Cytomegalovirus infection in kidney allografts: a review of literature

Optimizing the approach to monitoring allograft inflammation using serial urinary CXCL10/creatinine testing in pediatric kidney transplant recipients

BACKGROUND

Urinary CXCL10/creatinine (uCXCL10/Cr) is proposed as an effective biomarker of subclinical rejection in pediatric kidney transplant recipients. This study objective was to model implementation in the clinical setting.

METHODS

Banked urine samples at a single center were tested for uCXCL10/Cr to validate published thresholds for rejection diagnosis (>80% specificity). The positive predictive value (PPV) for rejection diagnosis for uCXCL10/Cr-indicated biopsy was modeled with first-positive versus two-test-positive approaches, with accounting for changes associated with urinary tract infection (UTI), BK and CMV viremia, and subsequent recovery.

RESULTS

Seventy patients aged 10.5 ± 5.6 years at transplant (60% male) had n = 726 urine samples with n = 236 associated biopsies (no rejection = 167, borderline = 51, and Banff 1A = 18). A threshold of 12 ng/mmol was validated for Banff 1A versus no-rejection diagnosis (AUC = 0.74, 95% CI = 0.57-0.92). The first-positive test approach (n = 69) did not resolve a clinical diagnosis in 38 cases (55%), whereas the two-test approach resolved a clinical diagnosis in the majority as BK (n = 17/60, 28%), CMV (n = 4/60, 7%), UTI (n = 8/60, 13%), clinical rejection (n = 5/60, 8%), and transient elevation (n = 18, 30%). In those without a resolved clinical diagnosis, PPV from biopsy for subclinical rejection is 24% and 71% (p = .017), for first-test versus two-test models, respectively. After rejection treatment, uCXCL10/Cr level changes were all concordant with change in it-score. Sustained uCXCL10/Cr after CMV and BK viremia resolution was associated with later acute rejection.

CONCLUSIONS

Urinary CXCL10/Cr reliably identifies kidney allograft inflammation. These data support a two-test approach to reliably exclude other clinically identifiable sources of inflammation, for kidney biopsy indication to rule out subclinical rejection.

Effects of Induction Therapy on Graft Functions in Terms of Immunologic Risk

BACKGROUND

Advances in immunosuppressive therapies and surgical techniques have led to a significant reduction in the incidence of rejection within 1 year after kidney transplantation. Immunologic risk is an important factor affecting graft functions and guiding the clinician in the selection of induction therapy. The aim of this study was to investigate graft functions based on serum creatinine levels, Chronic Kidney Disease Epidemiology Collaboration (CKD- EPI) and proteinuria levels, frequency of leukopenia, cytomegalovirus (CMV) and BK virus polymerase chain reaction (PCR) positivity in patients with low and high immunologic risk.

MATERIAL AND METHODS

This retrospective study included 80 renal recipients. Recipients were divided into 2 groups: patients at low immunologic risk who received basiliximab only and those with high immunologic risk who received low-dose (1.5 mg/kg for 3 days) antithymocyte globulin and basiliximab.

RESULTS

No significant differences were observed between the 2 risk groups in terms of first, third, sixth, and 12th-month creatinine levels, CKD-EPI, proteinuria levels, leukopenia frequency, and CMV and BK virus PCR positivity.

CONCLUSION

One-year graft survivals did not differ significantly between these 2 treatment modalities. The combined use of low-dose antithymocyte globulin and basiliximab in the induction treatment of patients with high immunologic risk seems promising in terms of graft survival, leukopenia frequency, and CMV and BK virus PCR positivity.

CMV-associated collapsing focal segmental glomerulosclerosis after kidney transplant in a pediatric patient

BACKGROUND

Cytomegalovirus (CMV) is a significant cause of morbidity among immunocompromised patients who have undergone kidney transplantation and is known to rarely induce collapsing focal segmental glomerulosclerosis (FSGS) among adults.

METHODS

We present the first reported case of CMV-induced collapsing FSGS in a pediatric patient after kidney transplant.

RESULTS

Our patient underwent a deceased donor kidney transplant due to end-stage renal disease secondary to lupus nephritis. Approximately 4 months after transplantation, he developed signs of worsening kidney function in the setting of CMV viremia and was found to have collapsing features of FSGS on kidney transplant biopsy. He was managed with a prompt escalation of antiviral therapy along with a reduction of immunosuppression and recovered without significant complication. At follow-up, he continued to have undetectable CMV titers, creatinine within normal limits, and no significant proteinuria.

CONCLUSION

This report demonstrates CMV as a cause of collapsing FSGS and should be considered among pediatric transplant recipients who present with acute kidney injury, as should early assessment of APOL1 genetic status in both donor and recipient.

De Novo Cytomegalovirus Colitis in a Donor-Seronegative/Recipient-Seronegative Kidney Transplant Recipient

Cytomegalovirus (CMV) is one of the most frequent microbes linked with kidney transplant recipients. CMV infection is typically classified as CMV virus isolation in any body fluid or specimen. We present a 43-year-old man who underwent a deceased donor kidney transplant with CMV donor-seronegative and recipient-seronegative (CMV D-/R-) status and completed three months of CMV prophylaxis with high-dose acyclovir given his low-risk status. He was admitted for complaints of profuse watery diarrhea and persistent fevers lasting one week in duration. His infectious workup led to a CMV quantitative nucleic acid amplification test (QNAT) polymerase chain reaction (PCR) of 239,977 IU/mL with a biopsy-proven diagnosis of invasive CMV colitis. He was treated inpatient with intravenous ganciclovir for two weeks and then de-escalated to oral valganciclovir until achieving viremia resolution with undetectable CMV QNAT PCR as an outpatient. This case illustrates the importance of the changing epidemiology and clinical presentation of CMV disease in solid organ transplant (SOT) recipients in an era of new immunosuppression regimens and improved CMV disease detection in the early post-transplant period.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Seroprevalence of Cytomegalovirus in Haemodialysis Patients

Cytomegalovirus (CMV) is prevalent worldwide. It belongs to the β-herpesvirinae subfamily of Herpesviridae and comprises a double-stranded linear DNA genome and capsid, surrounded by an envelope. CMV infection is most prominently found in patients with kidney failure caused by various possible reasons such as urinary tract infection or systemic disease and are undergoing dialysis. The present study was conducted during the period of March 2020 to April 2021. It included 96 patients with chronic kidney disease undergoing hemodialysis (44 of patients were women and 52 men) within the age range of 11-70 years. Five-mL of the venous blood sample was drawn from each patient to conduct the rapid antibody test for the presence of CMV-specific antibodies (both IgG, and IgM). This study showed that the seroprevalence of CMV infection among haemodialysis patients was 75%. The seropositivity for CMV-IgG was 72.9% which was significantly higher than that for CMV-IgM (2.1%) for both sexes. The present study further demonstrated that the prevalence of positive CMV-IgG in males was higher than that in females (38.5% and 34.4%, respectively). In addition, the positivity of CMV-IgM was highest in the age group 61–70 years old (2.1%), while the positivity of CMV-IgG was highest in patients age groups 41–50 years (24%). The present study revealed a high seroprevalence of CMV infection among haemodialysis patients in Basrah City. The elevated seroprevalence could be related to many factors, including the endemicity of the virus, public health, patient immunity, environmental factors, and geographical location. CMV infection increases with age, and the infection rate in men was higher than that in women. The seroprevalence rate of CMV-IgG antibodies was higher than that of CMV-IgM antibodies, indicating a previous infection or reactivation of CMV virus among haemodialysis patients, leading to a high risk of CMV infection.

Cytomegalovirus nephritis in kidney transplant recipients: Epidemiology and outcomes of an uncommon diagnosis

BACKGROUND

Data on epidemiology and outcomes of cytomegalovirus (CMV) nephritis in kidney transplant patients are limited due to the rarity of this condition.

METHODS

A retrospective review of all kidney transplant recipients (KTR) (n = 6490) and biopsy-proven CMV nephritis between 1/1997 and 12/2020 was performed.

RESULTS

The prevalence of CMV nephritis was low: 13/6490 (0.2%). The diagnosis was made at a median of 7.0 months (range 2.6-15.6 months) after transplant. 6 of 13 (46%) patients were CMV (D+/R-). Median CMV DNA load at biopsy was 376,000, IU/mL (range 87,000-6,460,000 IU/mL). Main biopsy features were CMV glomerulitis (n = 7/13, 54%) followed by CMV tubulointerstitial nephritis (6/13; 46%). Mean eGFR at biopsy (22.7 ± 12 mL/min/1.73 m² ) was significantly decreased compared to baseline eGFR (38.7 ± 18.5 mL/min/1.73 m² , p = 0.02). The vast majority, 11 of 13 (85%), experienced graft failure including 5 of 13 (38%) death-censored. 5 of 13 (38%) patients were diagnosed with acute rejection: three had concurrent acute rejection, and two had rejection within 3 months of index biopsy, respectively. Patients with tubulointerstitial CMV nephritis were significantly more likely to have rejection at the time of biopsy (50% vs. 0%, p < 0.05) compared to those with glomerular CMV nephritis. There were no significant differences between these groups in terms of eGFR at all time points, death, graft failure, immunosuppression changes or rejection after biopsy.

CONCLUSION

CMV nephritis is rare but appears to be associated with poor patient/allograft outcomes. Early identification and timely treatment of CMV infection may prevent end-organ involvement and improve patient and allograft-related outcomes.

Renal Involvement in Congenital Cytomegalovirus Infection: A Systematic Review

Background: Congenital cytomegalovirus (cCMV) infection is the most frequent mother-to-child transmitted infection worldwide and a prevalent cause of neonatal disease and long-term morbidity. The kidney is a target organ for CMV, which replicates in renal tubules and is excreted in large quantities in urine for years in children with cCMV infection. Nonetheless, kidney disease has rarely been reported in cCMV-infected patients. Objective: We aimed to describe the available data on renal involvement in patients with cCMV infection at the pathologic, functional, anatomical, and/or clinical levels. Methods: A systematic search was performed in the MEDLINE/PubMed, SCOPUS, and Cochrane databases. Studies describing any renal involvement in fetuses or neonates aged ≤3 weeks at diagnosis of microbiologically confirmed cCMV infection were eligible. Results: Twenty-four articles were included, with a very low level of evidence. Pathologic findings in autopsy studies universally described CMV typical inclusion bodies in tubular cells. No functional studies were identified. cCMV infection was not associated with an increased risk of kidney malformations. Congenital nephrotic syndrome was the most common clinical condition associated with cCMV, but a causal relationship cannot be established. Conclusions: Typical pathological features of cCMV infection are very common in renal tissue, but they do not seem to entail significant consequences at the anatomical or clinical levels.

No association of genetic variants in TLR4, TNF-α, IL10, IFN-γ, and IL37 in cytomegalovirus-positive renal allograft recipients with active CMV infection-Subanalysis of the prospective randomised VIPP study

Background

Cytomegalovirus (CMV) infection is amongst the most important factors complicating solid organ transplantation. In a large prospective randomized clinical trial, valganciclovir prophylaxis reduced the occurrence of CMV infection and disease compared with preemptive therapy in CMV-positive renal allograft recipients (VIPP study; NCT00372229). Here, we present a subanalysis of the VIPP study, investigating single nucleotide polymorphisms (SNPs) in immune-response-related genes and their association with active CMV infection, CMV disease, graft loss or death, rejection, infections, and leukopenia.

Methods

Based on literature research ten SNPs were analyzed for TLR4, three for IFN-γ, six for IL10, nine for IL37, and two for TNF-α. An asymptotic independence test (Cochran-Armitage trend test) was used to examine associations between SNPs and the occurrence of CMV infection or other negative outcomes. Statistical significance was defined as p<0.05 and Bonferroni correction for multiple testing was performed.

Results

SNPs were analyzed on 116 blood samples. No associations were found between the analyzed SNPs and the occurrence of CMV infection, rejection and leukopenia in all patients. For IL37 rs2723186, an association with CMV disease (p = 0.0499), for IL10 rs1800872, with graft loss or death (p = 0.0207) and for IL10 rs3024496, with infections (p = 0.0258) was observed in all patients, however did not hold true after correction for multiple testing.

Conclusion

The study did not reveal significant associations between the analyzed SNPs and the occurrence of negative outcomes in CMV-positive renal transplant recipients after correction for multiple testing. The results of this association analysis may be of use in guiding future research efforts.

Cytomegalovirus Disease, Short-Term Cardiovascular Events and Graft Survival in a Cohort of Kidney Transplant Recipients With High CMV IgG Seroprevalence

INTRODUCTION

Both cytomegalovirus (CMV) infection and CMV disease have been linked with several long-term indirect effects in kidney transplant recipients. Research questions: We conducted a retrospective study to assess the association between cytomegalovirus disease and risks of death, shortterm cardiovascular events and graft loss in a cohort of renal transplant recipients.

DESIGN

The associations between CMV disease and death and cardiovascular events were determined using Cox regression models, while the association between viral disease and graft loss risk was analyzed through a competing risks regression according to the Fine and Gray method. Death with a functioning graft was considered as a competing risk event.

RESULTS

A total of 865 consecutive renal transplant recipients were included. The prevalence of seropositive donor/seronegative recipient (D+/R-) group was 89.9% with the remaining patients classified as seropositive recipient (R+). After median follow-up time of 24.4 months, CMV disease was not a risk factor for all-causes mortality (HR = 1.75; 95% CI 0.94-3.25), early cardiovascular events (HR = 0.54; 95% CI 0.16-1.82) or graft loss (subhazard ratio [the HR adjusted for competing risk of death with functioning graft] = 0.99; 95% CI 0.53-1.84).

CONCLUSIONS

In this cohort with high prevalence of CMV IgG antibodies, we found no association between cytomegalovirus disease and risk of death or graft loss. The relationship between CMV and cardiovascular disease remains to be unraveled and probably corresponds to a multifactorial phenomenon involving individual risk factors and the immune response to infection rather than the virus effect itself.

Human Cytomegalovirus Inhibits Autophagy of Renal Tubular Epithelial Cells and Promotes Cellular Enlargement

Human Cytomegalovirus (HCMV) is a frequent opportunistic pathogen in immunosuppressed patients, which can be involved in kidney allograft dysfunction and rejection. In order to study the pathophysiology of HCMV renal diseases, we concentrated on the impact of HCMV infection on human renal tubular epithelial HK-2 cells. Our aim was to develop a model of infection of HK-2 cells by using the viral strain TB40/E, that contains the extended cell tropism of clinical isolates and the efficient viral multiplication in cell culture of laboratory-adapted strains. We observed that HK-2 cells can be infected by HCMV and expressed viral antigens, but they do not produce extracellular viral particles. We then studied the interplay of HCMV with ciliogenesis and autophagy. Primary cilium (PC) is a stress sensor important to maintain renal tissue homeostasis that projects from the apical side into the lumen of tubule cells. PC formation and length were not modified by HCMV infection. Autophagy, another stress response process critically required for normal kidney functions, was inhibited by HCMV in HK-2 cells with a reduction in the autophagic flux. HCMV classically induces an enlargement of infected cells in vivo and in vitro, and we observed that HCMV infection led to an enlargement of the HK-2 cell volume. Our results constitute therefore an excellent starting point to further explore the role of these mechanisms in renal cells dysfunction.

Herpesviruses oral shedding and viremia in renal transplant recipients: A longitudinal study

BACKGROUND

The objective was to assess the oral shedding and viremia of human herpesviruses in renal transplant recipients.

METHODS

This is a cohort study in which the participants were examined in three different periods: the first within 24 hours before renal transplantation and the second and third ones 15-20 and 45-60 days after the transplantation. Mouthwash and blood samples were collected in each period and then submitted to screening for the presence of eight types of human herpesviruses by using multiplex PCR.

RESULTS

HSV-1 and EBV were more frequent in the saliva after renal transplantation, 15- to 20-day period after the transplant. EBV was found in the saliva of 26 (35.6%) patients before renal transplantation and in 56.2% and 46.6% of them, in the 15- to 20-day and 45- to 60-day periods after the transplant, respectively. High detection rates (75.3%-78.1%) were found for HHV-7 despite the lack of significant variations between the study periods. There was no concordance between herpesviruses oral shedding and viremia.

CONCLUSION

We concluded that the pattern of excretion of HSV-1 and EBV in saliva is changed immediately after renal transplantation, increasing in the 15- to 20-day period after the transplant surgery. No concordance between herpesviruses oral shedding and viremia was observed.