CD4+8+

From: ctnebe (ctnebe@t-online.de)
Date: Wed Dec 10 1997 - 17:24:50 EST


Dear collegues,

I got the impression that in this ongoing discussion two different phenomena got 
mixed up.

The one phenomenon that Maryalice described is the unspecific binding due to 
substances in the blood sample that cause unspecific binding of some but not all 
antibodies in your panel.  It disappears by washing before staining or by adding 
access amounts of normal mouse serum.  We see it in about one in a hundred cases 
esp. in the BD CD3-FITC/CD19-PE and CD3-FITC/CD16&56 combination.  You see only 
two clusters in the two colour dot plot (see the quoted Cytometry paper).

The other phenomenon of CD4+8+ has first been described to my knowledge by 
Diether Recktenwald in the application part of the first edition of the FACScan 
manual (it was removed later on).  There he used it as an example for a three 
colour application where these double positive cells are propidium (or 7-AAD, I 
donīt remember exactly) positive.  I have seen a few patients, where in all 
cases the normal mutual exclusive CD4 and CD8 are present and the third 
cluster of double positives in addition (in our hands in the BD CD4-FITC/CD8-PE 
test tube).  The percentage of CD4+8+ was very stable in the two cases where we 
were able to get consecutive tests over a longer period of time.  Interestingly, 
the first case was also a women from the lab where I did my PhD who was on 
thyroid hormones for the same reason.  Others were outside patients where we 
could not get more clinical information. Taken all information together, 
apoptotic escapees form the thymus would be an attractive explanation.  As these 
self reactive cells shouldnīt leave the special thymic environment, the 
attribution to autoimmune diseases is not a bad idea.  

I stop it here and apologize for my long comment I sent before.

Thomas Nebe
Klinikum Mannheim



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