الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Summary & Conclusion
SUMMARY & CONCLUSION
This is a retrospective study on 92 needle biopsies of 61 patients who
have been transplanted during period (January 1995 and December 1996).
Fifty patients were male and eleven patients were female with mean age 30.4
±13.
These biopsies were re-diagnosed and reclassified histologically
according to Banff (97) classification. 40 were diagnosed as borderline
changes, 30 were diagnosed as type I rejection, 18 were diagnosed as type II
rejection and 4 were diagnosed as type III rejection.
Also immunohistochemical stalnlng were done for these 92 biopsies
using six monoclonal antibodies (CD45, CD4, COB,CD68, CD57 and CD74)
to analyse interstitial inflammatory infiltrate.
Acute cellular rejection remains a major problem in the management of
patients during the early phase after renal transplantation (Erren et al.,
1999) .. Acute rejection is the most significant variable in renal allograft
survival and function (Palomar et al., 1999).
The core of needle biopsy is the gold standard by which establish the
correct diagnosis of clinically apparent renal allograft dysfunction (Waiser et
al., 2000). So, standardization of renal allograft biopsy interpretation is
necessary to determine the most sensitive and specific pathologic findings to
diagnose the extension and severity of rejection. Also, to guide therapy in
transplant patients and to establish an objective end point for clinical trails of
new antirejection drugs (Racusen et al., 1996, and Palomar et al.,
1999).
A series of meeting at Banff were introduced an international standard
for evaluation of biopsies after renal transplantation. This allowed
classification of renal allograft pathology and acute rejection in particular. The
goal of the Banff classification of renal allograft rejection was a schema in
which a given biopsy grading would imply a prognosis for a therapeutic
response or long-term function.
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Summary & Conclusion
The Banff (97) working classification is the modification of two
classifications that are most widely used in diagnosis of renal allograft
pathology [Banff (93-95) working classification and Collaporative Clinical
Trails in Transplantation (CCTT)].
This study confirm a significant association between histologic grading
for acute rejection according to the new revised Banff (97) classification and
graft survival (P value 0.01). Also we demonstrate that among the specific
pathologic lesions the presence of vasculitis (intimal arteritis), but not severity
of glomerulitis and tubulitis or extent of interstitial inflammation, was the only
predictor of a poor graft survival (P value 0.006).
Immunohistochemical analysis of the interstitial inflammatory cellular
infiltrate gives the chance to more accurate recognition and phenotype these
mononuclear cells in renal biopsy specimens during acute rejection.
In this study we demonstrated that the composition of interstitial
inflammatory infiltrate is heterogeneous. This reflect the fact that allograft
rejection can be mediated by a variety of immune mechanisms, includlnq Tlymphocytes
and antibody, either directly or through antibody dependent cell
mediated cytotoxicity and natural killer ceils.
We demonstrated T- lymphocytes as the principle effector cells during
acute rejection. Moreover, both T helper/inducer cells and T
cytotoxic/suppressor cells can mediate allograft rejection. T helper cells have
the main role as it represent the largest percentage in the interstitial
inflammatory infiltrate. Also, T helper cells can mediate graft destruction via
different immune mechanisms, mainly delayed-type hypersensitivity reactions
via activation of macrophages. Also activate T cytotoxic cells that mediate graft
damage via direct or indirect contact with graft cells and activate B-cells that
mediate antibody- mediated immune reactions.
While cytotoxic T- cells have the strongest or the severest effects, as its
percentage in the infiltrate was increased directly with increasing of the grade
of acute rejection (ie, the highest percentage in type III rejection).
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Summary & Conclusion
Other inflammatory cells were also detected in the interstitial
inflammatory infiltrate, but present as a lesser percentage, as macrophages,
natural killer and a-celts. These findings indicate that T- lymphocytes (mainly
T helper cells) have the major role in the process of acute rejection but also
the other inflammatory cells share in this process but to a lesser extent.
In this study, we did not found that immunohistochemical analysis of
interstitial inflammatory infiltrate have a predictive value on graft survival.
In conclusion, immunohistochemical analysis of the interstitial
inflammatory infiltrate gives a good idea about the events that occur inside the
renal allograft during acute rejection and the immune mechanisms that are
responsible for this, but it has no prognostic impact on graft survival. While, the
new revised Banff (97) classification is the most predictive for graft survival.
Among the histopathological criteria that diagnose acute rejection, vasculitis is
the only predictive parameter for poor graft survival. Other variables are
detected to have prognostic value on graft survival as number of both graft
biopsies and acute rejection episodes, and pattern of the interstitial
inflammatory infiltrate. As the increased number of graft biopsies, number of
acute rejection episodes and the diffuse pattern of the interstitial infiltrate are
associated with poor graft survival.