Dear flowers, First of all thanks for your many helpful replies. I will try to answer your questions as fully as possible. 1. Paula Fukushima wrote: Do you parallel test your lots? I haven't done paralel testing because I have this problem with CD10 only in lymph node GC and FCL but in B-ALL works perfectly and I didn't noticed any problem between different lots with these later cases. 2. Maryalice Stetler-Stevenson wrote: Do you use FITC or PE labeled CD10? This is important. FITC is very dim and, although it is good enough for ALL, it is not good enough for follicular lymphoma. I use CD10 FITC but I have a question too. I know that FITC is dimmer than PE but have you tested CD10 with the two different flourescent dye or your statement - "it is good enough for ALL, it is not good enough for follicular" - is only an assumption ? Of course this may be the solution of my problem and Frederic Preffer's anwer affirms this too. 3. Frederic Preffer wrote: I have no specific experience with the clones you utilize. However, i have no problem detecting follicular lymphomas or GC cells with CD10PE available from Becton Dickinson. 4. Mike Suter wrote: We have used Dako CD10 with good success for diagnosing follicular lymphoma from lymph nodes. Blood neutrophils are positive and serve as a useful measure for validating new lot numbers of antibody. You might want to verify reactivity of your CD10 with blood neutrophils by flow cytometry. In my experience our DAKO CD10 FITC reacts always with mature neutrophils of blood and I also use them as internal positve control but in lymph node biopsies and fine needle aspirates I have not enough neutrophil for control purposes. Do you use FITC or PE labelled CD10 ? This would be very important because of the above mentioned advice of Maryalice Stetler-Stevenson. 5. Lerachmiel Daskal wrote: Were you doing three or four colors? On what were you gating? I use three colors: CD10 FITC, CD19 PE and CD45 PE-Cy5 and I always gate on lymphoid cells (R2) using CD45/SSC gating (except in case of kappa FITC/lambda PE/CD19 PE-Cy5 where CD19/SSC is used) as the attached figure shows below. Before the CD45/SSC gating I use FCS/SSC gating for exlude the debris (R1). You can also see the dim or partial CD10 positivity in two of our cases. Unfortunaly still in many instances we don't see any CD10 positivity although cytology an and immunocytochemistry give the obvious diagnosis of FCL ! FCM of FCL in bone marrow: <File attached: FCL_in_BM.jpg> FCM of FCL in lymph node fine needle aspirate: <File attached: FCL_in_lymphnode.jpg> 6. Dirk Van Bockstaele wrote: I also find no agreement with the pathological diagnosis and I'm using the CD10-FITC monoclonal of Becton Dickinson: so the BD monoclonal is no good choice either! I would be interested in the suggestions that you receive: could you forward them to me? I think your reply also confirms what Maryalice Stetler-Stevenson suggested, namely we should try to switch to CD10 PE from CD10 FITC. As you could read in Frederic Preffer answer CD10 PE from BD works fine in their hands. However it's possible that you don't use the same clone because BD sells two clones with FITC (W8E7 and HI10A) while the HI10A is the only one labelled with PE. Finally I've found and article in the latest American Journal of Clinical Pathology on the web by Yin Xu: Assessment of CD10 in the Diagnosis of Small B-Cell Lymphomas A Multiparameter Flow Cytometric Study. This article is accesible for anybody for free on the AJCP website: http://www.ajcp.com/ and currently can be found in the previews section. In this paper they found that of the 58 FLs, 57 were positive (98 sensitivity!!!) and they used CD10 (W8E7 clone) FITC (!!!) from BD. In their case repertoire they saw three CD10 expression pattern: 1. Uniform strong expression: more than 50% of the cases showed obvious CD10 expression 2. Uniform dim expession 3. Partial CD10 expression. I'm very eager to read you future comments, Pal Jakso University of Pecs Faculty of Medicine Dept. of Pathology 7643, Hungary 12. Szigeti str.
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