Chromosome analyses of lymphoid cell lines derived from patients with chronic lymphocytic leukemia

To study chromosome complements of chronic lymphocytic leukemia cells, six Epstein‐Barr virus‐transformed lymphoid lines were established from two patients with this disease who were heterozygous for the X‐chromosome‐linked enzyme glucose‐6‐phosphate de‐hydrogenase (G6PD). Immunoglobulin and G6PD were used as markers of the leukemic versus normal cell origin of the cell lines. The two lines, derived from putative normal cells, had no chromosomal changes. In contrast, chomosome abnormalities were found in each of the four cell lines of presumed leukemic cell origin. Although the chromosome aberrations are not as specific as the Philadelphia chromosome, there appears to be non‐random involvement in chronic lymphocytic leukemia of some chomosomes, such as the No. 12.