SUBCLINICAL INTRAGRAFT EVENTS: ITERATIVE BIOPSIES FROM THE TIME OF RENAL TRANSPLANTATATION (TX) TO ONE-YEAR POST-TX.

 

L Murer, M Della Vella, G Montini, F Fusaro, B Andreetta, C Carasi, G Zacchello.

Department of Pediatrics-University of Padova, Italy.

 

Subclinical immunological and non-immunological events participate to the chronic allograft nephropathy (CAN)and influence the long-term graft prognosis.

 

Aim:

To analyse iterative graft biopsies performed at time of tx (T0), 6 and 12 months post-tx (T6,T12) in pediatric recipients with stable renal function and receiving an immunosuppressive protocol foresees  Basiliximab induction, withdrawal of steroids 7months post-tx, with tacrolimus and mophetilmycophenolate regimen. Histological evaluation is performed according 1997Banff’s classification. The fibrogenetic processes are investigated with antibodies anti-TGFb-1, Angiotensinogen, PAI-1 and asmooth-musle-actin(aSMA).At the present we have analysed 60 scheduled biopsies performed in twenty patients: R/D mean age 10,7+5,3/15,8+11 y.; mean CreatinineClearance 58,4+15,3 and 56,2+13 ml/m’/1.73m2, and tacrolimus through level 9,1+2 and 8,7+2,1 ng/ml at T6 and T12, respectively; none episode of clinical acute rejection.

 

Results:

1) T0:  mild/moderate cellular tubular damage with a mild diffuse Angiotensinogen and Vimentin tubular positivity are evident; in few cases glomerular sclerosis or interstitial fibrosis related to donor-age are present; 2)T6: there is no evidence of histological acute rejection and only 10% of biopsies show signs of CAN grade1; at T12 one case of Banff 4(gradeIA) and 28% CAN gradeI; 3)T6 and T12 biopsies show an increased focal tubular expression of TGFb-1 and vimentin, also in absence of relevant histological lesions; vimentin tubular and aSMA interstitial staining are more evident in biopsies with CAN; PAI-1 immunostaining at T6 correlates with grade of fibrosis at T12.

 

Conclusions:

Safety of regimen protocol on the development of acute rejection, but presence of chronic renal graft damage in suclinical condition and early activation of the fibrogenetic loop will be further evaluated.

 

SUBCLINICAL INTRAGRAFT EVENTS: ITERATIVE BIOPSIES FROM THE TIME OF RENAL TRANSPLANTATATION (TX) TO ONE-YEAR POST-TX.

 

LUISA MURER

Department of Pediatrics, University of Padova

Via Giustiniani 3,

35128 Padova

Italy

 

luisam@pediatria.unipd.it