Dear Ian,
Would you share with us your protocol for demonstrating immune complexes
in formalin fixed paraffin embedded renal biopsies. In my experience it
is not the easiest thing to unmask the immune complexes within the
basement membrane  and at the same time eliminate the staining of
trapped serum in the capillaries. I do have a protocol that works quite
reliably with trypsin digestion, but I have not had a very good success
with the linear staining of Goodpasture's syndrome. Routinely we still
do the old direct immunofluorescence method on frozen sections. I would
be very interested to hear (read), what other labs are doing to
demonstrate the immuno complexes in renal biopsies.
In anticipation, Katri.

Katri Tuomala
Anatomic Pathology
St.Joseph's Hospital
Hamilton, Ontario, Canada