Expression of multidrug resistance P-glycoprotein on lymphocytes from nephrotic children treated with cyclosporine A and ACE-inhibitor

The aim of this work was to determine the expression of P-glycoprotein (P-gp) on peripheral lymphocytes (CD3) in children with steroid-dependent nephrotic syndrome (SDNS) during cyclosporine A (CyA) and ACE-inhibitor (ACE-I) treatment. The study group (I) consisted of 20 children with SDNS aged 5–18 years, with a subsequent proteinuria relapse at the time of prednisone dose reduction. All nephrotic syndrome (NS) children were examined three times: A—at proteinuria relapse, before CyA treatment; B—after 3 months; C—after 12 months of CyA administration. The control group (II) consisted of 20 healthy children. CD3/P-gp was measured using a flow cytometry assay. The serum CyA level was assessed by means of the immunofluorescence method. The expression of CD3/P-gp in NS relapse, prior to CyA+ACE-I administration, was much higher (median 9.15%, range 1.50–13.50%) when compared to healthy controls (median 1.20%, range 0.30–5.70%). The absolute number of CD3/P-gp in this examination was almost five times higher when compared to healthy controls (p