What are white blood cells? What are the different types, and which are affected in acute myeloid leukemia?

What are white blood cells? What are the different types in which are affected in AML? So white blood cells are your body's way of helping you fight infection and different parts of the differential tell you what type of white blood cell does what function. Blasts are really immature cells and they go up when you have AML. So the more blasts you have, it's like having a bigger tumor burden. You shouldn't be able to see blasts circulating around. The neutrophils help you fight bacterial infections. If you had a different type of leukemia, you can have lymphocytes that increase in the differential. But it is important to be at a facility where they're really looking closely at the differential. So if you're not getting a differential done with your CBC with Diff, that would be a good place to start. Like, you need that Diff because you need to know what type of white blood cells you have. And we look at neutrophils to determine if you're neutropenic. Severe neutropenia is really a problem as far as your risk of a bacterial infection, which can take people's lives when you have AML. So it's really important to monitor that absolute neutrophil count. And you can get your health care provider to show you that. It's the percentage of your total white blood cell. But a lot of times they'll give you an absolute neutrophil count. And so if you look at that absolute neutrophil count, if it's 1.0, then we say your neutrophils are 1,000. So less than that is neutropenia. And severe neutropenia is an absolute neutrophil count less than 0.5 if you get your differential. And then most labs don't just do percentages. We used to have to calculate it. That's how old I am. And you wouldn't look at your total and calculate the percentage, and then that would tell you what your neutrophil count is. So you'll usually have both values, the percentage and then the automated or differential that tells you ANC. So that's the abbreviation for absolute neutrophil count. So the white blood cells are the cells in our body that help fight infection. Typically, when we focus on the white blood cells, we're really looking at the neutrophil count. Those are the cells that help fight bacterial infections. And we use a number called the absolute neutrophil count, which is a calculation of the neutrophil. When that dips down below 1000, we call that neutropenia, which can impair the immune system in fighting infection. Are white blood cells high or low at diagnosis, and why does this vary among patients? So in acute myeloid leukemia, the problem is that there's bone marrow dysfunction. So within our bones, there's a core and there's a liquid portion. And within that liquid portion, there are things called stem cells, and those create our blood and they create our white blood cells, they create our red blood cells, they create our platelets, which help in blood clotting. So acute myeloid leukemia is a disorder of the myeloid lineage, which is a lineage that's devoted to white blood cells, to red blood cells, to platelets. And so within this disorder, there's dysregulation. So at diagnosis in AML, you can have actually either an elevation in your white blood cell count or you can actually have a very low white blood cell count. And it all depends on the genetic drivers of the acute leukemia. It depends on whether your blood count, whether the disease itself is crowding out your bone marrow because in acute leukemia and acute myeloid leukemia, the reason your cell lines are low, especially your red blood cell counts, your platelets, are because of the disease and because of the fact that it's crowding out the bone marrow. So at AML diagnosis, patients can vary. Some patients can have an elevated white blood cell count or even a low white blood cell count. Typically, it's the immature cells that we might see in the blood that are representative of the leukemia cells. So when a person is first diagnosed with AML, it's most common to see a white blood count that is lower than normal. But in a significant minority of patients, the white count is quite elevated. So it all speaks to the proliferative capacity of the leukemic cell to really help determine how high the white blood count is at the time of diagnosis. Like I said, in some cases, if the white blood count is very high, you see a lot of these leukemia cells circulating in the blood and it's much easier to make a diagnosis than if the white blood count is very low when you don't necessarily see the leukemia cells circulating. And, of course, you have to do a bone marrow biopsy to be sure that it's leukemia. You have to do a bone marrow biopsy anyway to get all the important details of the leukemia and the subtype and so forth. But you can often make a diagnosis of acute leukemia, AML in particular, when the white blood count is high and you see a lot of circulating blast cells in the peripheral blood, which usually is a clear indication of the diagnosis. A high white blood count in acute myeloid leukemia is typically a worse thing than a low white blood count because there is the potential for increased release of cytokines or inflammatory chemicals that can cause damage to various organs such as the kidneys. There's also the potential risk of something called leukostasis if the white blood count is too high, where these leukemic blast cells accumulate and sort of clog up the blood vessels and can lead to problems such as stroke or cardiac ischemia, lack of blood flow to the heart and other organs, and really wreak havoc when the white blood count is too high. So if a patient has a very high white blood count at the time of presentation, we'll typically bring them into the hospital right away, start them on fluids, some chemotherapy to help bring the white blood count down, and sometimes something called leukophoresis, which is a mechanical intervention that helps physically remove the white blood cells from the circulation to help reduce the overall white blood count. What is considered a low white blood count for someone with AML? So it really depends on the laboratory. Most labs have a range of about 3.5 to 10,000 cells per microliter. So that's the normal range. So white blood cell counts usually are within that range. If they're on the lower side or the higher side, it could indicate an underlying problem with your bone marrow. So low white blood cell count, every laboratory is different. Typically when the white blood cell count is less than three, we consider that low. But again, really focusing on that neutrophil count I think is important. What happens when white blood cell counts are low? So if your white blood cell count is low, you may have no symptoms, you may have very severe symptoms, you may have...and so the range is pretty broad in terms of the symptoms you can have with your white blood count being low. Really what happens is when your white blood cell count is low, you're at risk for infections. When white blood cells are low, if your total white blood cell count is less than one, then you don't even have to worry about calculating an absolute neutrophil count because you know that you're neutropenic. Sometimes patients say they feel fatigued. We don't know really if that's a function of having the leukemia or is it a function of the white blood cell count. Really the biggest risk is the risk of infection, overwhelming infection. Paying close attention to that total white blood cell count, if it's less than one, then you're neutropenic. Sometimes we use prophylactic or preventive antibiotics to prevent patients from getting an overwhelming bacterial infection. Also the longer that your neutrophils are less than 1.0 or your white blood cell count is less than 1.0, then over time you're more at risk for other types of infections like fungal infections. So that's something to keep in mind to ask your healthcare provider about. Am I on the right preventive medications to help me not get an overwhelming infection? So really infection risk is the biggest thing we think of. How will I feel if my white blood cell count is low? Typically patients may experience again more fatigue. They may have signs or symptoms of infection, but sometimes the white blood cell count can be off and maybe no symptoms may show or the patient may not feel any different. A common complaint that some will say is more fatigue and weakness. So when your white blood cell count is low, you're at risk of getting fevers, you're at risk of getting an infection that can lead to that fever. So all of those symptoms can be secondary to the underlying infection. When your white blood cell count is low, you also want to check your red blood cell count and your platelet count as well because you can also additionally be at risk of fatigue from having a low red blood cell count as well as potentially bleeding. What precautions do I need to take if my white blood cell count is low? So if your white blood cell count is low, you should take general precautions. You are at risk for infection, so going into big crowds you need to be especially mindful of that because you're at an increased risk of infection. If you end up going anywhere, you should take appropriate precautions, wash your hands, wear a mask if appropriate in a large crowd. When the white blood cell count is low, the most important precaution I would say is hand hygiene. Definitely washing your hands is one of the most effective ways of preventing infection. Staying away from very crowded public areas and other people that are sick, sometimes young children.