Sami Khella, MD, explains the importance of baseline immunoglobulin testing in myasthenia gravis, particularly when considering FcRn inhibitors, and the need to balance treatment benefits against the risk of further lowering Ig levels.
Transcript
As part of my protocol baseline testing, I like to get quantitative immunoglobulin levels, for example, especially before I start using IVIg. And I’m often surprised by finding very low IgG levels in a patient. It turns out that they have common variable immune deficiency and didn’t know it, or have had recurrent infections. And nobody has made that diagnosis before.
So I’ve had a number of these patients, especially with thymoma, who tend to have low Ig levels (so-called Good syndrome) and so I like to check that.
When I do find that, I tend to avoid FcRn inhibitors, for example, because they are going to lower the Ig levels further, and we don’t want that.
Like everything else in medicine, I have a couple of patients who have common variable immune deficiency and who have not responded to anything except the FcRn inhibitors.
So here we’re playing a game of chicken, basically. You lower the Ig level, you treat them, they get better from their myasthenia, then the Ig level drops and you go, “Oh my goodness.”
