Histopathological Response Patterns Following Treatment of Acute Renal Allograft Rejection
Mukul K Divatia, Sadhna Dhingra, Samir Patel, Jennifer Devos, Luan D Truong, Roberto Barrios, Richard J Knight, A Osama Gaber, Lillian Gaber. Methodist Hospital, Houston, TX
Background: Biopsy evaluation plays a key role in the diagnosis and grading of acute rejection and chronic changes. To date there are few descriptions of the histological outcomes of anti-rejection therapy. This study aimed to evaluate and compare post-rejection treatment biopsies with index biopsies to assess treatment response patterns.
Design: A retrospective review of 713 transplant biopsies from 2009-11 yielded 30 cases of acute rejection with biopsies performed to evaluate the response to therapy. Biopsies were obtained within 15-223 days (mean 54.6) after an index rejection biopsy. Banff 2007 criteria were used to classify acute cell mediated rejection (ACMR) and/or acute antibody mediated rejection (AAMR). The post treatment histological response was graded as: 1-complete resolution; 2-near complete if ACMR downgraded to borderline/ C4d staining reduced to ≤ 10 % of peritubular capillaries (PTC) in AAMR; 3-partial: ACMR downgraded by at least one grade/ C4d staining reduced by 50%; 4.-persistent without improvement. Features of new onset chronic changes including interstitial fibrosis and tubular atrophy (IFTA) and other chronic changes in tubules, interstitium, vessels and glomeruli were recorded.
Results: The cases were grouped based on type of rejection in the index biopsy into AAMR, AACMR, and Mixed AAMR/ACMR. The histological resolution responses are shown in Table 1.
|Histological response||AAMR (n=4)||ACMR (n=12)||Combine AAMR/ACMR (n=14)|
|AAMR Changes||ACMR Changes|
|1 Complete resolution||50%||66.8%||14.3%||64.3%|
|2 Near complete resolution||25%||16.6%||42.8%||7.1%|
|3 Partial resolution||25%||16.6%||14.3%||14.3%|
|4 Persistent rejection||0%||0%||28.6%||14.3%|
|New onset IFTA||25%||33.3%||50%|
|New onset glomerulopathy||0%||0%||7.1%|
|New onset vasculopathy||0%||0%||28.6%|