RESUMEN
Anti-OJ antibody is relatively rarely detected in patients with the anti-synthetase syndrome, which is polymyositis (PM)/dermatomyositis (DM) with anti-aminoacyl transfer ribonucleic acid (RNA) synthetase antibodies. There have been few case reports of anti-OJ antibody-positive PM/DM complicated by other connective tissue disorders. Herein, we report the case of a 33-year-old woman who was admitted to our hospital with fever, muscle weakness, and dyspnoea on exertion. She was diagnosed with anti-OJ antibody-positive PM, overlapping systemic lupus erythematosus, and Sjögren's syndrome (SS). Her symptoms and clinical findings improved after treatment with prednisolone 1 mg/kg/day without immunosuppressive agents. This is the first case of overlap syndrome with anti-OJ antibody-positive PM, systemic lupus erythematosus, and Sjögren's syndrome.
Asunto(s)
Enfermedades Autoinmunes , Dermatomiositis , Lupus Eritematoso Sistémico , Polimiositis , Síndrome de Sjögren , Femenino , Humanos , Adulto , Síndrome de Sjögren/complicaciones , Síndrome de Sjögren/diagnóstico , Enfermedades Autoinmunes/complicaciones , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/diagnóstico , Polimiositis/complicaciones , Polimiositis/diagnóstico , Polimiositis/tratamiento farmacológico , Dermatomiositis/complicacionesRESUMEN
BACKGROUND: The peculiar presentation of overlap syndrome in children makes precise diagnosis difficult. Children with overlap syndrome may or may not have specific antibodies. We present the case of a 12-year-old girl diagnosed with overlap syndrome of systemic lupus erythematosus (SLE) and juvenile polymyositis (JPM) who tested positive for anti-OJ antibodies. CASE PRESENTATION: We describe the case of a 12-year-old girl diagnosed with SLE at the age of 7 and presented with fever with malar rash, periungual erythema, generalized weakness, and multiple joint pain at admission. The patient had persistent joint pain and weakness after intravenous methylprednisolone administration and complained of an inability to walk with a positive test for Gower's sign one week after admission, accompanied by elevated alanine aminotransferase (ALT) and creatine-phospho-kinase (CPK) levels. The results of nerve conduction velocity test were normal. Electromyography revealed abundant spontaneous activity and myopathic motor unit action potentials in the right deltoid, biceps, and iliopsoas, in addition to fibrillation and mild myopathic motor unit action potentials in the right rectus femoris muscle. Magnetic resonance imaging revealed diffusely increased signal intensities in the myofascial planes of the bilateral iliopsoas, gluteus, obturator, pectineus, and hamstring muscles. Anti-nuclear antibody, anti-RNP, and rheumatoid factor IgG tests were positive, and inflammatory myopathy autoantibodies revealed anti-OJ antibody positivity, which strongly indicated autoimmune myositis. High-resolution computed tomography of the lung revealed mild pericardial effusion without any evidence of interstitial lung disease. We initiated intravenous pulses of methylprednisolone treatment, followed by cyclosporine, mycophenolate mofetil, and oral steroids. Clinical improvement with a delayed, slowly reduced CPK level after the above treatment and she was discharged after the 18th day of hospitalization. CONCLUSION: Overlap syndrome with inflammatory myositis can occur years later in pediatric SLE cases. We should be alert when patients with SLE develop a new presentation characterized by decreased SLE-specific autoantibody titers, positive anti-RNP antibodies, and elevated CPK. Treatment of the overlap syndrome of SLE and JPM is individualized, and the course differs between pediatric and adult patients.
Asunto(s)
Ciclosporinas , Lupus Eritematoso Sistémico , Miositis , Polimiositis , Adulto , Femenino , Humanos , Niño , Factor Reumatoide , Ácido Micofenólico/uso terapéutico , Alanina Transaminasa/uso terapéutico , Creatina/uso terapéutico , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/diagnóstico , Lupus Eritematoso Sistémico/tratamiento farmacológico , Polimiositis/complicaciones , Polimiositis/tratamiento farmacológico , Miositis/complicaciones , Síndrome , Anticuerpos Antinucleares , Autoanticuerpos , Metilprednisolona/uso terapéutico , Artralgia , Ciclosporinas/uso terapéutico , Inmunoglobulina GRESUMEN
OBJECTIVE: Anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are useful for identifying a clinical subset of patients with idiopathic inflammatory myopathies (IIMs). Anti-OJ antibodies, which recognize multi-enzyme synthetase complexes including isoleucyl-tRNA synthetase (IARS) and lysyl-tRNA synthetase (KARS), are among the anti-ARS antibodies. Although testing antibodies to other ARSs have been used clinically, no validated immunoassays for detecting anti-OJ antibodies are available. We aimed to establish an anti-OJ ELISA. METHODS: Serum samples were collected from 279 patients with IIMs and 22 patients with idiopathic interstitial pneumonia. Sixty-four of the samples that had been confirmed to be negative for anti-OJ by standard immunoprecipitation were used as the negative control, and 12 anti-OJ-positive reference sera were used as the positive control. Antibodies to IARS and KARS were assayed by ELISA using biotinylated recombinant proteins generated by in vitro transcription/translation. RESULTS: The anti-OJ-positive sera strongly reacted with the KARS and IARS recombinant proteins in ELISA. Although all 12 reference sera were positive in the anti-KARS ELISA, 4 of the 64 anti-OJ-negative sera were also weakly positive. The sensitivity and the specificity were 100% and 93.8%, respectively. Since our anti-KARS ELISA performed well, showing a high agreement with the results for immunoprecipitation (Cohen's κ > 0.8), the remaining 237 samples were also tested. Thirteen anti-KARS-positive sera were newly found by ELISA, all of which were anti-OJ positive by immunoprecipitation. CONCLUSION: Immunoassays for detecting anti-OJ antibodies using KARS and IARS recombinant proteins were developed. Our ELISAs performed well, with very high agreement of the results by immunoprecipitation and can be applied to the first reliable, easy-to-use measurement assays for anti-OJ antibodies.
Asunto(s)
Autoanticuerpos/aislamiento & purificación , Isoleucina-ARNt Ligasa/metabolismo , Lisina-ARNt Ligasa/metabolismo , Miositis/diagnóstico , Adulto , Anciano , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Autoanticuerpos/metabolismo , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática/métodos , Estudios de Factibilidad , Femenino , Voluntarios Sanos , Humanos , Isoleucina-ARNt Ligasa/inmunología , Lisina-ARNt Ligasa/inmunología , Masculino , Persona de Mediana Edad , Miositis/sangre , Miositis/inmunología , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/metabolismo , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
A 13-year-old girl was admitted for persistent thigh pain and remittent fever and was diagnosed as having juvenile polymyositis. Although the initial treatment with 2 cycles of methylprednisolone pulse therapy failed to achieve full remission, the second-line treatment with intravenous cyclophosphamide pulse therapy was effective. Anti-OJ antibody, which is one of anti-aminoacyl-tRNA synthetase (ARS) antibodies and is rare in adult polymyositis, was detected. Assessment of anti-ARS autoantibodies may facilitate diagnosis and management of juvenile polymyositis.