The diagnostic value of several immunological tests for anti-nuclear antibody in predicting the development of connective tissue disease in patients presenting with Raynaud's phenomenon

A comprehensive framework for navigating patient care in systemic sclerosis: A global response to the need for improving the practice of diagnostic and preventive strategies in SSc

Systemic sclerosis (SSc), the most lethal of rheumatologic conditions, is the cause of death in >50% of SSc cases, led by pulmonary fibrosis followed by pulmonary hypertension and then scleroderma renal crisis (SRC). Multiple other preventable and treatable SSc-related vascular, cardiac, gastrointestinal, nutritional and musculoskeletal complications can lead to disability and death. Vascular injury with subsequent inflammation transforming to irreversible fibrosis and permanent damage characterizes SSc. Organ involvement is often present early in the disease course of SSc, but requires careful history-taking and vigilance in screening to detect. Inflammation is potentially reversible provided that treatment intensity quells inflammation and other immune mechanisms. In any SSc phenotype, opportunities for early treatment are prone to be under-utilized, especially in slowly progressive phenotypes that, in contrast to severe progressive ILD, indolently accrue irreversible organ damage resulting in later-stage life-limiting complications such as pulmonary hypertension, cardiac involvement, and malnutrition. A single SSc patient visit often requires much more physician and staff time, organization, vigilance, and direct management for multiple organ systems compared to other rheumatic or pulmonary diseases. Efficiency and efficacy of comprehensive SSc care enlists trending of symptoms and bio-data. Financial sustainability of SSc care benefits from understanding insurance reimbursement and health system allocation policies for complex patients. Sharing care between recognised SSc centers and local cardiology/pulmonary/rheumatology/gastroenterology colleagues may prevent complications and poor outcomes, while providing support to local specialists. As scleroderma specialists, we offer a practical framework with tools to facilitate an optimal, comprehensive and sustainable approach to SSc care. Improved health outcomes in SSc relies upon recogntion, management and, to the extent possible, prevention of SSc and treatment-related complications.

Development of autoantibodies precedes clinical manifestations of autoimmune diseases: A comprehensive review

The etiology of autoimmune diseases is due to a combination of genetic predisposition and environmental factors that alter the expression of immune regulatory genes through various mechanisms including epigenetics. Both humoral and cellular elements of the adaptive immune system play a role in the pathogenesis of autoimmune diseases and the presence of autoantibodies have been detected in most but not all autoimmune diseases before the appearance of clinical symptoms. In some cases, the presence or levels of these autoantibodies portends not only the risk of developing a corresponding autoimmune disease, but occasionally the severity as well. This observation is intriguing because it suggests that we can, to some degree, predict who may or may not develop autoimmune diseases. However, the role of autoantibodies in the pathogenesis of autoimmune diseases, whether they actually affect disease progression or are merely an epiphenomenon is still not completely clear in many autoimmune diseases. Because of these gaps in our knowledge, the ability to accurately predict a future autoimmune disease can only be considered a relative risk factor. Importantly, it raises the critical question of defining other events that may drive a patient from a preclinical to a clinical phase of disease.

The primary care physician in the early diagnosis of systemic sclerosis: the cornerstone of recognition and hope

Systemic sclerosis (SSc) is a disease of unknown causative factor that manifests as a heterogenous group of multiorgan system manifestations and is characterized by vasculopathy and fibrosis of the skin and internal organs, with mortality related to pulmonary, cardiac, renal or gastrointestinal involvement. The prevalence of SSc may be underestimated in the general population. Cases are often undiagnosed or misdiagnosed, particularly cases with mild or no skin manifestations. Because of late referrals to rheumatologic care, many moderate-to-severe cases progress to irreversible end-organ damage that might have been prevented by early diagnosis. Early diagnosis of SSc with initiation of appropriate treatment is essential, with great impact on morbidity and mortality. This review examines presenting features, ensuing complications and treatment providing a focus on SSc as a treatable disease. Primary care providers play a pivotal role in recognizing initial symptoms associated with SSc and securing early diagnosis through early referral to specialists.

A systematic overview on the use and relevance of capillaroscopy in systemic sclerosis

Capillaroscopy is a non-invasive and safe technique that allows the detection and quantification of the early microvascular abnormalities that characterize secondary Raynaud's phenomenon. The well-established role of capillaroscopy for the early diagnosis of systemic sclerosis, its inclusion in the classification criteria, combined with its predictive value for clinical complications of the disease and its potential for monitoring disease progression and treatment response, makes nailfold capillaroscopy an important assessment in clinical practice and research. Capillaroscopy provides a unique window into the microcirculation and its application in diseases in which a microvascular component is suspected; it also may provide new insights into their pathophysiology and natural history.

The Influence of Different Beta-Blocking Drugs on the Peripheral Circulation in Raynaud's Phenomenon and in Hypertension

In a double-blind, randomized, placebo-controlled study, the authors investigated the effects of different beta-adrenoceptor blocking drugs on the peripheral circulation. A single intravenous injection of the nonselective beta-blocker propranolol (0.20 mg/kg), the beta 1-selective adrenoceptor blocker metoprolol (0.25 mg/kg), and the nonselective beta-blocker with partial agonistic activity (PAA) pindolol (0.04 mg/kg) and of placebo (saline) was given to eight patients with a primary Raynaud's phenomenon and to nine untreated patients with primary hypertension. The authors measured finger skin temperature (FST), and laser Doppler estimated finger skin blood flux (LDF) before, during, and after a standardized finger cooling test, performed 25 minutes after the administration of the drugs. In both patients groups propranolol, metoprolol, and pindolol had no significant effect on FST and LDF in the first 25 minutes after administration both in comparison to baseline value and to placebo. Also, no significant differences were found in the recoveries of FST and LDF after cold challenge between all drugs and placebo in both groups. The authors conclude that no adverse effect of any type of beta-adrenoceptor blocker in comparison to placebo could be detected after a single administration on both the baseline finger skin perfusion and the recovery after cold-induced vasoconstriction. In addition, the authors could not demonstrate a favorable effect of beta 1-selectivity or PAA in comparison to a nonselective beta-adrenoceptor blocker without PAA, in any group.

Improving outcome prediction of systemic sclerosis from isolated Raynaud's phenomenon: role of autoantibodies and nail-fold capillaroscopy

OBJECTIVE

A simple weighted prognostic algorithm, based on capillaroscopy and autoantibodies, is developed to classify patients at different risk of transition from isolated RP to SSc within 5 years from the screening visit.

METHODS

Two hundred and eighty-eight of 768 patients with isolated RP who underwent capillaroscopy were recruited. The prognostic contributions of capillaroscopic findings (giant loops, haemorrhages and the number of capillaries) and SSc-associated autoantibodies (ACAs, anti-topo I and ANAs) were assessed in a semi-parametric regression models suitable for competing risks. A prognostic index was built by a bagging technique. A structured tree approach was used to extract simple classificatory rules that can be directly interpreted.

RESULTS

Thirty-four transitions from isolated RP to SSc and 42 to other CTDs were observed. All of the chosen variables had a substantial prognostic impact. A complex non-linear prognostic pattern was observed for capillaries, with the risk of developing SSc increasing as the number of loops decreased. The presence of ANAs had a strong impact on prognosis [hazard ratio (HR) = 9.70], which was increased by the presence of ACA (HR = 3.94; P < 0.001). A weighted prognostic classification for the development of SSc was constructed using capillary number, giant loops and ANAs. The prognostic discrimination was satisfactory (Harrell's C-index = 0.86).

CONCLUSION

Our prognostic model is based on easy-to-obtain features (i.e. the number of capillaries, giant loops and ANAs) and could be used to facilitate clinical decision making in the screening phase, and may also have important implications for stratifying patients into risk groups for future clinical assessment.

Autoantibodies and microvascular damage are independent predictive factors for the progression of Raynaud's phenomenon to systemic sclerosis: a twenty-year prospective study of 586 patients, with validation of proposed criteria for early systemic sclerosis

OBJECTIVE

To identify in patients with Raynaud's phenomenon (RP) independent markers that predict progression to definite systemic sclerosis (SSc) and to determine in patients with progression to SSc the type and sequence of microvascular damage and its relationship to SSc-specific autoantibodies.

METHODS

Consecutive patients referred for evaluation of RP who had no definite connective tissue disease were evaluated for microvascular damage by nailfold capillary microscopy (NCM) and for anticentromere (anti-CENP-B), anti-Th/To, anti-topoisomerase I, and anti-RNA polymerase III (anti-RNAP III) autoantibodies by specific assays. Patients were studied prospectively.

RESULTS

Of the 586 patients who were followed up for 3,197 person-years, 74 (12.6%) developed definite SSc. A characteristic sequence of microvascular damage was identified, starting with enlarged capillaries, followed by capillary loss, and then by capillary telangiectases. Definite SSc was diagnosed in close temporal relationship to capillary loss. Enlarged capillaries, capillary loss, and SSc-specific autoantibodies independently predicted definite SSc. Anti-CENP-B and anti-Th/To antibodies predicted enlarged capillaries; these autoantibodies and anti-RNAP III predicted capillary loss. Each autoantibody was associated with a distinct time course of microvascular damage. At followup, 79.5% of patients with 1 of these autoantibodies and abnormal findings on NCM at baseline had developed definite SSc. Patients with both baseline predictors were 60 times more likely to develop definite SSc. The data validated the proposed criteria for early SSc.

CONCLUSION

In RP evolving to definite SSc, microvascular damage is dynamic and sequential, while SSc-specific autoantibodies are associated with the course and type of capillary abnormalities. Abnormal findings on NCM at baseline together with an SSc-specific autoantibody indicate a very high probability of developing definite SSc, whereas their absence rules out this outcome.

Incidence and natural history of Raynaud phenomenon: a long-term follow-up (14 years) of a random sample from the general population

BACKGROUND

Because the natural history of primary Raynaud phenomenon (RP) is unclear, we undertook this long-term (14 years) follow-up of an epidemiologic study on RP to investigate the incidence, remittance rate, and transition rate toward systemic sclerosis and other scleroderma spectrum disorders in a population-based sample of subjects.

METHODS

In 1988 and 1989, 296 subjects obtained from a random sample of the general population of the Alpine valley of Tarentaise (southeast France) completed a cross-sectional study on RP. Of these, 78 met the diagnostic criteria for RP (RP+). From April 2002 to March 2003, we were able to get follow-up information on 292 people (dropout rate, 1.4%). Eighteen subjects (6.1%) had died, and the remaining 274 were successfully contacted. They were first evaluated by a standardized phone interview regarding their cold sensitivity, digital color changes, and RP. If any significant medical changes related to RP and/or suggesting scleroderma were reported, these subjects were invited for a medical evaluation.

RESULTS

Mortality was similar in RP+ and RP- subjects, and no death was due to an RP-related condition. Seven cases of new RP were diagnosed in the RP- group, which corresponds to an annual incidence rate of 0.25%. Among the 72 RP+ subjects and the 7 subjects with a new RP available for follow-up, none developed clinical features of scleroderma. A disappearance of RP attacks for 2 winters or more was reported by 24 RP+ subjects (33%).

CONCLUSIONS

These results show that, in the general population, RP is most often a benign condition and may disappear in a substantial proportion of subjects.

Predictive value of nailfold capillaroscopy in patients with Raynaud's phenomenon

The objective of this study was to evaluate the long-term follow-up of patients with Raynaud's phenomenon (RP) and pathological nailfold capillaroscopy (NC) in order to analyse the predictive value of specific features of capillaroscopy for the development of a connective tissue disease (CTD). From 1992 to 2002, NC alone or combined with fluorescence videomicroscopy with sodium fluorescein (NaF) was performed in 1024 consecutive patients because of RP. We analysed the follow-up and pathological features of NC in all patients who had neither clinical nor serological signs of a CTD at the time of NC. Of 308 patients with neither serological findings nor clinical signs of CTD but with RP and pathological features in NC suspicious for CTD, follow-up data were available for 133 patients. An additional NaF test had been performed in 51 (38.4%) patients. After a mean follow-up of 6.5 years (range: 1-15 years), 109 patients had developed a CTD and 24 patients did not show any clinical signs or serological markers for a CTD after a mean follow-up of 8.5 years (range: 2-15 years). There were no differences in age, duration of RP or of follow-up in patients who developed a CTD compared to patients who did not. Significantly more giant capillaries (p=0.0001), avascular fields (p=0.02) and irregular architecture (p=0.0001) had been observed in patients who had developed a CTD during the follow-up of 6.5 years. The presence of giant capillaries, avascular fields and irregular architecture of nailfold capillaries is predictive for the development of a CTD in patients with RP.

Autoantibodies in systemic sclerosis and fibrosing syndromes: clinical indications and relevance

PURPOSE OF REVIEW

Systemic sclerosis, or scleroderma, is associated with a variety of autoantibodies, each of them having their own clinical associations. The fibrosing disorders, other than systemic sclerosis, represent a diverse group of diseases with systemic or localized effect and with limited understanding of their pathogenesis. The purpose of this review is to analyze the literature on the clinical usefulness of examining serum autoantibodies in patients with known or suspected scleroderma and fibrosing disorders.

RECENT FINDINGS

Studies on autoantibodies within the past year highlight their clinical utility in systemic sclerosis. Anticentromere antibodies are most often seen with limited cutaneous involvement and lower frequency of pulmonary fibrosis and lower mortality (despite an increased risk for pulmonary hypertension) compared with anti-Scl-70 and antinucleolar antibodies. Anti-Scl-70 antibodies are associated with diffuse cutaneous involvement, increased frequency of pulmonary fibrosis, and higher mortality. The anti-polymyositis-scleroderma autoantibody is associated with the polymyositis-scleroderma overlap syndrome. Anti-Th/To antibodies are associated with milder skin and systemic involvement but with more severe pulmonary fibrosis and overall worse prognosis. Anti-RNA-polymerase family antibodies and antifibrillarin antibodies are predictive of diffuse cutaneous and systemic involvement and greater mortality. Less specific autoantibodies for systemic sclerosis and limited data on some other autoantibodies limit their clinical utility in patients with systemic sclerosis. For the most part, the association between autoantibodies and fibrosing disorders other than systemic sclerosis remains inconclusive.

SUMMARY

Autoantibodies in systemic sclerosis provide important and prognostic information and are useful in defining clinical subsets of the disease. When used appropriately, they can be a useful instrument in the management of scleroderma.

Nailfold digital capillaroscopy in 447 patients with connective tissue disease and Raynaud's disease

The presence of megacapillaries and a decreased capillary density are the hallmarks of the scleroderma capillary pattern, which can be detected by nailfold capillarmicroscopy. One hundred and eighty-six patients with Raynaud's phenomenon, 65 cases with undifferentiated connective tissue disease (UCTD), 47 patients with systemic lupus erythematosus (SLE), 26 patients with dermato/polymyositis, 14 with rheumatoid arthritis, seven cases with primary Sjögren's syndrome and 102 patients with systemic sclerosis (SSc) were investigated. Of the 16 patients with diffuse cutaneous SSc and the 86 limited cutaneous SSc cases, 14 (87.5%) and 53 (61.6%) showed the scleroderma capillary pattern, respectively. Nine of the 65 (13.8%) cases with UCTD and 24 of the 186 (12.9%) cases with Raynaud's phenomenon also exhibited the same pattern. Four of the 47 (8.5%) with SLE and seven of the 26 (26.9%) with dermato/polymyositis, and no patients with rheumatoid arthritis or Sjögren's syndrome, exhibited the scleroderma capillary pattern. The conclusion is that the scleroderma capillary pattern is often present in SSc and dermato/polymyositis. Furthermore, patients with Raynaud's phenomenon and UCTD may also occasionally exhibit this pattern. Therefore, capillarmicroscopy seems to be a useful tool for the early selection of those patients who are potential candidates for developing scleroderma spectrum disorders.

The clinical relevance of autoantibodies in scleroderma

Scleroderma (systemic sclerosis) is associated with several autoantibodies, each of which is useful in the diagnosis of affected patients and in determining their prognosis. Anti-centromere antibodies (ACA) and anti-Scl-70 antibodies are very useful in distinguishing patients with systemic sclerosis (SSc) from healthy controls, from patients with other connective tissue disease, and from unaffected family members. Whereas ACA often predict a limited skin involvement and the absence of pulmonary involvement, the presence of anti-Scl-70 antibodies increases the risk for diffuse skin involvement and scleroderma lung disease. Anti-fibrillarin autoantibodies (which share significant serologic overlap with anti-U3-ribonucleoprotein antibodies) and anti-RNA-polymerase autoantibodies occur less frequently and are also predictive of diffuse skin involvement and systemic disease. Anti-Th/To and PM-Scl, in contrast, are associated with limited skin disease, but anti-Th/To might be a marker for the development of pulmonary hypertension. Other autoantibodies against extractable nuclear antigens have less specificity for SSc, including anti-Ro, which is a risk factor for sicca symptoms in patients with SSc, and anti-U1-ribonucleoprotein, which in high titer is seen in patients with SSc/systemic lupus erythematosus/polymyositis overlap syndromes. Limited reports of other autoantibodies (anti-Ku, antiphospholipid) have not established them as being clinically useful in following patients with SSc.

Clinical spectrum of Raynaud's phenomenon in patients referred to vascular clinic

Difficulties to establish general characteristics of patients with Raynaud's phenomenon, especially frequency, rates and predisposing factors of the evolution of primary to secondary cases probably originate from substantial variation of evaluated cohorts. We conducted a prospective study using standardised diagnostic procedures in order to look for the specificity of patients referred to the vascular centre; moreover, we assayed anticardiolipin antibodies in these patients using double ELISA and compared its frequency to sex and age matched a control group of 50 healthy individuals. 124 patients (20 men), mean age at onset 35.5 yr, range 9-69 yr, had confirmed diagnosis of Raynaud's phenomenon. Ninety nine patients were found to have secondary phenomenon, 72% of them had trophic changes of fingers and/or toes. Anticardiolipin antibodies assay was positive in seven patients and four healthy donors. Vascular diseases constituted about 20%, and connective tissue diseases 50% of secondary cases, but SLE (17 cases) not a scleroderma (11 cases) was the most frequent clinical entity in the latter group. There were only two patients with Buerger's disease and one with atherosclerosis as an underlying disease for vasospastic disorder. We concluded in the vascular medicine centre that there were a lot of patients with ischemic necrosis or other type of trophic changes, and very little primary, benign Raynaud's disease cases; surprisingly, peripheral arterial occlusive disease was very seldom responsible for vasospastic episodes. Primary or secondary antiphospholipid syndrome is not associated with Raynaud's phenomenon.

New methods for detection of anti-nuclear antibodies

Many different autoantibodies which react with a variety of different nuclear and cytoplasmic antigens have been described. Detection of some these antibodies has been shown to be clinically useful in a number of different autoimmune diseases. For many years, the detection of most of the clinically relevant antibodies was done with by immunofluorescence on tissue substrates and human cultured cell lines. Within the past few years, a number of technical advances has now made it possible to convert to enzyme immunoassay. The paper reviews the clinically relevant antibodies and discusses the variety of new methods which are now available for ANA detection in diagnostic laboratories.

Undifferentiated connective tissue disease: natural history and evolution into definite CTD assessed in 84 patients initially diagnosed as early UCTD

Connective tissue diseases (CTDs) are chronic multisystemic inflammatory disorders whose indicative signs or symptoms have a high sensitivity but poor specificity in predicting the evolution into a given CTD. We have analysed 84 consecutive patients initially diagnosed as having an early undifferentiated CTD (early UCTD) with the aim of verifying the evolution into one definite CTD and of evaluating the predictive value of clinical and laboratory parameters. During a 5-year study period, 33 patients developed signs of a full-blown CTD; the highest probability of evolution was in the first 48 months after the onset. Multivariate analysis allowed us to select those variables correlating with evolution into a particular CTD, such as sclerodactyly and oesophageal dysfunction for systemic sclerosis, xerostomia and anti-nuclear antibodies (SS-A pattern) for Sjögren's syndrome, and fever and anti-DNA antibodies for systemic lupus erythematosus. Furthermore, we assessed the prevalence of various clinical and laboratory manifestations, complications and prognosis of those patients diagnosed after a 5-year disease duration period as having a UCTD. In our series, major organs such as the kidney or heart seem to be spared, whereas we detected a relatively high prevalence of endocrine disease of autoimmune origin.

Prevalence of scleroderma spectrum disorders in the general population of Estonia

The purpose of this study was to estimate the prevalence of scleroderma spectrum disorders (SDS) in the general population of Estonia while taking into account environmental and ethnic factors. A random sample of 14,467 subjects from the general population were surveyed by mail questionnaire to detect those with suspected Raynaud phenomenon (RP) and SDS. A subsample of 2,154 participants was then seen during the field study to confirm the RP diagnosis and to perform a short clinical examination. Of 581 subjects with RP, 13 cases (all women) were diagnosed as having SDS; based on these findings, the estimated prevalence of SDS in the adult population is 228 per 100,000 (95% CL 121; 391), while in women alone it is 354 per 100,000 (95% CL 188; 605). The best estimate of SD (systemic scleroderma), based on ACR criteria, is 35 per 100,000 (95% CL 4; 127). No significant difference in SDS prevalence was found between the two environmentally different regions we studied. Although statistically not significant, the prevalence of SDS, especially of SD and CREST syndrome, among Russians was higher than among Estonians, as we had hypothesized. The distribution of SDS subtypes also suggests an ethnic difference. The overall prevalence of SD/CREST that we found is higher than that reported in studies not based on a random sample of the general population.

Raynaud's phenomenon

Raynaud's phenomenon is a common clinical problem occurring in 3% to 5% of the general population. The first symptom of scleroderma is often Raynaud's phenomenon, which is associated with a diffuse small vessel vasculopathy and ischemia and reperfusion injury to skin and other organs targeted in this disease. Current studies support the concept that Raynaud's phenomenon is secondary to a local defect in the regulation of regional blood flow. New evidence demonstrates that there is a profound sensitivity to alpha 2-adrenoceptors mediated vasoconstriction in scleroderma vessels. Traditional treatment of Raynaud's phenomenon is cold avoidance and the use of vasodilators. Oral prostaglandins have shown promise as therapeutic agents.

Long-term outcome of Raynaud's syndrome in a prospectively analyzed patient cohort

PURPOSE

Knowledge of the long-term clinical outcome of Raynaud's syndrome (RS), essential both for patient counselling and formulation of optimal therapeutic recommendations, is conspicuously deficient in current medical literature. We have prospectively monitored 1039 patients with RS, 118 (11.4%) for more than 10 years to determine whether initial characterization was able to predict outcome.

METHODS

At initial presentation, patients were divided into four groups on the basis of vascular laboratory and serologic testing results: vasospastic, serologically positive (spast,sero+) and negative (spast,sero-) and obstructive, serologically positive (obst,sero+) and negative (obst,sero-).

RESULTS

Connective tissue disease (CTD) was present initially in 48.6% of patients with spast,sero+ results and 72.9% of patients with obst,sero+ results. Of the remaining patients in these groups, progression to CTD during follow-up occurred in 16.4% of patients with spast,sero+ results and 30.4% of patients with obst,sero+ results. In the > 10-year follow-up group, progression to CTD occurred in 81.8% of patients in the obst,sero+ group. Progression to CTD occurred in 2.0% of patients in the spast,sero-group and 8.5% of patients in the obst,sero- group. Digital ulcers occurred in 15.5% of patients in the spast,sero+ group, 5.2% of patients in the spast,sero- group, 55.6% of patients in the obst,sero+ group, and 48.2% of patients in the obst,sero- group. Digital or phalangeal amputations were required in 1.4%, 1.6%, 11.6%, and 19.0% of these patients, respectively.

CONCLUSIONS

The long-term outcome of patients with RS can be predicted by initial serologic studies and separation into vasospastic and obstructive categories. Initial serologic positivity strongly predicts the development of CTD. Initial vascular laboratory classification of obstructive RS strongly predicts digital ulcerations, which occurred in half of these patients regardless of initial serologic study results. Amputations were required in 10% to 20% of patients with obstructive RS. These occurrences did not increase with increased duration of disease. Ulcerations and amputations were rare in patients initially with vasospastic RS.

Venodilation in Raynaud's disease

The pathogenesis of Raynaud's disease is unclear; an enhanced response to catecholamines has been hypothesised to contribute to this vasospastic disorder. Impaired endothelium-dependent dilation occurs in other diseases associated with vasospasm, such as coronary atherosclerosis. We investigated both endothelium-dependent and endothelium-independent venodilatory function in Raynaud's disease using the hand-vein compliance technique. Full dose-response curves to noradrenaline were constructed in 10 subjects with primary Raynaud's disease and 10 age and sex matched control subjects. The two groups did not have a different response to noradrenaline. Mean (SD) log values of ED50s (the dose producing half maximum response) were 1.00 (0.59) (geometric mean 10 ng/min) in Raynaud's disease compared with 1.29 (0.66) (20 ng/min) in control subjects (p = 0.16). The efficacy of noradrenaline as a venoconstrictor was similar in the two groups: mean maximum dilation (Emax) to noradrenaline was 81 (14)% in the Raynaud's group and 89 (8)% in the control group (p = 0.08). Full dose-response curves to the endothelium-dependent dilator bradykinin were constructed. Emax to bradykinin was significantly lower in the Raynaud's group than in the control group (65 [21] vs 91 [29%], p = 0.02). ED50 values (doses producing half maximum response) for bradykinin were similar in the two groups. Maximum dilation with nitroprusside, a direct releaser of the vasodilator nitric oxide, was not diminished in the Raynaud's group (94 [23] vs 102 [15]% in controls, p = 0.26). These results suggest that endothelium-dependent venodilation is impaired in peripheral vessels in Raynaud's disease, possibly due to diminished release of nitric oxide, and may contribute to the pathogenesis of the disorder.

A recombinant topoisomerase I ELISA: screening for IgG, IgM and IgA anti-topo I autoantibodies in human sera

An ELISA for the detection of anti-topoisomerase I autoantibodies in sera from patients with suspected or manifest rheumatic diseases is described. The antigen source used in this assay consists of a recombinant protein containing the last 695 C-terminal amino acid residues of human topoisomerase I (topo I). The sensitivity of the assay was 61%, while the specificity was more than 98%. Using this ELISA, 47 sera from scleroderma patients and immunopositive for anti-topo I antibodies, were screened for the presence of the isotypes IgG, IgA and IgM to topo I. Our finding that relatively high levels of IgA antibodies to topo I are present in most of the sera tested is consistent with the results of Hildebrandt et al. [1]. In addition, it is demonstrated that the IgG and IgA antibodies in a serum may recognize different epitope regions on the topo I polypeptide.