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Anti-PL-7 Antisynthetase Syndrome with Eosinophilic Pleural Effusion

A 68-year-old woman was admitted to our hospital with fever and pleural effusion. Her thoracentesis showed eosinophilic pleural effusion (EPE) without any evidence of malignancy, infection, or trauma. Pleural biopsy revealed pleuritis and intercostal myositis. Characteristic skin manifestations, including Gottron's sign, interstitial lung disease, and pericardial effusion, appeared later in the clinical course. She was finally diagnosed with anti-PL-7 antisynthetase syndrome (ASS) based on the presence of anti-PL-7 antibody, and she fulfilled the diagnostic criteria for dermatomyositis. These clinical manifestations improved with immunosuppressive therapy. EPE might therefore be one of the characteristic features of anti-PL-7 ASS.

Pleural effusion associated with connective tissue disease (CTD) is frequent in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), but it is relatively rare in polymyositis/dermatomyositis (PM/DM) or ASS (7). Eosinophilic pleural effusion (EPE), defined as an eosinophil count ! 10% in the pleural fluid (8), is commonly seen in malignancy, infection, trauma and CTD (9,10). Pleural effusion associated with CTD is usually lymphocytic (7); however, this patient, who was diagnosed with anti-PL-7 ASS, had EPE. To the best of our knowledge, there has been no previous report of EPE associated with anti-PL-7 ASS. We herein report a case of anti-PL-7 ASS with EPE in which remission was achieved with a combination of corticosteroids and immunosuppressive agents.

Case Report
A 68-year-old Japanese woman was admitted to our hospital with fever and left chest pain for the previous two weeks that did not respond to treatment with garenoxacin. She was a never smoker and had no significant past medical history or trauma. Chest X-ray showed left pleural effusion (Fig. 1A). Computed tomography (CT) of the chest confirmed left pleural effusion, while no other abnormality was noted Fig. 1B and C.
Thoracentesis was performed and revealed the presence of exudative pleural effusion with no evidence of malignancy. A biochemical analysis revealed the following results: TP, 3.1 g/dL; LDH, 232 U/L; WBC, 4,610/μL; glucose, 108 mg/ dL; Adenosine deaminase (ADA), 11.4 U/L; and CEA, 1.8 ng/mL. The differential WBC count showed a high eosinophil count (neutrophils 38.2%, lymphocytes 5.8%, eosinophils 52.6% and monocytes 3.4%). A pleural fluid culture was negative. For a definitive diagnosis, a surgical biopsy of the pleura was performed. The samples contained pleura and intercostal muscle specimens, and the histopathological findings revealed pleuritis and myositis of the intercostal muscle ( Fig. 2A). The pleura was predominantly infiltrated by lymphocytes and plasma cells with relatively few eosinophils, suggestive of nonspecific pleuritis (Fig. 2B). The intercostal muscle showed degeneration and infiltration with inflammatory cells, including lymphocytes and plasma cells, suggestive of myositis (Fig. 2C). There were few eosinophils in the pleura and intercostal muscle specimens.
The clinical course after pleural biopsy is shown in Fig.  3. The patient was started on oral prednisolone, 0.5 mg/kg/ day, which resulted in a transient remission of fever. However, fever recurred along with new skin manifestations, including Gottron's sign (Fig. 4A), mechanic's hand (Fig. 4B), and Shawl sign (Fig. 4C). In addition, a high-resolution CT (HRCT) scan of the chest revealed new-onset ILD and pericardial effusion (Fig. 3). ILD demonstrated a patchy groundgrass attenuation and consolidation without honeycombing and/or traction bronchiectasis in bilateral basal lungs, suggestive of nonspecific interstitial pneumonia (NSIP) and/or organizing pneumonia (OP)-like pattern, in HRCT. Although she had no muscle symptoms, such as muscle pain or weakness, further laboratory investigations showed a high level of muscle enzymes, including CPK and aldolase; needle electromyogram revealed myopathic changes in the tibialis anterior and biceps brachii muscles. Based on these findings, she was considered to fulfill the diagnostic criteria for DM (Fig. 3).
Since we considered that this case might be a rapidly progressive ILD with anti-melanoma differentiation-associated gene 5 (MDA-5) antibody before obtaining the results of myositis-associated antibodies, she was started on combina-  A B C tion immunosuppressive therapy with methyl prednisolone (1 g/day intravenously on days 1-3 and 40 mg/day orally from day 4), cyclophosphamide (750 mg/body intravenously on days 4 and 28), and tacrolimus (3 mg/day orally from day 4) in a sequential manner (Fig. 3). With this treatment, the pleural effusion resolved immediately, while the other clinical manifestations including myositis, skin findings, ILD and pericardial effusion also improved. Lung function tests showed an improvement in the predicted vital capacity (%VC) from 80.5% to 106.4% and in the diffusing capacity for carbon monoxide (%DLco) from 77.4% to 123.2%. Finally, after performing a screening test using an enzymelinked immunosorbent assay (ELISA) kit for anti-ARS antibodies (MESACUP anti-ARS test; MBL, Nagoya, Japan), including five anti-ARS antibodies (anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, and anti-KS antibody) (3), a developed ELISA for each anti-ARS antibody (MBL) revealed the presence of anti-PL-7 antibody, which confirmed the diagnosis of anti-PL-7 ASS (Fig. 3). In addition, anti-MDA-5 antibody was negative. The remarkable improvement noted with immunosuppressive therapy suggested that our patient had several features, including EPE, associated with anti-PL-7 ASS. Although the immunosuppressive therapy was gradually reduced to 8 mg/day of prednisolone and 1.5 mg/day of tacrolimus, she continues to be in remission after 12 months.

Discussion
Interestingly, our patient presented with EPE as one of the early findings of anti-PL-7 ASS. To the best of our knowledge, there has been no previous report of EPE in a patient with anti-PL-7 ASS. In addition, inflammatory myopathy was confirmed in the intercostal muscle according to the histopathological findings. Noguchi et al. studied skeletal muscle involvement in detail in 51 myositis patients with ASS and showed that the respiratory muscle involvement was rare, accounting for only 8% (11). Intercostal myositis, leading to muscle weakness, may have led to respiratory dysfunction in our case. Our patient tested positive for anti-PL-7 antibody and thus was diagnosed with anti-PL-7 ASS; she also fulfilled the diagnostic criteria for DM. Our findings suggest that the clinical features and presence of EPE are associated with anti-PL-7 ASS in this case, as she showed a good improvement with immunosuppressive therapy.
Pleural effusion in CTDs is a frequent manifestation which is most commonly found in patients with RA and SLE (7). However, it is considered rare in other CTDs, including PM/DM or ASS. Fujisawa et al. noted pleural effu- PSL+CPA+Tac Improved * pulmonary insufficiency due to interstitial pneumonia, ** gastric cancer.  Table ( [18][19][20][21][22][23][24][25]. In patients with pleural effusion associated with PM/DM, there was a male predominance along with a higher incidence of DM and ILD. Four patients were positive for anti-ARS antibody, including 3 with anti-Jo-1 and 1 with anti-PL-7 antibody (our case). Exudative pleural effusion was seen in 8 cases, with either a lymphocytic, neutrophilic, or eosinophilic predominance. Although two patients died from pulmonary insufficiency due to ILD or malignancy, the pleural effusion improved in all cases after treatment with corticosteroids and/or immunosuppressive agents. EPE is usually defined as an eosinophil count ! 10% in the pleural fluid (8). In a systemic review of 687 cases with EPE, Oba et al. reported that EPE was most often due to malignancy (26%), followed by idiopathic (25%), parapneumonic effusion (13%), pleural air/blood (13%), tuberculosis (7%), transudate (7%), other causes (6%), and CTD (3%) (10). In our case, the etiology of EPE was most likely related to local immune pleuritis associated with myositis and/or ILD due to anti-PL-7 ASS because our case had no other cause for EPE, including malignancy, infection, or trauma, and the pleural effusion resolved with immunosuppressive therapy. The pathogenesis of EPE is still poorly understood, but IL-5 has been suggested to play an important role in the pathogenetic pathway of EPE (8,26). A pleural biopsy should not be routinely performed, but it most commonly shows nonspecific pleuritis without eosinophil infiltration in patients with EPE (8). As in our case, in a previous report, a pleural biopsy demonstrated nonspecific pleuritis and an improvement in EPE with corticosteroid therapy in a patient with EPE associated with PM and systemic sclerosis overlap syndrome (case 5 in Table) (21).
The presence of anti-ARS antibody including anti-PL-7 antibody has been reported to be associated with a favorable response to immunosuppressive therapy and an increased overall survival in PM/DM patients with ILD (27)(28)(29). However, it has been suggested that the clinical phenotype and prognosis vary with the type of anti-ARS antibody in patients with ASS. Some reports have demonstrated that ASS patients with anti-PL-7/12 antibodies have a lower survival rate than those with anti-Jo-1 antibody (5, 6). Fujisawa et al. reported that the anti-PL-7 antibody is one of the significant predictors of pulmonary worsening during a long-term follow-up of more than a year in patients with PM/DM-ILD (30). Based on these data, a careful long-term followup was therefore deemed to be required in our case.
In conclusion, we herein described a case of anti-PL-7 ASS with EPE. Our case showed that EPE can sometimes be associated with anti-PL-7 ASS, and that the symptoms improved after the administration immunosuppressive therapy. EPE might therefore be one of the characteristic features of anti-PL-7 ASS.