First report of macrophage activation syndrome in hyperimmunoglobulinemia D with periodic fever syndrome.

We describe for the first time a case of macrophage activation syndrome in a child with hyperimmunoglobulinemia D with periodic fever syndrome who required intensive care support. Up-regulated monokine production, high serum levels of triglycerides and ferritin, clotting abnormalities with hypofibrinogenemia, and rapidly evolving pancytopenia should alert the clinician to the possible diagnosis of macrophage activation syndrome, even in autoinflammatory diseases characterized basically by the periodic recurrence of unprovoked inflammatory attacks. Bone marrow aspiration showing well-differentiated macrophages phagocytosing hematopoietic elements remains the main tool for a final diagnosis, and cyclosporine is the best strategy for treatment.