Harsha Gunawardena

Bio: Harsha Gunawardena is an academic researcher from North Bristol NHS Trust. The author has contributed to research in topics: Dermatomyositis & Autoantibody. The author has an hindex of 22, co-authored 51 publications receiving 2010 citations. Previous affiliations of Harsha Gunawardena include University of the West of England & University of Bath.

Myositis-specific autoantibodies: their clinical and pathogenic significance in disease expression

Abstract: The idiopathic inflammatory myopathies (IIMs)--DM and PM--have been historically defined by broad clinical and pathological criteria. These conditions affect both adults and children with clinical features including muscle weakness, skin disease, internal organ involvement and an association with cancer in adults. Using a clinico-serological approach, DM and PM can be defined into more homogeneous subsets. Over the last few years, myositis-specific autoantibodies (MSAs) have been better characterized including autoantibodies directed against the aminoacyl tRNA-synthetase enzymes, the signal-recognition particle and the Mi-2 protein. In addition, clinically significant novel autoantibodies--anti-CADM-140, anti-SAE (small ubiquitin-like modifier activating enzyme), anti-p155/140 and anti-p140--have been described in the adult and juvenile disease spectrum. MSAs are directed against cytoplasmic or nuclear components involved in key regulatory intracellular processes including protein synthesis, translocation and gene transcription. The striking association between unique serological profiles and distinct clinical phenotypes suggests that target autoantigens may play a role in disease induction and propagation. In this review, we discuss the clinical utility and pathogenic significance of MSAs in disease expression.

Autoantibodies to a 140‐kd protein in juvenile dermatomyositis are associated with calcinosis

Abstract: Juvenile dermatomyositis (DM) is the most common of the idiopathic inflammatory myopathies (IIMs) of children. The reported incidence is 0.8–4.1 per million children per year (1–3). Juvenile DM is chronic, potentially debilitating, and can be associated with significant morbidity. Due to the heterogeneity of the condition with multisystem disease, the clinical outcome (and thus prognosis) is difficult to predict. Certain clinical features, such as skin ulceration, calcinosis, gastrointestinal involvement, and respiratory disease, have been proposed as predictors of a severe disease course in juvenile DM (4–7). The precise etiology of IIMs is unknown, but there is increasing evidence to suggest an important role for autoimmunity. Knowledge of an autoantibody profile is an important cornerstone in the diagnosis of patients with a wide variety of autoimmune connective tissue disorders. Myositis-specific autoantibodies (MSAs) are being observed with increasing frequency in adult patients with IIM. There is now increasing evidence that MSAs are associated with homogeneous clinical subsets within the IIM spectrum, which can help predict clinical outcomes (8–10). For example, autoantibodies directed against the aminoacyl–transfer RNA synthetases (aaRS) form the largest group of MSAs in adult IIM and are associated with the antisynthetase syndrome (10,11). Other well-described MSAs in adult IIM that are associated with specific clinical manifestations include anti-signal recognition particle (anti-SRP) and anti–Mi-2 autoantibodies (10). To date, MSAs in juvenile myositis, including juvenile DM, have been less well characterized. Previous reports have described myositis-associated autoantibodies (MAAs), including anti–PM-Scl and anti–U1 RNP, in juvenile DM overlap syndromes (12). Anti–Mi-2 has been described more frequently, but this autoantibody specificity and others such as aaRS and anti-SRP are detected in a relatively small number of juvenile myositis cases (13–15). Recently, our group and other investigators have observed that autoantibodies to a 155-kd protein and a 155/140-kd doublet protein are a major serologic subset in juvenile DM (16,17). In addition, anti-p155/140 autoantibodies appear to define a distinct clinical phenotype within the juvenile DM spectrum (17). A further autoantibody termed anti-MJ, which targets a 140-kd protein, has been described in a US cohort of patients with juvenile DM (18). The MJ autoantigen was recently identified as nuclear matrix protein NXP-2 (19). In this study, we describe the prevalence, clinical associations, and immunogenetic associations of autoantibodies targeting a p140 protein in children recruited to the Juvenile DM Registry and Repository for UK and Ireland (JDRR) (for review, see refs.6 and12). We demonstrate that anti-p140 and anti-p155/140 are different autoantibody subsets and investigate the identity of the p140 target, which is likely to be the same as the previously identified MJ autoantigen NXP-2 (also termed MORC3) (18,19).

Clinical associations of autoantibodies to a p155/140 kDa doublet protein in juvenile dermatomyositis.

Abstract: OBJECTIVES: Myositis-specific autoantibodies (MSAs) may define homogeneous clinical subsets of adult patients with dermatomyositis (DM). Recently, there have been descriptions of novel autoantibodies in DM. This study was conducted to establish the clinical significance of anti-p155/140 autoantibodies in juvenile DM (JDM). METHODS: The first 116 children recruited to the JDM National Registry and Repository (UK and Ireland) were studied. Comprehensive clinical features were recorded and sera screened for anti-p155/140 autoantibodies using radio-immunoprecipitation. Sera from adults with DM (n = 20), PM (n = 25), SSc (n = 150), SLE (n = 40) and healthy subjects (n = 50) were used for comparison. Immunodepletion experiments were used to establish whether the p155/140 kDa targets recognized by JDM sera were the same as adult DM sera. RESULTS: Twenty-seven out of 116 (23%) JDM cases were positive for anti-p155/140 in comparison with 6/20 (30%) adults with DM. Immunodepletion confirmed that the 155/140 kDa proteins recognized by JDM and adult DM sera were the same targets. All other adult control sera were negative for anti-p155/140 autoantibodies. There was a higher frequency of males in the anti-p155/140-positive JDM group (P = 0.02). JDM patients with anti-p155/140 autoantibodies had significantly more cutaneous involvement including Gottron's papules (P = 0.003), ulceration (P = 0.005) and oedema (P = 0.013). The distribution of skin lesions was more extensive particularly periorbitally (P = 0.014) and over the small (P < 0.001) and large joints (P = 0.003). CONCLUSIONS: Anti-p155/140 autoantibodies are clinically significant in JDM and may define a clinical subset in terms of disease severity and outcome. The same autoantigen target is detected in adult DM patients

Anti-synthetase syndrome: a new autoantibody to phenylalanyl transfer RNA synthetase (anti-Zo) associated with polymyositis and interstitial pneumonia

Abstract: Objective. Autoantibodies directed against the aminoacyl tRNA synthetases are associated with myositis, arthritis, Raynaud’s phenomenon, mechanic’s hands, fever and interstitial pneumonia, clinically referred to as the anti-synthetase syndrome (ASS). The aim of this study was to characterize the autoantibody profile in a patient with clinical features of ASS whose routine diagnostic testing was negative for the previously identified anti-synthetase autoantibodies. Methods. Serum from a patient presenting with interstitial pneumonia followed by proximal myopathy, Raynaud’s phenomenon and arthrlagia was analysed for autoantigen specificity by routine methods including indirect immunofluorescence, immunodiffusion, ELISA and immunoblotting. The autoantibody specificity was further analysed by RNA and protein immunoprecipitation. Novel autoantigens found on protein immunoprecipitation were further characterized using a proteomic approach, combining immunoprecipitation, SDS-PAGE and MALDI-TOF mass spectrometry. Results. Diagnostic testing on the patient’s serum was negative by ELISA and immunodiffusion. Indirect immunofluorescence using Hep-2 cells was ANA negative, although a strong cytoplasmic speckle was seen. Immunoblotting with the patient serum displayed an unknown positive band at approximately 60kDa. Protein immunoprecipitation revealed the presence of two proteins with molecular weights of approximately 60 and 70kDa, and RNA immunoprecipitation revealed the presence of a band corresponding to a tRNA synthetase. Using a combination of immunoprecipitation and mass spectrometry, the novel immunoprecipitation targets were identified as phenylalanyl tRNA synthetase alpha and beta chains. Conclusions. We report the identification of previously uncharacterized autoantibodies to phenylalanyl tRNA synthetase, entitled anti-Zo. This is the eighth anti-synthetase autoantibody in a patient with anti-synthetase syndrome.

Clinical and human leucocyte antigen class II haplotype associations of autoantibodies to small ubiquitin-like modifier enzyme, a dermatomyositis-specific autoantigen target, in UK Caucasian adult-onset myositis

Abstract: Objectives: Autoantibodies to a novel autoantigen small ubiquitin-like modifier activating enzyme (SAE) associated with dermatomyositis (DM) have previously been identified. The aim of this study was to establish the frequency of anti-SAE autoantibodies in a UK myositis cohort and investigate clinicoimmunogenetic associations. Methods: Clinical data and sera were studied from 266 patients recruited to the Adult Onset Myositis Immunogenetic Collaboration. Myositis sera, control sera including 250 patients with other connective tissue diseases and 50 healthy participants were screened using radio-immunoprecipitation. Immunodepletion was performed on all sera immunoprecipitating 40 and 90 kDa bands to confirm the presence of anti-SAE. DNA from 202 patients with myositis was genotyped for human leucocyte antigen (HLA)-DRB1 and DQB1; DQA1 data were inferred. Results: Out of 266 patients with myositis, 11 (4%) were positive for anti-SAE, which was found exclusively in DM with a frequency of 8%. Patients with anti-SAE had a high frequency of cutaneous lesions including heliotrope (82%) and Gottron rash (82%). Of the 11, 9 (82%) had systemic features and 7 of 9 (78%) developed dysphagia. Of those nine, seven (78%) presented with skin disease before myositis onset. All patients with anti-SAE possessed at least one copy of HLA-DQB1*03. HLA-DRB1*04-DQA1*03-DQB1*03 was a significant risk factor in anti-SAE positive versus patients who were anti-SAE negative (haplotype frequency 18% vs 6%, p Conclusions: Anti-SAE is a myositis-specific autoantibody that identifies a subset of patients with adult DM. The majority of patients with anti-SAE presented with cutaneous disease and progressed to myositis with systemic features including dysphagia. This novel autoantibody has a strong association with the HLA-DRB1*04-DQA1*03-DQB1*03 haplotype.

Rituximab in the Treatment of Refractory Adult and Juvenile Dermatomyositis and Adult Polymyositis: A Randomized, Placebo-phase Trial

Abstract: The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of acquired disorders characterized by chronic inflammation of striated muscle leading to predominantly proximal muscle weakness. The most common subsets of IIM include adult polymyositis (PM), adult and juvenile dermatomyositis (DM), myositis in overlap with cancer or another connective tissue disease and inclusion body myositis (IBM). The IIM are frequently associated with constitutional symptoms and commonly involve other organ systems including the skin, joints, lungs, gastrointestinal tract and heart. They are rare with an estimated incidence of 4-10 cases/million population per year and a bimodal incidence pattern reflecting childhood onset of juvenile DM (JDM) and a later peak in adulthood [1]. Although the precise pathogenesis is unknown, the IIM likely result from immune-mediated processes initiated by environmental factors in genetically susceptible individuals [2]. Factors strongly supporting their autoimmune basis include: the association of myositis with other autoimmune diseases such as Hashimoto thyroiditis, Grave’s disease and various connective tissue diseases, the high frequency of circulating serum autoantibodies, and their response to immunosuppressive (IS) or immunomodulatory therapy. The treatment of IIM is challenging, complicated by its rarity and heterogeneity as well as the lack of controlled trials and partially validated outcome measures. Most studies involve single referral centers using cross-sectional and retrospective analyses of small numbers of treatmentrefractory patients observed for relatively short time periods. In addition, widely disparate inclusion criteria have complicated the assessment of treatment response, as disease damage and the inclusion of misdiagnosed patients contribute to suboptimal therapeutic outcomes. Although glucocorticoids have not been formally tested in controlled trials, expert consensus is that they are the primary therapy to be followed by a variety of immunosuppressive or immunomodulatory agents alone or in combination [2]. Rituximab, a B cell depleting agent long recognized as an effective therapy for B cell lymphomas, has gained increased favor in the treatment of many autoimmune diseases and is FDA-approved for use in rheumatoid arthritis [3] as well as granulomatosis with polyangiitis and microscopic polyangiitis [4]. The effectiveness of rituximab in PM and DM has been suggested by case reports and case series in adult and pediatric patients with refractory disease [5-9]. B cells play a critical role in the initiation and propagation of the immune response and are implicated in the pathogenesis of myositis. They localize to the perivascular region of DM muscle and are found in the inflammatory infiltrates of both PM and DM [10]. In addition to functioning as the precursor of autoantibody-producing plasma cells, B cells present antigen to T cells and secrete proinflammatory cytokines [10]. Therefore, based on the autoimmune characteristics of myositis and the aforementioned immunopathogenic role of the B cell, the Rituximab in Myositis (RIM) trial assessed the effectiveness of rituximab in refractory adult PM and adult and juvenile DM using validated measures of myositis disease activity and damage, a consensus-driven definition of improvement [11-13] and a unique randomized placebo-phase trial design [14, 15].

RNA helicase encoded by melanoma differentiation-associated gene 5 is a major autoantigen in patients with clinically amyopathic dermatomyositis: Association with rapidly progressive interstitial lung disease

Abstract: Objective To identify the autoantigen recognized by the autoantibody that is associated with clinically amyopathic dermatomyositis (C-ADM) and rapidly progressive interstitial lung disease (ILD). Methods An anti–CADM-140 antibody–positive prototype serum sample was used to screen a HeLa cell–derived complementary DNA (cDNA) library. Selected cDNA clones were further evaluated by immunoprecipitation of their in vitro–transcribed and in vitro–translated products using anti–CADM-140 antibody–positive and anti-CADM-140 antibody–negative sera. The lysates of COS-7 cells transfected with the putative antigen were similarly tested. An enzyme-linked immunosorbent assay (ELISA) to detect the anti–CADM-140 antibody was established using a recombinant CADM-140 antigen, and its specificity and sensitivity for C-ADM and rapidly progressive ILD were assessed in 294 patients with various connective tissue diseases. Results By cDNA library screening and immunoprecipitation of in vitro–transcribed and in vitro–translated products, we obtained a cDNA clone encoding melanoma differentiation–associated gene 5 (MDA-5). The anti–CADM-140 antibodies in patients' sera specifically reacted with MDA-5 protein expressed in cells transfected with full-length MDA-5 cDNA, confirming the identity of MDA-5 as the CADM-140 autoantigen. The ELISA, using recombinant MDA-5 protein as the antigen, showed an analytical sensitivity of 85% and analytical specificity of 100%, in comparison with the “gold standard” immunoprecipitation assay, and was useful for identifying patients with C-ADM and/or rapidly progressive ILD. Conclusion Given that RNA helicase encoded by MDA-5 is a critical molecule involved in the innate immune defense against viruses, viral infection may play an important role in the pathogenesis of C-ADM and rapidly progressive ILD. Moreover, our ELISA using recombinant MDA-5 protein makes detection of the anti–CADM-140 antibody routinely available.

The mucocutaneous and systemic phenotype of dermatomyositis patients with antibodies to MDA5 (CADM-140): A retrospective study

Abstract: Background Dermatomyositis (DM) is a multisystem autoimmune disease, in which serologic evidence of immune responses to disease-specific antigenic targets is found in approximately 50% to 70% of patients. Recently, melanoma differentiation-associated gene 5 (MDA5) has been identified as a DM-specific autoantigen that appears to be targeted in patients with DM and mild or absent muscle inflammation and with an increased risk of interstitial lung disease. Objective We wished to understand the role of MDA5 in DM skin inflammation by testing it to determine if a specific cutaneous phenotype is associated with MDA5 reactivity. Methods We retrospectively screened plasma from 77 patients with DM in the outpatient clinics at the Stanford University Department of Dermatology in California. Results We found that 10 (13%) patients had circulating anti-MDA5 antibodies, and had a characteristic cutaneous phenotype consisting of skin ulceration, tender palmar papules, or both. Typical areas of skin ulceration included the lateral nailfolds, Gottron papules, and elbows. Biopsy specimens of the palmar papules showed a vasculopathy characterized by vascular fibrin deposition with variable perivascular inflammation. Patients with anti-MDA5 antibodies also had an increased risk of oral pain and/or ulceration, hand swelling, arthritis/arthralgia, and diffuse hair loss. Consistent with previous reports, these patients had little or no myositis and had increased risk of interstitial lung disease. Limitations This study was conducted at a tertiary referral center. Multiple associations with MDA5 antibodies were tested retrospectively on a relatively small cohort of 10 anti-MDA5-positive patients. Conclusion We suggest that MDA5 reactivity in DM characterizes a patient population with severe vasculopathy.