Disclosed herein are methods and compositions comprising fingolimod and anti-CD74 antibodies or fragments thereof. In preferred embodiments, the fingolimod increases the expression of CD74 in target cells and increases the sensitivity of the cells to the cytotoxic effects of the anti-CD74 antibodies. The compositions and methods are of use to treat diseases involving CD74+ cells, such as cancer cells, autoimmune disease cells or immune dysfunction disease cells.
