrogenic cascade in anti–topo I–positive SSc patients.

     

Direct binding of anti–DNA topoisomerase I autoantibodies to the cell surface of fibroblasts in patients with systemic sclerosis

Objective

Fibroblasts play a crucial role in the development of systemic sclerosis (SSc), and antifibroblast antibodies (AFAs) capable of inducing a proinflammatory phenotype in fibroblasts have been detected in the sera of SSc patients. This study examined the prevalence of AFAs in SSc and other diseases and the possible correlation between AFAs and known antinuclear antibody specificities in SSc patients.

Methods

Sera from 99 patients with SSc, 123 patients with other autoimmune and nonautoimmune diseases, and 30 age‐ and sex‐matched healthy controls were examined. AFA prevalence was assessed by flow cytometry and further characterized by indirect immunofluorescence, enzyme‐linked immunosorbent assay (ELISA), and immunoblotting. Anti–topoisomerase I (anti–topo I) from SSc sera were purified by affinity chromatography on topo I.

Results

AFAs were more common in SSc patients (26.3%) than in any other disease groups studied. The presence of AFA was significantly associated with pulmonary involvement and death. AFA‐positive sera from SSc patients bound to all human and rodent fibroblasts tested, but not to human primary endothelial cells or smooth muscle cells. All SSc AFAs strongly reacted with topo I by ELISA and immunoblotting. The binding intensity of SSc AFAs correlated strongly with reactivity against topo I on immunoblots of fibroblast extracts and with the immunofluorescence pattern typical of anti–topo I on permeabilized cells. Total IgG and affinity‐purified anti–topo I from AFA‐positive SSc sera were found to react with the surface of unpermeabilized fibroblasts by flow cytometry as well as by immunofluorescence and confocal microscopy.

Conclusion

This is the first report establishing that AFAs in SSc are strongly correlated with anti–topo I and, furthermore, that anti–topo I antibodies themselves display AFA activity by reacting with determinants at the fibroblast surface.

     

Association of the PTPN22 R620W polymorphism with anti–topoisomerase I– and anticentromere antibody–positive systemic sclerosis

Objective

To determine any associations of the PTPN22 R620W single‐nucleotide polymorphism (SNP) with systemic sclerosis (SSc) or with anticentromere antibody (ACA)–positive or anti–topoisomerase I (anti–topo I) antibody–positive SSc, in a case–control study of US white, black, Hispanic, and Choctaw Indian individuals.

Methods

A total of 850 white, 130 black, 120 Hispanic, and 20 Choctaw Indian patients with SSc were compared with 430 white, 164 black, 146 Hispanic, and 76 Choctaw Indian control subjects, respectively. All subjects were living in the US. PTPN22 SNP (rs2476601) genotyping was performed by TaqMan 5′ allelic discrimination assay and pyrosequencing.

Results

The PTPN22 CT/TT genotype showed significant association with anti–topo I antibody–positive SSc in white patients (odds ratio [OR] 2.21, 95% confidence interval [95% CI] 1.3–3.7) and with ACA‐positive white patients with SSc (OR 1.70, 95% CI 1.1–2.7). Frequency of the PTPN22*T allele also showed significant association with anti–topo I antibody–positive SSc in white patients (OR 2.03, 95% CI 1.3–3.2). When data for patients in the 3 ethnic groups (black, white, and Hispanic) were combined, a significant association with both genotype and allele frequencies was observed, suggesting a trend toward association in ACA‐positive and anti–topo I antibody–positive SSc. Stepwise logistic regression analysis (controlled for the confounding effects of sex and race) showed that the PTPN22 CT/TT genotype was associated with a significantly higher risk of SSc compared with the CC genotype (for patients with SSc, OR 1.64, 95% CI 1.2–2.2; for ACA‐positive patients with SSc, OR 1.63, 95% CI 1.0–2.6; for anti–topo I antibody–positive SSc, OR 2.33, 95% CI 1.5–3.7).

Conclusion

Our results indicate that the PTPN22 R620W polymorphism is associated with ACA‐positive and anti–topo I antibody–positive subsets of SSc and represents a risk factor in both white patients and black patients. The association of subsets of SSc with the PTPN22 R620W polymorphism further strengthens the classification of SSc within the spectrum of autoimmune diseases and strongly suggests the involvement of common susceptibility genes and similarly disordered immunoregulatory pathways.

     

Clinical significance of anti-topoisomerase I antibody levels determined by ELISA in systemic sclerosis

OBJECTIVE: To determine the clinical associations of the levels of anti-topoisomerase I (topo I) antibody in patients with systemic sclerosis (SSc). METHODS: Anti-topo I antibody levels were determined by enzyme-linked immunosorbent assay. In a longitudinal study, 125 sera from 21 patients were analysed during a follow-up period of 0.2-4.7 yr. RESULTS: Anti-topo I antibody levels were correlated positively with skin thickness score and renal vascular resistance, and inversely with percentage vital capacity. In the longitudinal study, five patients with a low anti-topo I antibody level at their first visit exhibited a stable antibody level or a small decrease in the level during the follow-up period, and their skin sclerosis was stable. Of 16 patients with a high anti-topo I antibody level at their first visit, seven showed a stable level, four had an increasing level and five had a decreasing level. The decreasing levels were accompanied mainly by atrophic skin change during the follow-up period, whereas the increasing levels were associated with new onset or worsening of organ involvement. CONCLUSIONS: These results suggest the potential clinical significance of anti-topo I antibody levels in evaluating disease severity and the prognosis in SSc.     

Elevation of serum lymphotactin levels in patients with systemic sclerosis

OBJECTIVE: To determine serum concentrations of lymphotactin, a Th1 chemokine, and their clinical association in patients with systemic sclerosis (SSc). METHODS: Lymphotactin levels were examined in serum samples from patients with SSc (n = 68), systemic lupus erythematosus (SLE; n = 42), or dermatomyositis (DM; n = 29), and healthy controls (n = 18) by enzyme linked immunosorbent assay. RESULTS: Serum lymphotactin levels were significantly elevated in SSc patients compared to patients with SLE or DM as well as controls. Serum lymphotactin levels were similar in patients with limited cutaneous SSc and diffuse cutaneous SSc (dSSc). Clinical correlation of elevated lymphotactin levels was not detected in the total group of patients with SSc, while elevation of lymphotactin levels was significantly associated with higher percentage vital capacity and percentage diffusing capacity of carbon monoxide, lower lung severity grade and serum IgG levels, and less frequent presence of short sublingual frenulum in patients with dSSc. CONCLUSION: Our results indicate that elevated serum lymphotactin levels correlate with relatively milder manifestations in dSSc, especially lower severity of lung involvement, suggesting that lymphotactin may play a role in the development of dSSc.     

Clinical significance of serum levels of matrix metalloproteinase-13 in patients with systemic sclerosis

OBJECTIVES: To investigate the clinical significance of serum matrix metalloproteinase-13 (MMP-13) levels in patients with systemic sclerosis (SSc). METHODS: Serum MMP-13 levels were determined by using a peptide substrate cleavage assay in 20 patients with diffuse cutaneous SSc (dcSSc), 20 with limited cutaneous SSc (lcSSc) and 10 normal controls. RESULTS: The serum MMP-13 levels in patients with dcSSc or lcSSc were significantly lower than those in normal controls (53.4 +/- 14.1 vs 73.2 +/- 11.5 ng/ml, P < 0.0005; 59.4 +/- 14.8 vs 73.2 +/- 11.5 ng/ml, P < 0.005, respectively), but there was no significant difference in the serum MMP-13 levels between patients with dcSSc and those with lcSSc. Disease duration prior to the diagnosis was significantly shorter in SSc patients with decreased serum MMP-13 levels than in those with normal levels (3.0 +/- 2.2 vs 8.6 +/- 7.6 yr, P < 0.0005). In addition, serum MMP-13 levels were moderately correlated with the duration of the disease (r = 0.451, P < 0.05). Though there was no significant difference in the frequencies of pulmonary fibrosis or reduced %DLco (diffusing capacity of lung for carbon monoxide), the frequency of reduced %VC (vital capacity) was significantly greater in patients with decreased serum MMP-13 levels than in those with normal levels (73 vs 24%, P < 0.05). CONCLUSIONS: Matrix metalloproteinase-13 may be involved in the fibrotic process of SSc, especially in the initiation of fibrosis. The serum MMP-13 levels may serve as a useful marker for the severity of pulmonary fibrosis in patients with SSc.     

Changes in anti–U1 RNA antibody levels correlate with disease activity in patients with systemic lupus erythematosus overlap syndrome

Objective. To evaluate correlations between changes in anti–U1 RNA antibody levels and disease activity in 9 patients with systemic lupus erythematosus (SLE) overlap syndrome who were prospectively followed up for at least 3 years. Methods. Anti–U1 RNA antibody levels were measured quantitatively, using a nitrocellulose filter binding assay. Disease activity was measured with a validated SLE activity index. Results. All 9 major disease exacerbations were associated with peaks in anti–U1 RNA antibody level. Conclusion. These results seem to indicate that measuring anti–U1 RNA antibody levels can be useful for monitoring disease activity.     

Clinical significance of serum levels of secretory leukocyte protease inhibitor in patients with systemic sclerosis

We aimed to investigate the clinical significance of serum levels of secretory leukocyte protease inhibitor (SLPI), which is widely expressed in lung tissues and serves as a useful marker reflecting the activity of various lung diseases, in patients with systemic sclerosis (SSc). Serum SLPI levels were measured by a specific enzyme-linked immunosorbent assay (ELISA) in 58 SSc patients and 16 healthy controls. Serum SLPI levels in diffuse cutaneous SSc and in limited cutaneous SSc with interstitial lung disease (ILD) were significantly higher than those in healthy controls (43.1?±?18.4 vs. 30.9?±?3.76?ng/ml, p?相似文献   

Increased serum soluble CD40 levels in patients with systemic sclerosis

OBJECTIVE: To determine serum levels of soluble CD40 (sCD40) and clinical association in patients with systemic sclerosis (SSc). METHODS: Serum sCD40 levels were examined by ELISA in 49 patients with SSc, 15 patients with systemic lupus erythematosus, and 26 healthy individuals. sCD40 levels in plasma samples, which were obtained at the same time, were also determined. SSc patients were grouped into 22 patients with limited cutaneous SSc (lcSSc) and 27 patients with diffuse cutaneous SSc (dcSSc). RESULTS: There was no significant difference between sCD40 levels of sera and those of plasma. Serum sCD40 levels were significantly elevated in patients with SSc compared to patients with systemic lupus erythematosus and controls (p < 0.001). Serum sCD40 levels were higher in patients with lcSSc than in those with dcSSc (p <0.001). There was no correlation between sCD40 and sCD40 ligand levels in patients with SSc. CONCLUSION: Elevated serum sCD40 levels were associated with lcSSc. These results suggest that the blockade of CD40/CD40 ligand interaction could be a potential therapeutic strategy in SSc.     

Clinical significance of serum levels of secretory leukocyte protease inhibitor in patients with systemic sclerosis

Abstract

We aimed to investigate the clinical significance of serum levels of secretory leukocyte protease inhibitor (SLPI), which is widely expressed in lung tissues and serves as a useful marker reflecting the activity of various lung diseases, in patients with systemic sclerosis (SSc). Serum SLPI levels were measured by a specific enzyme-linked immunosorbent assay (ELISA) in 58 SSc patients and 16 healthy controls. Serum SLPI levels in diffuse cutaneous SSc and in limited cutaneous SSc with interstitial lung disease (ILD) were significantly higher than those in healthy controls (43.1 ± 18.4 vs. 30.9 ± 3.76 ng/ml, p < 0.05 and 39.8 ± 10.3 vs. 30.9 ± 3.76 ng/ml, p < 0.01, respectively). The incidences of decreased percent diffusing capacity for carbon monoxide (%DLco) and decreased percent vital capacity (%VC) were significantly greater in SSc patients with elevated SLPI levels than in those with normal levels (73 vs. 31%, p < 0.01 and 24 vs. 4%, p < 0.05, respectively). Furthermore, serum SLPI levels were inversely correlated with %DLco (r = ?0.40, p < 0.01), while they were positively correlated with surfactant protein D (r = 0.28, p < 0.05). Longitudinal study revealed the association of serum SLPI levels with the disease activity of SSc-ILD. SLPI serves as a useful serum marker for evaluating SSc-ILD.     

Anti–topoisomerase I (Anti–Scl‐70) antibodies in patients with systemic lupus erythematosus

Objective

To investigate the presence and clinical significance of anti–Scl‐70 antibodies in patients with systemic lupus erythematosus (SLE).

Methods

Levels of antibodies against Scl‐70 were determined by a commercial clinical enzyme‐linked immunosorbent assay (ELISA) during routine evaluation. Results were verified by an additional ELISA with a characterized bovine Scl‐70, by ELISA with a recombinant human topoisomerase I, by Western blot, and by double diffusion in agar gel. Disease activity was estimated retrospectively by the Systemic Lupus Activity Measure (SLAM).

Results

Of 128 consecutive SLE patients, 25% were positive for anti–Scl‐70 antibody; this antibody activity was cognate in nature. No SLE patient could be classified as also having systemic sclerosis. The levels of anti–Scl‐70 were significantly correlated with the SLAM score for the entire cohort (r = 0.563, P < 0.001) and for 7 individual patients with multiple longitudinal measurements (r = 0.755–0.951, P < 0.001; n = 6) (r = 0.378, P < 0.05; n = 1). A significant correlation was also found between the levels of anti–Scl‐70 and anti–double‐stranded DNA antibodies (r = 0.558, P < 0.001). Patients with anti–Scl‐70 had significantly higher risk of pulmonary hypertension (P < 0.01) and renal involvement (P < 0.001) than patients without this antibody.

Conclusion

Anti–Scl‐70 antibody is present in a significant subset of patients with SLE. For this subset, it offers a good correlate of disease activity and suggests increased risk for pulmonary hypertension and nephritis.