Re: cd4 cd8 coexpression

From: Maciej Simm (simmmmer@yahoo.com)
Date: Tue Oct 30 2001 - 18:59:06 EST


Thank you Jacek - you made a very good point,

I also remembered that I forgot about NKT cells. Only about a half of
NKT cells express CD8(dimly), which means a lot of them will end up
with the  CD3+CD4/8doublenegatives. I will have to test this during
our next DAIDS IQA -  which is next week.

I did however test the DN's against BD's anti-human TCR-gammadelta
and the numbers still didn't add up.

maciej



--- Jacek Polski <jpolski@usouthal.edu> wrote:
> Maciej,
> We do CD45/CD3/CD4/CD8 in one tube (B-C tetrachrome) and also see
> these CD4+CD8+ events. But there are very rare.
> One the other hand, CD4-CD8- are frequent and correspond to
> gamma-delta T-cells. These are increased in many conditions
> including mycobacterial infections.
> Regards,
> Jacek Polski, MD
> Univ. South Alabama
>
> >>> Maciej Simm <simmmmer@yahoo.com> 10/29 5:37 PM >>>
>
> Matt,
>
> I see them too in the amount of 1-10% in the CD3+ population. If
> you
> stick to NIAD-DAIDS guidelines for CD4/CD8 enumeration you should
> be
> allright. We only report CD45bright/CD3bright/CD4 bright and
> */*/CD8
> bright, respectively. We do not add the double positives to either
> CD8 total or CD4 total, as they may be artifacts from a damaged
> thymus or dead cells. In fact to make our analysies easier and our
> numbers more confident, we test for CD45/CD3/CD4 and CD45/CD3/CD8
> in
> separate tubes (gives us one extra CD3 value for each set's
> average).
>
>
> Double negative CD3+'s also happen, which IMHO are CD4's with a lot
> of virus blocking the CD4 epitopes.
>
> --- MatGrnthm@AOL.com wrote:
> > i'm currently working on a flow monitoring HIV patients.
> > i have noticed some samples exhibiting cd4 cd8 coexpression.
> > this leads to some problems obtaining valid results.
> >
> > i was wondering if you had any information on this problem.
> >
> > thanks
> >
> > matt grantham.

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