Systemic Lupus Erythematosus and Cytokine Storm

Systemic lupus erythematosus (SLE) is the prototype of autoimmune diseases and can manifest with a plethora of clinical signs and symptoms associated with a myriad of laboratory abnormalities. An infrequent but potentially lethal complication of SLE is macrophage activation syndrome (MAS). The diagnosis of MAS in SLE can be very challenging due to similarities in presentation of both flares and infections, such as fever, lymphadenopathy, splenomegaly, and cytopenias. These aggravating factors contribute to the increased risk of poor outcomes in SLE-associated MAS. Indeed, at the moment MAS remains invariably lethal if untreated and still has a high mortality rate with treatment. In this chapter, we discuss several aspects of MAS in the context of SLE and in particular, the pathogenesis of MAS in SLE, how MAS presents in pediatric versus adult SLE, and, finally, MAS treatment in SLE and future directions.