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. __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com
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