Plasma cell dyscrasias
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What are plasma cell dyscrasias?
- [Voiceover] All right, in this video we're going to be talking about what is plasma cell dyscrasia? I want to start by just breaking down the term. And the first word in here that kind of sticks out to a lot of people is this dyscrasia here. And this is a word that isn't frequently used and not well understood and so I'm really going to just cross it out and write dysfunction. Because plasma cell dyscrasia is a group of disorders that is characterized by dysfunction of plasma cells. So what exactly are plasma cells? In a simple definition, plasma cells are a type of blood cell that help the body fight infection. So let's go through some of these blood cells to figure out what exactly plasma cells are and how they work. There's three main types of blood cells. And the first type I'm going to mention here are the red blood cells, which are also known as erythrocytes. They look something a little bit like this. And red blood cells, or erythrocytes, are responsible for the transport of oxygen and carbon dioxide in the blood. And the next type of blood cells I'm going to mention are the platelets, which are also know as thrombocytes. And thrombocytes are kind of some fragments of their precursor cells, so I'm just going to kind of draw them in like this, they're very small. And what they do is they help the blood clot. So if you get a cut and you start bleeding, platelets, or thrombocytes, help the body stop that bleeding, so just writing clotting here. And then the other major type of blood cell is white blood cells. And white blood cells are kind of like the infection fighters of the body, but unlike erythrocytes and thrombocytes, which are a specific cell type on their own, white blood cells is more of a group of a bunch of different types of cells. And they can be further split into two categories and these are the myelocytes, which include cells like basophils and nutrophils and eosinophils, as well as lymphocytes, and these include things like T cells and B cells, as well as our plasma cells. But you may be asking yourself what are the difference between these two groups of white blood cells and why am I making a point to separate them? Well, the major thing is how they approach their infection fighting. What's their strategy? And myelocytes are part of a strategy that's know as innate, which means it's nonspecific. So anytime the body is injured or has a potential infection the action of these myelocytes is the same regardless of what that type of injury or infection is. They have the same response. Whereas lymphocytes are adaptive, or specific. And lymphocytes have a very targeted strategy for destroying and removing infections from the body. And another important characteristic of lymphocytes is that they have memory. All right, so now that we've kind of figured out what plasma cells are and we know that plasma cell dyscrasia is a dysfunction of them, what exactly does this all mean? And let's use a-- I'm just going to erase my work here and then we're going to use an example to kind of figure this out. So imagine you're in your kitchen chopping ups some vegetables for dinner and maybe you're listening to some music on the radio and your favorite song comes on and you're not exactly paying attention and there you go, you cut your hand and it starts bleeding, but what are some of the other first symptoms that you're going to experience when you cut your hand here with that knife? Well some of the things are probably going to be pain, maybe some swelling, some redness around the cut, as well as some warmth. And these symptoms here, these are that innate immune system. Those myelocytes release certain factors that cause these symptoms to occur. And it's called innate or nonspecific because it doesn't matter whether you cut yourself, or you have a cold, or you have any other sort of chance where there could be an infection, the body has these responses, this pain, swelling, redness, and warmth that make it difficult for a bacteria to survive. So they're not specific to any one type of bacteria. But what if that knife wasn't very clean? What if there was some bacteria on it? Well if the cut becomes infected with a bacteria, say here. This innate immune system is probably not going to be sufficient to kill and remove this bacteria from the body. And so this is where the adaptive immune system comes into play. So all bacteria and different cells on their surface have markers. And these markers are called antigens. And it's these antigens that identify this bacteria as something that is foreign, it is not part of the body. And the body has these cells that are known as B cells and these B cells have receptors on them, as you can see here. And they recognize the antigens. And when a B cell recognizes an antigen, say on a bacteria like from the knife that cut your hand, they start to transform into a couple different types of cells. And the first type that they turn into are plasma cells. And what plasma cells do is they produce antibodies. And these antibodies then attach to the antigens on the bacteria cell surface. So let's see that happen here. And the other pathway that the B cells goes down is to create another type of cell known as a memory B cell. So once these antibodies have attached to the antigens on the bacteria, the immune system is better able to kill and remove this bacteria from the body and thus fight the infection. Now that we've talked about what plasma cells are and what they do, you can imagine that if these cells were dysfunctional, as in a plasma cell dyscrasia, or dysfunction, that there's likely going to be a problem with anitbodies and if there's a problem with antibodies, perhaps an individual with a plasma cell dsycrasia will have a hard time fighting an infection and this indeed is the case in some plasma cell dyscrasias, such as multiple myeloma. But in some of the other plasma cell dyscrasias, this function isn't as prominent and what's more noticed is changes in the blood concentration and type of antibodies. And some of these conditions include something known as monoclonal gammopathy of undetermined significance. That's a little bit of a mouthful, so it's usually just abbreviated MGUS, a condition known as Waldenstrom macroglobulinemia, and another one known as Langerhans cell histiocytosis. So these are the diseases that are known as plasma cell dyscrasias and they are caused by dysfuction of these antibody producing blood cells that are known as plasma cells.