Analysis of sister-chromatid exchanges (SCEs) in familial and sporadic multiple sclerosis.

The levels of sister-chromatid exchanges (SCEs) were calculated in 17 multiple sclerosis (MS) patients (14 familial and 3 sporadic cases) and 16 healthy controls matched for sex and age. The SCEs were significantly increased for MS patients (p = 0.0002), while there was no statistically significant difference between men and women and between younger and older subjects in both groups. Such factors as familial occurrence and severity of MS, smoking habits, and distribution of lymphocyte subpopulations were discussed. Although there was a significant difference between the MS patients taking medication and the patients taking none (p = 0.038), the latter were still significantly different from the controls (p = 0.035), supporting the fact that the disease itself increases SCEs. Our study, done with 2 doses of BrdU, also shows that the increased SCEs in MS patients are not due to a hypersensitivity to this substance known to be an inducer of SCEs. Thus we suggest that the increased SCEs found are probably disease-related.