If you are consistently getting these samples from one source, it sounds like they are getting mis-handled in some fashion on the way to your lab; and cells are being killed. Does the same thing happen with fresh control blood from more local supplies, like from your lab? If so that would suggest that you are somehow misshandling things. There are no 'more' populations I have heard of that are lymphocyte-sized than T, B and NK cells. From bone marrow, there is a consistent presence of nucleated red cells which are easily identified with CD45 and CD71. More mature reds will also express glycophorin...both rbc populations are scant in normal PB, anyway. Plasma cells wont express the antigens you are using, but are physically larger and are not usually seen in PB anyway. In disease states immature reds can get into the PB. Platelets are friggn tiny, so unless they are clumping up like crazy in ways I have never seen , thats not the answer either. In rare cases of looking at thousands of cases of PB from leukemics, we will sometimes encounter what you are seeing... we dont know what they are but they usually take up PI or DAPI and merge into what we define as a cluster of dreck. We are likely not far away from eachother...send over some data if you like F Preffer At 04:40 PM 6/6/01 -0400, Mikayla Kob wrote: > > Dear cytometry community, > > We have been establishing a panel to phenotype lymphocytes from clinical > peripheral blood samples. We have been using a whole blood staining and lysis > procedure. The samples that I have received so far have had an unusually > large percentage of CD45- cells (over 50%) in the lymphocyte gate as > determined by forward and side scatter. These cells are also CD3, 4, 8, and > 19 negative, appear to be CD43 negative, and are not NK cells. It may be > helpful to know that these samples had very poorly defined populations in the > forward vs. side scatter plot. I have not yet tried erythrocyte or platelet > stains to rule out aggregates or nucleated red blood cells, nor have I tried > staining isolated mononuclear cells. > > Does anyone have an idea what these cells may be? Could anither cell fraction > with these scatter qualities potentially be large enough to make up over 50%? > Has anyone had any experience with a pathological state of which this may be > symptomatic or for which whole blood staining and lysis may yield erroneous > results? Any information or advice would be appreciated. Thank you in > advance. > > Sincerely, > > Mikayla Kob > <mailto:kob@cbr.med.harvard.edu>kob@cbr.med.harvard.edu Frederic I. Preffer Department of Pathology Charlestown Navy Yard- 7140 149 13th Street Massachusetts General Hospital -East Charlestown, MA 02129 voice [617] 726-7481 fax [617] 724-3164
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