Hemophagocytic Lymphohistiocytosis (HLH)

What is hemophagocytic lymphohistiocytosis?

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease of the immune system that sees lymphocytes and histiocytes attack the other blood cells. There are two forms: primary and secondary. 

What are the symptoms of hemophagocytic lymphohistiocytosis?

Symptoms of this condition include:

• Enlargement of the spleen and/or liver
• Fever
• Skin rashes
• Jaundice
• Swollen lymph nodes
• Issues with the digestive system
  • Vomiting, diarrhea, stomachaches
• Coughing
• Difficulty breathing
• Issues with the nervous system
  • Weakness, headaches, visual disturbances, and trouble walking

Very young children or babies may experience additional symptoms, such as a failure to thrive and irritability. 

What causes hemophagocytic lymphohistiocytosis?

The cause of HLH depends on which type one is impacted by. Primary HLH is a genetic, inherited condition that is passed down in an autosomal recessive pattern. It accounts for about a quarter of all cases. 

Secondary HLH is the result of another condition or outside factor. Possible causes of secondary HLH include but are not limited to cancer, viral infections, a diseased or weakened immune system, and other forms of infection. 

How is hemophagocytic lymphohistiocytosis diagnosed?

Doctors will first perform a physical exam and look for the characteristic symptoms. This is followed by lab tests, such as blood tests, blood cultures, bone marrow biopsy, and genetic testing. 

What are the treatments for hemophagocytic lymphohistiocytosis?

Treatment for HLH is tailored to each patient based on their age, overall health, the type of HLH they have, and disease severity. Treatment is extremely necessary for primary HLH, as it can be fatal without it. Options for this form include chemotherapy, steroids, and immunotherapy. These options, along with antibiotics and antiviral drugs, are also for persistent secondary HLH. Otherwise, doctors treat this form by addressing the other condition that’s causing HLH. If none of these options work, a stem cell transplant is the last option. 

Where can I find out more about hemophagocytic lymphohistiocytosis?

• • Johns Hopkins
  • Cincinnati Children’s Hospital
  • Immune Deficiency Foundation