Multidrug transport in human autoimmune T line cells and peripheral blood lymphocytes.

We studied multidrug transport in human autoimmune T line cells and peripheral blood leukocytes, because multidrug transport is pleiotropically limiting the intracellular accumulation of immunosuppressive and chemotherapeutic agents. We observed that a subpopulation of peripheral blood leukocytes containing CD4+, CD8+ and Ig+ lymphocytes expressed a multidrug transport system. Lymphocytic multidrug transport was seen with all peripheral blood samples analyzed, but showed considerable variations between individuals. In further studies with human lymphocytic cell lines multidrug transport was seen with 18/23 human CD4+ T cell lines. Interestingly, expression of multidrug transport was independent of T cell activation. No significant transport was observed with EBV-transformed human B lymphocytes, rat T line cells or rat, mouse, or guinea pig leukocytes.