To evaluate the role of IgA, IgG subclasses, κ-LC, and λ-LC in the treatment of multiple myeloma, we extracted a part of patients with over upper limit of reference range of testing items and analyzed the serum or urine levels of IgA, IgG, IgG1, IgG2, IgG3, and IgG4 and κ-LC and λ-LC in patients with multiple myeloma before, during, and after treatment. Here, IGHG3 is linked to plasma cell myeloma.