Follow-up study of biological indicators in three accidently-exposed patients

Objective To identify the candidate biomarkers for early diagnosis or the therapeutic targets in late ionizing radiation injury by analyzing the lymphocyte subgroups,serum protein levels and gene expression profiles in the peripheral blood of three60 Co γ-ray accidentally-exposed patients during three years after irradiation.Methods Flow cytometry and agarose gel electrophoresis were used to investigate lymphocyte subgroups and serum protein levels,respectively.Gene expression profiles were obtained by using whole genome gene expression chip assay.Results Three-years after irradiation,the percentage of CD4+T lymphocytes declined and the percentage of CD8+T lymphocytes increased so that the ratio of CD4+to CD8+decreased,meanwhile,the serum albumin level declined whereas beta globulin increased in the patient peripheral blood.In addition,the expressions of 285 genes were up-regulated while those of 446 genes were down-regulated in the irradiated patient samples,where the expressions of KDR,CEACAM8 and OSM were further confirmed by real-time RT-PCR.Conclusions The changes of the percentage of CD4+T cells and the ratio of CD4 +/CD8+T cells in peripheral blood may be useful as biomarkers of late radiation injury. Key words: Accidental exposure; Gene expression profile; CD4 +/CD8+ratio; Lymphocyte subpopulations; Albumin