Immunohisto problem

Does anyone know the solution of the "strong edge, weak/negative center"
problem we have with some routinely processed immuno slides (from paraffin
blocks)?

What we get on the edge is a _real_ staining, i.e. the cells that should
stain do stain, and these that should not do not.  The problems seems to
affect more severly some antibodies (like DAKO LCA or CD20).  People from
the company know about it (it is not only ours), but offer no reasonable
solution.

Z. Rudzki
staff pathologist
Jagiellonian Univ., Poland