I’ve had lupus for 20 years. About a year ago my allergy doctor came across IG deficiencies in blood work – all of them. It was assumed that I had CVID. That info was sent back to my Rheumatologist who gave me the pneumonia booster vaccine to check for response. I did respond so they thought I didn’t need to do anything at that time. 6 months later new blood work comes back with MGUS, follow up on that was crazy high Lambda free light chains. Follow up on that with hematologist who reran the bloodwork because she thought the test might have been messed up. They came back similar. Followed that up with bone marrow biopsy and got a diagnosis of Multiple Myeloma. I was IG deficient because the Myeloma cells were crowding out the other cells. It can be a crazy ride through doctors so definitely find some you trust to work with.