Osmotic behavior of normal and leukemic lymphocytes

The response of normal human peripheral blood lymphocytes to a hypotonic environment may be divided into two phases: the cells first exhibit rapid osmotic swelling, followed by a slower shrinking phase, during which they regain their initial physiologic volume. This osmotic behavior is characteristic of most mammalian and avian nucleated cells so far examined. The normal human blood lymphocyte, however, shows the most rapid recovery phase (5 min). Lymphocytes from chronic lymphatic leukemia patients, in comparison, show a strikingly slower rate of return to their initial isotonic volumes. The mechanism underlying osmotic cell volume regulation and its significance are discussed.