Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal condition in which certain white blood cells (histiocytes and lymphocytes) build up in and damage organs, including the bone marrow, liver and spleen, and destroy other blood cells. It most commonly affects infants and young children. In addition, certain aspects of immune function, such as natural killer cell and cytotoxic T-cell activity, are abnormal in HLH. While HLH is not cancer, certain cancer treatments, including chemotherapy, can be used to treat it.
HLH may be inherited (familial) or caused by another condition (secondary), such as infection. Familial HLH usually affects children under 1 year of age, while the secondary form typically occurs after age 6. A genetic cause is identified in most, but not all, cases of familial HLH.
Children with HLH are treated at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center through our Histiocytosis Program. Continue reading to learn more about hemophagocytic lymphohistiocytosis or visit the Histiocytosis Program homepage to learn about our expertise and treatment options.
The symptoms of HLH include:
Children with HLH
may also have central nervous system symptoms, including headache,
irritability, sleepiness, or seizures.
diagnose HLH with:
HLH may be fatal if
untreated. Rapid diagnosis and early therapy are key. The most common
Familial HLH is fatal without treatment, with median survival of about
two to six months. Chemotherapy and/or
immunotherapy temporarily control the disease, but symptoms inevitably return. Stem cell transplant is the only way to cure
familial HLH. The five-year survival
rate for children who have undergone a stem cell transplant is 66 percent. Infections, especially fungal infections, are
an important cause of death in children with HLH.
Secondary HLH can be effectively treated with
chemotherapy and/or immunotherapy medications. Stem cell transplant is not necessary in most cases of secondary
HLH. However, children without a known
genetic cause for the HLH who experience progressive or recurrent disease are
candidates for stem cell
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