Serosal involvement in adult-onset Still's disease: A multicentre and retrospective study

Objectives This study evaluated the characteristics of serosal involvement in adult-onset Still's disease (AOSD). Methods Patients meeting the Yamaguchi classification criteria were classified into AOSD with and without serosal involvement according to their manifestations and sonography/radiography. Clinical data was retrospectively reviewed from 102 patients with AOSD in two centres. Results Forty-two patients (41.2%) had serosal involvement. The frequencies of pulmonary infiltrate and impaired liver function were significantly higher in patients with serosal involvement (p = .002 and p = .007, respectively), who also had a higher modified systemic score (p = .009). In addition, the percentages of CD3(+) T cells (p < .001) and, especially, the CD8(+) T cells (p = .004) were significantly increased in the peripheral blood of AOSD patients with serosal involvement. Notably, patients with serosal involvement were more likely to develop macrophage activation syndrome (p = .047) and a chronic pattern (p = .016) during the follow-up. Conclusions Patients with serosal involvement demonstrated the more severe disease activity and different immune phenotypes; these patients were more likely to develop macrophage activation syndrome, and they may require more aggressive treatment at an early time to control their systemic inflammation.