Importance of simultaneous active cytomegalovirus and Epstein-Barr virus infection in renal transplantation

Herpesviruses in patients after renal transplantation

Aim. To estimate graft function after kidney transplantation during active herpesviruses or superinfection Materials and methods. The study included 32 patients (men 21, women 11) with end-stage chronic kidney disease. The median age was 43 years. Cytomegalovirus (CMV), EpsteinBarr virus (EBV) and human herpes virus 6 (HHV-6) DNAs were screened by RT-PCR in the donor's transplant biopsy, and recipients peripheral blood and urine after kidney transplantation (KT) on 0, 1, 2, 4, 6, 12 months. Antiviral antibodies (IgM and IgG) were also screened by Enzyme-linked immunoassay analysis (ELISA) along with PCR. The 500 or less copies of viral DNA per 105 nuclear cells or 1 ml of urine was considered as low, more than 1000 copies high. Results. On the first month after KT CMV DNA was detected in 50% of pts., EBV DNA in 40% and HHV-6 DNA in 33%. During first year after KT two or three viruses simultaneously were found in 12 recipients: CMV, EBV, and HHV-6 were detected in 5 recipients; CMV and EBV in 4 patients; CMV and HHV-6 in 2 pts; EBV and HHV-6 in 1 pt. Graft dysfunction was observed in 9 patients with a high concentration of viral DNA of one, two or three viruses simultaneously. An upraise of the concentration of virus DNA (CMV, EBV and HHV 6) was detected primarily in the urine, while in the blood its concentration was less than 500 cop or undetectable. Renal dysfunction was not observed on the background of low concentrations of viral DNA in urine and blood. However, with an increase of DNA concentration, an impaired graft function in 8 of 12 patients appeared. Low viral DNA level proved to be a background for another virus activation or bacterial/fungal superinfection. Conclusion. Graft dysfunction occurs at high viral DNA levels detection during mono-or superinfection. Low viral load can serve as a background for another virus activation and/or bacterial/fungal superinfection.

BKV, CMV, and EBV Interactions and their Effect on Graft Function One Year Post-Renal Transplantation: Results from a Large Multi-Centre Study

Background

BK virus (BKV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivations are common after kidney transplantation and associated with increased morbidity and mortality. Although CMV might be a risk factor for BKV and EBV, the effects of combined reactivations remain unknown. The purpose of this study is to ascertain the interaction and effects on graft function of these reactivations.

Methods

3715 serum samples from 540 kidney transplant recipients were analysed for viral load by qPCR. Measurements were performed throughout eight visits during the first post-transplantation year. Clinical characteristics, including graft function (GFR), were collected in parallel.

Findings

BKV had the highest prevalence and viral loads. BKV or CMV viral loads over 10,000 copies·mL⁻¹ led to significant GFR impairment. 57 patients had BKV-CMV combined reactivation, both reactivations were significantly associated (p = 0.005). Combined reactivation was associated with a significant GFR reduction one year post-transplantation of 11.7 mL·min⁻¹·1.73 m⁻² (p = 0.02) at relatively low thresholds (BKV > 1000 and CMV > 4000 copies·mL⁻¹). For EBV, a significant association was found with CMV reactivation (p = 0.02), but no GFR reduction was found. Long cold ischaemia times were a further risk factor for high CMV load.

Interpretation

BKV-CMV combined reactivation has a deep impact on renal function one year post-transplantation and therefore most likely on long-term allograft function, even at low viral loads. Frequent viral monitoring and subsequent interventions for low BKV and/or CMV viraemia levels and/or long cold ischaemia time are recommended.

Fund

Investigator Initiated Trial; financial support by German Federal Ministry of Education and Research (BMBF).

The impact of early cytomegalovirus infection and disease in renal transplant recipients

Human cytomegalovirus (HCMV) infection is the single most frequent infectious complication in the early period after kidney transplantation. The HCMV load in blood, measured by HCMV PCR or the HCMV pp65 antigen test, is a predictor of HCMV disease in seropositive recipients. However, plasma virus load measurements are of only modest value in predicting the risk of HCMV disease in seronegative recipients of kidneys from seropositive donors. HCMV infection is an independent risk-factor for acute kidney graft rejection. There is also evidence that HCMV is associated with an increased long-term mortality and post-transplant diabetes mellitus. Whether pre-emptive or prophylactic therapy should be the preferred strategy is not yet decided. Some studies indicate that HCMV prophylaxis may reduce the risk of acute rejection, and thereby increase long-term graft survival in seronegative recipients of kidneys from seropositive donors.

A prospective study of the natural course of cytomegalovirus infection and disease in renal allograft recipients

BACKGROUND

Cytomegalovirus (CMV) infection is the single most frequent infectious complication in renal transplant recipients. Because no CMV-prophylaxis is given and ganciclovir is used only as deferred therapy for CMV disease at our center, we have been able to study the natural course of CMV infections. The aim was to assess risk factors for CMV infection and disease and thus identify subgroups of patients likely to benefit from CMV prophylaxis or preemptive therapy.

METHODS

Between October 1994 and July 1997, 477 consecutive renal transplant recipients (397 first transplants and 80 retransplants) were included in the study. The patients were followed prospectively for 3 months with serial measurements of CMV pp65 antigen for monitoring activity of CMV infections.

RESULTS

The incidence of CMV infections in first transplants was 68% in D+R- and D+/-R+ serostatus groups, whereas the incidence of CMV disease was higher in D+R- (56%) than in D+/-R+ (20%, P<0.001). No difference in severity of CMV disease in D+R- and D+/-R+ was seen except for an increased incidence of hepatitis in primary infections. One of 14 deaths could be associated with CMV disease in a seropositive recipient. Cox regression analysis showed that rejection (RR 2.5, P<0.01) and serostatus group D+R- (RR 3.9, P<0.001) were significant risk factors for development of CMV disease. The maximum CMV pp65 antigen count had significant correlation to disease only in CMV seropositive recipients, P<0.001. Conclusion. Renal transplant recipients can safely be given deferred ganciclovir therapy for CMV disease if they are intensively monitored for CMV infection. Patients with primary CMV infection (D+R-), CMV infected patients undergoing anti-rejection therapy and R+ patients with high CMV pp65 counts seem to have a particular potential for benefit from preemptive anti-CMV-therapy.

Prophylaxis against herpes infections in kidney transplant patients with special emphasis on CMV

METHOD

Since 1990, we have treated all kidney transplanted patients with cyclosporin (CsA)+ an initial 10 d antilymphocyte globulin (ALG) course, from September 1995 supplemented with mycophenolate mofetil (MMF). In 170 consecutive transplantations from June 1992 to the end of 1996, aciclovir 3200 mg/d (adjusted for kidney function and in children to age) was given prophylactically for 3 months post-transplantation (Tx), monitored with systematic and frequent tests for HSV and CMV. In case of CMV infection, we gave ganciclovir intravenously (oral ganciclovir from 1996) in doses according to kidney function for 3 months, followed by a further 3 months observation and monitoring period. In case of acute cellular rejection, ganciclovir was given during the 10-d OKT3 course and 1 week further. In case of delayed graft function combined with aciclovir side effects, ganciclovir was given until aciclovir could be reintroduced.

RESULTS

39% were HSV seronegative at Tx. There were no seroconversions or reactivations within the observation period. No mucocutaneous HSV infections was observed. No resistant strains developed. 26% were both HSV and CMV negative at Tx. 52% were CMV negative at Tx. 30% experienced a CMV infection post-transplant. The patients were grouped according to CMV status in the donor (D) and recipient (R) before Tx. We found approximately the same number of patients in the 4 CMV groups D-/R-, D+/R-, D-/R+ and D+/R+. Most infections occurred in the D+/R- group compared to D-/R- (p = 0.009). A significant increase in the number of CMV infections occurred in this subgroup when we gave reduced doses in case of delayed graft function (p = 0.015), from 1994. We observed only 1 CMV disease (in 1992). Serological EBV testing were performed concomitantly. No correlation was seen between CMV and EBV infections. From September 1995 we have treated all transplanted patients (n = 40) with CsA/ALG/MMF. We found no significant increase in CMV infections in this group.

CONCLUSIONS

Prophylaxis with aciclovir (combined with ganciclovir during acute rejections and in case of delayed graft function with aciclovir side effects) gives a good protection against HSV and CMV infections and prevents CMV disease effectively. High-dose aciclovir post-transplantation (or shift to ganciclovir) seems to be important to obtain effective prophylaxis. Better immunosuppression with MMF does not result in more CMV infections.

The human polyomavirus BK T antigen induces gene expression in human cytomegalovirus

Co-infections or co-habitations of cells by two or more viruses may occur in the human organism. Human cytomegalovirus (HCMV) and the human polyomavirus BK (BKV) have common host cells and may both establish lifelong latency/persistence following primary infection. Both viruses may become reactivated by immunosuppression or other conditions which upset host-virus balance, and they encode gene products with the inherent potential of acting as heterologous transacting factors for expression of cellular or viral genes. It has been shown that HCMV induces gene expression and replication of primate polyomaviruses. We now demonstrate that BKV is able to enhance the expression of HCMV immediate early (IE1 and 2) as well as the early (E) protein pp65 during double infections in semi-permissive cells. By transfection experiments it was established that the phenomenon is due to heterologous transcriptional transactivation of the HCMV major IE promoter (MIEP) by the BKV large T antigen, without contribution from the small t antigen.

Comparative evaluation of three ELISA techniques and an indirect immunofluorescence assay for the serological diagnosis of Epstein-Barr virus infection

BACKGROUND

The reference method for detecting specific Epstein-Barr virus (EBV) antibodies is indirect immunofluorescence (IF) with EBV-infected cells. The availability of protein purified from infected cells and more recently of recombinant polypeptides designed to contain immunodominant epitopes, has enabled the development of commercial enzyme-linked immunosorbent assays (ELISA) for the specific serodiagnosis of EBV infection.

OBJECTIVE

Evaluation of ELISA-based EBV serodiagnosis in comparison with indirect immunofluorescence.

STUDY DESIGN

We have first compared three commercial ELISA test systems with our in house indirect immunofluorescence assay for classifying correctly a set of serum samples into clinical categories (acute infection, past infection, interfering non-EBV infection, persistent infection). Additionally a prospective analysis with the best performing ELISA test (Enzygnost) was then carried out by running the ELISA test in parallel with the indirect immunofluorescence assay on 324 consecutive clinical samples sent to our laboratory for EBV serodiagnosis.

RESULTS

For the serodiagnosis of past EBV infection and acute EBV infection all three commercial ELISAs performed well in comparison with indirect immunofluorescence. When testing samples positive for cytomegalovirus (CMV), Toxoplasma or herpes simplex IgM, interference in the IgM tests was observed with the three ELISAs. In some instances we could demonstrate that the positive IgM results were due to EBV reactivation. The observed discrepancies between ELISA and IF for the serodiagnosis of chronic EBV infection or EBV reactivation, point to the difficulty for the serodiagnosis of persistent EBV infection on single serum samples. According to our prospective study the EBV IgG determination was accurate. A positive IgM result was not always indicative of an acute infection. Positive IgM results due to EBV reactivation were observed. A positive EBV nuclear antigen (EBNA) IgG result in those samples precluded acute infection.

CONCLUSIONS

90-95% of samples could be classified correctly into clinical categories by a two parameter ELISA system detecting IgG and IgM against a standardized mixture of EBV antigens, allowing standardization and automation of EBV-specific serology. The absence of EBNA IgG was useful as a second line confirmatory assay for acute EBV infection.