> BCL6 is indeed a pain. We are using clone PG-B6p from Dako at a
> concentration of 24 ug Ig/ml after HIER in a pressure cooker, 
> 10 mM citrate
> buffer, pH 6.0 (gave somewhat better results than an urea 
> containing high pH
> buffer). After looking at numerous follicular lymphomas and 
> tonsils it is
> our impression that good staining depends largely on quick 
> fixation, 

Hi, 

recipe copied and pasted from the "Original Viennese Laboratory Cooking
Book":

bcl-6	(Dako M7211) 1:10, HIER in a household pressure cooker for 6 min,
cooling phase 20 min, 
0.01M citrate buffer, pH 6.0.

I never encountered this problem on own material, BUT:

all our lymph nodes are sent immediately and are cut in thin (1 mm) slices
and fixed for 24 h (not longer!!!) in phosphate buffered formalin 4% pH 7.4.

bcl-6 on cases sent from other hospitals frequently show some kind of
"fainting" as Andi described.

IMHO, immunohistochemistry has only three little mysteries:

1. fixation (remember the discussion a few days ago on this board!)

2. thorough washing in buffer.

3. position of stars (especially the fast Red Sirius) in relation to name
and age of the performing technician (I once had some kind of kabbalistic
formula for this, but unfortunately I lost it...)

Merry Christmas to all!

Alexander Nader
Path. Institut Hanuschkrankenhaus
A-1140 Vienna, Austria