AN ANALYSIS OF INFANTILE ACUTE-LEUKEMIA BY A CASE-CONTROL STUDY

Infantile leukemias (IL) are rare diseases. We analyzed 18 IL cases (age at diagnosis (AD) < 1 year), treated in a single institution over a 15 year period. IL cases were paired with elder leukemic children (1:3) according to: (1) type of leukemia (ALL and ANLL); (2) sex; (3) year of diagnosis; (4) regional residence. For ALL, 2 control groups (CG) were chosen: AD 3-6 years (CG1) (pediatric ALL age incidence peak in Italy) and AD > 6 years (CG2); for ANLL, not having a significant age incidence peak: AD > 3 years. In ALL the main biological differences between IL and CGs are represented by initial WBC count and IgM at onset, significantly higher in IL cases (for IgM p < 0.05; for WBC p < 0.001 and 0.005 vs CG1 and CG2, respectively). In ANLL a significant excess of M4/M5 morphology was found among IL (p < 0.05). Moreover, a significantly shorter survival was found in infantile ALLs vs CG1 (p < 0.05). The small sample is a problem in this study. However, age at diagnosis and other risk factors seem to have different prognostic and/or etiologic value according to leukemia subtypes in infants.