DNA repair, sensitivity to gamma radiation and to heat shock in lymphocytes from acute, untreated multiple sclerosis patients

Increases in spontaneous sister chromatid exchange (SCE) and gamma radiation-induced chromosome aberrations have been reported in peripheral blood lymphocytes (PBL) from multiple sclerosis (MS) patients, suggesting the presence of an abnormality in repair in this disease. We tested this hypothesis by measuring the ability to repair DNA and survival, after exposure to low (2-12 Gy) and high (100 Gy) gamma ray doses or to a high temperature (37-45°C), of freshly isolated PBL from 15 patients affected by definite MS and 15 healthy subjects. The MS patients were untreated and in the acute phase of the disease. No significant difference was found between the two groups. We suggest that the previously reported genomic instability may be of viral origin and not due to a genetic defect in repair of DNA in these patients. © 1989.