Clinical features of anti-synthetase syndrome associated interstitial lung disease: a retrospective cohort in China.

BACKGROUND: Anti-synthetase syndrome (ASSD) is a chronic autoimmune condition characterized by antibodies directed against an aminoacycl transfer RNA synthetase (ARS) along with a group of clinical features including the classical clinical triad: inflammatory myopathy, arthritis, and interstitial lung disease (ILD). ASSD is highly heterogenous due to different organ involvement, and ILD is the main cause of mortality and function loss, which presents as different patterns when diagnosed. We designed this retrospective cohort to describe the clinical features and disease behaviour of ASSD associated ILD. METHODS: Data of 108 cases of ASSD associated ILD were retrospectively collected in Beijing Chaoyang Hospital from December 2017 to March 2019. Data were obtained from the Electronic Medical Record system. Patients were divided into 5 groups according to distinct aminoacyl tRNA synthetase (ARS) antibodies. RESULTS: Overall, 108 consecutive patients were recruited. 33 were JO-1 positive, 30 were PL-7 positive, 23 were EJ positive, 13 were PL-12 positive and 9 were OJ positive. The JO-1 (+) group had a significant higher rate of mechanic's hand (57.6%) than other 4 groups. Polymyositis/dermatomyositis (PM/DM) was diagnosed in 25 (23.1%) patients and no difference was observed among the 5 groups. The PL-7 (+) group had a higher frequency of UIP pattern (13.3%) than the other 4 groups but the difference was not significant, and the EJ (+) group had the most frequent OP pattern (78.2%), which was significantly higher than the PL-7 (+) (P < 0.001) and PL-12 (+) groups (P = 0.025). The median follow-up time was 10.7 months, during which no patients died. All received prednisone treatment, with or without immunosuppressants. At the 6-month follow-up, 96.3% of all patients (104/108) had a positive response to therapy, the JO-1 (+) and EJ (+) groups had a significantly higher improvement of forced vital capacity than the other 3 groups (P < 0.05), and the PL-7 group had the lowest FVC improvement (P < 0.05). The JO-1 (+) group and EJ (+) group had significantly higher anti-Ro-52 positive occurrence than the other 3 groups (P < 0.05). CONCLUSION: Anti PL-7 antibody had the same frequency as anti-JO-1 in ASSD-ILD, in which the ILD pattern was different with distinct anti-ARS antibodies. Most ASSD-ILD had a positive response to steroid therapies, with or without immunosuppressants. The PL-7 (+) group had the highest occurrence of UIP pattern, and a significantly lower response to therapy.

Anti-alanyl tRNA positive antisynthase syndrome with Kaposi sarcoma.

We report a rare case of antisynthase syndrome (ASS) complicated with Kaposi sarcoma, analyze its clinical characteristics, and review the literature on the topic. An 80-year-old male patient developed fever, cough, and shortness of breath. Lung high-resolution computed tomography showed nonspecific interstitial pneumonia in both lungs, and myositis antibody examination showed strongly positive anti-alanyl tRNA synthase (PL-12) antibodies. Based on these findings, the patient was diagnosed with ASS. After full-dose glucocorticoid treatment, the symptoms of fever and cough were relieved, but skin thickening and pigmentation in both feet were observed. We confirmed Kaposi sarcoma through skin pathology and immunohistochemical examination of the bottom of the patient's feet, and the patient was transferred to a cancer hospital for radiotherapy. ASS presents with some skin changes that might lead to misdiagnosis. ASS complicated with Kaposi sarcoma is rare, and to our knowledge, this is the first case reported in China.

Pulmonary Pathologic Manifestations of Anti-Alanyl-tRNA Synthetase (Anti-PL-12)-Related Inflammatory Myopathy.

CONTEXT: - Patients with anti-aminoacyl-tRNA synthetase syndrome (ARS), a subset of idiopathic inflammatory myopathy, have a high prevalence of lung involvement. Autoantibodies directed against alanyl-tRNA synthetase (anti-PL-12 Abs) represent 1 of the 8 autoantibodies currently described under the rubric of ARS. OBJECTIVE: - To describe the clinical, radiographic, and pulmonary histopathologic findings in patients possessing anti-PL-12 autoantibodies. DESIGN: - Patients with anti-PL-12 ARS were identified in the University of Pittsburgh Idiopathic Inflammatory Myopathy registry. Lung biopsies from 10 patients and lung explants from 2 patients with anti-PL-12 ARS were reviewed, together with chest computed tomography and clinical records. RESULTS: - Patients primarily presented with dyspnea and variable combinations of cough, fever, mechanic's hands, Raynaud phenomenon, and skin and muscle involvement. Chest computed tomography most commonly showed lower lung zone-predominant reticular infiltrates and traction bronchiectasis, with or without honeycomb change. Surgical lung biopsies and pneumonectomies for lung transplantation revealed usual interstitial pneumonia in 8 of 12 cases (67%), nonspecific interstitial pneumonia in 2 of 12 cases (17%), and organizing pneumonia in 2 of 12 cases (17%). Lymphoplasmacytic interstitial inflammation with lymphoid aggregates was common. CONCLUSIONS: - Lung disease is often the first manifestation of anti-PL-12 ARS. There are no pathognomonic histopathologic features to distinguish anti-PL-12 ARS-related lung disease from idiopathic variants of diffuse interstitial lung disease. Increased inflammation, lymphoid aggregates, and nonspecific interstitial pneumonia-like areas in a biopsy, as well as clinical features of mechanic's hands, Raynaud phenomenon, arthritis, and fever, should prompt pathologists to suggest involvement by ARS.

[Anti-synthetase syndrome: anti-PL-7, anti-PL-12 and anti-EJ]. / Síndrome antissintetase: anti-PL-7, anti-PL-12 e anti-EJ.

OBJECTIVES: Due to the scarcity of studies in the literature, we conducted an analysis of a series of patients with the anti-PL-7, PL-12 and EJ types of antisynthetase syndrome (ASS). METHODS: We conducted a retrospective cohort study of 20 patients with ASS (8 with anti-PL-7, 6 with PL-12, 6 with EJ) monitored in our department between 1982 and 2012. RESULTS: The mean patient age at disease onset was 38.5 ± 12.9 years, and the disease duration was 4.5 ± 6.4 years. Of all the patients, 70% were white and 85% were female. Constitutional symptoms occurred in 90% of cases. All patients presented objective muscle weakness in the limbs; in addition, 30% were bedridden and 65% demonstrated high dysphagia at diagnosis. Joint and pulmonary involvement and Raynaud's phenomenon occurred in 50%, 40% and 65% of cases, respectively, with more than half of the patients presenting incipient pneumopathy, ground-glass opacity and/or pulmonary fibrosis. There were no cases of neurological and/or cardiac involvement. All patients received prednisone or other immunosuppressants depending on tolerance, side effects and/or disease refractoriness. Importantly, patients with the anti-EJ type of ASS demonstrated higher rates of recurrence. Two patients died during follow-up, and 1 patient had breast cancer at the time of diagnosis. CONCLUSIONS: ASS (anti-PL-7, PL-12 and EJ) was found to predominantly affect white women. Although the autoantibodies described in the present study are more related to pulmonary than joint involvement, our patients showed a significant percentage of both types of involvement and a high percentage of myopathy. We also observed a low mortality rate.

Síndrome antissintetase: anti-PL-7, anti-PL-12 e anti-EJ / Anti-synthetase syndrome: anti-PL-7, anti-PL-12 and anti-EJ

OBJETIVOS: Devido à escassez de trabalhos na literatura, realizamos análise de uma série de pacientes com síndrome antissintetase (SAS) do tipo anti-PL-7, PL-12 e EJ. MÉTODOS: Estudo de coorte, retrospectivo, envolvendo 20 pacientes com SAS (8 com anti-PL-7, 6 com PL-12, 6 com EJ), em acompanhamento em nosso serviço, entre 1982 e 2012. RESULTADOS: A média de idade dos pacientes ao início da doença foi de 38,5 ± 12,9 anos, e a duração da doença de 4,5 ± 6,4 anos. Setenta por cento dos pacientes eram brancos e 85% eram mulheres. Sintomas constitucionais ocorreram em 90% dos casos. Todos apresentavam fraqueza muscular objetiva dos membros; ao diagnóstico, 30% encontravam-se acamados e 65% com disfagia alta. Envolvimento articular, pulmonar e fenômeno de Raynaud ocorreram, respectivamente, em 50%, 40% e 65% dos casos; mais da metade dos pacientes apresentava pneumopatia incipiente, opacidade em vidro-fosco e/ou fibrose pulmonar. Não houve casos de envolvimento neurológico e/ou cardíaco. Todos receberam prednisona e, como poupadores dessa medicação, diferentes imunossupressores, dependendo da tolerância, efeitos colaterais e/ou refratariedade da doença. De relevância, os pacientes com anti-EJ apresentaram maiores taxas de recidiva. Dois pacientes evoluíram para óbito ao longo do seguimento, e um paciente teve neoplasia mamária na ocasião do diagnóstico da doença. CONCLUSÕES: A SAS (anti-PL-7, PL-12 e EJ) afetou predominantemente mulheres brancas. Embora os autoanticorpos descritos no presente estudo estejam mais relacionados com o acometimento pulmonar comparativamente ao articular, nossos pacientes apresentaram uma porcentagem significativa de ambos e com percentagem alta de miopatia. Além disso, houve menor taxa de mortalidade.

OBJECTIVES: Due to the scarcity of studies in the literature, we conducted an analysis of a series of patients with the anti-PL-7, PL-12 and EJ types of antisynthetase syndrome (ASS). METHODS: We conducted a retrospective cohort study of 20 patients with ASS (8 with anti-PL-7, 6 with PL-12, 6 with EJ) monitored in our department between 1982 and 2012. RESULTS: The mean patient age at disease onset was 38.5 ± 12.9 years, and the disease duration was 4.5 ± 6.4 years. Of all the patients, 70% were white and 85% were female. Constitutional symptoms occurred in 90% of cases. All patients presented objective muscle weakness in the limbs; in addition, 30% were bedridden and 65% demonstrated high dysphagia at diagnosis. Joint and pulmonary involvement and Raynaud's phenomenon occurred in 50%, 40% and 65% of cases, respectively, with more than half of the patients presenting incipient pneumopathy, ground-glass opacity and/or pulmonary fibrosis. There were no cases of neurological and/or cardiac involvement. All patients received prednisone or other immunosuppressants depending on tolerance, side effects and/or disease refractoriness. Importantly, patients with the anti-EJ type of ASS demonstrated higher rates of recurrence. Two patients died during follow-up, and 1 patient had breast cancer at the time of diagnosis. CONCLUSIONS: ASS (anti-PL-7, PL-12 and EJ) was found to predominantly affect white women. Although the autoantibodies described in the present study are more related to pulmonary than joint involvement, our patients showed a significant percentage of both types of involvement and a high percentage of myopathy. We also observed a low mortality rate.

Calcineurin inhibitors in a cohort of patients with antisynthetase-associated interstitial lung disease.

OBJECTIVES: The aim of this paper is to assess the effect of calcineurin inhibitors (tacrolimus or cyclosporine) for treating patients with interstitial lung disease (ILD) associated with antisynthetase autoantibodies. METHODS: Sixty patients with antisynthetase autoantibodies were identified in our myositis cohort of 179 patients. The medical records of 15 patients with antisynthetase autoantibody-associated ILD treated with tacrolimus/cyclosporine (11 for refractory disease and 4 as first-line therapy) between 1980 and 2011 were retrospectively reviewed. Serial pulmonary function tests were used to assess the clinical response. Qualitative data are presented as a number and percentage, and quantitative data as the median and interquartile range (IQR). RESULTS: Patients were classified as having probable or definite idiopathic inflammatory myopathy (8 dermatomyositis and 4 polymyositis), and pure interstitial lung disease (3 cases). The 15 patients had received tacrolimus/cyclosporine for an average of 19 (IQR 14-30) months. Median age at onset of ILD was 42.3 (IQR 32.4-56.8) years and median duration of lung disease before administration of calcineurin inhibitors was 11 (IQR: 5-49) months. Median duration of follow-up was 24 (IQR 12-32) months. Thirteen patients had anti-histidyl-transfer RNA synthetase autoantibody (anti-Jo-1) and two had anti-alanyl-transfer RNA synthetase autoantibody (anti-PL-12). A more than 10% increase in FVC or stabilisation was observed in 13 (87%; 95%CI 56-98) patients who received calcineurin inhibitors (9 [81%] refractory cases and 4 [100%] as first-line therapy). CONCLUSIONS: Calcineurin inhibitors seem to be a good therapeutic option for managing ILD associated with antisynthetase autoantibodies, not only in refractory cases, but also as first-line treatment.

Outcome of anti-PL12 positive patients with antisynthetase syndrome.

OBJECTIVES: The aim of the present study was to assess the outcome in anti-PL12 patients with antisynthetase syndrome (ASS). METHODS: The medical records of anti-PL12 (n=5) patients with ASS were retrospectively analyzed without prior selection. To exclude false-positive patients, we included patients who were successively tested positive for anti-PL12 antibody at least twice by immunodot and/or Western blot. RESULTS: Anti-PL12 patients experienced: myositis (n=2), Raynaud's phenomenon (n=2), mechanic's hands (n=1), joint impairment (n=4), digestive involvement (n=2), and interstitial lung disease (ILD) (n=4). The two patients with myositis exhibited deterioration of muscle manifestations despite therapy. As regards outcome of ILD, patients developed resolution (n=1), stabilization (n=1) or deterioration (n=2) of pulmonary status. One patient died of pyogenic pneumonia. CONCLUSION: Our series underscores that the presence of anti-PL12 antibody is associated with a particular phenotype of ASS characterized by: (1) less frequent although severe/steroid refractory myositis; (2) less common mechanic's hands and calcinosis cutis; (3) both frequent and severe ILD. Taken together, our findings suggest that PM/DM patients should routinely undergo the search for anti-PL12 antibody as this autoantibody appears to impact patients' prognosis. Furthermore, ILD patients with anti-PL12 antibody should routinely undergo clinical screening for underlying ASS.

Comparison of long-term outcome between anti-Jo1- and anti-PL7/PL12 positive patients with antisynthetase syndrome.

The aims of the present study were to: compare the characteristics between antisynthetase syndrome (ASS) patients with anti-Jo1 antibody and those with anti-PL7/PL12 antibody. The medical records of 95 consecutive patients with ASS were reviewed. Seventy-five of these patients had anti-Jo1 antibody; the other patients had anti-PL7 (n=15) or anti-PL12 (n=5) antibody. At ASS diagnosis, the prevalence of myalgia (p=0.007) and muscle weakness (p=0.02) was significantly lower in the group of anti-PL7/PL12-positive patients than in those with anti-Jo1 antibody; median value of CK (p=0.00003) was also lower in anti-PL7/PL12 patients. Anti-Jo1 positive patients developed more rarely myositis resolution (21.3% vs. 46.2%); in addition, the overall recurrence rate of myositis was higher in anti-Jo1 positive patients than in patients with anti-PL7/PL12 antibody (65.9% vs. 19.4%). Anti-Jo1-positive patients, compared with those with anti-PL7/PL12 antibody, more often experienced: joint involvement (63.3%vs. 40%) and cancer (13.3% vs. 5%). By contrast, anti-PL7/PL12 positive patients, compared with those with anti-Jo1 antibody, more commonly exhibited: ILD (90% vs. 68%); in anti-PL7/PL12 positive patients, ILD was more often symptomatic at diagnosis, and led more rarely to resolution of lung manifestations (5.6% vs. 29.4%). Finally, the group of anti-PL7/PL12 positive patients more commonly experienced gastrointestinal manifestations related to ASS (p=0.02). Taken together, although anti-Jo1 positive patients with ASS share some features with those with anti-PL7/PL12 antibody, they exhibit many differences regarding clinical phenotype and long-term outcome. Our study underscores that the presence of anti-Jo1 antibody results in more severe myositis, joint impairment and increased risk of cancer. On the other hand, the presence of anti-PL7/PL12 antibody is markedly associated with: early and severe ILD, and gastrointestinal complications. Thus, our study interestingly indicates that the finding for anti-Jo1 and anti-PL7/PL12 antibodies impacts both the long-term outcome and prognosis of patients with ASS.

Clinical manifestations of anti-synthetase syndrome positive for anti-alanyl-tRNA synthetase (anti-PL12) antibodies: a retrospective study of 17 cases.

OBJECTIVE: To describe the clinical manifestations of the anti-synthetase syndrome (ASS) specifically associated with anti-alanyl-tRNA (anti-PL12) synthetase antibodies. METHODS: In a retrospective study, 17 patients (eight males, nine females, mean age = 60.3 years) with ASS symptoms confirmed by two consecutive tests (cyto-dot and/or immunoblot, or both), with positive results for anti-PL12 antibodies, were included. RESULTS: All patients presented with interstitial lung disease (ILD), which was associated with mild myositis in 41% of the cases. RP and general impairment were common, whereas rheumatic and dermatological symptoms were uncommon. Four patients suffered from SS, and four others had an atypical oesophageal involvement. The long-term course was assessable for 10 patients (follow-up of 41.1 months). Five patients required immunosuppressive drugs. Two patients are waiting for a lung transplant because of disproportionate and refractory pulmonary hypertension. CONCLUSION: The severity of anti-PL12 ASS varied because of the constant pulmonary involvement. ILD was the predominant prognosis factor, which was notable in cases associated with pulmonary hypertension.

Anti-synthetase syndrome in ANA and anti-Jo-1 negative patients presenting with idiopathic interstitial pneumonia.

OBJECTIVES: To describe the clinical features of patients presenting with "idiopathic" interstitial pneumonia that were diagnosed with anti-synthetase syndrome based on clinical features and positive anti-PL-7 or PL-12 antibodies. METHODS: Over a 24-month period, we evaluated 37 patients who presented with clinical features of anti-synthetase (AS) syndrome, negative anti-Jo-1 antibodies, and who were assessed for other anti-tRNA synthetase (anti-tRS) antibodies. All data were abstracted from the medical record. RESULTS: Nine (24%) were confirmed to have non-anti-Jo-1 positive AS syndrome based on clinical features and the presence of other anti-tRS antibodies (seven with anti-PL-7, two with anti-PL-12 antibodies). All presented with dyspnea as the initial symptom and with ILD as the first manifestation. Elevated CPK was identified in three patients but only two had muscle weakness. Pulmonary physiology revealed restriction (forced vital capacity 60% of predicted) and impaired gas transfer (diffusing capacity for carbon monoxide 40% of predicted). All had similar findings on thoracic HRCT scans, with basilar predominance of abnormalities and patterns suggestive of non-specific interstitial pneumonia and organizing pneumonia. Immunomodulatory therapies were used to treat the ILD-responses were variable, but some subjects clearly improved. CONCLUSION: Anti-PL-7 and PL-12 antibodies may be more common among patients presenting with "idiopathic" interstitial pneumonia than formerly considered and should be checked in patients with features of AS syndrome despite a negative screen for anti-nuclear or anti-Jo-1 antibodies. Further research is needed to advance understanding of anti-PL-7 or anti-PL-12-positive AS syndrome, including its prognosis and optimal approaches to therapy.

Autoantibody to alanyl-tRNA synthetase in patients with idiopathic pulmonary fibrosis.

BACKGROUND AND OBJECTIVES: The pathogenesis of IPF is unknown and it is hypothesized that immunological responses are involved. The purpose of this study was to detect autoantibodies in IPF patients and to identify the relevant antigens. METHODS: Sera from 37 healthy subjects and 22 IPF patients who had no clinical symptoms of collagen vascular disease were examined for immunostaining of A549 human type II cells and human lung tissue. Immunoprecipitation and proteome analysis were performed to identify the antigen. RESULTS: Fifty per cent of the patient sera and none of the control sera exhibited positive staining. Sera from 10 of the 22 IPF patients showed positive immunohistochemistry and immunoprecipitated a 110-kDa protein from the A549 cell lysate. Sera from only two of 41 patients with collagen vascular disease showed positive immunoreactivity. Proteome analysis using tandem mass spectrometry revealed that the protein was alanyl-tRNA synthetase. Transfection of cDNA of this enzyme into CHO-K1 cells conferred positive staining on these cells with the patients' IgG. The 135-kDa fusion protein consisting of 108-kDa enzyme protein and 27-kDa YFP from the cell lysate of the transfected cells was immunoprecipitated by the patient IgG. In addition, sera from IPF patients significantly inhibited the enzyme activity of alanyl-tRNA synthetase. CONCLUSION: A significant number of IPF patients possess circulating autoantibodies against alanyl-tRNA synthetase, suggesting the involvement of an autoimmune background in the pathogenesis of IPF.

Unusually high frequency of autoantibodies to PL-7 associated with milder muscle disease in Japanese patients with polymyositis/dermatomyositis.

OBJECTIVE: Autoantibodies to aminoacyl transfer RNA synthetases, such as histidyl (Jo-1), threonyl (PL-7), alanyl (PL-12), glycyl (EJ), and isoleucyl (OJ), are closely associated with a subset of patients with polymyositis/dermatomyositis (PM/DM) complicated by interstitial lung disease (ILD). Anti-Jo-1 is by far the most common, found in 15-25% of patients with PM/DM, whereas the other types are found in only approximately 3% of these patients. In this study, the clinical associations of these autoantibodies in Japanese patients with PM/DM were investigated. METHODS: The diagnoses of PM/DM and amyopathic DM (ADM) were based on the Bohan and Peter criteria and Sontheimer's definition, respectively. Sera from 36 Japanese patients with PM/DM (13 with PM, 20 with DM, 3 with ADM) were screened by immunoprecipitation and by enzyme-linked immunosorbent assay (for Jo-1). Clinical and laboratory data were collected. RESULTS: The frequencies of autoantibodies to Jo-1 (22%) and to EJ, OJ, and PL-12 (3-6%) were similar to those found in previous studies, including studies of Japanese subjects. However, anti-PL-7 was found in 17% of patients, in contrast to a frequency of 1-4% in previous studies (P < 0.02-0.0002). The 6 anti-PL-7-positive patients were not related, and no skewing in year or month of disease development, place of residence or work, or occupation was found. All patients had ILD, consistent with the clinical features of antisynthetase-positive patients. The patients with anti-PL-7 had lower serum muscle enzyme levels and milder muscle weakness (P < 0.05) compared with anti-Jo-1-positive patients. CONCLUSION: Anti-PL-7 was found at an unusually high frequency in this group of Japanese patients with myositis. Although anti-PL-7, similar to anti-Jo-1, is associated with PM/DM with ILD, muscle involvement in the patients with anti-PL-7 appeared to be milder than that in the anti-Jo-1 subset.

Treatment of antisynthetase-associated interstitial lung disease with tacrolimus.

OBJECTIVE: To assess the efficacy of tacrolimus in patients with anti-aminoacyl-transfer RNA synthetase (anti-aaRS)-associated interstitial lung disease (ILD) and idiopathic inflammatory myopathy (IIM). METHODS: Ninety-eight patients with anti-aaRS autoantibodies were identified in our IIM cohort of 536 patients. The medical records of 15 patients with anti-aaRS-associated ILD treated with tacrolimus between 1992 and 2003 were retrospectively reviewed. Pulmonary parameters of response included forced vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide. Manual muscle testing results, serum creatine kinase (CK) levels, and the daily corticosteroid dosage were used to assess improvement in myositis. Random coefficient modeling considering polynomials of time was used to assess the clinical response to tacrolimus. RESULTS: All patients, except for 1, who had pure ILD, had definite or probable IIM. Two patients received tacrolimus for fewer than 3 months, and their data were not analyzed. For the remaining 13 patients, the mean age at onset of ILD was 46.9 years, and the mean duration of pulmonary disease was 14.7 months. Twelve patients had anti-histidyl-transfer RNA synthetase autoantibody (anti-Jo-1) and 1 had anti-alanyl-transfer RNA synthetase autoantibody (anti-PL-12). Patients received tacrolimus for an average of 51.2 months. A significant improvement was observed in all pulmonary parameters measured. The serum CK level declined significantly, and 10 patients had either an improvement in muscle strength or maintained normal muscle strength. A statistically significant reduction in the corticosteroid dosage was also observed. CONCLUSION: Tacrolimus is a well-tolerated and effective therapy for managing refractory ILD and myositis in anti-aaRS-positive patients.

Long-term clinical course of a patient with anti PL-12 antibody accompanied by interstitial pneumonia and severe pulmonary hypertension.

We report a case of a patient with anti PL-12 antibody accompanied by interstitial pneumonia and severe pulmonary hypertension. At first presentation, hyperkeratotic skin lesions were found, although the diagnosis of CVD was not conclusive. Lung histology showed diffuse fibrosing interstitial pneumonia predominantly in the subpleural regions. During the seven-year follow-up period, severe pulmonary hypertension developed, although the progression of lung fibrosis was relatively limited. Anti-PL12 antibody was detected, and therefore the patient was diagnosed as having antisynthetase syndrome. Lung histology and pulmonary arteriogram suggested that vascular involvement of the disease contributed to the development of severe pulmonary hypertension.

Detection of anti-PL-12 autoantibodies by ELISA using a recombinant antigen; study of the immunoreactive region.

Autoantibodies to aminoacyl-tRNA synthetases are highly associated with myositis and detection is important in clinical diagnosis; however, current methods of screening limit its clinical utility. In the present study, alanyl-tRNA synthetase (PL-12) recombinant protein was obtained by immunological screening of a HeLa expression library and used in an ELISA with 22 anti-PL-12 sera, 200 autoimmune sera negative for PL-12 and 100 healthy individual sera. Sensitivity of the method was 95% (21/22) and specificity 100%. Mapping of the immunoreactive region was carried out using three anti-PL-12 sera and different recombinant protein-derived peptides. Results show that the same conformational epitope located within amino acids 730-951 of the PL-12 antigen outside the catalytic region was recognized by the three anti-PL-12 sera tested. We conclude that ELISA using recombinant protein is an effective and useful method for routine screening for anti-PL-12 autoantibodies.