aberrant CD34 marking?

From: Rees Beth (beth.rees@dchs.tas.gov.au)
Date: Mon Jun 04 2001 - 01:24:35 EST


Hi Flowers

Help!

In October last year we received  a bone marrow aspirate from an 18 weeks
pregnant lady for ?AML.  Morphology on the bone marrow was performed in
another lab, but within a few days we also received peripheral blood which
had Hb 64g/L, wcc 13.2, neutrophils 2.5, band 0.1, lymphocytes 3.3, and the
comment on the film was "a large population of abnormal and somewhat
primitive monocytes and a small number of agranular frank blasts.  Many
neutrophils are agranular.  There are occasional nucleated RBC.  ? evolving
leukaemia on a dysplastic background."
Cytogenetics revealed no consistent anomalies, and no evidence of deletion
or rearrangement of 11q23.

On flow, there was a population of cells (about 58% of total CD45+ events)
which had the FSC/SSC characteristics of monocytes and/or
promyelocytes/myelocytes, and the 45/SSC characteristics of mature myeloid
cells - 45 almost as bright as lymphocytes and a higher sidescatter than
would be expected for monocytes.
The majority of these cells were CD33+CD14weak+CD15+HLADr+ and CD13-.  About
half were also CD11b+, and about 1/4 CD34+.
They were reported as consistent with an M4/M5 leukaemia.

She was treated with a modified ICE protocol - without etoposide on account
of the pregnancy.

A month later there were 10% of cells with the scatter characteristics of
monocytes, and were CD33+CD14+CD13+CD11b+HLADr+ and CD15- - in other words,
monocytes.  No CD34+ cells to be seen.

The baby was delivered by caesarean section in February, and treatment was
resumed 2 weeks later, with conventional consolidation protocol.

Three weeks ago we received another bone marrow aspirate.  This time the
aspirate morphology was normal, but 47% of CD45+ events had scatter
properties of mature myeloid cells.  Approximately 40% of these were
CD34+CD14+CD33+CD13+CD15+CD11b+HLADr+.
9% of the cells had scatter properties of monocytes, and approximately half
of these were also CD34+.
ie. total CD34+ cells 22%.
CD34 was checked and was positive using Dako FITC (clone QBEnd 10, class II)
and  BD PE (clone 8G12 Anti-HPCA-2).

We suggested a repeat aspirate, which we received last week.  This time the
corresponding 45/SSC population has the FSC/SSC characteristics of mature
myeloid cells, and the immunophenotype
CD34-CD14-CD33+CD13+CD15+CD11b+HLADr-; in other words, normal myeloid cells.
What's happening???


beth

Beth Rees
Flow Cytometry Lab
Pathology Dept
Royal Hobart Hospital
Hobart, Tasmania
Australia

ph. 03 6222 8913



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