A comparative study of immunological and cytochemical profiles between adult and childhood acute lymphoblastic leukemias (ALLs): heterogeneity in adult common ALL

Possibilities and limitations of cytochemical methods in diagnosis of acute leukemia

Accurate identification and classification of leukemic blast cells is a very important prerequisite of the precise diagnosis of acute leukemia and has a great impact on therapy and prognosis. The purpose of this review is to consider, in the broad sense of the word, the present possibilities and limitations of enzyme cytochemistry and to emphasize how cytochemistry may contribute, on integration with the other methods of study, to the final classification and differential diagnosis of acute leukemia, a highly variable hematological disorder. In this review, the role of conventional enzyme cytochemistry, either dominant or subsidiary, in the discrimination of acute leukemia subtypes is discussed. The survey confirms the absolute necessity of immunologic marker analysis in the accurate diagnosis of acute lymphoblastic leukemia, undifferentiated or minimally differentiated leukemia and mixed-lineage leukemia because in these cases, the cytochemical evaluation provides insufficiently relevant information regarding blast cell origin, specificity of leukemia subtypes and the discrete stages of leukemic cell maturation. On the other hand, cytochemical investigation is appreciated to be dominant over immunophenotyping in characterizing acute myeloid leukemia, because of the lack of specificity of the majority of immunological markers against myeloid antigens and, because of the availability of standardized and sufficiently specific cytochemical reactions. The cytogenetic, molecular biological and electron microscopic studies mentioned in this review supplement the important information for correct differential diagnosis of acute leukemia. The prognostic impact of enzyme cytochemistry in correlation to other methods is evaluated.

Cell kinetics in acute lymphoblastic leukaemia: comparative analysis between adults and children

Cell kinetics were studied in 124 patients with acute lymphoblastic leukaemia (ALL) by flow cytometry, comparing cell cycle characteristics between adults (57 cases) and children (67 cases). S, G2 + M and the low protein content fraction of G1 (LPC fraction) were determined and studied in relation to other clinical and biological features. No difference was found between adults and children in the distribution of these variables. The proliferative rates according to organomegaly, leukocytosis, the FAB cytological groups and the immunological groups did not present any significant differences between the two groups of patients. However, cell cycle did seem to have a very different prognostic value for adults and for children. G2 + M was a strong prognostic indicator for childhood ALL: duration of CR and survival were significantly longer when G2 + M was higher (P less than 0.01). In adults, survival was longer for intermediary (between 3.8 and 5.8%) and high (over 7.2%) G2 + M values (P less than 0.01). The negative correlation between S and G2 + M observed in adults and the absence of correlation in children raise the possibility of differences in duration of the different phases for the two groups and perhaps an accumulation of cells in G2 or tetraploidy in some cases.