Correct me if I am wrong, but lymphoid and myeloid blasts express HLADR
rather nicely. Also, CD45 negativity may be due to loss of expression
completely, low level expression not detected, or failure to expresson
surface. Neoplastic cells drop antigens at will.
Maryalice
>Dear Chang
>Your description is quite interesting and I would like to suggest a couple
>(?) of markers that you may be considered worthy to study
>1-Since your cells express quite high DR (96%), and since the cells that
>express highest DR are Dendritic cells-Langerhans cells, one marker that
>could be interesting to check would be CD1a, and the markers associated to
>Antigen presenting cells like CD11c, CD56, B7.1 and B7.2. (sorry, a lot of
>work for the weekends of a third year resident). Please check the cells
>also for Fc receptors (IgG and IgA receptors are express in some of those
>cells)
>2-The fact that your cells do not show CD45, does not mean that they are
>negative for that marker, may be you have a cell that will express a splice
>out isoform of CD45. My best shot is that your cell is CD45RO. I have
>observed some cell lines that do not express CD45 but they are CD45RO. We
>are going to present in Colorado at ISAC some cells with that
>characteristics.
>3-Please try to get cell lines from this patient. I recall the work from K.
>Nielsson who, got a cell line form a patient and now after more that 25
>years still is a very useful one, that cell line is U937 a monocytic cell
>line. May be you have something quite similar. (it means, a lot of lab work
>and more weekends in the lab).
>Cheers, good luck and keep in touch (What is your opinion Anna?)
>Rafael
>>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
>>==================================
>
>
> \|/
> (o o)
>________________________________oOo__(_)__oOo_________________________________
> ___/\_ | Rafael Nunez mailto:rafaeln@vetvir.unizh.ch
> / o \/| | University Inst.for Virology http://www.vetvir.unizh.ch/
> / _| | Winterthurerstr. 266a Telephone: (+41) 1 6358710
> /_/\__/-\/ | 8057 Zurich SWITZERLAND Faximile : (+41) 1 6358911
>______________________________________________________________________________
Maryalice Stetler-Stevenson
Director Flow Cytometry Unit
Laboratory of Pathology, NCI, NIH
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