When you say "AFB", I assume that you mean mycobacteria?  I use an
immunoperoxidase method for the demonstration of mycobacterial antigens
in formalin-fixed, paraffin-embedded tissue.  However, I don't think you
should do it unless you have extensive experience with the demonstration
of organisms (especially bacteria) with immunohistochemistry.  There are
demanding technical and interpretative issues.  The polyclonal antibody
that we use comes from DakoCytomation (Carpinteria, CA) and you must use
an exquisitely clean detection system.  The method is extremely
sensitive, allowing for low to medium magnification evaluation.  I
always recommend confirmation by AFB histochemical staining or molecular
identification by PCR.  However, I have seen cases where one or both of
these confirmatory tests are negative.

R. Cartun

>>> "Mcleod, H, Heather"  11/18/02 08:14AM
>>>
------- Forwarded Message Follows -------
From:          Self 
To:            histonet@pathology.swmed edu
Subject:       TB / IHC
Date:          Mon, 18 Nov 2002 15:12:54 +0200

Hi All

Does anybody in histoland stain AFB (in FFPE tissue) using a 
peroxidase system rather than immunofluorescence?  Will appreciate 
ANY information.  Pathologist wants to do this as well as ZN's

Thanks
Heather