Pulmonary arterial hypertension in adults with Still's disease: another pulmonary manifestation associated with HLA-DRB1*15.

Objectives: Inflammatory lung disease in Still's disease (SD) has recently been described. Among its manifestations, pulmonary arterial hypertension (PAH) is a rare and life-threatening event, with only a few case reports published. The objective was to report the largest adult cohort of PAH occurring in the context of SD.

Methods: We identified 16 adult SD patients with PAH (PAH+) by a call for observations from the CRI-IMIDIATE (Club Rhumatismes & Inflammation - Immune-Mediated Inflammatory Disease Alliance for Translational and Clinical Research) network (https://cri-net.com/recherche/reseau-CRI-Imidiate/) and a search of the French pulmonary hypertension network registry. Patient characteristics and disease evolution were retrospectively compared with those of 111 SD controls without PAH (PAH-) followed in a reference centre.

Results: The profile of patients in the PAH+ and PAH- groups differed: 100% versus 69.4% female (P = .006), 75% versus 17.1% Black (P < .0001), more active SD both at diagnosis and throughout the disease course, and more likely to present macrophage activation syndrome (62.5% vs 14.4%, P < .0001) and exhibit eosinophilia during the disease course (68.7% vs 7.2%, P < .0001). For the 84 out of 127 patients with genetic typing, the HLA-DRB1*15 allele was more prevalent in PAH+ than PAH- patients (8/11 [72.7%] vs 22/73 [30.1%], P = .014). PAH+ patients more frequently received canakinumab and immunosuppressants than did PAH- patients and had higher frequency of drug reactions to interleukin 1 (IL-1) and/or IL-6 inhibitors (37.5% vs 7.2%, P = .002). Mortality was higher in PAH+ than PAH- patients (37.5% vs 0.9%, P < .0001), and all deaths were related to SD flare.

Conclusions: These results reinforce the association between the HLA-DRB1*15 allele and severe forms of SD and raise the question of therapeutic optimisation in such patients.