Mike,
I have seen this very artifact in my own peripheral blood. Since
this occured about 8 years ago (and continues today) and I am still
healthy, I don't think it is a problem. The artifact I observed is only
seen when you don't wash the blood before staining. There is something in
the serum that causes this. It also causes a false double positive for CD5
and CD20 (that made me nervous). If you take my serum and incubate it with
another person's cells, they too will have this artifact. This artifact is
seen in a sub-population of people. See the paper on this- Cytometry
(Communications in Clinical Cytometry) 18:140-146 (1994). If you washed
several times before staining then this doesn't help
Maryalice
> I'd like to thank all those that have responded to my question. I
> have alittle more info for you.
>
> The subject is a human female in her 30s. She is one of our labtechs
> that we draw when we are playing with new assays. She is in excellent
> health with the exception of being hypothyroid and on synthetic
> thyroid hormone. I did CD3/4/8 staining on her and 2 others at the
> same time. The other 2 where completely normal. She had no normal
> CD8+ 4- cells. All the CD8+ cells were CD4+. Her CD4+/8- cells
> looked fine. They had no CD8 expression. The FS/SS profile of the
> CD8/4 double positives looked normal, and were evenly distributed just
> like the CD4 cells. The CD45/14 was also good. I am going to run her
> again next week and include Coulter count. Any further advice very
> welcome.
>
> Thanks,
>
> Mike Koratich
> USARIEM
> mkoratich@natick-ccmail.army.mil
Maryalice Stetler-Stevenson
Director Flow Cytometry Unit
Laboratory of Pathology, NCI, NIH
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