In recent years, endothelin receptor antagonism has emerged as an important therapeutic strategy for pulmonary arterial hypertension (PAH). Bosentan, an orally active endothelin receptor antagonist, has proved to be effective in primary PAH or PAH related to connective tissue diseases.^1–3

Of 18 patients with PAH related to systemic sclerosis (SSc) treated with bosentan at our division of rheumatology during the past 2 years, two were also affected by rheumatoid-like arthritis before starting bosentan. We here report the clinical course of these two cases.

The first patient, a 55 year old woman, with SSc since 1988, developed a non-erosive polyarthritis affecting the hands, knees, and ankles, with positive rheumatoid factor (RF; 585 U/l) in March 2002. The second patient, a 57 …