Monitoring of rejection in renal transplantation

With better immunosuppression, the results of kidney transplantation have improved greatly during the last 10 years. It has never been possible to completely suppress rejection, and transplant physicians and surgeons still need to maintain a constant vigilance in order that rejection does not go unrecognised in their patients. 1.1. CLINICAL FEATURES. These are often absent, although the patient may have noted a decreased urine volume and gain in weight. The kidney is sometimes tender and enlarged. 1.2. BIOCHEMICAL FEATURES. There is a rise in the plasma urea and creatinine and a reduced creatinine clearance. Unfortunately, other conditions such as cyclosporin nephrotoxicity can produce similar changes. 1.3. RADIOLOGICAL FEATURES. Isotope renography may demonstrate reduced renal perfusion and excretion but this is also seen in ATN. Ultrasound may demonstrate an increase in renal size. On Duplex renal ultrasonography changes in renal perfusion patterns can often be demonstrated. MRI has shown a loss of cortico-medullary differentiation during rejection, but this is not very specific. 1.4. CYTOLOGICAL FEATURES. The presence of lymphocytes in the urine is often indicative of rejection, as is the finding of inflammatory cells in fine needle aspirates from the transplanted kidney. 1.5. HISTOLOGICAL FEATURES. Renal biopsies are best obtained using a Biopty Gun under ultrasound control. Cellular rejection is characterised by a heavy infiltrate of lymphocytes which invade the renal tubules (tubulitis). Vascular rejection is characterised by endothelial proliferation and fibrinoid necrosis of the vessel wall. 1.6. CONCLUSION. Several of the above tests are often required to establish the presence or absence of rejection.