The concurrence of rheumatoid arthritis and limited systemic sclerosis: clinical and serologic characteristics of an overlap syndrome

Secondary cardiac amyloidosis in a patient with mixed connective tissue disease: A case report

We report the case of a 62-year-old man who presented with shortness of breath, cough, bilateral lower limbs' swelling, and blackish discoloration of multiple fingertips over the past 2 months. Anti-Ribonucleoprotein antibodies were found to be present, and gadolinium-based cardiac MRI showed non-vascular subendocardial enhancement with diffuse symmetrical thickening of the left ventricular wall. A diagnosis of Mixed connective tissue disease with secondary cardiac amyloidosis was thus made, and the patient was successfully managed with intravenous cyclophosphamide, corticosteroids, and other supportive measures. Although extremely rare, this case shows that secondary cardiac amyloidosis should be considered while managing patients with MCTD.

A novel overlap syndrome: Rheumatoid arthritis, Sjogren's syndrome, antiphospholipid syndrome, and dermatomyositis

Key Clinical Message

This is an extremely rare case that has not been presented or discussed in the literature to the best of our knowledge. The overlap of connective tissue disease is a challenge for physicians and patients, and it needs special care and regular clinical and laboratory follow-up.

Abstract

This report describes a rare case of overlapping connective tissue diseases in a 42-year-old female with rheumatoid arthritis, Sjogren's syndrome, antiphospholipid syndrome, and dermatomyositis. The patient presented with a hyperpigmented erythematous rash, muscle weakness, and pain, highlighting the challenges of diagnosis and treatment that require regular clinical and laboratory follow-up.

Anti-hnRNP B1 (RA33) autoantibodies are associated with the clinical phenotype in Russian patients with rheumatoid arthritis and systemic sclerosis

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are potent autoantigenic targets in systemic autoimmune rheumatic diseases (SARD). Loss of tolerance to the RA33 complex consisting of hnRNP A2 and its alternatively spliced variants B1 and B2 has been the interest of rheumatologists. A novel ELISA for the detection of anti-hnRNP B1 autoantibodies has been developed to investigate the prevalence thereof in 397 patients with SARD, including patients with rheumatoid arthritis (RA), spondyloarthropathy (SPA), juvenile chronic arthritis, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and Sjögren's syndrome (SS), in comparison to 174 controls. Anti-hnRNP B1 autoantibodies were significantly more prevalent in patients with SARD than controls (47/397, 11.8% versus 2/174, 1.1%; P < 0.001). In particular, anti-hnRNP B1 were found more frequently in the disease cohorts than in the controls and were present in 24/165 (14.5%) patients with RA, 6/58 (10.3%) SPA, 11/65 (16.9%) SSc, and 4/50 (8.0%) SLE. In RA patients, anti-hnRNP B1 autoantibodies correlated significantly with C-reactive protein levels and erythrocyte sedimentation rate, while in patients with SSc it was associated with features of arterial wall stiffness and presence of hypertension. Anti-hnRNP B1 autoantibodies occur in SARD and seem to be correlated with distinct clinical characteristics in patients with RA and SSc.

Potential use of TNF-α inhibitors in systemic sclerosis

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by chronic inflammation and fibrosis of the skin, vascular abnormalities and variable involvement of organs. TNF-α has a central role in initial host response to infections and in the pathogenesis of various systemic immune-mediated diseases. Serum levels of TNF-α are elevated in patients with SSc and favor the development of pulmonary fibrosis and pulmonary arterial hypertension. Inflammatory arthritis can occur in patients with SSc. Infliximab and etanercept may improve the inflammatory arthritis and disability in SSc. TNF-α inhibitors reduce the systemic inflammation, improve the endothelial function decreasing the risk of pulmonary arterial hypertension progression and of acute cardiovascular and/or cerebrovascular events. Physicians need to be aware of the potential risks of tuberculosis reactivation and opportunistic infections. Randomized controlled trials with TNF-α inhibitors in patients with SSc are needed to confirm the potential role of these agents in the treatment of SSc.

The value of pattern capillary changes and antibodies to predict the development of systemic sclerosis in patients with primary Raynaud's phenomenon

The aim of this study is to assess the prognostic value of major provisional criteria for the development of systemic sclerosis (SSc) in primary Raynaud's phenomenon (RP) patients. We retrospectively studied the chart of 497 patients with primary RP in whom anticentromere (ACA) and antitopoisomerase I (ATA) antibodies tests and a capillary reading were available. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratios (LHR+), negative likelihood ratios (LHR-), odds ratio (OR), and area under the receiver operating characteristics curve (AUC) of those criteria were assessed to predict the development of SSc. During the average follow-up of 2.3 ± 1.9 years, 159 (32 %) patients evolved to SSc, 245 (49.3 %) evolved to other connective tissue diseases, and 93 (18.7 %) patients did not progress. The SSc pattern predicted SSc satisfactorily (LHR+ 4.12, LHR- 0.07, OR 63, AUC 0.819; P < 0.001). ACA were not significantly associated with the development of SSc (LHR+ 1.19, LHR- 0.9, OR 1.32, AUC 0.538, P = 0.156). ATA were significantly associated with the development of SSc (LHR+ 9.32, LHR- 0.67, OR 15.13, AUC 0.777; P < 0.001). Both SSc pattern and ACA or ATA were significantly associated with the development of SSc (LHR+ 2.98, LHR- 0.70, OR 4.2, AUC 0.674; P < 0.001 vs. LHR+ 16, LHR- 0.68, OR 24, AUC 0.819; P < 0.001, respectively). SSc pattern or ATA as independent risk factors, as well as following two parameters together (SSc pattern and ATA or SSc pattern and ACA) were good predictors for the development of SSc.

Evaluating hand in systemic sclerosis

Articular symptoms are common in SSc and joint pain is a frequent presenting feature of this disease. Hand involvement is often the first clinical manifestation of SSc and could be resulted from fibrosis or synovitis or an overlap syndrome with rheumatoid arthritis (RA); though, the latter is a controversy in practice. To define the clues when identifying the nature of the hand arthropathy in SSc. In order to determine the hand arthropathy, serological tests, hand radiography, finger-to-palm (FTP) distance and other clinical features, disease activity and functional scoring parameters were assessed. Twenty-eight consecutive SSc patients and 43 controls (21 rheumatoid arthritis and 22 healthy controls) were included. Radiographic findings in SSc patients were: Erosions 25%, joint space narrowing 17.9%, arthritis 10.7%, radiological demineralisation 42.9%, acro-osteolysis 25%, flexion contracture 28.6% and calcinosis 17.9%. Anti-CCP antibody and RF positivity were as follows: In SSc group: 3 (11%) and 7 patients (25%); In RA group: 13 (62%) and 19 patients (90.5%); In healthy control group: 1 (4%) and 3 persons (13.6%), respectively. Two patients (7.14%) were regarded as RA overlap, whom both had positive RF and positive anti-CCP results and their radiographs revealed arthritis. Seventeen patients (61%) were regarded as SSc arthropathy; all were negative for RF and anti-CCP but revealed nonarthritic radiological findings. (Among them, only one patient had positive anti-CCP result). The remainder (9 patients) had no radiological or serological finding positive for arthropathy. Arthritis was found to have correlation with heart involvement and FTP was correlated with lung involvement. Hand involvement in SSc is a challenge in rheumatology practice; Radiographic testing when evaluated with RF and anti-CCP will be a helpful tool to discriminate SSc arthropathy from RA-SSc overlap. Hand arthropathy should increase the interest in the serious internal organ involvements of SSc.

Scleroderma pattern of nailfold capillary changes as predictive value for the development of a connective tissue disease: a follow-up study of 3,029 patients with primary Raynaud's phenomenon

To assess the prognostic value of scleroderma pattern of nailfold capillary changes for the development of connective tissue diseases (CTD) in subjects with primary Raynaud's phenomenon (RP). The study included 3,029 consecutive patients with primary RP who had been followed at 6-month intervals during the mean of 4.8 years. The pathological features of nailfold capillaroscopy were recorded in all patients who had neither clinical nor serological signs of a CTD. In patients who developed CTD, capillary changes obtained 6 months prior to diagnosis were analyzed. A possible relationship between capillary changes and the presence of associated CTD was assessed. At the end of follow-up, 1,660 (54,8%) patients have still the primary RP, 246 (8,1%) had suspected secondary RP, and 1,123 (37,1%) patients developed CTD (363 undifferentiated CTD, 263 systemic sclerosis, 143 systemic lupus erythematosus, 106 rheumatoid arthritis, 102 Sjögren's syndrome, 61 overlap syndrome, 30 vasculitides, 24 mixed CTD, 19 polymyositis, 7 dermatomyositis, and 5 primary antiphospholipid syndrome). Scleroderma pattern were significantly associated with the development of systemic sclerosis [P = .00001, sensitivity 94%, specificity 92%, positive predictive value 52%, negative predictive value 99%, and odds ratio 163 (95% CI, 97,9-271,5)], as well as dermatomyositis (P = .0004), overlap syndrome with signs of systemic sclerosis (P = .0001), and mixed connective tissue disease (P = .007). Capillary microscopy is effective method for differentiation between primary and secondary RP and useful tool for the prediction of scleroderma spectrum disorders in RP patients.

Clinical and serological evaluation of a novel CENP-A peptide based ELISA

Introduction

Anti-centromere antibodies (ACA) are useful biomarkers in the diagnosis of systemic sclerosis (SSc). ACA are found in 20 to 40% of SSc patients and, albeit with lower prevalence, in patients with other systemic autoimmune rheumatic diseases. Historically, ACA were detected by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed by immunoassays using recombinant CENP-B. The objective of this study was to evaluate a novel CENP-A peptide ELISA.

Methods

Sera collected from SSc patients (n = 334) and various other diseases (n = 619) and from healthy controls (n = 175) were tested for anti-CENP-A antibodies by the novel CENP-A enzyme linked immunosorbent assay (ELISA). Furthermore, ACA were determined in the disease cohorts by IIF (ImmunoConcepts, Sacramento, CA, USA), CENP-B ELISA (Dr. Fooke), EliA^® CENP (Phadia, Freiburg, Germany) and line-immunoassay (LIA, Mikrogen, Neuried, Germany). Serological and clinical associations of anti-CENP-A with other autoantibodies were conducted in one participating centre. Inhibition experiments with either the CENP-A peptide or recombinant CENP-B were carried out to analyse the specificity of anti-CENP-A and -B antibodies.

Results

The CENP-A ELISA results were in good agreement with other ACA detection methods. According to the kappa method, the qualitative agreements were: 0.73 (vs. IIF), 0.81 (vs. LIA), 0.86 (vs. CENP-B ELISA) and 0.97 (vs. EliA^® CENP). The quantitative comparison between CENP-A and CENP-B ELISA using 265 samples revealed a correlation value of rho = 0.5 (by Spearman equation). The receiver operating characteristic analysis indicated that the discrimination between SSc patients (n = 131) and various controls (n = 134) was significantly better using the CENP-A as compared to CENP-B ELISA (P < 0.0001). Modified Rodnan skin score was significantly lower in the CENP-A negative group compared to the positive patients (P = 0.013). Inhibition experiments revealed no significant cross reactivity of anti-CENP-A and anti-CENP-B antibodies. Statistically relevant differences for gender ratio (P = 0.0103), specific joint involvement (Jaccoud) (P = 0.0006) and anti-phospholipid syndrome (P = 0.0157) between ACA positive SLE patients and the entire SLE cohort were observed.

Conclusions

Anti-CENP-A antibodies as determined by peptide ELISA represent a sensitive, specific and independent marker for the detection of ACA and are useful biomarkers for the diagnosis of SSc. Our data suggest that anti-CENP-A antibodies are a more specific biomarker for SSc than antibodies to CENP-B. Furthers studies are required to verify these findings.

Ultrasonographic features of the hand and wrist in systemic sclerosis

OBJECTIVES

To investigate ultrasonographic hand and wrist features in patients with SSc and their correlation with clinical and X-ray examinations.

METHODS

All the patients and controls underwent clinical examination, X-ray and ultrasonography (US) evaluations of the hands and wrists. Forty-five SSc patients all of whom satisfied the ACR criteria and 45 controls-15 patients with RA, 15 patients with FM syndrome and 15 healthy subjects were assessed. US was performed by a General Electric Logiq-5 PRO using a 7-12 MHz linear array transducer.

RESULTS

Joint effusion was found in 22 (49%) SSc patients; synovial proliferation in 19 (42%), which was associated with a power Doppler signal in 11 of them; marginal bone erosions in 5 (11%); joint space narrowing in 8 (18%); periarticular calcinosis in 12 (27%); and osteophytosis in 26 (59%). In SSc patients, the prevalence of synovitis as detected by US (i.e. effusion and/or synovial proliferation) was found to be significantly higher than that found by clinical examination (i.e. tenderness and/or swelling) (26 vs 15 out of 45 cases; P = 0.03). US indicated a significantly higher number of joints with osteophytes than X-rays (59 vs 27%; P < 0.005).

CONCLUSIONS

Our study depicts the main sonographic abnormalities of the SSc hand. Using US, we found an unexpectedly high prevalence of joint pathology in SSc without clinically involved hands. The clinical usefulness of US in the assessment of SSc articular involvement either in clinical practice or in therapeutic trials is yet to be defined.

Anti-hnRNP and other autoantibodies in systemic sclerosis with joint involvement

OBJECTIVES

To investigate joint involvement in SSc and its relationship with autoantibody to the hnRNP and to anti-cyclic citrullinated peptide (anti-CCP).

METHODS

Sera from 55 SSc patients were investigated. Joint involvement was determined by clinical, radiological and ultrasonographical evaluation. Anti-hnRNP proteins A1 and A2 (anti-hnRNP-A1/A2) antibodies were determined by immunoblotting. Anti-CCP, ACA, anti-topo I (ATA), Sm, U1-RNP, ribosomal RNP, Ro/SSA, La/SSB autoantibody and RF were determined.

RESULTS

Six patients were positive for anti-hnRNP-A2 autoantibody and two were anti-A1 positive. Eight patients had joint erosions: seven of the eight patients positive for anti-hnRNP-A2 or A1 presented articular involvement (P < 0.04) and five of the eight erosive patients were positive for either of the two autoantibodies (P < 0.02). Of the four patients positive for anti-CCP, none had anti-hnRNP but three had erosive aspects. ATAs were found in 10 patients, six of which were also positive for anti-hnRNP (P < 0.05). RF was positive in 16 patients and in seven among those with articular involvement (P < 0.04). RF was significantly associated with anti-hnRNP in patients with erosive arthritis (P < 0.02), but not with the presence of anti-hnRNP alone. Epitope mapping of the three strongest anti-hnRNP-A2-positive sera recognized the same major epitope as patients with RA. SSc patients have higher incidence of erosions and anti-hnRNP-A2/A1 positivity. RF test and anti-hnRNP had a statistically significant diagnostic value for articular involvement.

CONCLUSIONS

These parameters might suggest that autoantibody to both hnRNP antigens might become a non-specific but useful marker for joint involvement in SSc patients and identify SSc patients prone to develop joint damage.

The "sclerodermic hand": a radiological and clinical study

OBJECTIVE

To assess the clinical and radiographic features of hand involvement in patients with systemic sclerosis (SSc).

METHODS

Forty-one unselected Sardinian SSc patients (32 women, 9 men; mean age 58.9, range 31-81 years; mean disease duration 11.8 years, range 1-36 years) were evaluated in this observational cross-sectional study. Twenty-six patients had diffuse scleroderma (dSSc) and 15 limited scleroderma (lSSc). Radiological examination of the hands was performed and the films were read by two independent rheumatologists blinded to the diagnosis using a classification system of four predefined radiological patterns (normal/minimal changes, articular degenerative, articular inflammatory and periarticular pattern). Correlations between radiological pattern, clinical and serological features were assessed.

RESULTS

The skeletal and articular involvement of the hand was frequent in SSc, being clinically evident in 30/41 (73%) and radiologically in 33/41 (80%) of patients. The periarticular pattern (defined as the occurrence of bone resorption of ungueal tufts, soft tissue calcifications and/or flexion deformities) was the most frequent pattern detected (14/41, 34.1%) and finger flexion contractures and bone resorptions were significantly associated with interstitial lung disease, reduced FVC, oesophagus involvement and prostacycline therapy. Calcinosis (29.2%) was found to be associated with erosions, suggesting a pathogenic link. An inflammatory pattern was also radiologically frequent (8/41, 19.5%), but erosions, with the exception of those localized at distal interphalangeal joints, were demonstrated mainly in patients with clinical picture of rheumatoid arthritis overlapped with SSc. We found no significant differences in terms of radiographic findings between lSSc and dSSc with the exception of calcinosis, which was more frequent in patients with lSSc.

CONCLUSION

This cross-sectional study confirms that the skeletal and articular involvement of the hand is frequent in SSc.

Multiple specificities of autoantibodies against hnRNP A/B proteins in systemic rheumatic diseases and hnRNP L as an associated novel autoantigen

Spliceosomal small nuclear ribonucleoproteins (U-snRNPs) are frequent and specific targets of autoantibodies in systemic rheumatic diseases. The abundant, functionally related heterogeneous nuclear ribonucleoprotein complexes (hnRNPs) have later defined as a new target of autoantibodies, of which their immunochemical/immunogenic and pathogenic properties are still under investigation. Among hnRNP proteins, those belonging to the A/B type are considered as the major autoantigens targeted by antibodies in sera of patients suffering with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). By performing an extensive screening using rat liver 40S hnRNP antigenic material, we document here the existence of multiple specificities of anti-hnRNP A/B autoantibodies in sera of Greek patients suffering with a spectrum of systemic rheumatic diseases. This included patients with SLE, Sjogren's syndrome (SS), Scleroderma (SSc) and a specific group of patients mostly with undifferentiated disease (UD patients). In total, four distinct types of anti-hnRNP A/B autoantibodies have been recognized. The first two referred to the known anti-hnRNPA2(RA33) and anti-hnRNP A1; the latter appearing very rarely. The third was of the new type selectively reacting with hnRNP B2 and an hnRNP A3 variant, while the fourth was a rare case of anti-hnRNP B2 alone. In addition, a novel specificity of autoantibodies against hnRNP L protein was identified in association with anti-hnRNP A/B antibodies. The co-existence within a serum of autoantibodies having variable specificity for hnRNP A/B and L autoantigens was shown. Specific immunochemical features of the identified autoantibodies are presented and a possible mechanism of autoepitope spreading within protein components of hnRNP complexes is discussed.

Use of antibodies recognizing cyclic citrullinated peptide in the differential diagnosis of joint involvement in systemic sclerosis

OBJECTIVE

To determine the prevalence of anti-cyclic citrullinated peptide (CCP) antibodies in systemic sclerosis (SSc) and to assess any association between the presence of anti-CCP, radiographic features, and clinical manifestations.

MATERIALS AND METHODS

Anti-CCP antibodies and rheumatoid factor (RF) were tested in serum samples from 75 patients with SSc (64 women and 11 men), with a mean age of 59.4 years (range 24-85) with either diffuse (dcSSc) and limited (lcSSc) cutaneous involvement. As a control group, 22 age- and sex-matched healthy controls (HCs) were examined. Standard radiographs of the hands and wrists were examined in each patient.

RESULTS

The presence of anti-CCP was found in sera of 10.6% (8/75) patients with SSc (lcSSc 3 of 44, 6.8%; dcSSc 5 of 31, 16.1%). None of the HCs was positive for anti-CCP. The positivity of RF was observed in 19 of 75 (25.3%) SSc patients (lcSSc 10 of 44, 22.7%; dcSSc 9 of 31, 29%). Statistically significant association was found between anti-CCP positivity and the presence of arthritis (p<0.0001) and marginal erosions (p=0.001).

CONCLUSION

Our data show that joint involvement is a common presenting feature of SSc. In this report, we show that anti-CCP antibodies can be detected also in patients with SSc, but they are generally less commonly present than in adults with rheumatoid arthritis (RA). Thus, the finding of high titers of anti-CCP antibodies may help to define the diagnosis of overlap syndrome SSc/RA and facilitate diagnosis and appropriate treatment.

Does Mixed Connective Tissue Disease Exist? Yes

For patients who have combined features of rheumatoid arthritis, the limited cutaneous form of systemic sclerosis, and inflammatory myopathies, the concept of mixed connective tissue disease (MCTD) often helps to predict and diagnose organ problems and to educate the patient accordingly. With high titer IgG antibodies to U1 ribonucleoprotein (U1-snRNP), this concept is supported by a specific serologic marker, and autoantibodies to U1-snRNP and to heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 display MCTD specificity with regard to the recognized epitopes. In addition, the association of MCTD with HLA-DR4 distinguishes it from systemic erythematosus lupus and systemic sclerosis, and speaks to its being a disease entity, rather than a mixture of yet undifferentiated collagen vascular diseases. The authors believe that the concept is useful in daily practice and accurate in the idea that MCTD constitutes a disease entity of its own.

Autoantibodies in the Pathogenesis of Mixed Connective Tissue Disease

Antibodies to U1-RNP are part of the clinical definition of mixed connective tissue disease (MCTD). These antibodies and other well-defined antibodies tend to arise together in affected patients. Although still speculative, hypotheses that link U1-RNP antibodies to the development of autoimmunity in MCTD and that associate U1-RNP antibodies with mechanisms of tissue injury in MCTD have emerged and are being tested. Salient features of these hypotheses include: (1) an antigen-driven response that is due to impaired clearance of potentially immunogenic self-antigens, (2) inadequate B- and T-cell tolerance to RNP autoantigens, and (3) immunogenic properties of the RNA component of targeted ribonucleoproteins. Further studies are needed to establish whether anti-RNP antibodies have prognostic importance that is relevant to practicing clinicians.

The arthropathy of systemic sclerosis: a 12 month prospective clinical and imaging study

OBJECTIVE

To assess the clinical and radiological features of systemic sclerosis (SSc) joint involvement in a prospective cross-sectional study.

DESIGN AND PATIENTS

Seventy-six consecutive patients with SSc divided into clinical and serological subsets were investigated. Clinical and radiological assessments of the hands and feet were carried out. Three radiological patterns of inflammatory, degenerative and fibrotic changes were predefined. The Health Assessment Questionnaire (HAQ) disability index (DI) and individual components of the HAQ-DI were also evaluated.

RESULTS

The highest impairments on the HAQ-DI (median 0.44; range 0-2.87) were detected in subdimensions such as hygiene, grip and activity components. Clinically articular involvement, arthralgia and finger contractures were seen more frequently than arthritis, and a significantly higher prevalence of finger flexion was found in patients with diffuse cutaneous SSc (P=0.03) compared with the other SSc subtypes. Radiologically, distal interphalangeal joint space narrowing and flexion deformity indicating periarticular fibrosis were frequently detected. Juxta-articular osteoporosis, joint space narrowing and flexion contractures of the fingers were seen significantly more frequently in the hands. A significantly higher frequency of fibrotic pattern were found in the hands whereas a degenerative pattern was more frequent in the feet (P<0.05). Finally, significant correlations were detected between flexion contractures and a radiological fibrotic pattern (P<0.001), and the severity scores of peripheral vascular impairment (P=0.026) and skin (P=0.007).

CONCLUSION

This cross-sectional prospective study confirms that an arthropathy is common in SSc patients and shows that it is a major determinant of disability. A classification of radiological alterations into three specific patterns is proposed.

Advances in B-cell epitope analysis of autoantigens in connective tissue diseases

The characterization of autoantibody specificities in rheumatic diseases is important in both diagnostic and basic research areas. Identification of the epitopes recognized by autoantibodies and their clinical and biological significance is not a trivial task. Epitopes may range in complexity from simple linear sequences of amino acids to complex quaternary structures. In addition to this structural complexity the frequency with which an autoantigen and its epitopes are recognized in a patient population may be useful in diagnosis, defining disease subgroups, and may offer information on disease prognosis. In this review recent advances in the epitope mapping of autoantigens in connective tissue diseases are discussed, with particular emphasis placed on the methodologies used to identify epitopes and the classification of the structural features of epitopes. To illustrate the identification of epitope structure, clinically relevant autoantigens, including CENP-A, PM/Scl-100, fibrillarin, filaggrin, Ro-52, and dsDNA, are discussed as examples of each type of epitope.

Musculoskeletal involvement in scleroderma

Scleroderma can be accompanied by arthralgias, inflammatory arthritis, flexion contractures, nerve entrapment, myositis, or myopathy. Antibodies in scleroderma can occur in other connective tissue diseases; overlap syndromes between scleroderma and Sjogren's syndrome, lupus, and rheumatoid arthritis are reported. Many of the musculoskeletal symptoms in scleroderma are treated symptomatically; most treatments are not proven in randomized controlled trials in these patients. Musculoskeletal manifestations are a major cause of morbidity and disability in scleroderma.

Heterogeneous nuclear ribonucleoproteins C1/C2 identified as autoantigens by biochemical and mass spectrometric methods

The antigenic specificity of an unusual antinuclear antibody pattern in three patient sera was identified after separating HeLa-cell nuclear extracts by two-dimensional (2D) gel electrophoresis and localizing the antigens by immunoblotting with patient serum. Protein spots were excised from the 2D gel and their contents were analyzed by matrix-assisted laser desorption-ionization (MALDI) or nanoelectrospray ionization time-of-flight (TOF) tandem mass spectrometry (MS) after in-gel digestion with trypsin. A database search identified the proteins as the C1 and C2 heterogeneous nuclear ribonucleoproteins. The clinical spectrum of patients with these autoantibodies includes arthritis, psoriasis, myositis, and scleroderma. None of 59 patients with rheumatoid arthritis, 19 with polymyositis, 33 with scleroderma, and 10 with psoriatic arthritis had similar antibodies. High-resolution protein-separation methods and mass-spectrometric peptide mapping in combination with database searches are powerful tools in the identification of novel autoantigen specificities.