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Objectives: Anti-asparaginyl tRNA synthetase (anti-KS) antibody is present in patients with interstitial lung disease (ILD) accompanied by polymyositis/dermatomyositis. We examined clinical/immunological features of these patients., Methods: Polymyositis/dermatomyositis or ILD patients were screened for autoantibodies, and clinical/immunological data were collected retrospectively. ILD was diagnosed by computed tomography, and clinical/immunological features of anti-KS-positive patients were compared with those of anti-Jo-1-positive patients., Results: Sixteen anti-KS-positive patients [female = 11; male = 5; average age 63.6 years (range, 40-81) years] were diagnosed: seven had ILD, four had clinically amyopathic DM (CADM) and ILD, three had Sjögren's syndrome (SS) and ILD one each had rheumatoid arthritis and ILD, or CADM/SS overlap and ILD. All patients had ILD with chronic onset and clinical course; 11/16 (69%) had nonspecific interstitial pneumonia, and five (31%) had usual interstitial pneumonia pattern. Regarding skin manifestations, 4 (27%) had typical DM rash and 11 (69%) had mechanic's hands. All anti-KS-positive patients had no clinical muscle weakness or serum creatine kinase elevation; 8/16 patients (50%) had sicca symptoms at a significantly high frequency compared with anti-Jo-1-positive patients (50% vs 11%, P = 0.01)., Conclusions: Anti-KS-positive patients might form a distinguishable subset closely associated with sicca symptoms, CADM and chronic-type ILD with a relatively favourable prognosis., (© Japan College of Rheumatology 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Dermatomyositis (DM) is a categorised as one of idiopathic inflammatory myopathy (IIM) indicated by symmetrical proximal muscle weakness as well as characteristic cutaneous manifestations typical of DM. Clinically amyopathic dermatomyositis (CADM), a subtype of DM, shows only the skin involvement without any clinical signs of myositis. This condition is often associated with fatal anti-MDA5 antibody-positive rapidly progressive interstitial lung disease (RP-ILD), especially in Eastern Asian populations. Here, we report a CADM patient with anti-MDA5 antibody-positive RP-ILD whom we successfully treated by early initiation of plasma exchange (PE) together with multiple immunosuppressive therapies. In this patient, initial treatment with high-dose prednisolone (PSL), tacrolimus and intermittent intravenous cyclophosphamide had resulted in no obvious improvement in the respiratory condition. Therefore, soon after the first evaluation, we initiated PE therapy in addition to these multiple immunosuppressive therapies. Although the patient had pneumomediastinum, cytomegalovirus and fungal infections over the clinical course, RP-ILD did gradually improved and the anti-MDA5 titre decreased down to within the normal range paralleled by improvement in the patient's respiratory condition.

A 59-year old woman had been suffering from myalgia, eruption and dyspnea on effort for a month. She was referred to our hospital because her symptoms were not improved by antibiotic therapy at a clinic. At first presentation she showed cutaneous manifestations including heliotrope eyelids and mechanic's hands, slightly elevated serum creatine kinase (CK), elevated serum C-reactive protein level, and interstitial pneumonia (IP), which led to a diagnosis as dermatomyositis. After admission to our hospital, her hypoxia due to IP progressed despite disappeared myalgia and normalized serum CK level. Intravenous steroid pulse therapy followed by oral cyclosporine and intravenous cyclophosphamide pulse therapy was not effective for the IP for more than a month. Gastroscopy revealed superficial depressed (0-IIc) type early gastric cancer. However, it was out of indication for endoscopic mucosal resection because of the histopathologic type (signet ring cell carcinoma) and possible submucosal invasion. In addition to those immunosuppressive therapies, proximal gastrectomy with total intravenous anesthesia was performed. One month after the operation, improvement of IP as well as cutaneous manifestations was confirmed by respiratory function test, pulmonary computed tomography, and discontinuance of oxygen inhalation. We conclude that this was a case of clinically amyopathic dermatomyositis with rapidly progressive IP and gastric cancer, which was ameliorated by a combination of medication (steroid, cyclosporine, and cyclophosphamide) and surgery (gastrectomy for early gastric cancer).