In patients who did not show hypogammaglobulinemia at diagnosis, 19 of 31 patients (61.3%) newly developed one or more classes of hypogammaglobulinemia during immunochemotherapy, and decreased IgG (n = 13), IgM (n = 10), IgD (n = 9), and IgA (n = 3) were identified. The gene discussed is CD40LG; the disease is Decreased circulating immunoglobulin concentration.