Rechavi, G., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Brok-Simoni, F., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Katzir, N., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Mandel, M., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Umiel, T., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Stark, B., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Zaizov, R., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Ben-Bassat, I., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel
Ramot, B., Institute of Hematology, The Chaim Sheba Medical Centre, Tel-Hashomer 52 621, Israel

Congenital and infant leukemia are rare conditions associated with a very poor prognosis due to a high frequency of adverse clinical and laboratory parameters. As the occurrence of multiple immunoglobulin heavy chain hybridization band in childhood leukemia has been associated with poor prognosis, we studied whether it was present in this type of leukemia as well. Seven cases were examined, 4 of them less than 7 months of age. The immunophenotype was lymphoid in 5 and hybrid in 2. Most had abnormal karyotypes. In 5 of the 7, including all with congenital leukemia, an immunoglobulin heavy chain J region multiband pattern was found by Southern blot. The multiband pattern, whether primary or due to clonal evolution, seems to be associated with poor prognosis.