Outcome of anti-PL12 positive patients with antisynthetase syndrome

Interstitial Lung Disease and Myositis in a Patient With Antisynthetase Syndrome and PL12 and Ro52 Co-positivity in a Retired Medical Officer

Antisynthetase syndrome (ASS) is an idiopathic inflammatory myopathy characterized by myositis, arthritis, interstitial lung disease (ILD), Raynaud's phenomenon, and distinctive cutaneous manifestations. Anti-PL12 is a rare myositis-specific autoantibody classically associated with an amyopathic presentation and rapidly progressive ILD. Anti-Ro52 is a myositis-associated antibody that has been postulated to be directly pathogenic in inflammatory myopathy patients. The disease phenotype, course, and response to treatment associated with anti-PL12 and anti-Ro52 co-positivity is not well described.

A 58-year-old man with anti-PL12 and anti-Ro52 ASS presented with rapidly progressive ILD and myositis refractory to high-dose prednisone. He ultimately required a dexamethasone burst with intravenous immunoglobulin and mycophenolate mofetil for disease control.

Severe and rapidly progressive myositis is infrequently reported in anti-PL12 ASS. This case suggests that concurrent anti-Ro52 positivity predicts a more aggressive disease phenotype and may require more initial immunosuppression. If rapid progression of this disease were to occur in an active duty service member, it would have significant implications for readiness and potentially catastrophic outcomes in the deployed setting. Early identification and treatment of the disease are imperative. The question must also be raised of an occupational exposure from military service.

Interstitial lung disease and inflammatory myopathy in antisynthetase syndrome with PL-12 antibody

We report the case of an 80-year-old Caucasian man with PL-12 antibody positive antisynthetase syndrome. He presented with progressive dyspnoea and weight loss, later developing dysphagia, mild proximal muscle weakness and mild sicca symptoms. Investigations revealed interstitial lung disease, inflammatory myopathy and an immunology profile consistent with PL-12 antisynthetase syndrome. Prednisolone and cyclophosphamide resulted in a significant improvement of all his symptoms.

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.

A Multidisciplinary Evaluation Helps Identify the Antisynthetase Syndrome in Patients Presenting as Idiopathic Interstitial Pneumonia

INTRODUCTION

Interstitial lung disease (ILD) is 1 possible manifestation of the idiopathic inflammatory myopathies (IIM). Occasionally, patients presenting with ILD are mistakenly diagnosed with idiopathic interstitial pneumonia (IIP), but after multidisciplinary evaluation, their ILD is determined to be because of antisynthetase syndrome (SynS) or myositis spectrum of disease.

METHODS

We used retrospective analytic methods to identify patients with ILD evaluated at the National Jewish Health between February 2008 and August 2014 and believed initially to have IIP but ultimately diagnosed with SynS or myositis spectrum of disease.

RESULTS

The cohort included 33 patients; most were white women with a mean age at presentation of 55 years. Their pulmonary physiologic impairment was moderate. In 31 cases, the ILD pattern by thoracic high-resolution computed tomography scan was nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), or a combination of the 2. Surgical lung biopsy was performed in 21 patients; NSIP was the most common pattern. Less than one-third of the cohort had positive antinuclear antibodies. Two-thirds had positive SSA. All patients had either myositis-specific or myositis-associated autoantibody. Most had subtle extrathoracic symptoms or signs of SynS; 12 had an elevated serum creatine phosphokinase, but none had clinical evidence of myositis. None met the Peter and Bohan classification criteria for polymyositis/dermatomyositis.

CONCLUSION

Among patients who present with presumed IIP, a multidisciplinary evaluation that includes the integration of clinical evaluations by rheumatologists and pulmonologists, morphologic (both histopathologic and radiographic) data, and serologic features is helpful in the detection of occult SynS or the myositis spectrum of disease.

Idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIM) consist of rare heterogeneous autoimmune disorders that present with marked proximal and symmetric muscle weakness, except for distal and asymmetric weakness in inclusion body myositis. Despite many similarities, the IIM are fairly heterogeneous from the histopathologic and pathogenetic standpoints, and also show some clinical and treatment-response differences. The field has witnessed significant advances in our understanding of the pathophysiology and treatment of these rare disorders. This review focuses on dermatomyositis, polymyositis, and necrotizing myopathy, and examines current and promising therapies.