*As determined during the Pathology Workshop (September 10,
2003) during the VIIIth International Small Bowel Transplant Symposium, Miami,
Fla.
No evidence of acute rejection: Grade 0
Unremarkable histological changes or pathological
changes clearly different than those seen in acute cellular rejection.
Indeterminate for acute rejection: Grade ind
Minor epithelial cell injury or destruction is
present, principally in the crypts.
Increase in crypt epithelial cell apoptosis (less
than 6 apoptotic bodies per 10 crypt cross sections)
Crypt injury and inflammation is usually focal
Typically an accompanying mixed but primarily
mononuclear inflammatory population (Character (eg, fewer blasts) and
intensity of the infiltrate may change according to the time post
transplant)
Inflammatory infiltrate is usually minimal but can
be diffuse or localized.
No evidence of nonspecific enteritis.
Edema, blunting, vascular congestion can be present
but these features are not necessary for the diagnosis.
Acute cellular rejection, mild; Grade 1
Defined by crypt injury,
including changes of mucin depletion, cytoplasmic basophilia, decreased
cell height with change to cuboid shape, nuclear enlargement and
hyperchromasia, increased mitotic activity, hyperplasia with “U”-shaped
lumen, and/or crypt destruction with apoptosis, attenuation, reparative
changes, or
dropout.
Increased crypt epithelial
cell apoptosis (six or more apoptotic bodies per 10 crypt cross sections
Mucosa is intact
Villus demonstrates blunting
and architectural distortion.
Epithelial cell changes tend
to be diffuse and are typically accompanied by a mixed but primarily
mononuclear inflammatory population, including blastic or activated
lymphocytes, eosinophils, and occasional neutrophils, involving the
lamina propria or below.
The inflammatory infiltrate
is often mild to moderate in intensity (the character and intensity of
the infiltrate may change according to the time posttransplant)
Edema and vascular
congestion are often present.
Acute cellular rejection, moderate; Grade 2
More diffuse and increased
crypt injury and destruction
Increased crypt epithelial
cell apoptosis (six or more apoptotic bodies per 10 crypt cross
sections)
Foci of “confluent
apoptosis,” (two or more adjacent cells undergoing apoptosis within a
crypt)
Focal crypt loss
Focal superficial erosions
of the surface mucosa (not required for the diagnosis)
A mixed but primarily
mononuclear inflammatory population, including blastic or activated
lymphocytes, involving the
lamina propria or below
often at moderate to severe intensity
Inflammatory infiltrate is
less affected by the time post transplant.
Edema, vascular
congestion, and villus blunting are often present
Acute cellular rejection, severe; Grade 3
Marked
degree of crypt damage and destruction (may be accompanied by crypt
loss)
Crypt
apoptosis is variable (may be an unimpressive level of apoptosis)
Adjacent viable epithelium usually exhibits rejection-associated changes
Diffuse
mucosal erosion and/or ulceration
Marked,
diffuse inflammatory infiltrate with blastic or activated lymphocytes,
eosinophils, and neutrophils.
Extended rejection typically results in complete loss of the bowel
morphological architecture
Arteritis may be evident (uncommon finding)
