Apparent IS by IFE. Gel 1 shows a IgG λ monoclonal protein with free λ light chain. The IgG λ monoclonal protein band resolved with pretransplant chemotherapy and a single IgG κ band appeared (gel 2). After the second transplant, the IgG pattern was polyclonal and a new IgM κ monoclonal band appeared (gel 3). This band was replaced by a polyclonal IgG pattern 1 month later (gel 4).