Macrophage activation syndrome characterized by all except
Hemophagocv_c Lymphohis_ocvtosis
o Hemophagocytic lymphohis_ocytosis (HLH) is a reactive condition marked by cytopenias and signs and
symptoms of systemic inflammation related to macrophage activation. For this reason, it is also
sometimes referred to as macrophage activation syndrome. Pathogenesis  The common feature of all forms of HLH is systemic activation of macrophages and CD8+ cytotoxic T Cells,
 The activated macrophages phagocytose blood cell progenitors in the marrow and formed elements in
the peripheral issues, while the “stew” of mediators released from macrophages and lymphocytes
Suppress hematopoietic and produce symptoms of systemic inflammation.
 These effects lead to cytopenias and a shock-like picture sometimes referred to as “cytokine storm” or
The systemic inflammatory response syndrome.
 Familial forms of HLH are associated with several different mutations, all of which impact the ability of
Cytotoxic T cells and NK to properly form or deploy cytotoxic granules,
 The most common trigger for HLH is an infection, particularly with Epstein-Barr virus (EBV).
Clinical Features
o Most patients present with an acute febrile illness associated with splenomegaly and hepatomegaly,
o Hemophagocytosis is usually seen on bone marrow examination, but is neither sufficient nor required to
Make the diagnosis.
 Laboratory studies typically reveal anaemia, thrombocytopenia, and very high levels of plasma functional and
Soluble IL-2 receptor, both indicative of severe inflammation, as well as elevated liver function tests and
Triglyceride levels, both related to hepatesises.
o Coagulation studies may show evidence of disseminated intravascular coagulation. If untreated, this A picture can progress rapidly to multiorgan failure, shock, and death.
Treatment Involves the use of immunosuppressive drugs and “mild” chemotherapy.
Parents with germline mutations that cause HLH or who have the persistent resistant disease are candidates for hematopoietic stem cell transplantation.
Without treatment, the prognosis is grim, particularly in those with familial forms of the disease, who typically survive for less than 2 months.
Activation of CD 8 + T cells
Low levels of plasma ferretin
Presence of cytokine storm
It is the other name for hemophagocy