[The infant with leukemia]

Infant leukemia is rare and especially in newborn leukemoid reactions should be excluded by careful cytogenetic analysis before starting cytotoxic therapy. Infants have either acute lymphoblastic leukemia, monoblastic leukemia or acute undifferentiated leukemia. At present they have a bad outlook due to many coinciding unfavorable initial disease characteristics: high leukocyte count, liver and spleen enlargement, meningeal involvement, no expression of common ALL antigen, and a high frequency of pseudodiploid cells, that is with a translocation 4;II. The immaturity of organs and systems makes it difficult to treat these infants, and requires optimal supportive care. Therapeutic protocols for prospective clinical trials for leukemia in this age group are urgently needed.