1. We find 2.3% (3/106) of our adult AMLs, 8% (11/130) of our adult
ALLs and 20% (9/45) of our pediatric ALLs to be CD45 negative.
2. I would recommend studying this case with more myeloid markers
(MPO, CD15, CD117, CD65), before calling it a biphenotypic acute
leukemia. To me, CD13 and CD33 are not enough. I would favor a
myeloid antigen positive ALL (Ph+).
Dan Arber
City of Hope
______________________________ Reply Separator _________________________________
Subject: A CD45-negative Leukemia?
Author: <kcdol@samsung.co.kr > at INTERNET
Date: 1/13/98 8:49 PM
Dear list members
Have you ever seen a case of CD45 (leukocyte common antigen)-negative
acute leukemia?
The male patient was in his early 30's and visited our hospital with
chief complaint of low platelet number. He felt fatigue and experienced
easy bruisability but looked well.
At the time of visit on Jan 6, 1998, the CBC data was WBC 6,000/uL,
Hb 8.5 g/dL, platelet 24K/uL. The peripheral blood smear showed
30% leukemic blasts and bone marrow revealed 89.6% medium sized leukemic
blasts with high N/C ratio, fine chromatin, and absent to one nucleolus.
Cytochemical stain was done; peroxidase (-), SBB (-), PAS (pinkish background
staining), Non-specific esterase (-).
Flow cytometric analysis of bone marrow aspirates revealed a predominant
population of cells with a lymphoid light scatter. These leukemic blasts
has following immunophenotype;
CD34 (+; 94%), HLA-DR (+; 96%), nuclear TdT (+; 92%)
CD33 (+; 53%), CD13 (+; 88%), CD61 (-)
CD7 (-), CD5 (-), CD2 (-)
CD20 (+; 27%), CD1
9 (+; 90%), kappa (-), lambda (-), CD10 (+; 90%)
and, interestingly CD45 was negative.
We could find CD45-bright normal lymphocytes on CD45-RALS (right angle
light scattle) dot plot thus false-negative for CD45 of these leukemic cells
was ruled out.
Anti-CD45 monoclonal antibody (Beckton-Dickinson Immunocytometry Systems,
Cat No. 347463, USA) clone 2D1 conjugated with FITC (IgG1) was used at that
time and we confirmed this CD45 negativity with immunostain on bone marrow
aspirate smears using DAKO monoclonal antibody.
Molecular and cytogenetic studies were also performed and demonstrated
minor bcr/abl (e1a2) rearrangement and t(9;22), respectively.
We concluded this case as a CD45-negative acute biphenotypic (myeloid and B
lymphoid)leukemia.
I tried to find out previously reported cases of CD45-negative acute leukemia
but failed except some lymphomas.
My questions are;
1. Is this case the first one of CD45-negative acute leukemia?
2. If it is not, could any one kindly tell
me his/her experience or
the source of literature of reported cases?
3. If it is the first one, I want to establish a new cell line with this case.
Could you give me a good reference or tips in doing this work?
Any comment will be greatly appreciated.
Thanks in advance.
==================================
Chang-Seok Ki, MD
3rd-year Resident
Dept. of Clinical Pathology
Samsung Medical Center
E-mail. kcdol@samsung.co.kr
Tel. 82-2-3410-2707
Fax. 82-2-3410-2719
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