The clinical heterogeneity of adult onset Still’s disease may underlie different pathogenic mechanisms. Implications for a personalised therapeutic management of these patients

Adult-onset Still's disease (AOSD) is a rare inflammatory disease of unknown aetiology usually affecting young adults and manifesting with a clinical triad of spiking fever, arthritis, and evanescent cutaneous rash. AOSD may be considered a highly heterogeneous disease, despite a similar clinical presentation, the disease course may be completely different. Some patients may have a single episode of the disease whereas others may evolve toward a chronic course and experience life-threatening complications. On these bases, to dissect the clinical heterogeneity of this disease, four different subsets were identified combining the manifestations at the beginning with possible diverse outcomes over time. Each one of these derived subsets would be characterised by a prominent different clinical feature from others, thus proposing dissimilar underlying pathogenic mechanisms, at least partially. Consequently, a distinct management of AOSD may be suggested to appropriately tailor the therapeutic strategy to these patients, according to principles of the precision medicine. These findings would also provide the rationale to recognise a different genetic and molecular profile of patients with AOSD. Taking together these findings, the basis for a precision medicine approach may be suggested in AOSD, which would drive a tailored therapeutic approach in these patients. A better patient stratification may also help in arranging specific designed studies to improve the management of patients with AOSD. Behind these different clinical phenotypes, distinct endotypes of AOSD may be suggested, probably differing in pathogenesis, outcomes, and response to therapies.