Production and characterization of lymphoblastoid cell lines with the paroxysmal nocturnal hemoglobinuria phenotype.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic disorder caused by a somatic mutation in a hematopoietic stem cell. The fact that, in some cases, not only myeloid but also lymphoid cells are affected suggests that the mutation has occurred in a multipotent stem cell. By studying the expression of CD59 antigen (membrane inhibitor of reactive lysis) and of decay accelerating factor (DAF) on the lymphocytes of 16 patients with PNH, we found an abnormal population of lymphocytes (with absent CD59 and DAF) in 10 cases. From 4 of these patients we were able to produce Epstein-Barr virus-immortalized lymphoblastoid cell lines (LCLs) that have a PNH phenotype (absent CD59, DAF, and CD48). PNH LCL cells have apparently normal DAF messenger RNA despite not having DAF on their surface. These cell lines will be a valuable resource for further investigation of the defect or defects underlying PNH.