Spectrum of renal allograft dysfunction in the first post transplantation month from living donors: A histopathological study

Abstract

Early renal transplant dysfunction is a major problem in the early post-transplantation (post. Tx) phase and is recognized as a major cause of graft loss. This work was designed to identify and differentiate between causes of early renal dysfunction in grafts taken from living donors for accurate diagnosis and better outcome.

Between January 1992 and December 2001, a total of 1398 renal allograft biopsies were referred to us from various renal units mostly in Greater Cairo area. Three hundred biopsies, obtained from 287 patients and performed within the first post Tx. month were included in this study. The clinical data were collected from patients' files and new 3-µm sections (30 serial) were prepared from the paraffin blocks.

All the studied cases were from living donors and 9.4% of them were living related. The cause of ESRD was unknown in 72.4% of cases and out of the known causes chronic interstitial nephritis and hypertension were the most common. The main indications for the allograft biopsies were impaired graft function (IGF 71.5%), while delayed graft function (DGF) was the cause in 3.1% of the cases.

The main diagnostic categories were acute rejection (AR 38%), acute tubular necrosis (ATN 23.7%) and tubular injury (23.3%). Infarction and cortical necrosis constituted 15.7% of the cases and 21.3% of them were associated with AR. Evidence of drug toxicity was detected in 9% of cases, while thrombotic microangiopathy was detected in 5 cases (1.6%) and related to cyclosporine (CSA) in 4 of them. Chronic allograft changes were detected in 6.3% of the cases and focal segmental glomerulosclerosis (FSGS) in one case.

Cellular rejection was the most common type of AR (68%), mixed cellular and vascular rejection was detected in 2.3% of cases, and low grades of rejection were the commonest grades (IA 69.3% and IIA 69.6%). It was found that ATN was the most common category in the first week (28.8%) and accounting for 70% of DGF cases, while the frequency of tubular affection (ATN + tubular injury) statistically decreases by time, that of AR significantly increases by time. On comparing ATN and AR, significant differences were detected between them as regards to the clinical presentation, serum creatinine (0.007) and in their frequency in the 2nd and last 2 weeks (P=0.02 and 0.0001). It is worth noting that 42.3% of ATN cases were associated with other pathological lesions (66.7% of them were associated with AR) which may modulate the line of treatment.

In conclusion, ATN and AR were the most common categories of early renal allograft dysfunction, however other pathological lesions, per se or coincide with the main categories may be the cause. So adequate allograft biopsy and full clinical data are helpful in differentiation between the causes and in establishment of a proper treatment protocol. Also, zero hour biopsies are recommended to provide base line information.