The question of renal transplantation in patients with a history of schistosomiasis infections raises a number of issues:
a) Surgical risk; b) pharmacokinetics and potential toxicity of immunosuppressive agents; c) short- and long-term outcomes; d) recurrence of the original disease; e) Reinfection.
In urinary schistosomiasis, the surgical risk is related to the presence of infection, motor abnormalities of the bladder, outflow or upstream obstruction. All these issues are amenable to adequate management, which may be simple or highly complicated. Pre-transplant urological procedures may be necessary for ensuring adequate bladder capacity and function. In some cases, persistent infection may require bilateral nephrectomy.
In hepatosplenic schistosomiasis the surgical risk is assessed by the usual CHILD criteria, which are quite valid in schistosomiasis. Please mind the frequent association with HCV infection, which has its own constraints with regards to transplantation. The presence of portal hypertension with ascites and porto-systemic shunts should be seen as a contraindication to transplantation.
A thesis presented to Alexandria University has evaluated the metabolism of immunosuppressive agents in patients with hepato-intestinal transplantation. It concludes that if the patient is fit for surgery, the liver function should be good enough not to impose a significant perturbation to the pharmacokinetics of commonly used immunosuppressive agents. We have not been able to show that the toxicity of antiproliferative agents, PSI’s or CNI’s is increased in patients with hepatosplenic schistosomiasis with fair liver functions that permit surgery.
The short-term outcomes of transplantation in patients with schistosomiasis are generally non-inferior to those without schistosomiasis, so long as the pre-operative criteria are favorable as described above. In one study, the incidence of ureteric leaks was relatively higher in patients with urinary schistosomiasis. Some surgeons prefer uretero-ureteric to uretero-vesical anastomosis to avoid cutting through the fibrotic bladder wall. I am unaware of any studies that compare this approach to standard uretero-vesical anastomosis.
In the few reports that addressed long-term outcomes, there have not been any significant alterations in patient or graft survival at 5 years. But all patients included were well selected according to the above criteria.
Recurrence of schistosomal nephropathy has been reported in Brazil, not in Egypt. I presume that adequate pre-transplant exclusion of active infection should obviate this remote possibility.
Re-infection has been addressed in a nice paper from Mansoura. Since many recipients eventually resume their social habits of contact with contaminated water, their chances of getting re-infected are obviously high, particularly with their immunosuppression. In the mentioned study, re-infection occurred in a higher proportion of patients receiving kidney transplants compared the norms in the same community.
So, the key for a good transplant outcome is good selection, which brings us back to the second and third paragraphs of this comment.