Cytomegalovirus post kidney transplantation: prophylaxis versus pre-emptive therapy?

QuantiFERON-CMV as a Predictor of CMV Events During Preemptive Therapy in CMV-seropositive Kidney Transplant Recipients

BACKGROUND

Prevention of cytomegalovirus (CMV) infection after kidney transplantation is costly and burdensome.

METHODS

Given its promising utility in risk stratification, we evaluated the use of QuantiFERON-CMV (QFCMV) and additional clinical variables in this prospective cohort study to predict the first clinically significant CMV infection (CS-CMV, ranging from asymptomatic viremia requiring treatment to CMV disease) in the first posttransplant year. A cost-effectiveness analysis for guided prevention was done.

RESULTS

One hundred adult kidney transplant recipients, CMV IgG + , were given basiliximab induction and maintained on steroid/mycophenolate/tacrolimus with weekly CMV monitoring. Thirty-nine patients developed CS-CMV infection (viral syndrome, n = 1; end-organ disease, n = 9; and asymptomatic viremia, n = 29). A nonreactive or indeterminate QFCMV result using the standard threshold around day 30 (but not before transplant) was associated with CS-CMV rates of 50% and 75%, respectively. A higher QFCMV threshold for reactivity (>1.0 IU interferon-γ/mL) outperformed the manufacturer's standard (>0.2 IU interferon-γ/mL) in predicting protection but still allowed a 16% incidence of CS-CMV. The combination of recipient age and type of donor, along with posttransplant QFCMV resulted in a prediction model that increased the negative predictive value from 84% (QFCMV alone) to 93%. QFCMV-guided preemptive therapy was of lower cost than preemptive therapy alone ( P  < 0.001, probabilistic sensitivity analysis) and was cost-effective (incremental net monetary benefit of 210 USD) assuming willingness-to-pay of 2000 USD to avoid 1 CMV disease.

CONCLUSIONS

Guided CMV prevention by the prediction model with QFCMV is cost-effective and would spare from CMV surveillance in 42% of patients with low risk for CS-CMV.

Five-year single-center analysis of cytomegalovirus viremia in kidney transplant recipients and possible implication for novel prophylactic therapy approaches

BACKGROUND

Cytomegalovirus (CMV) infections are a common complication after kidney transplantation (KTx) and negatively affecting patient outcome. Valganciclovir (VGC) prophylaxis is often limited by drug-induced side effects and dose reduction due to decline in kidney function.

METHOD

In the present study, episodes of CMV viremia in the first year after KTx in a cohort of 316 recipients were analyzed retrospectively to identify risk factors linked to persistent infections.

RESULTS

In the studied cohort, 18.7% of patients showed a high-risk (HR) constellation (D+/R-) for CMV infections. CMV viremia affected 22% of our cohort, with HR patients being the most affected cohort (44.1%). Within this group, most viremic events (65.3%) occurred while patients were still on prophylactic therapy, showing significantly higher viral loads and a longer duration compared to seropositive recipients.

CONCLUSION

The analysis at hand revealed that detection of viremia under ongoing antiviral prophylaxis bears an increased risk for sustained viral replication and antiviral drug resistance in HR patients. We identified low estimated glomerular filtration rate (eGFR) and lower dose VGC prophylaxis post-KTx as a risk factor for breakthrough infections in HR patients in our single center cohort. These patients might benefit from a closer CMV monitoring or novel prophylactic agents as letermovir.

Renal and Electrolyte Disorders and the Nervous System

OBJECTIVE

Neurologic complications are a major contributor to death and disability in patients with renal disease. Oxidative stress, endothelial dysfunction, accelerated arteriosclerosis, and uremic inflammatory milieu affect both the central and peripheral nervous systems. This article reviews the unique contributions of renal impairment to neurologic disorders and their common clinical manifestations as the prevalence of renal disease increases in a globally aging population.

LATEST DEVELOPMENT

Advances in the understanding of the pathophysiologic interplay between the kidneys and brain, also referred to as the kidney-brain axis, have led to more widespread recognition of associated changes in neurovascular dynamics, central nervous system acidification, and uremia-associated endothelial dysfunction and inflammation in the central and peripheral nervous systems. Acute kidney injury increases mortality in acute brain injury to nearly 5 times that seen in matched controls. Renal impairment and its associated increased risks of intracerebral hemorrhage and accelerated cognitive decline are developing fields. Dialysis-associated neurovascular injury is increasingly recognized in both continuous and intermittent forms of renal replacement therapy, and treatment strategies for its prevention are evolving.

ESSENTIAL POINTS

This article summarizes the effects of renal impairment on the central and peripheral nervous systems with special considerations in acute kidney injury, patients requiring dialysis, and conditions that affect both the renal and nervous systems.

LIS1, a glyco-humanized swine polyclonal anti-lymphocyte globulin, as a novel induction treatment in solid organ transplantation

Anti-thymocyte or anti-lymphocyte globulins (ATGs/ALGs) are immunosuppressive drugs used in induction therapies to prevent acute rejection in solid organ transplantation. Because animal-derived, ATGs/ALGs contain highly immunogenic carbohydrate xenoantigens eliciting antibodies that are associated with subclinical inflammatory events, possibly impacting long-term graft survival. Their strong and long-lasting lymphodepleting activity also increases the risk for infections. We investigated here the in vitro and in vivo activity of LIS1, a glyco-humanized ALG (GH-ALG) produced in pigs knocked out for the two major xeno-antigens αGal and Neu5Gc. It differs from other ATGs/ALGs by its mechanism of action excluding antibody-dependent cell-mediated cytotoxicity and being restricted to complement-mediated cytotoxicity, phagocyte-mediated cytotoxicity, apoptosis and antigen masking, resulting in profound inhibition of T-cell alloreactivity in mixed leucocyte reactions. Preclinical evaluation in non-human primates showed that GH-ALG dramatically reduced CD4+ (p=0.0005,***), CD8+ effector T cells (p=0.0002,***) or myeloid cells (p=0.0007,***) but not T-reg (p=0.65, ns) or B cells (p=0.65, ns). Compared with rabbit ATG, GH-ALG induced transient depletion (less than one week) of target T cells in the peripheral blood (<100 lymphocytes/L) but was equivalent in preventing allograft rejection in a skin allograft model. The novel therapeutic modality of GH-ALG might present advantages in induction treatment during organ transplantation by shortening the T-cell depletion period while maintaining adequate immunosuppression and reducing immunogenicity.

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.

Functional Consequences of Memory Inflation after Solid Organ Transplantation

CMV is a major infectious complication following solid organ transplantation. Reactivation of CMV leads to memory inflation, a process in which CD8 T cells expand over time. Memory inflation is associated with specific changes in T cell function, including increased oligoclonality, decreased cytokine production, and terminal differentiation. To address whether memory inflation during the first year after transplantation in human subjects alters T cell differentiation and function, we employed single-cell-matched TCRαβ and targeted gene expression sequencing. Expanded T cell clones exhibited a terminally differentiated, immunosenescent, and polyfunctional phenotype whereas rare clones were less differentiated. Clonal expansion occurring between pre- and 3 mo posttransplant was accompanied by enhancement of polyfunctionality. In contrast, polyfunctionality and differentiation state were largely maintained between 3 and 12 mo posttransplant. Highly expanded clones had a higher degree of polyfunctionality than rare clones. Thus, CMV-responsive CD8 T cells differentiated during the pre- to posttransplant period then maintained their differentiation state and functional capacity despite posttransplant clonal expansion.

Evolution of Cytomegalovirus-Responsive T Cell Clonality following Solid Organ Transplantation

CMV infection is a significant complication after solid organ transplantation. We used single cell TCR αβ sequencing to determine how memory inflation impacts clonality and diversity of the CMV-responsive CD8 and CD4 T cell repertoire in the first year after transplantation in human subjects. We observed CD8 T cell inflation but no changes in clonal diversity, indicating homeostatic stability in clones. In contrast, the CD4 repertoire was diverse and stable over time, with no evidence of CMV-responsive CD4 T cell expansion. We identified shared CDR3 TCR motifs among patients but no public CMV-specific TCRs. Temporal changes in clonality in response to transplantation and in the absence of detectable viral reactivation suggest changes in the repertoire immediately after transplantation followed by an expansion with stable clonal competition that may mediate protection.

Prevention of Congenital Cytomegalovirus Infection with Vaccines: State of the Art

Cytomegalovirus (CMV) is the most common cause of congenital infection and non-genetic sensorineural hearing loss in childhood. Up to 2% of neonates, with the highest percentages found in developing countries, are congenitally infected with CMV. At birth, most of these infants are asymptomatic. However, approximately 10% have signs and symptoms of the disease, and 40–60% of symptomatic neonates will later develop permanent neurologic sequelae. To reduce congenital CMV (cCMV) infection, a vaccine able to prevent primary infection is essential. In this narrative review, actual ongoing research about the development of a CMV vaccine is discussed. The progressive increase in knowledge on the ways in which the host’s immune system and CMV relate has made it possible to clarify that the development of a vaccine that is certainly capable of reducing the risk of cCMV infection, and preventing both primary and nonprimary infections is extremely difficult. Many of the ways in which the virus evades the immune system and causes cCMV infection are not yet fully understood, especially in cases of nonprimary infection. Moreover, the schedule that should be recommended and that subjects must be vaccinated to obtain the greatest effect have not been precisely defined. Further studies are needed before the problem of cCMV infection and its related challenges can be totally solved.

The NFKB1 Promoter Polymorphism (-94ins/delATTG) Is Associated with Susceptibility to Cytomegalovirus Infection after Kidney Transplantation and Should Have Implications on CMV Prophylaxis Regimens

Infections with cytomegalovirus (CMV) are one of the most frequent opportunistic infections in kidney transplant recipients. Current risk-adapted CMV chemoprophylaxis regimens are based almost solely on the donor and recipient CMV serostatus. Of note, the NFKB1 -94ins/delATTG promoter polymorphism was recently associated with a higher risk of CMV infection. Since single genetic association studies suffer from poor reliability for drawing therapeutic implications, we performed this confirmatory study and included 256 kidney transplant recipients from 2007 to 2014 in this retrospective study. Patients were genotyped for the -94ins/delATTG NFKB1 promoter polymorphism and followed up for 12 months. The incidence of CMV infection within 12 months after kidney transplantation was 37.5% (33/88) for the ins/ins, 21.5% (28/130) for the ins/del, and 23.7% (9/38) for the del/del genotypes (p = 0.023). Moreover, we evaluated the time of CMV infection onset. Ins/ins carriers had primarily late-onset CMV infection (median 194 days; interquartile range (IQR) 117–267 days) compared with heterozygous (ins/del; median 158 days; IQR 82–195 days) and homozygous deletion allele carriers (del/del; median 95 days; 84–123 days). Multivariate-restricted Cox regression model confirmed the ins/ins genotype to be an independent risk factor for the development of late-onset CMV infections. These findings should have an impact on post-kidney transplantation CMV chemoprophylaxis regimens.

Sex-Associated Differences in Cytomegalovirus Prevention: Prophylactic Strategy is Potentially Associated With a Strong Kidney Function Impairment in Female Renal Transplant Patients

Post-transplantation cytomegalovirus (CMV) syndrome can be prevented using the antiviral drug (val)ganciclovir. (Val)ganciclovir is typically administered following a prophylactic or a pre-emptive strategy. The prophylactic strategy entails early universal administration, the pre-emptive strategy, early treatment in case of infection. However, it is not clear which strategy is superior with respect to transplantation outcome; sex-specific effects of these prevention strategies are not known. We have retrospectively analyzed 540 patients from the multi-centre Harmony study along eight pre-defined visits: 308 were treated according to a prophylactic, 232 according to a pre-emptive strategy. As expected, we observed an association of prophylactic strategy with lower incidence of CMV syndrome, delayed onset and lower viral loads compared to the pre-emptive strategy. However, in female patients, the prophylactic strategy was associated with a strong impairment of glomerular filtration rate one year post-transplant (difference: -11.8 ± 4.3 ml min-1·1.73 m-2, p = 0.006). Additionally, we observed a tendency of higher incidence of acute rejection and severe BK virus reactivation in the prophylactic strategy group. While the prophylactic strategy was more effective for preventing CMV syndrome, our results suggest for the first time that the prophylactic strategy might lead to inferior transplantation outcomes in female patients, providing evidence for a strong association with sex. Further randomized controlled studies are necessary to confirm this potential negative effect.

Cytomegalovirus disease in de novo kidney-transplant recipients: comparison of everolimus-based immunosuppression without prophylaxis with mycophenolic acid-based immunosuppression with prophylaxis

PURPOSE

To compare everolimus (EVR) plus low-dose tacrolimus (TAC) with mycophenolic acid (MPA) plus standard-dose TAC with regards to rates of cytomegalovirus (CMV) disease in de novo kidney-transplant recipients (KTRs).

METHODS

This single-center retrospective study included 187 de novo KTRs; 59 patients (31.6%) received EVR/low-dose TAC (group 1); 128 patients (68.4%) received MPA with standard-dose TAC (group 2). All received anti-thymocyte globulins as the induction therapy, and steroid-sparing strategy. Valganciclovir prophylaxis was mandatory for CMV D+/R- KTRs (seronegative recipients of a seropositive donor) in both groups and for R+ seropositive recipients (only in group 2).

RESULTS

The 2-year incidence of CMV disease was low and comparable between groups: 6.8% and 7.0% in groups 1 and 2, respectively (p = 0.94). There was no statistical difference in CMV serostatus (p = 1). However, CMV disease tended to be less frequent, though not statistically different, in R+ KTRs receiving EVR without prophylaxis (3.7% vs. 8.5% in groups 1 and 2, respectively) and in patients without EVR discontinuation (2.6% vs. 6.9% in patients who did not discontinue MPA (p = 0.29). Two-year graft function was good and comparable between groups (median eGFR of 54.2 and 53.0 mL/min in groups 1 and 2, respectively; p = 0.47); incidence of immunological events was low. Significantly more patients in group 1 discontinued EVR because of adverse events than patients that discontinued MPA in group 2 (35.6% in group 1 vs. 10.2% in group 2; p < 0.001).

CONCLUSIONS

Everolimus plus low-dose TAC given to de novo KTRs was associated with low rates of CMV disease, especially in R+ patients with no CMV prophylaxis.

A split strategy to prevent cytomegalovirus after kidney transplantation using prophylaxis in serological high-risk patients and a pre-emptive strategy in intermediate-risk patients: Combining the best of two options?

BACKGROUND

Cytomegalovirus (CMV) remains an important challenge after kidney transplantation. Current Transplantation Society International Consensus Guidelines recommend antiviral prophylaxis or pre-emptive therapy for high-risk CMV-seronegative recipients with a CMV-seropositive donor (D+/R-) and moderate-risk CMV-seropositive recipients (R+). However, a split strategy according to CMV serostatus is not specifically mentioned.

METHODS

We evaluated a split strategy to prevent CMV infection after kidney transplantation in which D+/R- patients received valganciclovir (VGC) prophylaxis for 200 days, and R + patients were treated pre-emptively according to CMV DNAemia. Patients were followed until 1-year post-transplant.

RESULTS

Between April 2014 and March 2018, 40 D+/R- and 92 R + patients underwent kidney transplantation. Forty-six percent received antithymocyte globulin (ATG) induction, and 98% was treated with calcineurin inhibitors, mycophenolic acid (MPA), and steroids. No D+/R- patient developed CMV disease during prophylaxis (median 200 days), but 15% developed post-prophylaxis or late-onset disease. Fifty-three percent developed neutropenia during prophylaxis, including 16/40 (40%) grade 3 or 4 neutropenia requiring reduction/discontinuation of MPA (30%) and/or VGC (35%), and an occasional need for granulocyte colony-stimulating factor (5%). In the R + group, 40% received antiviral therapy for a median duration of 21 days; 5% developed early-onset CMV disease. Only 5% developed neutropenia. D+/R + status (hazard ratio (HR) 2.09,P = .004) and ATG use (HR 2.81, P < .0001) were risk factors for CMV reactivation.

CONCLUSIONS

Prophylaxis leads to acceptable CMV control in high-risk patients but comes with a high risk of neutropenia. Pre-emptive therapy is effective and limits drug exposure in those at lower risk of CMV.

Synthesis and Antiviral Properties of 1-Substituted 3-[ω-(4-Oxoquinazolin-4(3H)-yl)alkyl]uracil Derivatives

A series of uracil derivatives containing a 4-oxoquinazoline fragment bound to the nitrogen atom N3 of the pyrimidine ring by a short methylene bridge was synthesized to search for new antiviral agents. Some compounds in this series are shown to exhibit high inhibitory activity against human cytomegalovirus and the varicella zoster virus in a HEL cell culture.

Cytomegalovirus Viremia after Living and Deceased Donation in Kidney Transplantation

Despite screening, effective anti-viral drugs and risk-balanced prophylaxis, cytomegalovirus (CMV) remains a major cause of morbidity in transplant patients. The objective of this study was to retrospectively analyze the risk factors associated with CMV viremia after kidney transplantation in a large European cohort with standardized valganciclovir prophylaxis in the present era. A special focus was placed on the comparison of living and postmortal donation. We conducted a longitudinal observational study involving 723 adult patients with a total of 3292 patient-years who were transplanted at our center between 2007 and 2015. Valganciclovir prophylaxis was administered over 100 days for CMV+ donors (D) or recipients (R), over 200 days for D+/R−, and none in D−/R−. A CMV+ donor, rejection episodes, and deceased donor transplantation were identified to be associated with increased incidences of CMV viremia. Although we did not find a reduced overall survival rate for patients with CMV viremia, it was associated with worse graft function. Since we observed a relevant number of CMV infections despite prescribing valganciclovir prophylaxis, a pre-emptive strategy in patients with (suspected) adherence restrictions could be favored. Our data can help transplant physicians educate their patients about their individual CMV risk and choose the most appropriate CMV treatment approach.

The Aquaporin 5 -1364A/C Promoter Polymorphism Is Associated With Cytomegalovirus Infection Risk in Kidney Transplant Recipients

Background: The aquaporin 5 (AQP5) −1364A/C promoter single nucleotide polymorphism affects key mechanisms of inflammation and immune cell migration. Thus, it could be involved in the pathogenesis of cytomegalovirus infection. Accordingly, we tested the hypothesis that the AQP5 promoter −1364A/C polymorphism is associated with the risk of cytomegalovirus infection in kidney transplantation recipients.

Methods: We included 259 adult patients who received a kidney transplant from 2007 and 2014 in this observational study. Patients were genotyped for the AQP5 promoter −1364A/C single nucleotide polymorphism and followed up for 12 months after transplantation. Kaplan–Meier plots and multivariable proportional hazard analyses were used to evaluate the relationship between genotypes and the incidence of cytomegalovirus infection.

Results: The incidences of cytomegalovirus infection within 12 months after kidney transplantation were 22.9% for the AA genotypes (43/188) and 42.3% for the AC/CC genotypes (30/71; p = 0.002). Furthermore, multivariable COX regression revealed the C-allele of the AQP5 −1364A/C polymorphism to be a strong and independent risk factor for cytomegalovirus infection. In this analysis, AC/CC subjects demonstrated a more than 2-fold increased risk for cytomegalovirus infection within the first year after kidney transplantation (hazard ratio: 2.28; 95% CI: 1.40–3.73; p = 0.001) compared to that in individuals with homozygous AA genotypes.

Conclusions: With respect to opportunistic cytomegalovirus infections (attributable to immunosuppression after kidney transplantation), the C-allele of the AQP5 −1364A/C promoter polymorphism is independently associated with an increased 12-months infection risk. These findings emphasize the importance of genetic variations as additional risk factors of cytomegalovirus infection after solid organ transplantations and might also facilitate the discovery of novel therapeutic targets.

Low dose valganciclovir as cytomegalovirus prophylaxis in post-renal transplant recipients induced with alemtuzumab: A single-center study

OBJECTIVES

Alemtuzumab (Ale) is a recombinant monoclonal antibody which binds to CD52 causing profound lymphodepletion, thus allowing its use in renal transplantation induction therapy. However, patients may be at increased risk for opportunistic infections, such as Cytomegalovirus (CMV). We analyzed CMV infection in renal allograft recipients administered low-dose valganciclovir (VGCV) prophylaxis with alemtuzumab induction and steroid minimization.

MATERIALS AND METHODS

In this retrospective analysis, 678 kidney transplant recipients were evaluated, with 606 included for analysis. Patients were excluded for receiving induction therapy other than Ale, or for lack of follow-up within 1 year. VGCV prophylaxis was stratified by recipient CMV risk status and low-dose (450 mg) VGCV was given 3 times a week to low and moderate risk patients and daily to high risk individuals. Subject records were examined for recipient demographics, donor and recipient CMV serostatus, CMV viremia, and invasive infection.

RESULTS

Of the 606 recipients, 154 were defined as low risk for CMV infection (donor and recipient both negative, or D-/R-), 236 as moderate risk without mismatch (D+/R+), 122 as moderate risk with mismatch (D-/R+), and 94 as high risk (D+/R-). Twenty-nine (29) individuals (4.8%) tested positive by PCR for CMV viremia and 10 (1.7%) patients developed invasive CMV disease, including colitis (n = 4), esophagitis (n = 1), enteritis (n = 1), nephritis (n = 1), and pneumonia (n = 3). High risk recipients (D+/R-) accounted for the majority of invasive CMV disease (n = 5), followed by moderate risk (n = 4). CMV viremia was also more common in high risk and moderate risk (D+/R+) individuals. Overall rejection rate for our study population was 27%.

CONCLUSION

In this institution's experience, CMV incidence was reduced compared to historically reported data by using low-dose (450 mg) VGCV prophylaxis in combination with Ale induction and steroid minimization. However, overall rejection rate was significantly higher in our population, possibly influenced by the degree of steroid minimization.

Neurologic complications of kidney transplantation

Renal transplant is the most common organ transplant in the United States, and the frequency of kidney transplants continues to rise as transplant offers improved survival and quality of life compared to dialysis. However, complications are not uncommon and patients frequently encounter issues requiring hospitalization, especially in the first year postoperatively. Complications that arise are typically related to surgical complications, immunosuppressive medications, or infection due to immunosuppression. Neurological complications are fairly common post-operatively, and are associated with increased morbidity and mortality in this population. This review discusses the most common etiologies of neurological complications after kidney transplant, including infection, malignancy, medication related, acute neuropathy, and other neurological pathology.

Incidence, risk factors, and outcome of BK polyomavirus infection after kidney transplantation

BACKGROUND

Polyomavirus-associated nephropathy is a leading cause of kidney allograft failure. Therapeutic options are limited and prompt reduction of the net state of immunosuppression represents the mainstay of treatment. More recent application of aggressive screening and management protocols for BK-virus infection after renal transplantation has shown encouraging results. Nevertheless, long-term outcome for patients with BK-viremia and nephropathy remains obscure. Risk factors for BK-virus infection are also unclear.

AIM

To investigate incidence, risk factors, and outcome of BK-virus infection after kidney transplantation.

METHODS

This single-centre observational study with a median follow up of 57 (31-80) mo comprises 629 consecutive adult patients who underwent kidney transplantation between 2007 and 2013. Data were prospectively recorded and annually reviewed until 2016. Recipients were periodically screened for BK-virus by plasma quantitative polymerized chain reaction. Patients with BK viral load ≥ 1000 copies/mL were diagnosed BK-viremia and underwent histological assessment to rule out nephropathy. In case of BK-viremia, immunosuppression was minimized according to a prespecified protocol. The following outcomes were evaluated: patient survival, overall graft survival, graft failure considering death as a competing risk, 30-d-event-censored graft failure, response to treatment, rejection, renal function, urologic complications, opportunistic infections, new-onset diabetes after transplantation, and malignancies. We used a multivariable model to analyse risk factors for BK-viremia and nephropathy.

RESULTS

BK-viremia was detected in 9.5% recipients. Initial viral load was high (≥ 10000 copies/mL) in 66.7% and low (< 10000 copies/mL) in 33.3% of these patients. Polyomavirus-associated nephropathy was diagnosed in 6.5% of the study population. Patients with high initial viral load were more likely to experience sustained viremia (95% vs 25%, P < 0.00001), nephropathy (92.5% vs 15%, P < 0.00001), and polyomavirus-related graft loss (27.5% vs 0%, P = 0.0108) than recipients with low initial viral load. Comparison between recipients with or without BK-viremia showed that the proportion of patients with Afro-Caribbean ethnicity (33.3% vs 16.5%, P = 0.0024), panel-reactive antibody ≥ 50% (30% vs 14.6%, P = 0.0047), human leukocyte antigen (HLA) mismatching > 4 (26.7% vs 13.4%, P = 0.0110), and rejection within thirty days of transplant (21.7% vs 9.5%; P = 0.0073) was higher in the viremic group. Five-year patient and overall graft survival rates for patients with or without BK-viremia were similar. However, viremic recipients showed higher 5-year crude cumulative (22.5% vs 12.2%, P = 0.0270) and 30-d-event-censored (22.5% vs 7.1%, P = 0.001) incidences of graft failure than control. In the viremic group we also observed higher proportions of recipients with 5-year estimated glomerular filtration rate < 30 mL/min than the group without viremia: 45% vs 27% (P = 0.0064). Urologic complications were comparable between the two groups. Response to treatment was complete in 55%, partial in 26.7%, and absent in 18.3% patients. The nephropathy group showed higher 5-year crude cumulative and 30-d-event-censored incidences of graft failure than control: 29.1% vs 12.1% (P = 0.008) and 29.1% vs 7.2% (P < 0.001), respectively. Our multivariable model demonstrated that Afro-Caribbean ethnicity, panel-reactive antibody > 50%, HLA mismatching > 4, and rejection were independent risk factors for BK-virus viremia whereas cytomegalovirus prophylaxis was protective.

CONCLUSION

Current treatment of BK-virus infection offers sub-optimal results. Initial viremia is a valuable parameter to detect patients at increased risk of nephropathy. Panel-reactive antibody > 50% and Afro-Caribbean ethnicity are independent predictors of BK-virus infection whereas cytomegalovirus prophylaxis has a protective effect.

Common viral infections in kidney transplant recipients

Infectious complications have been considered as a major cause of morbidity and mortality after kidney transplantation, especially in the Asian population. Therefore, prevention, early detection, and prompt treatment of such infections are crucial in kidney transplant recipients. Among all infectious complications, viruses are considered to be the most common agents because of their abundance, infectivity, and latency ability. Herpes simplex virus, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, hepatitis B virus, BK polyomavirus, and adenovirus are well-known etiologic agents of viral infections in kidney transplant patients worldwide because of their wide range of distribution. As DNA viruses, they are able to reactivate after affected patients receive immunosuppressive agents. These DNA viruses can cause systemic diseases or allograft dysfunction, especially in the first six months after transplantation. Pretransplant evaluation and immunization as well as appropriate prophylaxis and preemptive approaches after transplant have been established in the guidelines and are used effectively to reduce the incidence of these viral infections. This review will describe the etiology, diagnosis, prevention, and treatment of viral infections that commonly affect kidney transplant recipients.

NFKB1 promoter polymorphism: A new predictive marker of cytomegalovirus infection after kidney transplantation

INTRODUCTION

Cytomegalovirus (CMV) infection represents a common cause of morbidity and mortality in kidney transplant recipients (KTR). The NF-kB signaling pathway is highly involved in the pathogenesis of CMV infection. The -94ins/delATTG functional polymorphism in the promoter of NFKB1 has been associated with low intracellular levels of the protein and high incidence of inflammatory and autoimmune disease. In this study, we evaluated the association of this NFKB1 polymorphism with the risk of CMV infection.

METHODS

CMV infection was defined as virus isolation or detection of viral antigens or nucleic acid in any body fluid or tissue specimen. Using Cox regression and survival analysis, we analyzed the association between the polymorphism and CMV infection as well as recurrence in the first 12 months after transplantation.

RESULTS

We analyzed the -94ins/delATTG NFKB1 polymorphism of 189 KTRs. The 65% of CMV infections occurred in ins/ins group. Survival free from CMV infection was 54.7% for ins/ins group and 79.4% for deletion carriers one year after transplantation (P < 0.0001). At multivariate regression, deletion carriers showed a lower risk of CMV infection and recurrence with respect to ins/ins KTRs (HR = 0.224 P = 0.0002; HR = 0.307, P = 0.012, respectively).

CONCLUSIONS

In conclusion, pretransplantation screening for NFKB1 -94ins/delATTG polymorphism may predict CMV infection and improve the management of patients at higher risk of infection in the post-transplant period.

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).

Vaccination against the human cytomegalovirus

The human cytomegalovirus (HCMV) is the most important infectious cause of congenital abnormalities and also of infectious complications of transplantation. The biology of the infection is complex and acquired immunity does not always prevent reinfection. Nevertheless, vaccine development is far advanced, with numerous candidate vaccines being tested, both live and inactivated. This article summarizes the status of the candidate vaccines.

Incidence and Risk Factors for Leukopenia in Kidney Transplant Recipients Receiving Valganciclovir for Cytomegalovirus Prophylaxis

Context:

Valganciclovir is used not only for cytomegalovirus prophylaxis after kidney transplantation but can also induce leukopenia, thereby making patients more susceptible to other infections. The epidemiology of leukopenia in patients on valganciclovir remains poorly understood.

Objective:

To determine the incidence and risk factors for leukopenia in patients receiving valganciclovir for cytomegalovirus prophylaxis after kidney transplantation.

Methods:

In this single-center, retrospective, cohort study, we included kidney recipients transplanted from January 1, 2003, to December 31, 2010, to determine the incidence and risk factors for leukopenia in patients who received valganciclovir for cytomegalovirus prophylaxis. The Kaplan-Meier product limit method was used to graphically assess time to leukopenia, and risk factors were assessed using Cox proportional hazards models.

Results:

A total of 542 kidney transplant recipients were included in the study cohort. The cumulative incidence of leukopenia at 6 months posttransplant was 39.3% (11.0% for neutropenia). Low baseline white blood cell count (hazard ratio [HR] 2.34 [95% confidence interval [CI], 1.37-4.00]) and high baseline body mass index (HR 1.05 [95% CI, 1.02-1.09]) were independently associated with an increased risk of leukopenia, while higher Cockcroft-Gault creatinine clearance (HR 0.87 [95% CI, 0.78-0.97]) was significantly associated with a decreased risk of leukopenia.

Conclusions:

These data suggest that recipient baseline white blood cell count, baseline body mass index, and kidney function are clinical predictors of new-onset leukopenia after kidney transplantation. Our results may inform the approach to cytomegalovirus prophylaxis to reduce the risk of valganciclovir-induced leukopenia in kidney transplant recipients.

Safety and Efficacy of Induction Therapy With Thymoglobulin in AB0-Incompatible Kidney Transplantation

INTRODUCTION

Data suggest an additional role of T cells in antibody-mediated rejections. In 2001 a protocol for AB0-incompatible kidney transplantation based on B-cell-depleting anti-CD20 antibody rituximab, antigen-specific blood group IgG immunoadsorption, intravenous immunoglobulins, and triple immunosuppression was introduced in Europe, which used induction therapy with the use of interleukin-2 receptor antibody (IL2-RA) basiliximab. We used thymoglobulin in AB0-incompatible patients as induction in the face of high immunologic risk.

METHODS

We retrospectively evaluated a cohort of 9 AB0i living donation (LD) recipients from 2011 to 2014. Desensitization included blood group-specific immunoadsorption. Eighteen AB0-compatible LD recipients receiving induction therapy with thymoglobulin served as control subjects. Another control group consisted of 18 AB0-compatible LD recipients receiving basiliximab. Follow-up was 24 months. We captured graft function by estimating glomerular filtration rate (eGFR by Modification of Diet in Renal Disease formula), rejection episodes, and bacterial and viral infections.

RESULTS

All patients experienced immediate graft function. No significant or clinical differences were observed regarding graft function, rejection rates, or infections between the groups, although there seemed to be slightly higher cytomegalovirus infection rates due to preemptive therapy strategy.

CONCLUSIONS

Thymoglobulin appears to be similar in safety and efficacy to IL-2-antagonists in AB0i kidney transplantation.

Impact of Desensitization on Antiviral Immunity in HLA-Sensitized Kidney Transplant Recipients

Viral infections represent significant morbidity and mortality factors in kidney transplant recipients, with CMV, EBV, and BKV infections being most common. Desensitization (DES) with IVIg and rituximab with/without plasma exchange followed by kidney transplantation with alemtuzumab induction increased successful transplant rates in HLA-sensitized patients but may represent an increased risk for viral infections due to severe lymphocyte depletion. Here, we report on the posttransplant viral infection status in 372 DES versus 538 non-DES patients. CMV and EBV viremia were significantly lower in DES patients, while BKV viremia was similar. This trend was observed primarily in CMV sero(-), EBV sero(+), and sero(-) patients. No patient developed PTLD. The incidence of BKAN, allograft, and patient survival was similar in both groups. These viral infections were not associated with subsequent allograft rejection which occurred within 6 months after the infection. Conclusions. The IVIg + rituximab desensitization combined with alemtuzumab induction with triple immunosuppression maintenance does not increase the risk for CMV, EBV, and BKV infections. Possible factors include, in addition to posttransplant antiviral prophylaxis and PCR monitoring, presence of memory T cells and antibodies specific to CMV and likely EBV, NK cell-mediated ADCC despite lymphocyte depletion, elimination of EBV and CMV reservoirs by rituximab and alemtuzumab, and use of IVIg with antiviral properties.

Clinical correlates of pp65 antigenemia monitoring in the first months of post kidney transplant in patients undergoing universal prophylaxis or preemptive therapy

Introduction

Human cytomegalovirus is a major cause of morbidity in kidney transplant patients.

Objectives

We aimed to study viral replication and serological response in the first months post kidney transplant in patients undergoing universal prophylaxis or preemptive therapy and correlate the findings with the clinical course of Human cytomegalovirus infection.

Patients and methods

Independent from the clinical strategy adopted for managing Human cytomegalovirus infection, prophylaxis versus preemptive therapy, the pp65 antigenemia assay and serological response were assessed on the day of transplantation, and then weekly during the first three months of post-transplant.

Results

From the 32 transplant recipients, 16 were positive for pp65 antigenemia, with a similar incidence rate in each group. There were no positive results in the first three weeks of monitoring; the positivity rate peaked at week eight. There was a trend for a higher and earlier frequency of positivity in the universal prophylaxis group in which the course of the Human cytomegalovirus infection was also more severe. Despite the differences in clinical picture and in the initial immunosuppressant schedule, the serological response was similar in both groups.

Conclusion

Routine monitoring during the first three post-transplant months has a positive impact on the early detection of Human cytomegalovirus viral replication allowing for timely treatment in order to reduce morbidity of the disease. The strategy of universal therapy employing intravenous ganciclovir was associated to a worse clinical course of the Human cytomegalovirus infection suggesting that the use of >10 cells/2 × 10⁵ leukocytes as a cut-off in this setting may be inappropriate.

Intestinal infection at onset of mycophenolic acid-associated chronic diarrhea in kidney transplant recipients

BACKGROUND

Chronic diarrhea after kidney transplantation is often attributed to mycophenolic acid (MPA) toxicity. We hypothesize that intestinal infections contribute to the pathogenesis of chronic MPA-associated diarrhea.

METHODS

In this retrospective study, all patients (n = 726) receiving a kidney transplant between 2000 and 2010 at the University Hospital Zurich were followed until July 2014 for occurrence of chronic diarrhea (≥4 weeks). Infectious triggers at diarrhea onset were assessed by reviewing medical history, stool microbiology, and histology of colon biopsies.

RESULTS

In 46 patients (6.3% of the cohort), a total of 51 episodes of chronic diarrhea during MPA treatment were documented. The diarrhea episodes were often severe, as confirmed by significant weight loss. The cumulative incidence of chronic diarrhea was uniformly distributed throughout the post-transplant period, with 2.0%, 5.1%, and 9.6% at 1, 5, and 10 years, respectively. Evidence was found for intestinal infection at diarrhea onset in 38 episodes (74.5%). Occurrence of diarrhea onset showed a seasonal distribution with peaks in April and October/November. Specific antimicrobial treatment alone was associated with a 19% resolution rate only, whereas combination with dose reduction of MPA or switch from mycophenolate mofetil to enteric-coated mycophenolate sodium resulted in a 22.7% and 76.5% resolution rate, respectively. Change to an MPA-free regimen was associated with a 100% resolution rate.

CONCLUSION

These results provide first evidence for a contribution of intestinal infections in chronic post-transplant diarrhea associated with MPA treatment.