(HLH) is a rare aggressive disease due to ecessive activation of the immune system. It primarily affects infants and young children. It can also happen to adults.Different conditions, including bacterial infections or viral infection like Dengue fever and cancer can cause HLH.
When you have HLH, your body's defence system, known as the immune system, does not function normally. Histiocytes and lymphocytes, two types of white blood cells, attack your other blood cells. These abnormal blood cells build up in your spleen and liver, causing them to swell.
Because HLH is a rare disease, caused by over activation of the immune system. HLH is classified into two types: familial or primary and acquired or secondary. Some individual has genetic predisposition to develop Familial HLH , which accounts for approximately 25% of cases, and the condition is passed down through families. A variety of conditions can result in acquired or secondary HLH. These are some examples: cancer, viral infections like Dengue fever, Epstein Barr virus infection (EB virus), bacterial infections, immune system diseases etc.
The most common symptoms of HLH are fever ,spleen enlargement and low hemoglobin and low platelet count ( any two cell lines will be low, either haemoglobin, white blood cells or platelet count). There are numerous other possible symptoms, such as:
Your healthcare provider will make a diagnosis of HLH based on your symptoms, physical exam findings, and the results of several lab tests. Persistent fever is a fairly common symptom. Key physical findings include an enlarged liver or spleen (located in the upper left side of the abdomen). Blood tests are performed by your healthcare provider to look for:
A bone marrow biopsy is another important test that involves taking a sample of your bone marrow (the centre of the bone where blood cells are made) and examining it under a microscope. Other tests that may be performed include genetic testing and blood cultures, which are blood samples that are used to look for infection in your blood.
The familial HLH needs a hematopoietic stem cell transplant, commonly called as Bone marrow transplantation.. Healthy bone marrow cells from a donor are used to replace your diseased bone marrow cells in this procedure. In most cases, a stem cell transplant can cure HLH.
There is no way to prevent HLH, but treatment is improving as healthcare providers learn more about it. Most successfully treated children go on to lead normal lives. If not treated at right time HLH can be life threatening.