Acute monocytic leukemia: a surface marker study

Diagnostic and prognostic factors in acute monocytic leukaemia: an analysis of 51 cases

Diagnostic features (cytochemistry, immunophenotyping and serum biochemistry) were examined in 51 cases of acute monocytic leukaemia (AMoL). Peroxidase, Sudan black B and alpha naphthyl acetate esterase (ANAE) cytochemical reactions were unrelated to morphological (FAB groups M5a and M5b) or immunological subtype. ANAE cytochemistry, however, indicated that AMoL cases could be subdivided into those with typical (M-type) reactions and those with insignificant staining or monocytic ANAE isoenzymes (defined by IEF). All cases were phenotypically CD13/CD33 positive and, with one exception, had greater than 30% HLA-DR positive cells. Membrane CD14 expression was insignificant or variable in 33% of M5a cases in contrast to 23/24 M5b cases which showed high proportions of CD14-staining cells with at least two monoclonal antibodies. Serum lysozyme, LDH and beta-2 microglobulin (beta 2m) were increased in 88%, 68% and 81% of cases respectively but, with the exception of statistically higher lysozyme levels in CD14+ cases, were unrelated to the morphological, cytochemical or immunological diagnostic subgroups. Clinical and diagnostic features were also examined as possible prognostic indicators. The morphological, cytochemical and immunological subgroups of AMoL were not found to be of prognostic relevance but age (P = 0.004), renal failure (P = 0.005) and serum beta 2m levels (P = 0.002) were related to patient survival. Moreover, renal failure and serum beta 2m remained significant (P = 0.012 respectively) when age was taken into account and were shown to be independent prognostic variables.

Acute leukemia with mediastinal mass, lymphadenopathy, and monocytic precursor cells

Cell marker analysis with monoclonal antibodies (MoAb) as well as differentiation studies with the chemical inducer TPA were used to identify a population of apparently lymphoid cells as monocytic precursor cells in a patient with acute leukemia. The initial manifestation of the disease with mediastinal mass and lymphadenopathy was followed by the appearance of small lymphocyte-like blast cells in bone marrow (BM) and peripheral blood (PB). Although a lymph node biopsy revealed an infiltration with monoblasts, the leukemic cells in BM and PB were not classifiable. However, when the patient relapsed after chemotherapy with large monoblasts and again with morphologically lymphoid blast cells, the latter could be classified by treatment with TPA. After incubation with the inducer (12-48 hr) the cells became positive with the MoAB VIM-D5, showed a strong reaction with alpha-naphthyl-acetate-esterase and developed macrophage like morphology, as well as phagocytic properties. During the terminal phase of the disease, small, lymphocyte-like blast cells predominated. These cells could be classified by a panel of MoABs. They expressed myeloid determinants (VIM-D5, VIM-2, MY 9, VIM-12, VIM-13) but showed no reactivity with MoABs specific for lymphocytic cells.

Monocytic leukemia in infancy. A review of eight children

The clinical and pathologic features of eight infants with monocytic leukemia are reviewed. The children were all aged 12 months or less at diagnosis and had a high incidence of extramedullary features, skin infiltration being particularly common. The diagnosis was established by conventional morphologic and cytochemical techniques. Using the French-American-British (FAB) classification, five infants had FAB 5a disease, and three had FAB 5b. The difficulties in making the diagnosis from extramedullary sites and the overlap that exists at this age between monocytic leukemia, true histiocytic lymphoma, and malignant histiocytosis are discussed. The treatments given to the group and their response are reviewed. Five of the patients received VP-16-213 and cyclophosphamide as primary induction chemotherapy, a combination that merits further evaluation in leukemia with monocytic features.

Membrane Fc-IgG and C3b receptors on myeloid leukaemia cells: a comparison with cytoplasmic acid naphthyl acetate esterase cytochemistry

Membrane receptors for IgG and C3b were examined on blast cells from 57 cases of acute myeloid leukaemia. These acute leukaemias were classified as myeloblastic, myelomonocytic or monocytic following morphological, cytochemical, and immunological investigations. The membrane receptors of leukaemic blast cells appear to be directly related to the degree of monocytic differentiation with the lowest receptor activities found in acute myeloblastic leukaemia. A comparison was also made between receptor and cytoplasmic acid naphthyl acetate esterase (ANAE) activities in 29 morphologically and immunologically-defined myelomonocytic and monocytic leukaemias. This study revealed that the receptor-positive "monocytic component" in a significant proportion of cases showed unexpectedly weak or negative ANAE reactions suggesting a more cautious approach to the interpretation of ANAE cytochemistry in acute leukaemias. The normal development of cytoplasmic ANAE and membrane receptors is also discussed and compared with their abnormal patterns of expression associated with leukaemic transformation.