Characterization of blast cells in chronic granulocytic leukaemia in transformation, acute myelofibrosis and undifferentiated leukaemia II. STUDIES WITH MONOCLONAL ANTIBODIES AND TERMINAL TRANSFERASE

Abstract

A panel of 19 monoclonal antibodies (McAb) and the enzyme terminal transferase (TdT) have been applied to the characterization of poorly differentiated blasts from 50 patients with chronic granulocytic leukaemia (CGL) and myelofibrosis in blast crisis (BC), acute myelofibrosis and undifferentiated leukaemia. These cells were also extensively studied by transmission electron microscopy (TEM) (see Polli et al, 1985a). McAb against platelet glycoproteins (GP) showed a high specificity for megakaryoblasts, in particular those reactive with the GPIIb/IIIa complex (J15) and GPIIIa (C15 and C17), which were positive in a higher proportion of blasts than the McAb to GPIb (AN51 and FMC25). Findings with these anti-platelet McAb paralleled those of the platelet-peroxidase (PPO) reaction in 76% of cases studied simultaneously. The PPO reaction was always positive in cases in which two or more of the McAb were reactive with the blast cells. The differences observed suggest, nevertheless, that PPO is more sensitive for megakaryoblasts than the McAb and that this TEM technique should be reserved for cases which are negative with the platelet specific McAb. Of the McAb against myeloid antigens used in this series OKM1 was positive in 50% of cases but the others failed to demonstrate early features of differentiation in myeloblasts and monoblasts. In only three cases were erythroid precursors demonstrated by TEM and these were the only ones reactive with a McAb to glycophorin-A (LICR LON/R10). TdT and the McAb J5 helped in the identification of lymphoblasts which were seen as a 'pure' proliferation in 23% of CGL-BC and as part of blast cell mixtures in another 17% of cases. The McAb reactive to haemopoietic precursor cells (RFB1, FMC8 and OKIa), on the other hand, were of no practical value for the classification of blast cell types. The lineage specificity of several of the McAb used in this study, confirmed by TEM, suggest that these reagents are valuable tools for the characterization of immature blast cells.

Morphological and Immunological Pattern of Blastic Transformation in Chronic Myeloid Leukemia in Saudi Arabia: Study of 90 Transformations Among 248 Patients

“…The proportion of mixed-lineage blast cells in our series is in keeping with the findings described in previous reports [13,14,16]. This group includes only patients whose transformed blasts have maintained lineage consistency during observation.…”

Characterization of myeloid leukemias with monoclonal antibodies 3C5 and MY9

“…These included MPO and PPO reactions at EM and the McAb C17, AN51 and LICR LON/R10 (San Miguel et al, 1985).…”

“…Two McAb against platelet glycoproteins IIIa (C17 ;Tetteroo et al, 1983) and Ib (AN51;McMichael et al, 1981) were used to demonstrate megakaryoblasts and a McAb against glycophorin A (LICR LONiR10; Edwards, 1980) was used to recognize erythroid precursors (San Miguel et al, 1985). Several anti-T cell McAb and E-rosettes were used for the diagnosis of T-cell lymphoblastic leukemia.…”

Diagnostic Flow Cytometry in Hematology: The Leukemias

“…The remaining 70% are conventionally thought to represent myeloblastic transformation. However, the recent study by San Miguel et al [50] would suggest that multiple-lineage transformation (mixed proliferations) consisting of lymphoblasts, myeloblasts, erythroblasts and megakaryoblasts is more common than previously ap preciated. Whether or not such immunologi cal classifications o f 'myelogenous' blast cri sis in CML will result in a significant im provement in therapy remains to be seen.…”