Is P-glycoprotein a sufficient marker for multidrug resistance in vivo? Immunohistochemical staining for P-glycoprotein in children and adult leukemia: correlation with clinical outcome.

Seventy-eight patients: 45 children, 33 adults and 27 normal healthy donors were enrolled in the study. Expression of P-glycoprotein (P-gp) was evaluated with three monoclonal antibodies (MAb's) directed to intra-(C219, JSB-1) and extra-cellular (MRK-16) epitopes of P-gp and immunocytochemical (IC) APAAP staining method. Twenty-seven healthy donors peripheral blood mononuclear cells (PBMC) were investigated by means of IC and FACScan analysis.