Relapsing polychondritis (RPC) is an uncommon but often life-threatening multisystem disease characterised by recurrent or persistent inflammation of cartilaginous tissues, with no known consistently efficacious treatment.1 A T cell-predominant autoimmune aetiology has been implicated.2 Abatacept is a costimulation modulator that suppresses T cell activity, and one report has suggested that abatacept may be efficacious in one case, but did not present disease endpoints.3 We report here our experience with abatacept in four subjects with RPC, which was performed in the context of a small open-label study (NCT01272856).

Key clinical characteristics of the subjects, all meeting the Michet criteria for RPC,4 are shown in table 1. Written informed consent was obtained from all subjects. Abatacept 125 mg subcutaneously weekly was planned to be administered for 24 weeks, but two subjects discontinued early: subject 001 developed worsening pulmonary and neurological disease and discontinued at …