Infant leukaemia: clinical, biological and therapeutic advances

Infant acute lymphoid leukaemia (IALL) represents a distinct subset with an extremely poor response to therapy, despite major progress in the treatment of childhood leukaemia. However, several studies have shown that, even in this generally considered homogeneous group, a distinction could be made with regard to prognosis. The outcome of IALL patients with ALL-1/MLL rearrangements at the 11q23 cytogenetic band, early pre-B immunophenotype, high WBC count and age below 6 mo is significantly worse than in patients without these characteristics, and current therapies appear inadequate in a significant number of cases. Therefore, an international protocol (Interfant 99) was recently started, using a more aggressive approach, which included lymphoid- and myeloid-specific drugs, and indications for stem-cell transplantation. We reviewed the clinical characteristics of the disease, the results of several recent international clinical trials, and our experience with 16 infants with acute lymphoid leukaemia diagnosed and treated at our institution.

It is extremely important to stratify patients for prognosis, taking into account clinical and biological variables with independent prognostic value. The aim is to select more adequate, risk-adapted, therapeutic strategies which also consider related or unrelated bone marrow transplant consolidation for patients with very poor prognosis.