Interested to hear if anyone has had a similar experience or explanation of how this may have occured. I was diagnosed with smoldering myeloma in 2016 that progressed to full blown disease in 2021. I was found to have an IgG lambda variant. Standard therapy (Revlimid, Darzalex, Velcade, and Dex) got my numbers down. Covid delayed my ASCT until Jan of 2023. Afterwards I initially went into complete remission but then routine followup in December of 2023 showed an uptick in my M-spike to 0.2. Protein electrophoresis still showed no evidence of the IgG lambda clone but now showed a spike consistent with the presence of an IgG kappa variant. There was some thought that may have been somehow related to an RSV infection I had just experienced but labs repeated mid February 2024 showed similar findings with still no evidence of the IgG lambda clone I had originally but a continued spike consistent with an IgG kappa variant. I'm scheduled for restaging with a repeat BM and PET/CT and further treatment based on those results but I am curious as to where this IgG kappa variant came from especially in light of what appears to have been an otherwise successful ASCT. Any thoughts?