Second primary tumors and immune phenomena after fludarabine or 2-chloro-2'-deoxyadenosine treatment

The purine nucleoside analogs fludarabine and 2-chloro-2'-deoxyadenosine di splay substantial activity in the treatment of various chronic lymphoprolif erative disorders. Their major toxicities are primarily immunosuppression a nd myelosuppression. The profound influence of these drugs on the immune sy stem has raised questions as to the emergence of secondary neoplasms or aut o-immune disorders after their use. Based on a literature review and on per sonal observations, this article reviews the potential clinical importance of these concerns.