OBJECTIVETo analyse the expression of glycosylphosphatidylinositol (GPI)-anchored protein and functional transition of lymphocyte subsets in paroxysmal nocturnal hemoglobinuria (PNH) patients.

METHODSFlow cytometer and multi-color McAbs were used to detect CD(59) expression on lymphocytes and their subsets. Stimulation test was used to examine the ability of affected T cells in converting from CD(45RA) phenotype to CD(45RO) phenotype.

RESULTSIn 14 PNH samples, CD(59) expression on affected lymphocytes was at a lower percentage than that on granulocytes and erythrocytes. B lymphocytes were widely affected than NK or T cells. CD(59)(-) deficient B lymphocytes existed in all PNH patients. More CD(8)(+) T cells were affected than CD(4)(+) T cells. Expression of HLA-DR and CD(45RO) on affected T cells were significantly lower than that on normal T cells (P < 0.01), whereas the expression of CD(45RA) was much higher on the former (P < 0.01). After stimulation with phytohemagglutinin (PHA), the expression of CD(45RA)(+) on affected T cells decreased sharply (the median value was from 82.7% to 26.6%), while the expression of CD(45RO)(+) increased significantly (the median value was from 19.6% to 64.3%).

CONCLUSIONSThe deficient CD(59) phenotype does involve in the different types of lymphocytes in PNH patients. Therefore affected B cells could be a good marker for diagnosis of PNH. The affected T cells were mainly comprised naive cells (CD(45RA)(+)HLA-DR(-)), which could acquire the memory phenotype (CD(45RO)(+)HLA-DR(+)) after stimulated by antigen.