Interstitial lung disease associated with systemic lupus erythematosus : a monocentric study of 23 cases

Chronic interstitial lung disease (ILD) occurs rarely in systemic erythematous pneumonia (SLE) compared to other connective tissue disease. The aim of the study was to describe the clinical, biological, and radiological presentation of SLE-ILD, as well as the treatment and survival. We conducted a monocentric retrospective study of ILD associated with SLE (SLE-ILD) from january 2005 to december 2020. We retrieved 23 patients with SLE-ILD (21 women, 91%) (median age at SLE diagnosis : 34 years, [13-87]). Seventeen patients (78%) had another connective tissue disease (CTD) associated with SLE : Sjogren’ syndrom (n = 10), polymyositis (n = 3), systemic sclerosis (n = 3) and rheumatoid arthritis (n = 1), and 5 patients had other autoantibodies associated with SLE without specific criteria for another CTD : Anti RNP (n = 4), Anti SSA (n = 3), Anti Ku (n = 1). ILD was diagnosed alongside with SLE in 9/23 cases or after a median time of 36 months after the SLE diagnoses. The HCT patterns were : non specific interstitial pneumonia (NSIP) (n = 10), indeterminate (n = 6), usual interstitial pneumonia (n = 3), cystic lung disease (n = 2), NSIP with organizing pneumonia (n = 1). All patients showed restrictive syndrome: TLC (67% [57-75]), FVC (71%, [64-100]), DLCO (52%, [26-70]). Patients received steroids (n=20) combined with rituximab (n = 11), cyclophosphamide (n = 9), or mycophenolate-mofetil (n = 7). After a median follow-up of 6,2 years, 7 patients died from ILD (median 16 years) and 3 patients received lung transplantation (7, 14 and 16 years). ILD is a rare but severe manifestation of SLE. SLE is then frequently associated with another connective tissue disease in this study.