Because mature B lymphocytes (plasma cells) are responsible for the production of large amounts of immunoglobulins, we next measured the number of plasma cells (CD138+ lymphocytes) in bone marrow and observed a 1.3-fold increase of CD138+ cells in 3xTg-AD mice compared to controls (P = 0.0405, Fig. 3). This evidence concerns the gene SDC1 and Alzheimer disease.