To that end, we evaluated serum total IgG level, IgG subclasses, and serum and urine κ-LC and λ-LC in patients with multiple myeloma and healthy controls, and monitored total IgA, IgG, and IgG subclasses, κ-LC, and λ-LC responses to multiple myeloma patients before, during, and after treatment. The gene discussed is CD79A; the disease is plasma cell myeloma.