From the authors

We thank our colleagues for their letter, providing the opportunity to underline the interest in the relevant case study 1.

Until recently, it was not well recognised that interstitial lung disease in polymyositis patients with anti-Jo-1 can present an acute onset with a severe outcome, as recently reported 2, 3.

Acute respiratory distress syndromes respond to a physiological definition, which does not always present in connection with diffuse alveolar damage but can be related to other processes. In our case report, we show an acute respiratory distress syndrome (ARDS) due to a nonspecific interstitial pneumonitis (NSIP), proven by an open lung biopsy. If an ARDS is properly diagnosed by such specific examinations, a more specific therapy may be applied. In our case, the presence of anti-Jo-1 antibodies with a predominant CD8 cellular NSIP and myositis allowed a precise diagnosis.

As shown in our study, this entity is corticosteroid sensitive but such treatment is often insufficient and makes an additional therapy with immunosuppressors necessary 2. Cyclophosphamide is still frequently recommended, despite its partial efficiency and high toxicity limiting its use beyond 6–12 months. Our case report underlines again the usefulness of calcineurin inhibitors in this T-cell-mediated disease, which has also been demonstrated previously 3, 4. The toxicity of these drugs, in particular of tacrolimus, is limited if drug monitoring is performed as it is in transplantation 5, currently allowing rather well-tolerated treatments for >10 yrs. The rapid improvement of gas exchanges and myositis should allow challenge of the concept that calcineurin inhibitors do not act quickly in settings where the cellular NSIP has not yet been followed by an irreversible lung fibrosis. A long-term improvement has previously been described in 13 patients with severe interstitial diseases 3, who did not respond to more classical immunosuppressors. In these cases, early treatment with tacrolimus is suggested before lung fibrosis is established and we can propose monitoring of the blood while levels of the drug are between 5 and 10 ng·mL⁻¹, in order to optimise the long-term incidence of side effects 5.

In our case and that reported by Wilkes et al. 3, low dose steroids and tacrolimus were applied without using other immunosuppressive drugs in order to avoid opportunistic infection. According to Wilkes et al. 3, patients received this treatment for an average duration of 51 months. Our patient returned abroad and follow-up was lost after 8 months of successful treatment. In our clinic, such good and long-term follow-up has been experienced in further cases but has not yet been published.

Statement of interest

None declared.