[Histonet] Endogenous enzyme activity - eosinophils

[Richard Cartun]

Do eosinophils have a different type of endogenous peroxidase that
survives quenching in 3% hydrogen peroxide prior to immunohistochemical
staining?  Thanks!  I have seen a few cases recently where the
eosinophils are strongly reactive following normal quenching. 
Interestingly, pretreatment with antigen retrieval using heat destroys
this reactivity.

Richard Cartun