Acute Lymphoblastic Leukæmia in Children: Classification and Prognosis

Developmental hierarchy of immunoglobulin gene rearrangements in human leukemic pre-B-cells.

“…Leukemic lymphocytes were obtained by Ficoll/Hypaque gradient centrifugation of leukophoresis-obtained cells from patients with high count (>40,000 cells/mm3) acute lymphocytic leukemia (ALL). Such leukemic lymphocytes from our eight cases ofcommon non-T/non-B-cell ALL were examined for their ability to form rosettes with neuraminadase-treated sheep erythrocytes (a T-cell marker) and for the presence of surface immunoglobulins ofclasses y, a, A, 8, K, and A by direct immunofluoresence (a B-cell marker) (26,27). They were also characterized with a number of monoclonal antibodies (28)(29)(30)(31)(32)(33).…”

“…Although prior studies ofthis class ofleukemias revealed that approximately 15-20% have small quantities of u chain in their cytoplasm, thus placing at least this subgroup in a pre-B-cell category (24,25), none have the characteristic surface markers of either T (rosette formation) or B cells (surface immunoglobulin) (26,27). Indeed, considerable controversy still exists as to the exact cellular origin of the majority of these cases, so that the ability to classify these leukemic cells in the B-or T-cell series remains an important diagnostic goal with possible therapeutic implications.…”

Immunophenotyping of acute leukemias and myelodysplastic syndromes

“…More than 20 years ago, ALL was already classified as B, T, or null ALL (non-B, non-T) depending on whether leukemic cells expressed surface immunoglobulins (sIg), formed rosettes with sheep erythrocytes, or lacked on both markers (30). Later on, the identification of the CD10 antigen, present in around two-thirds of all ALL patients, provided the basis for the more recent classifications through the definition of a new subgroup of patients that included most non-B, non-T cases (the common ALL phenotype) (31). The phenotypic immaturity of these morphologically-appearing lymphoid-lineage cells was supported on immunophenotypic grounds by their positivity for the terminal deoxynucleotidyl transferase enzyme (nTdt) (32).…”

Adjuvant low dose radiation in childhood T cell leukaemia/lymphoma (report from the United Kingdom Childrens' Cancer Study Group--UKCCSG)

“…Ten to 20% of children with a morphological diagnosis of acute lymphoblastic leukaemia (ALL) have lymphoblasts whose surface receptors indicate a T cell lineage, and these patients have an inferior prognosis when compared to patients with common ALL (Chessells et al, 1977). About one-third of children with NHL present with a mediastinal mass and the lymphoblasts from these lymphomas likewise indicate a T cell lineage.…”