Lymphocytes in ataxia telangiectasia: Implications of the DNA repair defect

Fibroblasts from patients with ataxia telangiectasia have been demonstrated to be more sensitive to ionizing radiation than controls and are defective in repair of such damage to DNA. We have investigated the DNA repair capacity of phytohemagglutinin-stimulated lymphocytes, from persons with ataxia telangiectasia, after exposure to ionizing radiation. Comparison with DNA repair in control lymphocytes indicates a much reduced capacity in ataxia telangiectasia. Measurement of DNA repair in stimulated lymphocytes thus provides a suitable and rapid assay for AT homozygotes. The lymphocyte DNA repair defect may be related to the immunological abnormalities seen in this disease