We have a single cell assay (SCA) to study repair of primarily single-stranded DNA breaks after in vitro ionizing radiation in children with systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (RA), prog...We have a single cell assay (SCA) to study repair of primarily single-stranded DNA breaks after in vitro ionizing radiation in children with systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (RA), progressive systemic sclerosis(PSS),and dermatomyositis. Patients with SLE, JRA, and PSS had significantly greater damage after 150 rads and 30 minutes incubation than did controls as assessed by comet length migration of damaged DNA. The average comet length in SLE was 42μm,in JRA was 40μm,and in PSS was 36μm, each of which was significantly greater than controls with an aver age comet length of 18μm (P<0.001,<0.001,and,CO.005 respectively).Patients with dermatomyositis (DMY) had an average comet length of 22 μm, which was similar to controls. In addition,the DNA damage was not repaired in as many cells from patients with autoimmune diseases. By 30 minutes after irradiation,64% of control PBL had re turned to a normal configuration. In contrast, only 18% of SLE PBL, 15% of JRA PBL,6% of PSS PBL returned to normal configuration (P<0.005);in dermatomyositis, 50%of the cells had completely repaired their DNA, which was similar to controls.These studies indicate that DNA repair is defective in patients with SLE,JRA, and PSS.Understanding this DNA repair defect may provide a new diagnostic tool and also aid in understanding the pathogenesis of these disorders.展开更多
文摘We have a single cell assay (SCA) to study repair of primarily single-stranded DNA breaks after in vitro ionizing radiation in children with systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (RA), progressive systemic sclerosis(PSS),and dermatomyositis. Patients with SLE, JRA, and PSS had significantly greater damage after 150 rads and 30 minutes incubation than did controls as assessed by comet length migration of damaged DNA. The average comet length in SLE was 42μm,in JRA was 40μm,and in PSS was 36μm, each of which was significantly greater than controls with an aver age comet length of 18μm (P<0.001,<0.001,and,CO.005 respectively).Patients with dermatomyositis (DMY) had an average comet length of 22 μm, which was similar to controls. In addition,the DNA damage was not repaired in as many cells from patients with autoimmune diseases. By 30 minutes after irradiation,64% of control PBL had re turned to a normal configuration. In contrast, only 18% of SLE PBL, 15% of JRA PBL,6% of PSS PBL returned to normal configuration (P<0.005);in dermatomyositis, 50%of the cells had completely repaired their DNA, which was similar to controls.These studies indicate that DNA repair is defective in patients with SLE,JRA, and PSS.Understanding this DNA repair defect may provide a new diagnostic tool and also aid in understanding the pathogenesis of these disorders.
