Dear Ian,
There is an interesting product from Chemicon: a directly alk. 
phosphatase-conjugated anti-mast cell antibody (MAB1222A). It works for 
both cryo and FFPE sections (1:500 overnight 4C; FFPE sections need 
citrate6.0 antigen retrieval). Alk. phosphatase activty is visualized with 
DAKO Fast Red (for single staining) or Vector Blue (for double staining). 
Using these products it will be relatively easy to double-stain with either 
CD68 and fibroblast antibodies.
Happy colorful staining!

Chris van der Loos
Academical Medical Center
Dept. of Cardiovascular Pathology
Amsterdam, The Netherlands

Ian wrote:
 >Date: 7 Jan 2003 10:45:22 -0600
 >From: Ian Montgomery 
 >Any suggestions for a stain or combination of stains, conventional
 >or IHC, that will enable me to distinguish between mast cells, macrophages
 >and fibroblasts.
 >Ian.
 >Dr. Ian Montgomery,
 >Histotechnology,
 >Graham Kerr Building,
 >Institute of Biomedical & Life Sciences,
 >University of Glasgow,
 >Glasgow