Mark,
in my experience with reference material, specimens processed with xylene
substitutes justed reeked havoc with immunos.  I have experienced a general,
non-specific staining from one lab. When I asked them what they were using,
they said they were using a xylene-substitute (I can''t remember the brand)
Why this happens, I don't know the actual chemical reaction.  I do know that
if you are deparaffinizing with a xylene substitute, you need to increase
the number of changes in addition to increasing the times.  I've heard that
some people have had to deparaffinize in three changes for 20 minutes each.
Hope this helps

Joe Nocito, B.S., HT(ASCP)QIHC
Histology Supervisor
Christus Santa Rosa Hospitals
San Antonio, Texas 


> -----Original Message-----
> From:	mark.lewis@shandon.com [SMTP:mark.lewis@shandon.com]
> Sent:	Wednesday, October 18, 2000 10:26 AM
> To:	Histonet@pathology.swmed.edu
> Subject:	Immuno Staining and Xylene Substitute
> 
> Hi everyone !
> 
> Has anyone heard or read anything with regard to poor antigenicity when
> tissues are cleared using Xylene substitutes during processing or
> staining?  Someone told me that they were told not to use xylene
> substitutes of any kind for tissue processing or for the deparaffinization
> and clearing steps in the staining process because it would effect immuno
> staining negatively. They did not have details as to how, what or why.
> Please enlighten me if you know anything with regard to this.
> 
> Thank You,
> Mark Lewis