PM-Scl and Th/To in systemic sclerosis: a comparison of different autoantibody assays.

OBJECTIVE: To compare test characteristics of the Euroimmun line blot assay with other assays for two uncommon autoantibody specificities in systemic sclerosis (SSc). METHODS: Patients from the Johns Hopkins Scleroderma Center were assayed routinely using the Euroimmun platform. Patients positive for anti-Th/To (N = 73) and anti-PM-Scl (PM75 and/or PM100; N = 290) by Euroimmun were compared with SSc patients negative for these autoantibodies. For Th/To antibodies, the comparison assay was immunoprecipitation (IP), performed using 4 Th/To complex components: POP1, RPP40, RPP30, and RPP25. For anti-PM-Scl, IPs were performed with PM100 and PM75. Different Euroimmun cut-offs for assigning antibody positive status (≥ 15/+, ≥ 36/++, ≥ 71/+++) were examined. Kappa statistics were calculated to determine agreement between assays. RESULTS: The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun, corresponding to a kappa statistic of 0.79, sensitivity 72% and specificity 100%. For anti-Th/To, kappa values were lower for all comparisons (κ < 0.5). Given the high sensitivity of defining anti-Th/To by ≥ 15/+ (91-95%), a potential approach is to use Euroimmun screening (15/+ cut-off), followed by confirmatory IP. CONCLUSION: Given the increasing utilization of Euroimmun and the importance of comparing data across cohorts, continued use of this platform is warranted, acknowledging discordance with IP for some specificities. For these, using a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested. KEY POINTS: • For less common SSc autoantibody specificities, some discordances exist between IP and Euroimmun LIA. • The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun. • For Th/To, a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested.

Pulmonary hypertension and interstitial lung disease within PHAROS: impact of extent of fibrosis and pulmonary physiology on cardiac haemodynamic parameters.

OBJECTIVES: We sought to examine the relationship between measures of ILD severity and PH in patients with SSc. METHODS: We identified 55 subjects from 12 PHAROS sites with RHC-proven PH and HRCT evidence of ILD. Subjects with PH due to left heart disease were excluded. Baseline HRCT scans were scored by a standardised system that graded severity of ILD. Summary statistics were generated for baseline characteristics. Spearman correlation and linear regression were used to examine relationships between ILD and PH severity variables. RESULTS: The majority of subjects were white women; nearly half had limited cutaneous SSc. Most subjects were New York Heart Association functional class II or III. Pulmonary function testing revealed moderate restriction (mean FVC 64.3 ± 17.2% predicted) with severe reduction in diffusing capacity (mean DLco 34.2 ± 13.3% predicted). RHC demonstrated mild to moderate PH (mean PAP 35 ± 9 mmHg, mean PVR 5.1 ± 3.7 WU). There was no correlation between severity of ILD (by either HRCT or PFT) and cardiac haemodynamic parameters of PH. CONCLUSIONS: No association between severity of ILD and cardiac haemodynamic profiles were identified in this cohort. We believe this underscores the complex nature of PH and ILD in individuals with SSc. We do suspect that some individuals with SSc-ILD will also have concomitant pulmonary vascular disease but simple assessments to grade severity of ILD - by PFT or HRCT estimates of ILD extent - are likely not enough to reliably distinguish between PAH versus PH-ILD. Further research into how to distinguish and manage these subsets is warranted.

Outcomes of hospitalisation for right heart failure in pulmonary arterial hypertension.

The aim of this study was to examine the causes and outcomes of hospitalisation in patients with pulmonary arterial hypertension (PAH). 205 consecutive hospitalisations occurring between 2000 and 2009 in 90 PAH patients were studied. The leading causes for hospitalisation were right heart failure (RHF; 56%), infection (16%) and bleeding disorders (8%). For patients with RHF, in-hospital mortality was 14% overall, 46% for patients receiving inotropes and 48% for those admitted to the intensive care unit. The predictors for in-hospital mortality were the presence of connective tissue disease (CTD) (OR 4.92), systolic blood pressure <100 mmHg (OR 4.32) and Na ≤ 136 mEq · L(-1) (OR 4.29). Mortality after discharge was 13, 26 and 35% at 3, 6 and 12 months, respectively. World Health Organization functional class prior to admission, renal dysfunction, Charlson comorbidity index, and the presence of CTD were all predictors of mortality after discharge. Hyponatraemia and low systolic blood pressure upon admission and underlying CTD are the main prognostic factors for in-hospital mortality in patients with PAH admitted for RHF. The short-term outcomes after discharge are poor and remarkably worse in patients with underlying CTD or renal impairment. Early recognition of these factors may guide decisions regarding more aggressive therapy, including consideration for lung transplantation.

Disproportionate elevation of N-terminal pro-brain natriuretic peptide in scleroderma-related pulmonary hypertension.

N-terminal pro-brain natriuretic peptide (NT-proBNP) is a marker of neurohormonal activation that is useful in the diagnosis and prognosis of various forms of pulmonary arterial hypertension (PAH). We sought to characterise and compare NT-proBNP in a cohort of PAH related to systemic sclerosis (PAH-SSc) and idiopathic PAH (IPAH) patients. NT-proBNP levels, collected from PAH-SSc and IPAH patients followed prospectively, were compared and correlated with haemodynamic variables. Cox proportional hazard models were created to assess the predictive value of NT-proBNP. 98 patients (55 PAH-SSc, 43 IPAH) were included. Haemodynamics were similar, except for lower mean pulmonary arterial pressure in PAH-SSc. NT-proBNP levels were significantly higher in PAH-SSc (3,419+/-3,784 versus 1,393+/-1,633 pg x mL(-1); p<0.01) and were more closely related to haemodynamics in PAH-SSc than IPAH. 28 patients died. NT-proBNP predicted survival (hazard ratio (HR) 3.18; p<0.01) in the overall cohort; however, when stratified by group, predicted survival only in PAH-SSc (HR 3.07, p<0.01 versus 2.02, p = 0.29 in IPAH). This is the first description showing NT-proBNP levels are 1) significantly higher in PAH-SSc than IPAH despite less severe haemodynamic perturbations, and 2) stronger predictors of survival in PAH-SSc, suggesting that neurohormonal regulation may differ between PAH-SSc and IPAH. Future studies to define pertinent mechanisms are warranted.

Biomarkers of vascular disease in scleroderma.

Vascular disease is present in every patient with scleroderma and is a major source of morbidity and mortality. There is a subset of patients who will develop severe and sometimes life-threatening vascular events. We have good evidence that an insult to the microvasculature occurs early in the disease course, but there is a subset of patients who have an ongoing chronic process, the end result of which are events such as digital loss and pulmonary arterial hypertension. The ability to detect this process at an early stage by simple means would be of great value as our ability to treat these vascular complications improves with time. We have a significant amount of evidence of vascular perturbation from studies of peripheral blood in scleroderma, but know very little about the ability of these biomarkers to predict vascular outcomes. In this review, we will critically assess our current knowledge of the use of biomarkers of vascular disease in scleroderma and the possible directions of future research in this area.

High-dose cyclophosphamide without stem cell rescue in scleroderma.

OBJECTIVE: To investigate the safety and tolerability of high-dose cyclophosphamide without stem cell rescue in scleroderma. METHODS: An open-label, single-site, uncontrolled study design entered patients with active diffuse cutaneous scleroderma. Patients were treated with cyclophosphamide (50 mg/kg) intravenously daily for 4 consecutive days (total 200 mg/kg) followed by granulocyte colony-stimulating factor (5 microg/kg/day). The primary clinical efficacy end point was the modified Rodnan skin score (mRSS). Secondary end points included the Health Assessment Questionnaire-Disability Index (HAQ-DI), physician global assessment (PGA) and pulmonary function tests. RESULTS: Six patients (4 men, 2 women) aged 19-60 years were entered into the study. One patients died early in the protocol, thus five patients had follow-up data. The percentage reduction of the mRSS in these five evaluable patients within 1 month of treatment was 60%, 55%, 41%, 31% and 0%. The patient with no decline in skin score at 1 month showed a decrease in skin score from 41 to 26 by the 3-month visit, a 37% improvement. Three patients sustained the improvement after treatment for 24, 12 and 12 months. Two patients relapsed at 12 and 6 months after treatment. The PGA and HAQ-DI scores improved in five of the six patients by 72% and 79% respectively at 3 months. The only serious adverse event was a death that occurred owing to infection after neutrophil count recovery. CONCLUSIONS: High-dose cyclophosphamide without stem cell rescue can lead to a clinically significant improvement in skin score and measures of disease severity in patients with diffuse cutaneous scleroderma.

A case-control study of the pathology of oesophageal disease in systemic sclerosis (scleroderma).

BACKGROUND: Atrophy of the smooth muscle layers of the muscularis propria characterises oesophageal involvement in systemic sclerosis (scleroderma). The aetiology of this atrophy and of the resultant oesophageal dysfunction is unknown. OBJECTIVES: To examine oesophageal tissue for evidence of fibrosis, vascular disease, inflammatory reactions and neural abnormalities to determine the possible causes of this disease process. METHODS: A case-control survey was conducted using oesophageal tissue from 74 scleroderma cases and 74 age, race and sex-matched controls from our autopsy files. Histological evidence of oesophageal muscle atrophy was correlated with the degree of vascular changes, inflammatory infiltration, fibrosis, abnormalities of the myenteric plexus and reduction of interstitial cells of Cajal (ICC) using a predesigned semiquantitative descriptive method. RESULTS: Smooth-muscle atrophy was found in 94% of scleroderma cases, and in 5% of controls (p<0.001). Atrophy was evident in the circular smooth muscle in 93% of cases, and in the longitudinal smooth muscle in 66% of cases. Intimal proliferation of arterioles was found in 38% of cases and in 5% of controls (p<0.001), but was not associated with smooth-muscle atrophy (p = 0.29). Despite these vascular changes, there was no evidence of compromised perfusion, such as findings suggestive of acute ischaemic necroses. Minimal cellular infiltrates were seen in the myenteric plexus in 82% of cases and in 92% of controls (p = 0.091). ICC were found in fewer numbers in areas of atrophic smooth muscle compared with adjacent normal smooth muscle in selected scleroderma cases. CONCLUSION: The pathological findings of oesophageal lesions in scleroderma seem inconsistent with either an ischaemic or an inflammatory process. The loss of circular and longitudinal smooth muscle in the distal scleroderma oesophagus may represent loss of normal neural function followed by secondary tissue atrophy, or may be a primary smooth muscle lesion.

Abnormal exhaled ethane concentrations in scleroderma.

Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml(-1) CO(2) (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml(-1) CO(2) (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=-2.8, p=0.026, CI=-5.2 to -0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.

Distinct recognition of antibodies to centromere proteins in primary Sjogren's syndrome compared with limited scleroderma.

BACKGROUND: Anticentromere antibodies are characteristically observed in scleroderma but have recently been reported in other autoimmune rheumatic disorders, including Sjögren's syndrome. It is not known whether distinct centromere proteins (CENP) are targeted in primary Sjögren's syndrome (pSS) and scleroderma. OBJECTIVE: To determine whether antibodies to CENP-B and CENP-C are present in these two disorders. METHODS: Sera from 45 patients with pSS and 33 with limited scleroderma were studied. All patients met classification criteria for pSS and scleroderma, respectively. Sera were used to immunoprecipitate in vitro translated CENP-B and CENP-C. The proportions recognising CENP-B or CENP-C were compared. RESULTS: 10 of 45 patients (22%) with pSS and 18 of 33 (55%) with scleroderma had antibodies recognising CENPs (p = 0.004). Seven of 10 (70%) CENP positive patients with pSS recognised CENP-C alone, compared with one of 18 (6%) CENP positive patients with scleroderma (odds ratio (OR) = 40 (95% confidence interval (CI), 3.5 to 450) (p = 0.003). In contrast, the majority (15 of 18 (83%)) of CENP positive scleroderma sera recognised both CENP-B and CENP-C, compared with none of 10 pSS sera (OR = 93 (95% CI, 4.4 to 1979) (p = 0.0001). CONCLUSIONS: The pattern of CENP recognition differs markedly in pSS and limited scleroderma. While patients with pSS predominantly recognise CENP-C alone, dual recognition of CENP-B and CENP-C is most frequent in scleroderma. These findings suggest that obtaining antibodies to specific centromere antigens is useful diagnostically, and imply that distinct mechanisms underlie the unique patterns of centromere autoreactivity in pSS and scleroderma.

Recurrent transverse myelitis associates with anti-Ro (SSA) autoantibodies.

Transverse myelitis (TM) is an idiopathic inflammatory disorder of the spinal cord. The authors observed cases of recurrent TM in patients where anti-Ro (SSA) antibodies were present and therefore performed a case-control study to examine the frequency of anti-Ro autoantibodies in patients with recurrent TM and control subjects. Antibodies to 52-kd Ro were demonstrated in 77% of cases (10/13) compared with only 33% of control subjects (4/12).