Myeloma is not something you catch. It is a disease caused by a chromosome change which may have started out as just a mistake during cell growth. When that cell divides again for growth, that mistake goes with it. Now you have two.
When the mistake is on a plasma cell, like chromosomes, 11 and 14 where part of 11 switches places with part of 14, you get Myeloma. There are many different mutations on all our cells, but the plasma cells make all our WBS, RBC and platelets.
When these mutated cells keep growing they push out the unmitated cells and crowd them out. Remember, they don't work correctly anymore because the chromosomes have changed, so we don't get enough WBCs and our immunity goes down.

Kathryn, my immunoglobins are very low. My unaffected ones were low at diagnosis. So it's not just from treatment. I guess our immune system isn't working right in the first place. That's why we got myeloma. I know that this doesn't answer your question. I wish I knew the answer.

Jessica, I’m no doctor, however, a fifth grader could tell you there is a HUGE problem with your health! IgG makes up 75% of your immune system. That’s correct, 75%! You say your reading is IgG 32! That is super deficient! The bottom of the normal range is 600+. It is a small wonder you don’t have much worse symptoms. You need to see a specialist immediately! And you need to have an IVIg done immediately, ASAP if your IgG is 32! You need to stop talking about your condition and get help ASAP. And your oncologist says you don’t have myeloma? I’d certainly get a second opinion on that diagnosis. Perhaps there is something I’m missing here. If so, tell me. Jessica, Godspeed.

Clarity in explanation is a gift! Thank you, Sally Torgeson. Although I exhibit no CRA symptoms - I had fractured vertebrae and lower back pain, a good example of low immunity are these readings: IgG =32, IgA=900. IgA takes over my immune defenses so that I am chronically ill with sinus and lung infections... yet I am not fully diagnosed with MM. It just depends on the doctor - my vascular doctor named it MM IgA Lambda. That is what I read too. But the oncologist and immunologist are slow to act - my assumption is because my immune system is so weak.

But according to my numbers, I'm not that bad. ...I thought. My coach says my immunity is low, but didn't elaborate on that. My oncologist doesn't even seem concerned either. OR are you speaking to Jessica's situation. I agree, she needs to get better help....STAT.