Loss of high frequency of sister chromatid exchanges in Epstein-Barr virus-established lymphoblastoid cell lines from two patients with Bloom's syndrome.

Seven lymphoblastoid cell lines were established through transformation by Epstein-Barr virus of peripheral blood lymphocytes from two patients with Bloom's syndrome (BS), the parents of a patient, and normal controls. High baseline levels of sister chromatid exchanges (SCEs) in peripheral blood lymphocytes of BS were reduced to about 10% of their initial value in BS lymphoblastoid cell lines, and the elevation of SCE frequencies induced by ethylmethanesulfonate was the same as in controls.