EXPRESSION OF MULTIDRUG-RESISTANCE P-GLYCOPROTEIN ON PERIPHERAL-BLOODMONONUCLEAR-CELLS OF PATIENTS WITH GRANULAR LYMPHOCYTE PROLIFERATIVE DISORDERS

The immunological findings and clinical course of 33 patients with gra nular lymphocyte-proliferative disorders (GLPD) are presented. Based o n the surface phenotypes of peripheral blood granular lymphocytes (GL) , the GLPD were divided into two groups, namely CD3(+) T cell-lineage GLPD (T-GLPD) and CD3(-) CD16(+) NK cell-lineage GLPD (NK-GLPD). Twent y-one patients had T-GLPD, and 12 had NK-GLPD. One patient with T-GLPD and two patients with NK-GLPD had progressive clinical courses and di ed of the disease despite receiving combination chemotherapy. Among el even patients analysed for the expression of multidrug resistance P-gl ycoprotein, six of eight patients with T-GLPD and all three patients w ith NK GLPD clearly expressed P-glycoprotein. Since patients with imma ture NK-GLPD appear to undergo a progressive clinical course, we sugge st that therapeutic trials using P-glycoprotein blockers in addition t o chemotherapy might be beneficial for such patients.