CORRECTION OF FANCONI-ANEMIA TYPE-C PHENOTYPIC ABNORMALITIES USING A CLINICALLY SUITABLE RETROVIRAL VECTOR INFECTION PROTOCOL

Fanconi anemia (FA) is a complex autosomal recessive disease with hema tologic manifestations characterized by a progressive hypoplastic anem ia, hypersensitivity to clastogenic agents, and an increased incidence of acute myelogenous leukemia, The cDNA that corrects one of four FA complementation subtypes, named Fanconi anemia Type C (FAC) has recent ly been identified. We constructed a simplified recombinant retrovirus (vMFGFAC) encoding only the FAC cDNA, and tested its ability to corre ct the FAC defect in a lymphocytic cell line and primary mobilized blo od progenitor cells, In addition, the gene transfer efficiency using a clinically applicable gene transfer protocol into normal primitive he matopoietic progenitor cells, high proliferating potential colony form ing cells (HPP-CFC), derived from CD34+ purified cord blood cells was examined. The gene transfer efficiency was significantly enhanced when cells were transduced with supernatant while adherent to a 30/35 KD f ragment of fibronectin, FN30/35, and was similar to efficiency obtaine d by coculture with retrovirus packaging cells. Transduction of an FAC deficient lymphoid cell line with VMFGFAC supernatant resulted in an enhanced cell viability, and G-CSF-mobilized peripheral blood cells fr om an FAC-deficient patient transduced with the vMFGFAC virus demonstr ated enhanced progenitor cell colony formation, These data indicate th at the vMFGFAC virus allows functional complementation of FAC in lymph oblasts and primary hematopoietic progenitors, and that primitive cord blood hematopoietic stem/progenitor cells can be transduced at an eff iciency comparable to protocols using cocultivation if adherent to FN 30/35 fragment.