What Is Hematopoiesis?

Hematopoiesis is the process in which blood cells are formed in the body from stem cells. The stem cells are located in the bone marrow of the pelvic bones, ribs, spine, skull, and the upper bones of the arms and legs, where hematopoiesis occurs.

There are three main types of blood cells:

•Red blood cells (RBCs)

•White blood cells (WBCs)

•Platelets

Each type of blood cell has a very different and important function in the body:

Red blood cells are responsible for carrying oxygen from the lungs to the various tissues and organs in the body, using a molecule called hemoglobin.

White blood cells maintain the body’s immune system and help fight diseases and infections. There are several types of WBCs, including neutrophils (the most abundant), eosinophils, basophils, monocytes/macrophages, and lymphocytes.

Platelets regulate blood clotting when an injury occurs.

What Are Disorders of Hematopoiesis?

Disorders of hematopoiesis are disruptions or malfunctions in the formation of one or more types of blood cells. These disorders are usually caused by an underlying condition or disease resulting from illness, a reaction to medicines or sometimes genetics.

Hematopoietic disorders include:

•Anemia: fewer RBCs are being made or more RBCs are being destroyed, caused by vitamin deficiency, excessive bleeding, chronic conditions such as cancer or kidney disease which lead to a decreased production of erythropoietin (EPO), a protein that stimulates RBC production

•Neutropenia: an increase in neutrophil destruction or a decrease in production, caused by illness, chemotherapy medicines or genetic conditions

•Neutrophilia: an increase in neutrophil production or a decrease in destruction, often due to bacterial infections, malignant tumors or leukemias

•Thrombocytopenia: a decrease in platelet production or an increase in destruction, sometimes caused by immune system destruction of platelets or cancer chemotherapy medicines

•Thrombocythemia: an increase in platelet production or a decrease in destruction

•Eosinophilia: usually an increase in eosinophil production, often due to parasitic diseases, allergies or allergic reactions

•Monocytosis: an increase in monocyte/macrophage production, usually caused by certain infections or leukemias

•Pancytopenia: decreases in WBC, RBC and platelet production at the same time, sometimes caused by tumors in the bone or a disease of the spleen

•Leukemias: abnormal increase in the number of WBCs in the tissues or the blood

•Tumors: abnormal masses of tissue without obvious cause

Many factors can cause the formation of blood cells to be disrupted or malfunction. The disruption or malfunction may occur in only one cell type or more than one cell type at once. It usually is due to an underlying condition or disease, such as genetic conditions, illness, or reactions to drugs. Problems with blood cell formation are usually confirmed through blood tests, which can show abnormally high or low levels of individual blood cell types and subtypes. A level that is too high or too low causes different signs and symptoms depending on the type of blood cell being affected. Some abnormalities of blood cell formation are seen more frequently than others.

Typically, treatment of the underlying disease will correct any abnormalities of hematopoiesis. However, in some cases, medicines are needed to help return the formation and function of the blood cells back to normal.

•Anemia is generally a sign that less RBCs are being made, more RBCs are being destroyed, or may be due to severe bleeding. Additionally, the cause of anemia may be because of a lack of iron, lack of vitamin B12, or a lack of folic acid, which are key to the function of a RBC. Anemia may also be due to problems with hemoglobin formation. Anemia can also be due to the presence of chronic diseases, such as cancer or kidney disease. These diseases can cause decreased production of a protein called erythropoietin (EPO). EPO is what stimulates RBC production. In the early stages of anemia, some people feel fatigue, weakness and loss of stamina. In more severe cases, one might feel their heart racing, feel lightheaded (especially when standing), and become short of breath easily, or even faint. Severe anemia, most often due to blood loss, can cause a loss of oxygen supply to vital organs in the body, resulting in loss of organ function or even death.

•The way to handle anemia depends on the cause. In some cases, replacement of iron, vitamin B12, or folic acid is sufficient to reverse the anemia. In severe cases of anemia, where organs within the body are not receiving the oxygen they need, blood transfusion is used to restore oxygen supply and organ function. However, when the cause of the anemia is due to a problem in the production of erythropoietin, the protein that stimulates RBC production, different therapies are required. There are three products available in the US that have changed the way anemia is managed, epoetin alfa (Epogen®, Procrit®), and darbepoetin alfa (Aranesp®). These products act like human erythropoietin to increase RBC production. Epogen and Procrit were developed at the same time by two different companies and first approved in July 1999. Aranesp was approved in September 2001. All three products are approved for the treatment of anemia due to chronic kidney failure and cancer chemotherapy. Epogen and Procrit are also approved for the treatment of anemia due to zidovudine therapy (in HIV patients) and to reduce the need for blood transfusions in patients requiring surgery.

•The most common side effects for all three products include increased blood pressure, headache, muscle ache, nausea/vomiting, and pain at the administration site. Rare but serious side effects include seizure, stroke, and heart attack. None of these products are for use in individuals with uncontrolled high blood pressure or if a known allergy exists to the drug or a component of the drug’s formulation. Each of these products is given via an injection under the skin (subcutaneous), however, the medication dosage and frequency is based on a person’s weight, as well as the cause and severity of the anemia.

•Neutropenia occurs when there is a great decrease in neutrophil production or an increase in neutrophil destruction. Neutropenia may be the result of illness, drugs (such as cancer chemotherapy agents), or it can also be due to genetic conditions such as Kostmann’s syndrome. The most common sign/symptom that a person has severe neutropenia is that they have an infection. A person with neutropenia is more likely to get infections because they do not have enough neutrophils to fight them. Sometimes, infection can be the cause of the neutropenia, but usually, the neutropenia is the cause of the infection. In blood tests, low WBC and low neutrophil levels are often seen.

•Treating neutropenia focuses on increasing WBC count, and preventing further problems. People with neutropenia are at a much higher risk of developing life-threatening infections and often get what is known as neutropenic fever. For this reason, individuals that develop severe neutropenia (usually with fever) will receive antibiotics (usually via intravenous infusion) to protect against infection. However, in situations where neutropenia is expected to occur (e.g., during the use of certain cancer chemotherapy agents), during bone marrow or stem cell transplant preparation (for the donor and/or the recipient), for individuals with genetic conditions that result in neutropenia that returns again and again, or for those who have developed neutropenia, everything is done to lessen the severity of neutropenia and prevent infection. This is done through the use of colony stimulating factors (CSFs). These medications help increase the production of neutrophils. There are three CSF products currently available in the US: filgrastim (Neupogen®, approved in February 1991), sargramostim (Leukine®, approved March 1991), and pegfilgrastim (Neulasta®, approved in January 2002).

•Both Neupogen and Leukine are given either as a subcutaneous injection (under the skin) or intravenous infusion. The dose of these two medications depends on a person’s weight and the cause of neutropenia. Neulasta is only available as a subcutaneous injection. It is given in a 6 mg dose. The most common side effects with these medications include bone pain, muscle pain, mental or physical sluggishness, and headache. Rare but serious side effects that should be reported to a health care professional include abdominal or shoulder tip pain and difficulty breathing.

•Neutrophilia is an increase in neutrophil production or decreased neutrophil destruction. It is most often seen in the presence of bacterial infection, but can be caused by malignant tumors or leukemias. The only treatment for neutrophilia is to treat the underlying disease or illness.

•Thrombocytopenia occurs when there is a decrease in platelet production or increase in platelet destruction. People with thrombocytopenia may experience increased or unusual bleeding and/or bruising, as well as purpura (a skin rash resulting from blood vessels leaking under the skin). Sometimes, thrombocytopenia occurs when a person’s immune system destroys the platelets. This rare disease is called idiopathic thrombocytopenic purpura (ITP). In children, ITP is usually temporary and does not need treatment. However, in some people, ITP is a life-long illness and is treated with blood or platelet transfusions or in severe cases, by surgery to remove the spleen. In blood tests, extremely low platelet levels indicate the presence of a problem.

•Thrombocytopenia is best treated with direct blood or platelet transfusion. However, in some cases, such as treatment with cancer chemotherapy agents, thrombocytopenia is common and can be prevented. In November 1997, oprelvekin (Neumega®) was approved to prevent severe thrombocytopenia for people that had severe thrombocytopenia during chemotherapy. Neumega works by simulating the action of a human protein called interleukin-11 (IL-11), which stimulates the production of platelets. It is given as a subcutaneous injection (under the skin) once a day for 10 to 21 days. The medication dose depends on a person’s weight. Neumega therapy must be completed at least 2 days prior to starting a chemotherapy cycle. The most common side effects with Neumega include fluid retention, shortness of breath, increased heart rate, and irregular heartbeat. Rare but serious side effects include stroke and anemia. Neumega must be used with caution in individuals with kidney and/or heart disease.

•Thrombocythemia is an increase in platelet production or decrease in platelet destruction. This results in clots forming in the blood vessels of the body, which can block blood flow. Individuals with thrombocythemia experience frequent headaches, increased risk for stroke or heart attack, as well as pain, burning, and redness at the extremities. It is most often treated with aspirin therapy, iron, radiation, or anti-platelet agents.

•Eosinophilia is most often an increase in eosinophil production. It is usually due to parasitic diseases, allergic conditions (e.g., seasonal allergies), or allergic reactions (e.g. allergic reaction to medications or bee stings). The best treatment for eospinophilia is to treat or control the underlying condition.

•Monocytosis is the increase in monocyte/macrophage production often seen in presence of certain infections or certain leukemias. Treatment for monocytosis involves treatment of the underlying disease.

•Pancytopenia is a unique condition in which decreases in WBC, RBC, and platelet production occur at the same time. It is usually due to failure of the bone marrow to make these cells because of tumors in the bone or disease of the spleen. Patients will generally have a combination of the signs and symptoms seen with anemia, thrombocytopenia, and neutropenia. Treatment of pancytopenia depends on the cause.

Caremark understands that people with hematopoietic disorders have special needs. We’ll make sure you get your prescribed Epogen®, Procrit®, Aranesp®, Neupogen®, Neulasta®, Leukine®, and/or Neumega® from our Specialty Pharmacy, along with the medically necessary supplies you need to safely and correctly administer your treatment.

Caremark has more than 25 years experience with injectable and infused medicines, working closely with each doctor, clinician and participant to make sure medicines are administered as effectively as possible. In addition to providing your prescribed medicines and supplies, Caremark Specialty Pharmacy Services helps in many other ways:

Education. We’ll provide you with information and resources to learn all about hematopoiesis, the medicines, lifestyle issues, ways to manage your disease and treatment, and the importance of following your treatment plan.

Customized Care. Sticking to your treatment plan is a top priority, so Caremark assigns each participant a pharmacist-led CareTeam. Your CareTeam will review your medicine schedule, work with you to resolve any injection-related issues, discuss proper waste disposal, and stress the importance of managing your own therapy. We’ll also coordinate nursing services when requested and approved.

Ongoing Communication. Your CareTeam will call you periodically to answer questions, help with treatment issues, schedule shipments of your medicine, and support you in your treatment plan. We also communicate regularly with the manufacturers of these medicines so we can keep you informed about additional support materials and services.

Discreet Deliveries. We know how important your privacy is, so we’ll ship your medicines in secure, plain, temperature-controlled packaging to your home, office or doctor’s office—at your direction.

24-Hour Availability. We’re here when you need us. Our Specialty Pharmacy pharmacists are available 24 hours a day, 365 days a year, in case of emergencies.

With Caremark, you’ll have a team of experts on your side, helping you get the most professional, caring, and cost-effective service. If you would like to find out more about our services, please call CaremarkConnect® toll-free at 1-800-237-2767.

Navigating Insurance

To inquire about or begin services with Caremark Specialty Pharmacy Services, please call or have your healthcare provider call CaremarkConnect® at 1-800-237-2767. You may also begin the enrollment process here. Once you fill out the requested information, one of our staff of specialists will contact you. Regardless of how you begin the process, our staff of specialists will work with you and your insurance carrier to confirm coverage for your treatment. We’ll conduct a full benefits investigation for you for the medicines you may need.

A specialist will assist you with:

•Securing coverage for your new prescription

•Determining your coverage and minimizing out-of-pocket costs

•Processing insurance paperwork and coordinating benefits

•Handling prior authorization issues

•Obtaining all necessary authorizations

•Communicating your financial obligations verbally and in writing

•Assisting in the coordination of home administration services

•Arranging delivery of your medicines

•Coordinating the start of therapy with your doctor

To explore financial coverage alternatives when insurance is not available to you, we offer Caremark Customer Assistance at 1-800-331-7171. Our staff of specialists will work with you to explore coverage alternatives when insurance is not an option. Please feel free to call us with questions or problems.

To inquire about or begin services with Caremark Specialty Pharmacy Services, please call or have your healthcare provider call CaremarkConnect® at 1-800-237-2767. You may also begin the enrollment process here. Once you fill out the requested information, one of our staff of specialists will contact you. Regardless of how you begin the process, our staff of specialists will work with you and your insurance carrier to confirm coverage for your treatment. We'll conduct a full benefits investigation for you for the medicines you may need.

You may find these Web sites/organizations helpful*:

•National Cancer Institute

•American Cancer Society

•National Institute of Diabetes & Digestive & Kidney Diseases

* Caremark does not operate the Web sites/organizations listed here, nor is it responsible for the availability or reliability of their content. These listings do not imply or constitute an endorsement, sponsorship or recommendation by Caremark. Information from these Web sites/organizations is not a substitute for medical advice or treatment. Discuss any information you find with your doctor or healthcare professional.

References

Copyright © 2005 Consumer Health Interactive

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