Langerhans cell histiocytosis (LCH) is a rare disorder that primarily affects children.  The disease was first described in medical literature around the turn of the 20th century. 

A histiocyte is a form of white blood cell.  Its job is to help destroy certain foreign materials and fight infection.  For unknown reasons, patients with this disease have too many histiocytes (Langerhans cells).  These cells accumulate in different organs and can result in a variety of symptoms.

The Histiocytosis Association works closely with an international group of physicians, known as the Histiocyte Society, who are dedicated to studying the histiocytic disorders.  Through this partnership more has been learned and better treatments have been discovered.

Langerhans cell histiocytosis has also been known as Histiocytosis-X, Eosinophilic Granuloma, Letterer-Siwe disease, and Hand-Schuller-Christian Syndrome.

There are also a number of other terms which have been used to describe syndromes which are considered to be Langerhans cell histiocytosis (LCH).  These include: Reticuloendotheliosis, Hasimoto-Pritzker syndrome, Self-healing histiocytosis, Pure cutaneous histiocytosis, Langerhans cell granulomatosis, Type II histiocytosis, and Non-lipid reticuloendotheliosis.

The cause of LCH is unknown.  It may be triggered by an unusual reaction of the immune system from something commonly found in the environment.  It is not a known infection or cancer.  It is not known to be hereditary or communicable.

Over the years, cancer treatments have been used in patients with histiocytosis. Consequently, hematologists and oncologists, who treat cancer, also treat children with Langerhans cell histiocytosis.  However, the disease is not cancer.  Chemotherapy, if used, is given in much lower doses than that which cancer patients receive. 

The vast majority of patients will survive the disease.  Some may develop life-long chronic problems, while others remain symptom free.  In some cases the disease is fatal.  Usually these are very young infants who have a rapid downhill course and do not respond to any known treatment. Whether or not the disease responds to treatment will often depend on the extent of organ involvement; however, it is often difficult to make definite predictions. Physicians will be able to discuss the patient's likelihood of responding to treatment and doing well.

It is estimated that 8.9 of every 1,000,000 children under the age of 15 have histiocytosis. Seventy-six (76) percent of the cases occur before ten (10) years of age, but the disease is also seen in adults of all ages.

National Cancer Institute Summary on LCH

Fantastic News!!!!

We are thrilled to inform you that the National Cancer Institute (NCI) at the U.S. National Institutes of Health has published an important summary of current knowledge about Langerhans cell histiocytosis (LCH) on its website.

LCH-IV Treatment Protocol Study Update

The HAA is pleased to provide the following update regarding the status of the LCH-IV Treatment Protocol Study. 
 
In designing the study, the Histiocyte Society Executive Board and study co-chairs Drs. Carlos Rodriguez-Galindo and Milen Minkov took a more ambitious approach than those used in previous histiocytosis clinical trials. Whereas past trials have been focused on evaluating the effectiveness of standard front line treatment methods, the LCH-IV Study will incorporate multiple salvage alternatives in addition to the front line treatment. This approach of combining multiple treatment modalities and research objectives in one protocol adds significant complexity to the study design; few studies in medical research have used this approach, making its introduction an important milestone in the field of histiocytosis research.
 
In this highly sophisticated study, patients with newly diagnosed LCH will initially be enrolled on the front line treatment protocol. Patients who experience reactivations of their disease will then be enrolled on the appropriate salvage treatment protocols included within the study. These salvage options – designed as independent treatment protocols – include low-risk, high-risk, and bone marrow transplant. As well, the study’s investigators have integrated an analysis of the long term effects of LCH and its treatment experienced by patients into the entire trial. The primary focus of this research will be to understand the risk factors for the development of neurodegeneration and neuroendocrine deficits, devise early diagnostic tools, and provide effective treatments. 
 
Because of its comprehensive design, this study will allow researchers to evaluate the effectiveness of five protocols for the treatment of LCH and examine a variety of important questions related to the study’s findings. As the field of medical research is currently subject to increasingly stringent regulatory requirements, the study’s investigators intend for its comprehensive structure to result in the participation of a higher number of institutions, an increase in the amount and quality of data generated, and the study’s overall success. While its launch has been delayed slightly due to the complexity and originality of its design, the study’s primary investigators intend for it to be finalized and opened in advance of the Histiocyte Society Annual Meeting, which will take place in Boston, Massachusetts in October 2010. 
 
The study’s investigators commend the staff of the Children's Cancer Research Institute in Austria, Vienna, led by Dr. Milen Minkov, for their extraordinary efforts in finalizing the study’s document and database for its impending launch. The final version of the protocol will be circulated for review to participating researchers within the next two months.
 
The study’s authors express their appreciation to the HAA for supporting this important initiative.