IMMUNOEXPRESSION OF ADHESION
MOLECULES AND INFLAMMATORY CELL Profile in VASCULAR
LESIONS of TYPE III ACUTE REJECTION OF THE RENAL
J.O., Franco m.f..
of Pathology. Federal University of São Paulo
(UNIFESP). São Paulo, São Paulo, Brazil.
Acute tubulo-interstitial and mild vascular
rejection are tipically T-cell mediated processes.
Acute severe vascular rejection (Banff type III)
however may be mediated by receptor antibodies
directed to donor cells and is histologically
characterized by transmural arteritis and/or
fibrinoid necrosis of the vessel wall. It is still
object of debate if transmural arteritis and
fibrinoid necrosis are pathogenetically distinct
entities. This study tries to shed some light over
this question by analyzing the immunoexpression of
adhesion molecules and the inflammatory cell profile
in renal allografts with type III rejection.
Seventy explanted renal allografts with acute severe
vascular rejection were analyzed. Vascular lesions
were classified as i) “FN”- fibrinoid necrosis; ii)
“TA”- transmural arteritis and iii) “M”- mixed
fibrinoid necrosis and transmural arteritis.
Formalin-fixed, paraffin-embeded tissue underwent
immunoperoxidase testing for: i) Presence of CD4,
CD8, CD20 and CD68 in vessel wall and interstitial
inflammatory cells; ii) Positivity for C4d in
peritubular capillaries; iii) Presence of ICAM-1 and
VCAM-1 in vessel wall. Groups were compared by
Fisher Exact Test, with p=0.005, corrected by
Bonferroni in multiple comparisons (p=0,018).
Statistically significant differences were observed
in: I) The presence of CD4 and CD8-positive
lymphocytes and CD68-positive hystiocytes in vessel
walls was higher in TA and M lesions than in FN
lesions; II) Endothelial and arterial tunica
media positive immunoexpression of ICAM-1 and
VCAM-1 was more consistently observed in TA and M
lesions than in FN lesions. Among the tested groups,
no statistically significant differences were
registered regarding C4d positivity in peritubular
capillaries and the positivity of the tested markers
in interstitial inflammatory cells.
results suggest that T-cell interactions are
involved in the increased positivity of vascular
adhesion molecules ICAM-1 and VCAM-1 in type III
renal allograft rejection. The peritubular capillary
C4d positivity in the three patterns of lesions
indicated that both transmural arteritis and
fibrinoid necrosis have an antibody-mediated injury