Post-transplant lymphoproliferative disease

An approach to finding indications and contraindications for nephrectomy in post-transplant renal graft lymphomas: PTLD.Int survey

BACKGROUND AND OBJECTIVES

Allograft involvement can occur in some renal transplant recipients who develop post-transplant lymphoproliferative disorders (PTLD). We aimed to find indications and/or contraindications for nephrectomy in renal allograft PTLD based on an outcome analysis of previous reports.

DESIGN AND SETTING

A comprehensive search of Pubmed and Google scholar was performed to find reports of different treatment strategies addressing PTLD occurring within the allograft after renal transplantation.

PATIENTS AND METHODS

Patients who underwent nephrectomy due to kidney allograft localization by PTLD were categorized as the case group, and renal recipients with kidney PTLD for whom nonsurgical treatment modalities were used served as controls.

RESULTS

Survival analysis demonstrated that patients with renal allograft involvement who underwent allograft nephrectomy had a significantly better outcome compared to patients for whom a non-surgical approach was used (P=.03). In patients with disseminated PTLD, nephrectomy was not useful (P>.1). Patients with simultaneous kidney and lung complications by PTLD benefitted from nephrectomy.

CONCLUSIONS

We found that patients with renal graft complication with disseminated PTLD do not benefit from nephrectomy, which can be considered the only contraindication. However, some particular PTLD co-localizations were not as likely to adversely affect the benefit of nephrectomy in these patients, and these can be considered indications for the procedure. Future multicenter studies are needed to confirm our results.

Viral prophylaxis in organ transplant patients

Viral pathogens have emerged as the most important microbial agents having deleterious effects on solid organ transplant (SOT) recipients. Antiviral chemoprophylaxis involves the administration of medications to abort transmission of, avoid reactivation of, or prevent progression to disease from, active viral infection. Cytomegalovirus (CMV) is the major microbial pathogen having a negative effect on SOT recipients. CMV causes infectious disease syndromes, augments iatrogenic immunosuppression and is commonly associated with opportunistic superinfection. CMV has also been implicated in the pathogenesis of rejection. Chemoprophylactic regimens for CMV have included oral aciclovir (acyclovir) at medium and high doses, intravenous and oral ganciclovir, and the prodrugs valaciclovir (valacyclovir) and valganciclovir. CMV prophylactic strategies should be stratified, with the highest-risk patients receiving the most 'potent' prophylactic regimens. Herpes simplex virus (HSV) reactivation in SOT recipients is more frequent, may become more invasive, takes longer to heal, and has greater potential for dissemination to visceral organs than it does in the immunocompetent host. Prophylactic regimens for CMV are also effective chemoprophylaxis against HSV; in the absence of CMV prophylaxis, aciclovir, valaciclovir or famciclovir should be used as HSV prophylaxis in seropositive recipients. Primary varicella-zoster virus (VZV) after SOT is rare and most commonly seen in the paediatric transplant population because of VZV epidemiology. Zoster occurs in 5-15% of patients, usually after the sixth post-transplant month. Prophylactic regimens for zoster are neither practical nor cost effective after SOT because of the late onset of disease and low proportion of affected individuals. All SOT recipients should receive VZV immune globulin after contact with either varicella or zoster. Epstein-Barr virus has its most significant effect in SOT as the precipitating factor in the development of post-transplant lymphoproliferative disorders. Antiviral agents that could be effective are the same as those used for CMV, but indications for and effectiveness of prophylaxis are poorly established. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are important pathogens in the SOT population as indications for transplantation. So-called 'prophylaxis' for recurrent HBV and HCV after liver transplantation is controversial, suppressive rather than preventive, and potentially lifelong. Influenza infection after SOT is acquired by person-to-person contact. During epidemic periods of influenza, transplant populations experience a relatively high frequency of infection, and influenza may affect immunosuppressed SOT recipients more adversely than immunocompetent individuals. Antiviral medications for prevention of influenza are administered as post-exposure prophylaxis to SOT recipients, in addition to yearly vaccine, in circumstances such as influenza epidemics and nosocomial outbreaks, and after exposure to a symptomatic individual during 'flu season'.

Renal malacoplakia: demonstration by MR imaging

We report herein a case of histologically verified bilateral renal malacoplakia. MRI features were distinctive and include multiple nodules 1-2 cm in diameter that were low in signal on T1, T2 and early and late post gadolinium images with intervening fibrous stroma. Demonstration of renal malacoplakia on MR images may obviate the need for major surgery and rapidly direct patients to appropriate antimicrobial therapy for treatment.