What is FLH/HLH?
HLH stands for Hemophagocytic Lymphohistiocytosis and is a rare disorder mainly affecting children at an early age. The illness consists of the malfunctioning of the hystiocyte, one of the primary cells to fight infections. Bone marrow produces these cells that then travel throughout the body to fight infections and destroy foreign material.
FLH/HLH patients have overactive histiocytes and lymphocytes, which are white blood cells that can cause swelling, redness, heat, pain and malfunction/damage of organs when they attack and accumulate on healthy lymph tissue (eg: Liver, Spleen, lymph nodes). There are two forms of HLH: 'Familial' and 'Secondary', both require Chemotherapy treatment but:
1) Familial FLH/genetic HLH is the worst of the two. Often young age onset is an indicator of FLH, however exceptions exist. If FLH, there is a 25% chance of other siblings having the same illness. The danger of FLH resides in the necessity of a bone marrow transplant in order for the patient to be cured.
2) Secondary HLH is none genetic and presents itself when the body's immune system goes into overdrive following a major infection. Secondary HLH is treated with more relative ease than FLH as although Chemo is required, generally following treatment the underlying infection is cured and no bone marrow transplant is needed.
Because the disease is relatively new from a research prespective (1985) and causes as well as symptoms are still being discovered, many cases go undiscovered (or too late) and lead to fatality for the patient. It is important to catch the illness early!
For more information on HLH, please see the Cincinnati Children's Hospital, the Histiocytosis Association of America, and the Icla da Silva Foundation.