title: Hyperinflammation, rather than hemophagocytosis, is the common link between macrophage activation syndrome and hemophagocytic lymphohistiocytosis.
abstract: OBJECTIVE
  Macrophage activation syndrome is the rheumatic disease-associated member of a group of hyperinflammatory syndromes characterized by uncontrolled cytokine storm. In this review, we highlight recent publications related to the pathoetiology of hyperinflammatory syndromes with an emphasis on how this new knowledge will guide our diagnosis, treatment, and future research efforts to better understand these deadly conditions.
  
  
  RESULTS
  The heterogeneity of clinical manifestations seen in patients with hyperinflammatory syndromes continues to grow as novel genetic and immunotherapeutic triggers of cytokine storm have been identified. Recent studies characterize unique cytokine and gene expression profiles from patients with different hyperinflammatory syndromes, whereas novel murine models begin to define networks of immune dysregulation thought to drive excessive inflammation in cytokine storm.
  
  
  CONCLUSIONS
  Emerging evidence suggests hypercytokinemia is the driving cause of immunopathology and morbidity/mortality in hyperinflammatory syndromes. Therefore, approaches to block cytokine function may be fruitful in treating hyperinflammatory syndromes with less toxicity than current therapies. However, not all hyperinflammatory syndromes result in the same pathogenic cytokine profile, implying that a personalized approach will be required for effective use of anticytokine therapies in the treatment of hyperinflammatory syndromes.
authors.affiliation: Division of Pediatric Rheumatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Lehn K
authors.initials: LK
authors.lastname: Weaver
authors.forename: Edward M
authors.initials: EM
authors.lastname: Behrens
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D051359:Lymphohistiocytosis, Hemophagocytic / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D055501:Macrophage Activation Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D051379:Mice; D010587:Phagocytosis
chemical_list: D000911:Antibodies, Monoclonal; D016207:Cytokines