Increased bleomycin-induced chromosome damage in lymphocytes of patients with common variable immunodeficiency indicates an involvement of chromosomal instability in their cancer predisposition.

To study mutagen-induced chromosome instability in cancer disposition, late S and G2 lymphocytes of 15 patients with common variable immunodeficiency and 14 healthy controls were exposed to bleomycin in vitro. The groups did not differ in the frequency of spontaneous chromosome aberrations. In bleomycin-treated samples we found higher numbers of break events per cell and increased frequency of cells with aberrations compared to the control group.