Macrophage activation syndrome (MAS) is the term used for hemophagocytic lymphohistiocytosis that occurs in people with an autoimmune or autoinflammatory disease. This is a type of secondary HLH. The diseases most commonly associated with MAS are juvenile systemic arthritis, adult-onset Still’s disease, and systemic lupus erythematosus.

https://rarediseases.org/rare-diseases/hemophagocytic-lymphohistiocytosis/