DELAYED REPAIR OF DNA-DAMAGE BY IONIZING-RADIATION IN CELLS FROM PATIENTS WITH JUVENILE SYSTEMIC LUPUS-ERYTHEMATOSUS AND RHEUMATOID-ARTHRITIS

We used a single-cell alkaline gel electrophoresis (SCAGE) assay to st udy repair of primarily single-stranded DNA breaks after in vitro expo sure to ionizing radiation in cells from children with systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (JRA), systemic scl erosis (SSc) and dermatomyositis, Peripheral blood lymphocytes from pa tients with SLE, JRA and SSc had significantly greater DNA damage afte r irradiation with 1.5 Gy and 30 min incubation (i.e. repair time) tha n did those from controls, as assessed by the length of the migrating DNA comet. The mean comet tail lengths were: SLE, 42 mu m; JRA, 40 mu m; and SSc, 36 mu m, Each of these was significantly different from co ntrols, which had a mean comet tail length of 18 mu m (P < 0.001, < 0. 001 and < 0.05, respectively), Cells from patients with dermatomyositi s had an average comet tail length of 22 mu m and were not significant ly different from controls. Understanding the etiology of the delay in DNA repair in these diseases may provide insight into disease pathoge nesis. (C) 1997 by Radiation Research Society