Q&A: What is Histiocytosis?

see also, Dr. McClain's video lectures on histiocytosis

Articles about Histiocytosis

Langerhans cell histiocytosis (LCH)

(Histiocytosis X, eosinophilic granuloma) 
Articles on LCH in children 
Articles on LCH in adults

Hemophagocytic Lymphohistiocytosis (HLH)

(familial erythrophagocytic lymphohistiocytosis (FEL), virus-associated hemophagocytic syndrome (VAHS) 
Articles on HLH

Sinus Histiocytosis with Massive Lymphadenopathy

(Rosai-Dorfman Syndrome)


Hi, my name is Dr. Ken McClain. I am a pediatric hematologist/oncologist at Texas Children's Cancer Center in Houston,Texas and the Clinical Director at the Histiocytosis Program.

Hi I am Carl Allen. I'm also hematologist/oncologist at Texas Children's Cancer Center and the Scientific Director of the Histiocytosis Program. I work with Ken Mcclain.

Histiocytosis is a disease in children that attacks white blood cells it's part of the immune system supposed to pick up information and pass the information on to another cell. The immune system call the lymphocyte together they make a response to and immunization a German for cancer cell. Histiocytosis is a general term for several diseases. up these white blood cells called his two sides and the issue cells have it the ability to change their I'll form and their function and and look differently in different the in these different diseases but just as a general class Histiocytosis are diseases where there are too many the cells along with some other cells collected in someplace nobody in causes the disease the estimate is that near between 5 to a per million children affected by his two sons buyout Langerhan's Cell Histiocytosis—that's the most frequent [type of hisytiocytosis].

The second most frequent [type of Histiocytosis] is hemophagocytic lymphohistiocytosis. We saw Rachel age an instance there's between one and two per million the his CC diseases are most frequently seen and children from birth to 6 years of age but can be a at any the most frequent is longer on cell Histiocytosis next is hemophagocytic when for his to use a dose is Rachel age there's juvenile xanthogranuloma JXT recite orphan disease RTD and finally I heard Manchester disease do September avail ch can look like a lot f different things it can be a simple skin rash that just won't go away am there can be bone lesions and some children may complain a bone pain LCH can attack a part of the brain called the pituitary that controls thirst and so some children I will come to us because they they can stop drinking are they lose the ability concentrate their year-end start wetting the bed when I never went to bed before I get all these things are sometimes that are part of much more common pediatric illnesses and really requires a pediatrician to think about when common treatments don't work much the next happening in the next step is to do a biopsy what to do imaging d do a biopsy to make their final diagnosis with a chill age children and I typically have a fever and that the fever quickly progresses to something beyond the normal illness where they get multi-system organ failure in a short period of time I'm really 1808 is the body has a 'em the normal child has a response to to a trigger to inflammatory trigger for the immune system mount an attack and then it goes away once the problem is solved financial age the main system gets revved up and never shuts itself off am and immune system then goes on to attack to organs of the body leading to basically what we call pathologic information and you require immune suppression medication to take care %uh oftentimes parents were asked us what caused LCH we don't know it's really do understand it as a dysregulation at the immune system but there have been no infections knowing environmental factors I really no strong connection with anything outside the bonior inside the body there's same very interesting correlation that many patientsm have family members with thyroid disease and we don't understand what that means but I think it tells us something about the immune system being a little bit on a balance in back to curtail the way we approach treating LCH arm is similar to the way we treat other I'm childhood cancers and related illnesses which is to take the experience a cooperative International Group the best published tentative care so the Histiocytes Society. Over the last 30 years or so is collected experiences from around the world and compared outcomes in children with different I'm treatment strategies so we use protocols that are pretty standard to start their the based on this, to cite the published data where things get tricky is when patients and don't respond well to the best published data and that's what we try to do at Texas Children's is create local protocols pilot studies with new drugs new agents based on our observations. how on patients have done over the last several years with different approaches and we're working on creating prospective clinical trials here at Texas Children’s Hospital that we then helped export to other institutions we're very good outcomes I am think patient is tied to bill ch here over a decade it's because we found new treatments to give to these children when the front-line treatment consumer this has been a very big success patients who don't respond to first there be really difficult because not a lot of published data on drugs that work for second-line a lot of patients do not respond the first there be about 30 percent or so patients will require additional on treatments so we're working on alternative strategies with I can with prospective clinical trials using agents have worked in the past based on observations at Texas Children's if we can put them into clinical trials that we can then take to other institutions of it will become standard of care nationally and internationally the disease and the treatment can cause long-term affects their disease can affect the pituitary in 'cause diabetes insipidus our growth problems and that may or may not be stopped by treatment the disease could also affect the back part of the brain and cause difficulties with balance and thinking and speaking if it affects the lungs them person might have some difficulty you running and plain vigorously some patients have bone marrow failure because a the disease or the drugs and likewise some the drugs can cause problems with growth and develop. One of the best ways to treat HLH is to first to recognize it so without therapy almost a 100% of patients who have HLH will die and so it's really crucial a be recognized and so on once the diagnosis is made treatment as a little bit challenging, but typically consists have strong immune suppression with steroids or antibodies that our aims to get rid of the parts and immune system they're hyper-activated. I'm again that the main point for treating each alleges first to recognize is to overall patients with  either receive the chemotherapy or go onto stem cell transplant have a 65% overall survival. There can be long-term effects from the treatment. Our goal is to give the best treatment, with the most effective treatment of early side effects so kids typically will have a prolonged period of intense pressure with steroids which can have some side effects including immune suppression and then for the children going to bone marrow transplant, that process has some significant side effects as well. What we're trying to do with each stage at this treatment is to find the most effective therapy, along with the therapy that will be the least toxic to the patient.

At Texas Children's, we have a program that's really designed to comprehensively studied in patients with all forms of this dissident diseases their model really is pretty simple it's to offer the best medical care we can and then for patients who come either locally or who come to us from other places we offer the opportunity for all these that patients and families to wrong I'm but clinical studies as well as biology studies and so what we're offering the best care that we know how to give today were also studying the disease is to figure out better treatments for the future and part in this cycle is then today to create pilot clinical trials at Texas Children’s Hospital they can then be exported to other institutions uh on when they're patient is referred to his to say toes is set center we have a very smooth process you call our Clinic at 1-800-CANCER9 or speak with our Clinic Coordinator, Paula Jones. She will facilitate your visit my helping you get the really grabs at the largest lives in the clinical information that will help us take care of your child the best we know when you come here your child will be fully evaluated by one remembers our team and we will look at all the items that are important for understanding this your child's disease will give you a recommendation. Treatment and that may be done here for me send you home with a plan that can be implemented there my place for adult patients we do the same thing can guy implement treatments here are we can send you home the plan