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Antisynthetase syndrome-associated interstitial lung disease — SCE Rheumatology MCQ

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ModerateMyositisAntisynthetase syndrome-associated interstitial lung diseaseSCE Rheumatology

A 32-year-old woman with anti-PL-12-positive antisynthetase syndrome has NSIP-pattern interstitial lung disease. She has received prednisolone 1 mg/kg/day and mycophenolate mofetil 1.5 g twice daily for 12 weeks. Her proximal muscle strength and creatine kinase have normalised, but exertional breathlessness is worsening and she now requires supplemental oxygen. Forced vital capacity has fallen from 61% to 46% predicted and transfer factor from 44% to 32% predicted. Repeat high-resolution CT shows increased bilateral ground-glass change without new established fibrosis. Bronchoalveolar lavage and extended microbiological testing are negative, and echocardiography shows no pulmonary hypertension. The specialist interstitial lung disease multidisciplinary team recommends immediate escalation to intravenous systemic therapy. She wishes to have children in the future and places a high priority on avoiding treatment that may cause irreversible ovarian failure. Which treatment is most appropriate?

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Correct answer: B — Initiate intravenous rituximab 1 g at weeks 0 and 2

This is severe, objectively progressive antisynthetase-associated ILD despite glucocorticoid and mycophenolate therapy. The worsening physiology, oxygen requirement and increasing ground-glass change support urgent escalation; improvement in muscle disease does not indicate control of the pulmonary manifestation. The BSR myositis guideline identifies rituximab or cyclophosphamide as options for severe or progressive IIM-associated ILD. RECITAL directly compared the proposed rituximab regimen with six four-weekly cyclophosphamide infusions in severe or progressive CTD-ILD, including idiopathic inflammatory myositis. Rituximab was not superior, but both groups improved FVC, and rituximab was considered a therapeutic alternative when intravenous therapy is required. Because cyclophosphamide may cause dose-dependent and potentially irreversible sterility, the patient’s reproductive priority makes rituximab the best choice. Cyclophosphamide remains a defensible induction agent but is not superior and carries the relevant gonadal toxicity. Intravenous immunoglobulin is useful for selected severe or refractory myositis manifestations, particularly muscle disease or dysphagia, but is not the RECITAL-supported alternative for this pulmonary presentation. Tacrolimus may be used in myositis-associated ILD, but oral calcineurin inhibition is a less appropriate next step after the stated decision for immediate intravenous therapy. Nintedanib targets progressive fibrosis and does not replace immunosuppression for worsening inflammatory ILD with increasing ground-glass change.

Reference: British Society for Rheumatology guideline on management of paediatric, adolescent and adult patients with idiopathic inflammatory myopathy (5 May 2022) — https://pubmed.ncbi.nlm.nih.gov/35355064/ Rituximab versus intravenous cyclophosphamide in patients with connective tissue disease-associated interstitial lung disease in the UK (RECITAL) (January 2023; published online 11 November 2022) — https://pubmed.ncbi.nlm.nih.gov/36375479/ Cyclophosphamide Injection 500 mg Summary of Product Characteristics (Text revised 7 June 2016; checked 19 August 2026) — https://www.medicines.org.uk/emc/product/1815/smpc