What is IgM MGUS?

What is IgM MGUS?

So when we talk about an MGUS, monoclonal gammopathy of undetermined significance is that you have this protein, this antibody in your blood that is sitting there, and it's a monoclonal protein, meaning that there's an excess of it and it's identical. And so that's akin to when your myeloma is making the antibody. But when you have an MGUS, you have the antibody, but we don't find an excess of any myeloma cells or lymphoma cells or any kind of cancerous cells that are making it. The protein is there by itself. And so it's unclear what that means. And some patients will eventually develop myeloma or lymphoma and some patients will never develop any of these diseases. IgM MGUS is just a subtype of MGUS. So there's a small group of patients that have an IgM instead of an IgG or IgA. And IgM MGUS usually is more likely to become this thing called Waldenström macroglobulinemia, which is a subtype of an indolent lymphoma. So when you look at myeloma and lymphoma as other sister diseases, because they arise from the same cell, it just depends on what level of their differentiation. So all B lymphocytes eventually mature, can mature into a plasma cell. So if your disease mutates at the level of the lymphocyte, you develop lymphoma, if this mutates at the level of the lymphocyte that's becoming the myeloma cell we call lymphoplasmacytic lymphocyte that becomes Waldenström, and that's more likely to make IgM. If it mutates at the point where it becomes a plasma cell, it becomes multiple myeloma.