Age-related aneuploidy analysis of human blood cells in vivo by fluorescence in situ hybridization (FISH).

All prior studies on human age-related chromosomal analysis were done using only metaphase figures derived from lymphocyte cultures in vitro. However, we believe that this procedure may provide only partial information, since the chromosomal abnormalities probably hidden in non-dividing and/or terminally differentiated leukocytes will not be detected by this method. We, therefore, have attempted to analyze the nature and extent of chromosome-specific aneuploidy at interphase by fluorescence in situ hybridization (FISH) in differentiated myeloid cells in vivo derived from various age-group people. Our data from an analysis of 30,032 cells derived from 12 healthy donors indicate that there is an increase in the mean percentages of myeloid cells with chromosome-specific aneuploidy in the older groups as opposed to that of the younger groups. This increase is applicable to all the three cell types examined (promyelocytes, metamyelocytes and polymorphs). In both the younger and older females, the relatively higher mean frequencies of cells with aneuploidy were noted for chromosome nos. 4, 6 and the X, whereas the lowest mean frequencies of cells with aneuploidy were consistently observed for chromosome no. 3. In the younger and older male donors, similar to the female donors except the X chromosome the higher percentages of aneuploid cells were observed for chromosome nos. 4 and 6 whereas the lowest mean frequencies of aneuploid cells were noted for chromosome no. 3. Among the five autosomes studied, chromosome no. 3 consistently yielded the lowest frequency of aneuploidy in all the three cell types derived from both the younger and older groups of males and females. This could presumably mean that the maintenance of a very high frequency of cells with disomy for chromosome no. 3 might be more beneficial for the process of survival and/or differentiation of myeloid cells as compared to that of other autosomes such as chromosome nos. 4 and 6. Among the five autosomes studied, chromosome no. I exhibited the highest rate of increment in the aneuploidy values of both males and females with advancing age.