Antonio Tonutti, Ilaria Cavazzana, Maria Gerosa, Francesco Caso, Maria De Santis, Francesca Trunfio, Andrew Barr, Vishal Kakkar, Kerem Abacar, Aamir Aslam, Letizia Pia Di Corcia, Tom Macleod, Ala Altaie, Dina Youssef, Md Yuzaiful Md Yusof, Sinisa Savic, Micaela Fredi, Francesca Crisafulli, Micol Frassi, Antonio Vitale, Addolorata Corrado, Franco Franceschini, Carlo Selmi, Roberto Giacomelli, Edward Vital, Piero Ruscitti, Dennis McGonagle
SLE-MAS diverged from SD-MAS with less organomegaly and liver injury but more pronounced CNS involvement and hematological involvement, the latter strongly linked to red blood cell directed autoantibodies. These findings indicate that SLE-MAS pathogenesis may be divergent and require distinct therapeutic approaches beyond extrapolation from SD-MAS.
OBJECTIVES: Macrophage activation syndrome (MAS) is a severe complication of Still's disease (SD-MAS), but may also, albeit rarely, complicate systemic lupus erythematosus (SLE-MAS). The clinical profile of SLE-MAS compared with SD-MAS remains unclear, as do the optimal treatment strategies.
METHODS: A retrospective multicenter cohort of adults with a history of SLE-MAS or SD-MAS was gathered from nine tertiary referral centers. MAS clinical/laboratory features, treatments and outcomes were compared; "inaugural MAS" was defined if occurring within 6 months from the onset of the underlying disease. exploratory multivariable profiling assessed for disease-specific features. The SLE-MAS group was also compared with large historical SLE cohorts to identify candidate risk signals.
RESULTS: While SD-MAS aligned with the prototypical hyperinflammatory pattern (more marked hyperferritinemia, very high CRP, organomegaly and liver injury; 100% meeting 2016 ACR/EULAR/PRINTO criteria), SLE-MAS (92% meeting criteria) more often featured CNS dysfunction, less liver injury, greater degree of cytopenias including anemia, with a strong signal of autoimmune hemolysis (73% direct Coombs [DCT] positivity). Therapeutically, IL-1 antagonism was used in 7 SLE-MAS with mixed results without any rapid MAS resolution. Mucocutaneous disease, autoimmune hemolysis, CNS involvement, less pronounced female preponderance and much higher DCT positivity dominated the SLE-MAS phenotype compared to historical SLE cohorts comprising 1000, 2228, and 2055 cases each.
CONCLUSIONS: SLE-MAS diverged from SD-MAS with less organomegaly and liver injury but more pronounced CNS involvement and hematological involvement, the latter strongly linked to red blood cell directed autoantibodies. These findings indicate that SLE-MAS pathogenesis may be divergent and require distinct therapeutic approaches beyond extrapolation from SD-MAS.