The use of monoclonal antibodies against primary myeloid granules in normal and leukemic cells.

Three monoclonal antibodies, K101, D46, and H36/71 (CD15), reactive with membrane components of primary granules of human promyelocytes, were studied to assess their binding to normal and leukemic cells. Using the alkaline phosphatase antialkaline phosphatase technique, these antibodies were applied to sections of normal organs and to peripheral blood and bone marrow films from hematologically normal individuals and patients with hematologic malignancies. In control experiments, antibodies showed reactivity with cytoplasmic constituents of granulocytes from the promyelocytic to the neutrophilic stage. In acute myeloid leukemia, antibody K101 was positive (more than 20% of blasts) in 13 of 21 (62%) cases, while antibody D46 was positive in 11 of 17 (65%) cases. Antibody H36/71 was positive in only 4 of 24 (17%) cases of acute myeloid leukemia. At least one marker was present in 6 of 8 (75%) cases of acute lymphoblastic leukemia with myeloid antigen-positive blasts and was negative in 20 cases of acute lymphoblastic leukemia with myeloid antigen-negative blasts. These results support the view that abnormal granules (with defective expression of the D46, K101, and H36/71 antigens) form in blastic and leukemic cells of patients with acute myeloid leukemia. Data also suggest that membrane components of myeloid granules are made in the cytoplasm of cells from some acute lymphoblastic leukemia patients with myeloid antigen-positive blasts.

The use of cytochemical procedures in the diagnosis and management of acute and chronic myeloid leukemia.

The use of Wright-Giemsa-stained smears alone for the classification of acute leukemias often proves unsatisfactory. Some cases of M1, M5a, M7, and L2 are morphologically similar. In such cases, cytochemical stains can provide an inexpensive and available diagnostic tool. M1 is positive for SBB and MPO. M5a is usually NSE positive, whereas SBB and MPO are negative. M7 usually is ANA esterase, PAS, and AP reactive, and do not stain with SBB, MPO, and ANB esterases. The megakaryocytic lineage usually is confirmed by ultrastructural cytochemistry for PPO or immunocytochemistry for platelet glycoproteins and von Willebrand factor. PAS block positivity and AP dotlike reactivity are suggestive of lymphoid lineage. NSE stains are useful in differentiating M2 from M4. Morphologic and cytochemical techniques also can suggest the presence of certain chromosomal abnormalities such as t(8;21) and inv(16), which may have an influence on prognosis. Because not all cases of acute leukemia are easily subtyped by morphology and cytochemistry, immunophenotyping, karyotyping, and molecular analysis of DNA and RNA of leukemia cells also may be required to define cell lineage.

Morphologic characteristics of erythroleukemia (acute myeloid leukemia; FAB-M6): a CALGB study.

We have reviewed the clinical, morphologic, immunophenotypic, and cytogenetic features of 52 patients with erythroleukemia (FAB Cooperative Group; AML-M6) studied by the Cancer and Leukemia Group B (CALGB). The purpose of this study was to correlate morphology with the clinical features, immunophenotypes, and karyotypes of neoplastic cells, and with the response to therapy of patients with AML-M6. Thirty-three patients (63%) were male, median age 59 (range 16-81) years, 47 patients (90%) were white, and 42 patients (81%) had a performance status of < 2. Myelodysplastic changes were observed in at least 1 cell lineage in all cases, and in 2 cell lineages in 45 of 52 (86%) cases. Fifty percent or more of cases studied were positive for CD11b, CD13, CD15, CD33, glycophorin-A, and HLA-DR markers. Fourteen of 27 cases (52%) in whom karyotypic analyses were conducted had cytogenetic abnormalities. Five (19%) were simple (< 3 karyotypic abnormalities), while 9 (33%) were complex (> or = 3 abnormalities). We observed either a complete or partial loss of chromosomes 5, 7, or 12p, or the presence of trisomy 8, in 11 of 27 (41%) patients. Cases of AML-M6 were divided into group 1 (14 patients with bone marrow proerythroblasts and basophilic erythroblasts > 25% of all erythroblasts) and group 2 (38 patients with proerythroblasts and basophilic erythroblasts < or = 25% of all erythroblasts). We observed no significant differences between groups 1 and 2 in regard to sex, age, race, performance status, percentage of blood erythroblasts or myeloblasts, percentage of bone marrow erythroblasts, and periodic acid-Schiff (PAS) or myelodysplasia scores. Six of 6 (100%) patients of group 1, and 7 of 21 (33%) patients of group 2, had normal karyotypes (P = .006). Nine of 13 (69%) patients of group 1 and 15 of 33 (45%) patients of group 2 had a complete remission (CR) (P = .2). Eight of 11 (73%) cytogenetically normal patients achieved CR: 5 of 6 (83%) in group 1, and 3 of 5 (60%) in group 2. Five of 12 (42%) cytogenetically abnormal patients achieved CR. No difference in duration of survival (group 1, median = 4.6 months vs. group 2, median = 10.2 months; P = .93) was observed between the 2 groups. We conclude that AML-M6 is typified by multilineage involvement of hematopoietic cells. The morphology of erythroblasts in patients with AML-M6 may correlate with cytogenetic abnormalities and rate of CR.

Morphologic and cytochemical characteristics of acute promyelocytic leukemia.

The existence of two distinct subtypes of acute promyelocytic leukemia was confirmed and characterized based on morphologic features of leukemic cells in a series of 63 patients studied by the Cancer and Leukemia Group B (CALGB). Seventeen patients (27%) had microgranular leukemic cells (M3V), and 46 patients (73%) had hypergranular leukemic cells (M3). These patient cohorts were studied for other laboratory and clinical features. Leukemic cells from M3V patients stained less frequently than leukemic cells from M3 patients for myeloperoxidase (median, 93% vs. 99%; P = .006), periodic acid-Schiff (median, 57% vs. 92%; P = .0001), ASD-chloroacetate esterase (median, 45% vs. 87%; P less than .0001), and alpha-naphthyl acetate esterase (0% vs. 37%; P = .0003). Patients with M3V had a higher platelet count (median, 50 vs. 30 x 10(9)/L; P = .01) and tended to have a higher leukocyte count (median, 7.4 vs. 2.2 x 10(9)/L; P = .06) than M3 patients. The patients with M3V morphology were more likely to be nonwhite (29% vs. 7%; P = .03), female (71% vs. 37%; P = .02), and to be infected at the time of presentation (71% vs. 35%; P = .02). No differences in the frequency of the t(15;17) karyotype or the immunophenotypic expression of the leukemic cells were noted in the two morphologic subtypes of acute promyelocytic leukemia. Fewer patients with M3V tended to enter complete remission (65% vs. 80%; P = .20), but no significant differences were found in the duration of complete remission (P = .81; 1 year rate, 50% vs. 85%), or probability of survival (P = .67; 1 year rate, 49% vs. 68%).