A reference that comes to mind: Hanson et al Lab Invest 66:78A, 1992 In this study- 12 out of 210 acute leukemias were CD45 negative. Of the CD45 negative B-precursor ALL's - 1 had a t(9;220 and 2 had t(4;11). I wouldn't call this one biphenotypic. There is no myeloperoxidase positivity, correct? It could be an ALL with aberrant expression of myeloid antigens. Thank you for sharing this interesting case. Maryalice >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 >================================== Maryalice Stetler-Stevenson Director Flow Cytometry Unit Laboratory of Pathology, NCI, NIH
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