What is Chronic Eosinophilic Leukemia (CEL)?

There are five types of white blood cells in your body: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Eosinophils take part to protect our body from infection, particularly in parasitic infection, and release various chemicals in response to the infection and allergic reaction. If your bone marrow makes an abnormally large number of eosinophils, this can lead to a condition called CEL. Your doctor will check your blood to exclude other conditions before reaching the confirmed diagnosis of CEL.

What Increases Your Risk for CEL?

• The risk factor of CEL is not well understood. CEL can develop in anyone, regardless of age, or sex, but is more common in men than women.
• A gene mutation (change) may also lead to CEL. Scientists are not yet sure about the link with certain gene types that may cause the change. The condition doesn't seem to be passed down in families.
• Research is ongoing to explore why it affects some people and not others.

What are the symptoms of chronic eosinophilic leukemia (CEL)?

CEL is often misdiagnosed because its symptoms closely resemble infection or inflammation. It is considered a more advanced or aggressive form of MPNs. You may experience fever,  fatigue, cough, or diarrhea. You may also notice your skin becomes red and itchy. You may develop swelling in different parts of your body similar to hives. These varied symptoms can make it difficult to diagnose CEL. In the most severe stage of the disease, eosinophils start accumulating in various areas of your body such as the heart, lung, gut, and brain. Dr. Ghaith Abu-Zeinah discussed: “these eosinophils that are malignant, and there is an excessive number of them, can cause an inflammatory response that can really damage organs if not treated appropriately.” Here are some other things to look out for:

• palpitation, breathing difficulty, leg swelling
• numbness and tingling of hands or feet
• memory problem, seizure, or stroke-like symptoms
• development of blood clot
• belly pain, swollen belly, vomiting, and jaundice

How Does My Doctor diagnose chronic eosinophilic leukemia (CEL)?

CEL is rare and thus can be difficult to diagnose. In most cases, your doctor’s aim is to rule out all other possible causes of your symptoms. The diagnostic work-up that your doctor may recommend include a complete physical exam, blood tests, biopsies, as well as molecular testing to rule out any mutation or genetic changes. Sometimes you may need to get several biopsies to confirm the diagnosis.

Your doctor will assess your symptoms, and then perform a range of tests, such as:

• Complete blood count (CBC): to look for hemoglobin, different types of white blood cells, and platelet. In CEL, your eosinophil count is higher than normal.
• The blood smear is to examine your blood samples under a microscope to rule out other types of blood cancer such as acute leukemia.
• Bone marrow aspiration and biopsy: A bone marrow aspiration and biopsy may be needed to confirm the diagnosis. Your doctor takes a small sample of your bone marrow, usually from the hip bone. Then the pathologist looks at the cells under a microscope to determine how many eosinophils your body has, the presence of mutation, or any other cancer cells.
• Your doctors may perform additional biopsies from other areas if he/she suspects damage caused by the excess eosinophils. This type of biopsies sometimes not only helps to confirm the diagnosis but also to run additional tests on the tissue to figure out the cause of high eosinophil count in your blood or bone marrow.
• Next-generation sequencing (NGS): It is a method to identify genetic error or mutation in your gene by using an advanced technology called NGS panel. It can be done in both the biopsy sample and/or in the blood. This test can help your doctor and pathologist to recognize the overall picture and correctly identify your condition.
• It may take a few weeks to get these results back. While waiting for test results can be a worrying time, it is important for your doctor to come to the correct diagnosis to offer the best treatment for you.

What Treatment Will Work Best Against My Chronic Eosinophilic Leukemia (CEL)?

Once a confirmed diagnosis of CEL is made, your doctor can focus on the next important step- how to treat you. Given that CEL is a very type of cancer, treatment options are unfortunately limited. Many of the treatment options focus on relieving symptoms and improving your quality of life.

• Corticosteroids and interferon alfa (Intron A) may help to lower your eosinophil numbers and protect your organs from chemical toxins released by the eosinophils.
• The steroid may not always work or can cause side effects such as weight gain, mood changes, muscle aches, difficulty sleeping, heartburn, or high blood sugar. In that case, your doctor may change the medicine to hydroxyurea (Hydrea). Hydroxyurea is an oral chemotherapy medication that decreases the production of eosinophils from your bone marrow. The possible side effects are nausea, vomiting, diarrhea, leg ulcers, flu-like symptoms, bone pain, and loss of appetite.
• Dr. Ghaith Abu-Zeinah discussed the treatment options: “Doctors may also use chemotherapy drugs, such as hydroxyurea (Hydrea), possibly in combination with steroids or tyrosine kinase inhibitors (TKI), that can inhibit the proteins, that come out from these translocations and are responsible for the excess production of eosinophils. So using TKIs can really control the eosinophil count and prevent the complications associated with having a high eosinophil count.”
• If your cancer is more aggressive, you can expect to get chemotherapies to destroy the cancer cells. But usually, these medications work only for some time and your disease may come back. Imatinib (Gleevec) may also be suggested by your doctor to control the disease. Imatinib (Gleevec) blocks an enzyme in the body called tyrosine kinases which regulate cancer cell growth. By blocking this enzyme, imatinib kills or slows down the cancer cell growth in your body. It is taken orally and may cause upset stomach, nausea, vomiting, diarrhea, headache, muscle or joint pain, blurred vision, or drowsiness. You need to consult your doctor urgently if you develop any of these symptoms.
• A bone marrow transplant is a medical procedure by which healthy bone marrow cells from bone marrow donors are transplanted into your bone marrow or your blood. This procedure is reserved if your disease progress, or if you develop acute leukemia. Your doctor will determine on a case-by-case basis to determine if you are a candidate for a bone marrow transplant.
• Treatment of CEL can be challenging as the disease can recur with the treatments. It is important to have regular follow-ups, and blood tests with your doctor. Your doctor is in the best position to guide you in the process.

 

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