Marzie Mahmoodi - Cell and Molecular Biology Department,faculty of Biological Sciences, Science and Research University(SRBIAU),Tehran, Iran,Department of medical genetics, Iran University of medical sciences. Tehran ,Iran, Department of human genetics, Tehran University o
Shahram Teimourian - Department of medical genetics, Iran University of medical sciences. Tehran ,Iran, Department of human genetics, Tehran University of medical sciences. Tehran ,Iran, Pediatrics Infectious Diseases Research Center, Department of Infectious Disease, School

Severe Combined Immunodeficiency Disease (SCID) is the most serious and rare but important primary immunodeficiency disorder. The defining characteristic of SCID is the absence of T cells andlack of functional B cells. This disease can be inherited in two forms of X-dependent and autosomalrecessive. Patients with SCID are treated with BMT. Imunocompetent NK cells in radiosensitive SCID patients pose a significant barrier to engraftment of HLA-mismatched donor stem cells as high-dose of chemotherapy or radiotherapy is applied to suppress NK cells to prevent GVHD. Radiosensitive SCID patients need HLA match donors. Method In this study, fibroblast cells of children suspected to SCID were cultured and were used in cometassay technique followed by comet score analysis by software freeware v1.5. and compared with colonogenic assay Result In this study, fibroblast cells of children suspected to SCID showed rate of DNA damage repair by colonogenic assay relatively the same as alkalin comet assay (The Single Cell Gel Electrophoresisassay) Discusion This technique is fast, inexpensive and accurate for radiosensitivity assay in children suspected to SCID disease relative to colonogenic assay .

SCID, comet assay, clonogenic assay, ARTEMIS