What is hemophagocytic lymphohistiocytosis?
Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder in which the immune system becomes overactivated and attacks normal cells within the body, including the liver, the spleen, and the tissues that create blood cells. In HLH, the immune system produces too many of several kinds of the cells that normally attack bacteria and other invaders.
There are two kinds of HLH. Primary HLH is a condition that a person is born with and is passed down through families. Secondary HLH can develop after a very severe infection, such as Epstein-Barr virus (EBV) or some types of cancer.
Our approach to HLH
The diagnosis of HLH is based on multiple factors, including fever, enlarged spleen, and blood tests that show certain abnormalities in blood cell counts and other irregularities in blood chemistry.
The treatment of HLH includes chemo-immunotherapy, which combines chemotherapy medicines with medicines that trigger immune response to attack the abnormal cells in more than way.
In patients who have primary HLH, or severe HLH that has not responded to medication therapy, a procedure called hematopoietic stem cell transplantation (HSCT) is also recommended.
Management of HLH is challenging as children tend to be very sick. Other than our team, we have physicians in the pediatric intensive care unit dedicated to the management of the many immune system signals (called the “cytokine storm”) associated with HLH. Our genome sequencing team can analyze defects at the level of the genes to quickly guide the team in deciding which therapy is appropriate.