Anti-Jo1 Syndrome: Understanding a Rare Cause of Interstitial Lung Disease

Anti-Jo1 syndrome is one of the most common amongst the various anti synthetase syndromes (ASS), which forms a subgroup of the idiopathic inflammatory myositis (IIM). It is characterised by myositis, interstitial lung disease (ILD), fever, Raynaud's phenomenon, and mechanic's hands; associated with the presence of anti-Jo1 antibodies in serum. Being an orphan disease, the clinical diagnosis is often delayed.

In this retrospective study, all patients diagnosed as Anti-Jo1 syndrome, from two tertiary care hospitals in Western Maharashtra, between 01 January 2019 - 31 December 2020, were enrolled. The parameters studied included demographic data, clinical features at presentation, laboratory parameters, spirometry, and radiographic findings, along with treatment instituted.

A total of 17 patients (8 males, 9 females) qualified for inclusion in the study. The mean age of diagnosis was 40 (±13) years with mean time to diagnosis being 2 years (± 0.6 years), from first clinical presentation. The most common presenting symptoms encountered were arthritis (n = 12, 70.5%), fever (n = 16, 70.5%), myositis (n=11, 64.7%) and breathlessness (n=10, 58.8%).10 patients had ILD at presentation on high resolution computerised tomography of chest (n=10, 58.8%) with restrictive lung defect on spirometry. Six patients required induction of immunosuppression using pulse methylprednisolone (n=6) and Rituximab (n=6), while 11 were managed with oral steroids. Mycophenolate mofetil (n=10) and Azathioprine (n=7) were used as maintenance immunosuppression.

Anti-Jo1 syndrome is a myositis syndrome, presenting with a multitude of clinical features. Steroids and disease modifying anti rheumatic drugs form mainstay of therapy.