Consecutive phases vary, giving rise to a kinetically distinct mitotic pool in which numbers expand to include the myeloblasts
, progranulocytes and myelocytes - loosely referred to as the fixed components of the microenvironment.
On special staining we found Myeloblasts
of AML and CML showed positive (coarse brown black granules) staining with MPO in more than 3% of blasts in all cases except one in which NSE stain was positive.
Leukocytosis is invariably present at diagnosis with less than 5% myeloblasts
and varying numbers of promyelocytes, myelocytes, metamyelocytes, basophils, and neutrophils (Slide 1).
(10-19 %) in peripheral blood and bone marrow.
Immature granulocytes are defined as the collection of maturing granulocytic myeloid cells that have differentiated beyond the myeloblast
stage, but have not yet reached the stages of band form neutrophils, eosinophils, or basophils.
GS is more common in patients with AML M4 or M5 with Myeloblast
which express T cell surface markers CD13 or CD14 and cytogenetic abnormalities of t (8, 21) or inv 16 (1).
Mylotarg is an antibody-drug conjugate composed of the cytotoxic agent calicheamicin, attached to a monoclonal antibody targeting CD33, an antigen expressed on the surface of myeloblasts
in up to 90 % of AML patients.
It is not unusual to identify two distinct blast populations in the same patient, one of small size with a high nucleus/cytoplasm ratio resembling lymphoblasts and the other larger with more abundant cytoplasm with or without granulation resembling myeloblasts
Gate D (pink) is shown here in the area typically occupied by myeloblasts
, but may be used to highlight other populations.
In more than 90% of patients suffering from acute myeloid leukaemia, CD33 has been recognised to be the antigen expressed on the surface of myeloblasts
Liver showed a massive intra and extra vascular accumulation of myeloblasts
, and showed congestion in the portal vein with focal lymphoid cells (Fig.
MYLOTARG is an antibody-drug conjugate (ADC) composed of the cytotoxic agent calicheamicin, attached to a monoclonal antibody (mAB) targeting CD33, an antigen expressed on the surface of myeloblasts
in up to 90 percent of AML patients.
Fluorescence in situ hybridization confirmed the CBFp rearrangement associated with inv(16) in myeloblasts
and myelomonocytic cells but not in CLL cells, confirming that the AML and CLL did not share clonality.
For example, normal myeloblasts
express CD13, CD34, and CD117, but not CD15.
In acute myeloid leukaemia, aspiration revealed abundant myeloblasts
with large cells, increased nuclear/cytoplasmic ratio, fine chromatin with 2-4 variably prominent nucleoli and Auer rods (Figure C).