What is Histiocytosis?
Histiocytosis is a rare oncological and hematological disease that mainly affects children, but can also affect adults. The disease was first introduced in the medical literature in 1868 by Paul Langerhans (1847-1888) and is essentially caused by an excessive concentration of mast cells – a class of cells that help destroy foreign elements and fight infection.
Histiocytosis is also known as Histiocytosis-X, Eosinophilic granuloma, Hand-Schuller-Christian syndrome, Hashimoto-Pritzker syndrome, and Letterer-Siwe disease. The international medical community, including Friends of the Artemis Association, are taking steady steps towards investigating the pathogenesis of the disease.
Symptoms
Possible symptoms include: skin rash; bone legions; lung, liver, or spleen dysfunction; loose/falling teeth; swollen gums; chronic ear conditions/discharge; vision problems; and swelling of the eyes.
The disease can also affect the central nervous system, causing an inability to move, complete paralysis, excessive thirst/urination, diabetes insipidus, or difficulty with memory/learning/ communication.
General symptoms can be fever, weakness, insufficient weight gain, lack of muscle strength or growth.
Diagnosis
The diagnosis of the disease is usually made after a biopsy and microscopic examination of the affected tissue, which can be skin, bones, glands, etc.
A patient may have limited involvement in one or more parts of the body. Usually, the disease is more severe when it occurs in infants or when several parts of the body are affected.
To determine the extent of the disease, various other tests must be done, such as blood tests, chest X-rays, bone scans and CT scans. A liver biopsy or bone marrow extraction (myelogram) is also done.
Treatment
Treatment depends on each individual patient. In some cases the disease resolves without any treatment. In other cases, doses of radiation or chemotherapy are recommended depending on the extent of the disease. Treatment is planned after a detailed and continuous monitoring of the patient to determine at each stage the extent of the disease and the performance of each treatment.
The goal of a comprehensive treatment plan is to use as little treatment as possible to keep the disease under relative control and allow the body to heal itself.
Research & Publications
Our organization has been a catalyst for research. Over the years, our Symposia have originated concepts and examined numerous questions, spurring advances in the quest for a cure. The clinical and pathological features of the disease are much better understood today because of this research and the dedicated work of scientists, researchers, clinicians, and other non-profits around the world.
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Dr. Cheryl Willman conducted tests and proved that, contrary to the earlier prevailing opinion, Langerhans Cell Histiocytosis (LCH) is a neoplastic process rather than a reactive disorder. Although the biological significance of the detection of clonality was not fully understood at the time, Willman’s data suggested that LCH may be a clonal neoplastic disorder with highly variable biological behavior and clinical severity. This discovery provided clear directions for studies that were further undertaken to understand more fully the biological and clinical significance of clonality in LCH.
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The “dendritic cells” – named after their tree-like shape – were discovered by Dr. Steinman (Nobel Prize in Physiology or Medicine) while conducting research on the production of antibodies in his lab in the ‘90s. Dendritic cells are the main T cell-stimulating cells. Immature dendritic cells lay in hibernation and are activated as soon as they take their first antigen stimulus. Dr. Steinman further discovered that not only do those cells train T cells how to fight foreign antigens/ intruders but also that they train T cells to tolerate harmless self-antigens.
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BRAF is a human gene that encodes a protein called B-Raf. It is involved in sending signals to cells involved in directing cell growth and is shown to be mutated in some human cancers. In 2011, it was discovered that about half of the patients suffering from Histiocytic diseases have a mutation in the BRAF gene. Based on this pivotal discovery, international studies have been conducted treating patients with a medicine that blocks this BRAF mutation.
Types of Disorders
Histiocytosis disorders differ in their symptoms, method of diagnosis, and recommended treatment. The Histiocytosis Association – an international non-profit organization dedicated to the special needs of people with the disease and their relatives – has categorized the disorders of these diseases. We thank them for providing us with this information to share with you.
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Hemophagocytic Lympho- histiocytosis
HLH is a disorder of the immune system that mainly affects young infants and children and can be hereditary or associated with infections, viruses, autoimmune diseases and malignancies.
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Diabetes Insipidus
DI can occur as a consequence of histiocytosis involving the pituitary gland. Although they have similar symptoms, it is different than diabetes mellitus, which results from too much sugar in the blood.
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Juvenile Xantho-granuloma
JXG is usually benign and self-limiting. It occurs most often in the skin of the head, neck, and trunk but can also occur in the arms, legs, feet, and buttocks. In young children it can affect the eye and cause skin lesions.
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Erdheim-Chester Disease
This involves the excessive production of histiocytes, a type of white blood cell. Instead of helping to fight infection, they gather in different organs and tissues and cause numerous ailments, including organ failure.
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Rosai-Dorfman Disease
RD, also known as sinus histiocytosis, involves the over-production of a type of white blood cell called non Langerhans sinus histiocyte. These cells then accumulate, most often in the lymph nodes and can lead to organ damage.