MP105
RELATIONSHIPOF THROMBOTIC MICROANGIOPATHY TO PERITUBULARCAPILLARY C4D DEPOSITION AND MICROVASCULAR INFLAMMATION IN LIVING DONORS RENALTRANSPLANTATION Free

Introduction and Aims: To determine the prevalence of thrombotic microangiopathy (TMA) with C4d deposits and microvascular inflammation in Egyptian living donors transplant patients

Methods: Renal allograft biopsies received from 2011 to 2015 (n=1940) at our centre was reviewed. Only adequate indication biopsies with C4d data and Banff score were included (n=1827).

Results: Out of the 1827 biopsies, 428 were C4d positive and 185 showed TMA. Out of the TMA cases, 25 % were C4d+ve and 24% had MI score ≥ 2. C4d significantly correlated with MI score (p value <0.001). When the cases were divided by post transplant period, 14% (65/457) of biopsies in ≤1month (m) had TMA,with 17 C4d+ve & 10% with MI score ≥ 2. Between 1 m and 1 year, TMA was seen in 10% (47/463) with 8 cases C4d +ve and 20% had MI score ≥ 2. After 1 year, TMA represented 8% (73/907) with 22 cases C4d+ve and 80% with MI score ≥ 2.

Conclusions: TMA was noted in 10% of cases in this study and represented 11% of cases with C4d positivity. It was related to morphological evidence of AMR in less than 50% of cases rendering other causes of TMA as calcineurin inhibitor toxicity more frequent. MI score ≥ 2 is a useful morphological marker of AMR only after 1-year post transplant. C4d is still an important tissue marker for AMR within the first year post transplant.