[Retinoic acid syndrome]

Retinoic acid syndrome still remains as the most significant complication of the differentiation treatment of acute promyelocytic leukemia. Of unknown pathogenesis this syndrome is close but not absolutely related to hyperleukocytosis developed during treatment. It shares clinico-biological characteristics with three other known syndromes: adult respiratory distress syndrome, endotoxic shock and capillary leak syndrome. It can be hypothesized that as in these cases, the main target is the endothelial cell. Some observations contribute to support this hypothesis. An interleukin storm is probably triggered by retinoic acid treatment as well as an increase in adhesion molecules, both contributing to an autocatalytic injury in patients developing the retinoic acid syndrome.