Ex vivo method of obtaining non-diseased living cells, said cells being suitable for treating a disease in a subject by destroying diseased cells, wherein said cells are obtained by a method comprising (a) determining the activity of at least one marker gene of disease in a population of cells obtained from said subject； (b) introducing into said cells a polynucleotide encoding a selectable marker and a polypeptide that is itself lethal to said cells, wherein the expression of said lethal polypeptide is directly or indirectly controlled by the promoter of said at least one marker gene of disease； (c) exposing said cells to selection conditions to obtain cells comprising said polynucleotide； (d) treating said cells under conditions that induce the expression of said lethal polypeptide, wherein said expression of said lethal polypeptide eliminates said cells expressing said at least one disease marker gene； and (e) separating said eliminated cells from the remaining non-diseased living cells, wherein said living cells do not express said lethal polypeptide to a sufficient extent to eliminate said non-diseased cells.Método ex vivo de obtención de células vivas no enfermas siendo dichas células adecuadas para tratar en un sujeto una enfermedad destruyendo células enfermas, en el que dichas células se obtienen mediante un método que comprende (a) determinar la actividad de al menos un gen marcador de enfermedad en una población de células obtenida de dicho sujeto； (b) introducir en dichas células un polinucleótido que codifica un marcador seleccionable y un polipéptido que es por sí mismo letal para dichas células, en donde la expresión de dicho polipéptido letal está controlada directa o indirectamente por el promotor de dicho al menos un gen marcador de enfermedad； (c) exponer dichas células a condiciones de selección para obtener células que comprenden dicho polinucleótido； (d) tratar dichas células en condiciones que induzcan a la expresión de dicho polipéptido letal
