Isolation of human peripheral blood lymphocytes: modification of a double discontinuous density gradient of Ficoll-Hypaque.

Incubation of whole blood with adenosine diphosphate (ADP) and carbonyl iron prior to layering on a double discontinuous gradient of Ficoll-Hypaque selectively reduced the number of platelets and monocytes found at the upper lymphocyte interface after centrifugation. This modification in combination with a double discontinuous gradient results in a lymphocyte isolation method that is simple, rapid and reproducible.