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

Clinico-epidemiological characteristics of early- versus late-onset cytomegalovirus disease among renal transplant recipients: A two-decade experience

BACKGROUND

Reactivation of cytomegalovirus (CMV) infection in transplant patients is high because of immunosuppression. We have evaluated the clinical and epidemiological characteristics of early versus late onset of CMV infection among renal transplant recipients.

METHODS

A single center retrospective observational study was conducted among renal transplant recipients who underwent kidney transplant between January 2002 and December 2021. CMV disease was classified as early or late depending on its detection prior to or after 90 days post-transplantation. Herein, we reported the differences between early and late onset of CMV disease with respect to clinical symptoms, the use of immunosuppression and the impact on graft outcomes.

RESULTS

Out of total 2164 renal transplant recipients, 156 patients (7.2%) were diagnosed with CMV disease. Among these 156 patients, 25 patients (16%) had early CMV while 131 patients (84%) had late CMV. Overall, the two groups did not differ with respect to the induction or maintenance of immunosuppressive agents. However, the proportion of CMV syndrome was greater among early (56.0%) than late (26.7%) CMV groups (p = 0.01). In contrast, tissue invasive disease was more frequent among late (73.3%) in comparison to early (44.0%) CMV groups (p = 0.01). Among clinical symptoms, diarrhea was more frequent in late (63.4%) vs. early (36%) CMV-affected patients (p = 0.01). Graft loss occurred in 4.0% of early CMV group vs. 25.2% of late CMV group (p = 0.03). Neither of the clinical groups differed with respect to occurrence of biopsy-proven allograft rejection post-infection.

CONCLUSIONS

Early CMV disease presents more frequently as CMV syndrome while late CMV disease usually manifests itself as tissue invasive disease. Graft loss is more common in patients with late onset of CMV disease.

Anti-Donor T-Cell Responses Are Not Necessarily Attenuated During Cytomegalovirus Infection in Kidney Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV), the most common opportunistic infection of kidney transplantation (KT), is preventable by prophylactic and preemptive antiviral drugs in CMV-immunoglobulin (Ig)G-positive donors. Our preemptive therapy optimized immunosuppressive doses based on mixed lymphocyte response (MLR) results, regardless of preoperative CMV-IgG serostatus pairing. This study used the MLR to compare the anti-donor T-cell responses between CMV antigenemia-positive and -negative cases.

METHODS

One hundred patients underwent KT using a cyclosporine (CsA)-based immunosuppressive regimen at Hiroshima University Hospital. CMV antigenemia-positive cells were defined as 4/50,000 CMVpp65-positive cells. T-cell responses to allo-antigens were measured using MLR assays to evaluate patients' anti-donor immune reactivity. After analyzing the proliferation of CD4+ and CD8+ T-cell subsets, the stimulation indices of CD4+ or CD8+ T cells were quantified. The study used no prisoners, and the participants were neither coerced nor paid. The manuscript was created in compliance with the Helsinki Congress and the Declaration of Istanbul.

RESULTS

Forty-three patients tested positive for CMV antigenemia within 3 months after KT. No significant differences were found between the CMV antigenemia-positive and -negative groups in the stimulation indices for CD4+ and CD8+ T-cell responses to anti-donor stimulation. However, T-cell responses to third-party stimuli during the postoperative month 1 were significantly less in the CMV antigenemia-positive than -negative group.

CONCLUSION

Anti-donor T-cell responses are not necessarily attenuated during CMV infection in KT recipients. In CMV-infected KT recipients, caution should be exercised against inadvertent dose reduction of immunosuppressants.

Cytomegalovirus High-risk Kidney Transplant Recipients Show No Difference in Long-term Outcomes Following Preemptive Versus Prophylactic Management

BACKGROUND

Following kidney transplantation (KT), cytomegalovirus (CMV) infection remains an important challenge. Both prophylactic and preemptive antiviral protocols are used for CMV high-risk kidney recipients (donor seropositive/recipient seronegative; D+/R-). We performed a nationwide comparison of the 2 strategies in de novo D+/R- KT recipients accessing long-term outcomes.

METHODS

A nationwide retrospective study was conducted from 2007 to 2018, with follow-up until February 1, 2022. All adult D+/R- and R+ KT recipients were included. During the first 4 y, D+/R- recipients were managed preemptively, changing to 6 mo of valganciclovir prophylaxis from 2011. To adjust for the 2 time eras, de novo intermediate-risk (R+) recipients, who received preemptive CMV therapy throughout the study period, served as longitudinal controls for possible confounders.

RESULTS

A total of 2198 KT recipients (D+/R-, n = 428; R+, n = 1770) were included with a median follow-up of 9.4 (range, 3.1-15.1) y. As expected, a greater proportion experienced a CMV infection in the preemptive era compared with the prophylactic era and with a shorter time from KT to CMV infection ( P  < 0.001). However, there were no differences in long-term outcomes such as patient death (47/146 [32%] versus 57/282 [20%]; P  = 0.3), graft loss (64/146 [44%] versus 71/282 [25%]; P  = 0.5), or death censored graft loss (26/146 [18%] versus 26/282 [9%]; P  = 0.9) in the preemptive versus prophylactic era. Long-term outcomes in R+ recipients showed no signs of sequential era-related bias.

CONCLUSIONS

There were no significant differences in relevant long-term outcomes between preemptive and prophylactic CMV-preventive strategies in D+/R- kidney transplant recipients.

Low dose thymoglobulin versus basiliximab in cytomegalovirus positive kidney transplant recipients: Effectiveness of preemptive cytomegalovirus modified strategy

BACKGROUND

We performed a retrospective trial to determine asymptomatic CMV reactivation and CMV disease in kidney allograft recipients with positive CMV serostatus.

METHODS

Preemptive modified strategy under low dose thymoglobulin versus basiliximab induction was evaluated. Patients were monitored by CMV-polymerase chain reaction (PCR); if the viral load was >4000copies/μl, they received valganciclovir adjusted for their renal function.

RESULTS

132 recipients were included in the study, 84 and 48 receiving basiliximab and thymoglobulin induction respectively, and followed up for 12 months. Asymptomatic CMV reactivation was significantly higher for thymoglobulin (77.1% vs. 16.7%, p<0.001). Treatment groups had similar rates of CMV disease (3.6% vs. 2.1%, p 0.538). The significant difference in asymptomatic CMV reactivation between two treatment groups did not have any impact on 1 year graft function (71±26ml/min vs. 74±19ml/min; p=0.475) and no histological differences in protocol biopsies were observed among patients with asymptomatic CMV reactivation vs those without CMV reactivation.

CONCLUSIONS

Due to the high asymptomatic CMV reactivation incidence in patients who received thymoglobulin induction, our results suggest that valganciclovir prophylaxis may be advantageous in CMV seropositive renal transplant recipients after low dose thymoglobulin induction. A preemptive strategy appeared to significantly reduce the likelihood of CMV disease in both groups. Rejection risk and negative impact in renal function associated with asymptomatic CMV reactivation was not found in our series.

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.

Clinical Manifestations and Outcomes of Renal Transplantation Patients With Pneumocystis jirovecii Pneumonia and Cytomegalovirus Co-infection

Background

Pneumocystis jirovecii pneumonia (PJP) and cytomegalovirus (CMV) infection are common opportunistic infections among renal transplantation (RT) recipients, and both can increase the risk of graft loss and patient mortality after RT. However, few studies had evaluated PJP and CMV co-infection, especially among RT patients. Therefore, this study was performed to evaluate the impact of CMV co-infection with PJP among RT recipients.

Methods

We retrospectively analyzed the clinical data of patients with confirmed diagnosis of PJP between 2015 and 2021 in our hospital. We divided patients into PJP and PJP+CMV groups according to their CMV infection status, and the clinical severity and outcomes of the two groups were evaluated.

Results

A total of 80 patients after RT were diagnosed with PJP. Of these, 37 (46.2%) patients had co-existing CMV viremia. There were no statistically significant intergroup differences in age, sex, diabetes, onset time of PJP after RT and postoperative immunosuppressant. Compared to serum creatinine (Cr) at admission, the serum Cr at discharge in both the PJP and PJP+CMV groups were decreased. The PJP+CMV group had a higher C-reactive protein level, higher procalcitonin level, and lower albumin level than the PJP group. The PJP+CMV group showed a higher PSI score than the PJP group. Moreover, the initial absorption time of the lesion was longer in the PJP+CMV group. However, the duration of hospitalization showed no significant differences between the two groups. The mortality rate was 9.4-times higher in the PJP+CMV group than in the PJP group. The rate of admittance to the intensive care unit was 3.2-times higher in the PJP+CMV group than in the PJP group.

Conclusion

CMV co-infection may result in more serious inflammatory response. RT patients with PJP+CMV infection had more severe clinical symptoms, slower recovery from pneumonia, and higher mortality than those with PJP alone. Therefore, when RT patients present with severe PJP, the possibility of CMV co-infection should be considered. Short-term withdrawal of immunosuppressants in case of severe infection is safe for the renal function of RT patients.

Thrombosis Associated With Cytomegalovirus (CMV) in a Kidney Transplant Recipient

Cytomegalovirus (CMV) infection is a common infectious complication after kidney transplantation. Indirect effects of CMV infection include an increased risk of secondary infections, increased risk of acute rejection, and chronic allograft dysfunction. However, it is not well known that CMV may also increase the risk of venous and arterial thrombosis. Here, we present a case of acute deep venous thromboembolism associated with acute CMV disease in a kidney transplant recipient. We also performed a literature review of cytomegalovirus-associated thrombosis in immunocompromised individuals.

Cytomegalovirus-Associated Hemophagocytic Syndrome Diagnosed by Liver Biopsy in a Kidney Transplant Recipient

Hemophagocytic syndrome (HPS) is a rare but potentially life-threatening disease in kidney transplant recipients, and is caused by systemic proliferation of macrophages actively phagocytizing other blood cells in the bone marrow, lymph nodes, and the spleen. Here, we report a 40-year-old male kidney transplant recipient who presented with fever, bicytopenia, and elevated liver enzymes 2 months after transplantation. Given that cytomegalovirus antigenemia and real-time polymerase chain reaction tests were positive, liver biopsy was performed under an assumption of cytomegalovirus-induced hepatitis. Hepatic histology revealed multifocal microabscess with cytomegalovirus inclusion bodies, marked Kupffer cell hyperplasia, and erythrophagocytosis by activated macrophages. As laboratory findings such as hyperferritinemia, elevated serum lactate dehydrogenase, low natural killer cell activity, and high soluble interleukin-2 receptor were also compatible with HPS, the recipient was diagnosed as having cytomegalovirus-induced hepatitis combined with reactive HPS. Following intravenous ganciclovir therapy with continuous administration of tacrolimus and corticosteroid, the symptoms resolved and laboratory findings were normalized. As far as we know, this is the first report of cytomegalovirus-induced hepatitis combined with reactive HPS in a kidney transplant recipient that is diagnosed by liver biopsy.

The burden of cytomegalovirus infection remains high in high-risk kidney transplant recipients despite six-month valganciclovir prophylaxis

Cytomegalovirus continues to be a concern after transplantation despite prophylaxis regimens. Our aim was to analyse post-prophylaxis primary cytomegalovirus infections among kidney transplant recipients after 6-month valganciclovir prophylaxis and to determine the usefulness of surveillance after prophylaxis. Data from all cytomegalovirus D+/R- kidney transplant recipients from January 2004 to October 2018 at our center who received 6-month prophylaxis with valganciclovir were retrospectively analysed (N = 481). Detailed analyses were performed for 136 patients who were monitored every 2-4 weeks for DNAemia after the discontinuation of prophylaxis. Post-prophylaxis primary cytomegalovirus infection occurred in 182/481 (38%) patients median 264 days after transplantation (IQR: 226-367) and median 84 days after the end of prophylaxis (IQR: 46-187). In 49% patients, cytomegalovirus infection occurred over 3 months after the end of prophylaxis. Cytomegalovirus infection was not associated with lower patient or graft survival and no independent risk factors for infection were found. From patients monitored closely, 71/136 (52%) patients developed post-prophylaxis primary cytomegalovirus infection. Altogether, 52/136 (38%) patients were diagnosed with probable post-prophylaxis cytomegalovirus disease and 19/136 (14%) patients had asymptomatic CMV infection. Recurrent infection occurred in 38/71 (39%) patients. The incidence of post-prophylaxis primary cytomegalovirus infection among D+/R- kidney transplant recipients remains high despite 6-month prophylaxis. Surveillance after prophylaxis was challenging as a considerable portion of the infections occurred late and already symptomatic.

Cytomegalovirus after kidney transplantation in 2020: moving towards personalized prevention

Cytomegalovirus (CMV)-related complications after kidney transplantation remain a substantial challenge. Rather than applying one preventive strategy to all at-risk patients, we can now adapt our strategy at the individual patient level. Antiviral prophylaxis or a strict pre-emptive strategy may be optimal for patients at the highest risk for CMV, while patients at lower risk may benefit particularly from pre-emptive monitoring and the administration of therapy only if needed. CMV-specific T-cell assays may be useful for further refining the pre-transplant determination of CMV risk, and for guiding decisions about antiviral therapy need or duration. An immunosuppressive regimen including a mammalian target of rapamycin inhibitor reduces CMV risk and may thus be an attractive option in some patients. New antiviral agents may further expand our therapeutic arsenal in the near future, and the prospects of CMV vaccination and adoptive T-cell therapy appear to be on the horizon.

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.

Population Pharmacokinetics and Bayesian Estimation of the Area Under the Concentration-Time Curve for Ganciclovir in Adult Chinese Renal Allograft Recipients After Valganciclovir Administration

Valganciclovir (VGCV) is the prodrug of ganciclovir (GCV). The objective of this study was to establish a population pharmacokinetic model (PPK) of GCV to investigate the PK characteristics of GCV after administration of VGCV in adult Chinese renal allograft recipients. Seventy Chinese renal allograft recipients were given 450 mg (n = 41) or 900 mg (n = 29) VGCV daily. Blood samples were drawn 0-24 hours after 5 days' therapy, and GCV plasma levels were determined. The PPK model was constructed using nonlinear mixed-effects modeling, and the Bayesian estimation of AUC_0-24h was constructed for an individual patient based on limited plasma samples. The PK of GCV was best described by a 2-compartment model with a first-order absorption process. The CL/F, V₂ /F, Q/F, V₃ /F, K_a , and lag time of GCV were 15.8 ± 0.71 L/h, 10.9 ± 2.38 L, 3.98 ± 0.40 L/h, 167 ± 44.0 L, 0.23 ± 0.0078 1/h, and 0.93 ± 0.017 hours, respectively. Clearance of creatinine was found to have a significant impact on the CL/F of GCV (P < .01). Sampling strategies consisted of plasma concentrations 0 and 2 and 0, 2, and 4 hours after VGCV administration were shown to be suitable for the estimation of the GCV AUC_0-24h . The PPK model was acceptable and can describe the PK of GCV in Chinese renal transplant patients administered VGCV. The AUC_0-24h of GCV in Chinese renal transplant patients can be calculated by a limited sampling strategy method.

Revisiting cytomegalovirus serostatus and replication as risk factors for inferior long-term outcomes in the current era of renal transplantation

BACKGROUND

Cytomegalovirus (CMV) serostatus and CMV replication are considered as risk factors for inferior graft and patient survival after renal transplantation, but long-term outcome data are limited. The aim of this retrospective single-centre study was to investigate the impact of CMV serostatus and CMV replication/disease on long-term outcomes in a well-defined cohort managed by a standardized CMV prevention/treatment protocol.

METHODS

We investigated 599 consecutive kidney transplantations having a CMV prevention protocol consisting of either prophylaxis (D+/R- and R+ with ATG induction) or screening/deferred therapy (R+ without ATG induction). Patients were grouped according to CMV serostatus [high risk (D+/R-): n = 122; intermediate risk (R+): n = 306; low risk (D-/R-): n = 171] and occurrence of CMV replication/disease (no CMV replication: n = 419; asymptomatic CMV replication: n = 110; CMV syndrome: n = 39; tissue-invasive CMV disease: n = 31). The median follow-up time was 6.5 years.

RESULTS

Graft and patient survival were not different among the three CMV serostatus groups as well as the four CMV replication/disease groups (P ≥ 0.44). Eighty-seven patients died, 17 due to infections (21%), but none was attributable to CMV. The overall hospitalization incidence for CMV-related infection was 3% (17/599 patients). The incidence of clinical and (sub)clinical rejection was similar among the groups (P ≥ 0.17). In a multivariate Cox proportional hazard model, neither CMV serostatus, nor CMV replication, nor CMV disease were independent predictors for patient death or graft failure, respectively.

CONCLUSIONS

This retrospective single-centre study suggests that the negative impact of CMV infection on long-term patient and allograft survival as well as on allograft rejection can be largely eliminated with current diagnostic/therapeutic management.

Murine cytomegalovirus dissemination but not reactivation in donor-positive/recipient-negative allogeneic kidney transplantation can be effectively prevented by transplant immune tolerance

Cytomegalovirus (CMV) reactivation from latently infected donor organs post-transplantation and its dissemination cause significant comorbidities in transplant recipients. Transplant-induced inflammation combined with chronic immunosuppression has been thought to provoke CMV reactivation and dissemination, although sequential events in this process have not been studied. Here, we investigated this process in a high-risk donor CMV-positive to recipient CMV-negative allogeneic murine kidney transplantation model. Recipients were either treated with indefinite immunosuppression or tolerized in a donor-specific manner. Untreated recipients served as controls. Kidney allografts from both immunosuppressed and tolerized recipients showed minimal alloimmunity-mediated graft inflammation and normal function for up to day 60 post-transplantation. However, despite the absence of such inflammation in the immunosuppressed and tolerized groups, CMV reactivation in the donor positive kidney allograft was readily observed. Interestingly, subsequent CMV replication and dissemination to distant organs only occurred in immunosuppressed recipients in which CMV-specific CD8 T cells were functionally impaired; whereas in tolerized recipients, host anti-viral immunity was well-preserved and CMV dissemination was effectively prevented. Thus, our studies uncoupled CMV reactivation from its dissemination, and underscore the potential role of robust transplantation tolerance in preventing CMV diseases following allogeneic kidney transplantation.

Infectious disease risks in pediatric renal transplantation

Renal transplantation is a vital treatment option in children with ESRD with more than 10,000 pediatric kidney transplants and survival rates of greater than 80% at 10 years post-transplant in the USA alone. Despite these advances, infection remains a significant cause of morbidity in pediatric recipients. Screening potential organ donors and recipients is imperative to identify and mitigate infectious risks in the transplant patient. Despite the unique risks of each patient, the timing of many infections post-transplant is predictable. In early post-transplant infections (within 30 days), bacterial and fungal pathogens predominate with donor-derived events and nosocomial infections. In the intermediate period (31-180 days after transplant), latent infections from donor organs, such as EBV and CMV, develop. Late infections occurring > 180 days after the transplant can be due to latent pathogens or community-acquired organisms. Approaching an infectious evaluation in a pediatric kidney recipient requires finesse to diagnose and treat this vulnerable population in a timely manner. The following article highlights the most relevant and common infections including clinical manifestations, risk factors, diagnostic techniques, and treatment options.

Cytomegalovirus infection in kidney allografts: a review of literature

Cytomegalovirus (CMV) is an important cause of renal transplantation complications. It can cause different syndromes or end-organ diseases that can lead to unfavourable clinical outcomes and kidney allograft dysfunction. Although well documented as a systemic disease on renal transplant patients, affecting non-renal tissue, as gastrointestinal and respiratory tract, few cases have been reported in English-language indexed journals involving renal allograft lesions secondary to CMV. As an important differential diagnosis and etiological agent to acute and chronic rejection, the possibility of CMV kidney direct infection needs prompt recognition for effective treatment. In this paper, we will review the current literature about CMV nephritis and discuss the findings from each case report.

Development and validation of multiplex real-time PCR assays for rapid detection of cytomegalovirus, Epstein-Barr virus, and polyomavirus BK in whole blood from transplant candidates

Transplant recipients are more susceptible to bacterial and viral infections. Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and polyomavirus BK (BK) are risk factors for graft dysfunction. All three of them are latent viruses that can cause serious disease in immunocompromised patients. Mainly qualitative PCR tests are required for diagnosis and quantitative monitoring, which are used to follow the response to transplantation. We developed a multiplex real-time PCR (qPCR) method to detect these viruses during blood screenings of transplant recipients. We also validated analytical and clinical performance tests using the developed multiplex qPCR. The limit of detection (LOD) was 100, 125, and 183 copies/ml for CMV, EBV, and BK, respectively. These results had high linearity (R² = 0.997) and reproducibility (CV range, 0.95-2.38%, 0.52-3.32%, and 0.31-2.45%, respectively). Among 183 samples, we detected 8 samples that were positive for CMV, while only 6 were positive for EBV, and 3 were positive for BK. Therefore, the viral infection prevalence in transplant candidates was 4.40% for CMV, 3.29% for EBV, and 1.64% for BK. This multiplex qPCR method should be used widely for diagnosing and monitoring latent viral infections in transplant recipients.

Human Cytomegalovirus-Encoded Receptor US28 Is Expressed in Renal Allografts and Facilitates Viral Spreading In Vitro

BACKGROUND

Renal transplantation is the preferred treatment for patients with end-stage renal disease. Human cytomegalovirus (HCMV) activation is associated with decreased renal graft function and survival. Human cytomegalovirus encodes several immune modulatory proteins, including the G protein-coupled receptor US28, which scavenges human chemokines and modulates intracellular signaling.

METHODS

Our aim was to identify the expression and localization of US28 in renal allograft biopsies by immunohistochemistry and determine its role in viral spreading in vitro.

RESULTS

Immunohistochemistry revealed US28 in 31 of 34 renal transplant biopsies from HCMV-seropositive donors. Expression was independent of HCMV viremia or IgG serostatus. US28 was predominantly expressed in the cytoplasm of vascular smooth muscle cells (VSMCs) and tubular epithelial cells, with a median positivity of 20% and 40%, respectively. Also, US28-positive cells were present within arterial neointima. In contrast to US28, HCMV-encoded immediate early antigen was detected in less than 5% of VSMCs, tubular epithelial cells, interstitial endothelium, interstitial inflammatory infiltrates, and glomerular cells.Primary VSMCs were infected with green fluorescent protein-tagged wild type or US28-deficient HCMV. The viral spreading of US28-deficient HCMV, via culture medium or cell-to-cell transmission, was significantly impeded as shown by green fluorescent protein (ie, infected) cell quantification and quantitative real-time polymerase chain reaction. Additionally, the number and size of foci was smaller.

CONCLUSIONS

In summary, HCMV-encoded US28 was detected in renal allografts from HCMV-positive donors independent of viremia and serostatus. Also, US28 facilitates HCMV spreading in VSMCs in vitro. Because the vasculature is affected in chronic renal transplant dysfunction, US28 may provide a potential target for therapeutic intervention.

Mcl-1 small-molecule inhibitors encapsulated into nanoparticles exhibit increased killing efficacy towards HCMV-infected monocytes

Human cytomegalovirus (HCMV) spreads and establishes a persistent infection within a host by stimulating the survival of carrier myeloid cells via the upregulation of Mcl-1, an antiapoptotic member of the Bcl-2 family of proteins. However, the lack of potent Mcl-1-specific inhibitors and a targetable delivery system has limited the ability to exploit Mcl-1 as a therapeutic strategy to eliminate HCMV-infected monocytes. In this study, we found a lead compound from a novel class of Mcl-1 small-molecule inhibitors rapidly induced death of HCMV-infected monocytes. Moreover, encapsulation of Mcl-1 antagonists into myeloid cell-targeting nanoparticles was able to selectively increase the delivery of inhibitors into HCMV-activated monocytes, thereby amplifying their potency. Our study demonstrates the potential use of nanotechnology to target Mcl-1 small-molecule inhibitors to HCMV-infected monocytes.

[Infectious diseases in immunocompromised patients]

Immunkompromittierung birgt immer ein erhöhtes Risiko für die Entwicklung infektiöser Komplikationen. Patienten nach solider Organtransplantation sind besonders gefährdet – in dieser Patientengruppe bilden Infektionen die zweithäufigste Todesursache. Prophylaxe und Impfungen sollten daher konsequent eingesetzt werden. Infektionen bei Immunsupprimierten können mit atypischen klinischen Symptomen einhergehen, was die Diagnose und Therapie für den behandelnden Arzt erschwert. Vor allem virale und opportunistische Infektionen stellen dabei eine Herausforderung dar. Umso mehr ist eine Überwachung der Patienten hinsichtlich Infektionserkrankungen notwendig, um frühzeitig die erforderlichen Maßnahmen einleiten zu können.

Management of Opportunistic Infections in Solid-Organ Transplantation

Solid-organ transplantation is often the last alternative in many patients with end-stage organ disease. Although advances in immunosuppressive regimens, surgical techniques, organ preservation, and overall management of transplant recipients have improved graft and patient survival, infectious complications remain problematic. Bacterial, fungal, viral, and parasitic infections are implicated after transplantation depending on numerous factors, such as degree of immunosuppression, type of organ transplant, host factors, and period after transplantation. Proper prophylactic and treatment strategies are imperative in the face of chronic immunosuppression, nosocomial and community pathogens, emerging drug resistance, drug-drug interactions, and medication toxicities. This review summarizes the pathophysiology, incidence, prevention, and treatment strategies of common post-transplant infections.

Uremia-Associated Premature Aging of T Cells Does Not Predict Infectious Complications After Renal Transplantation

Patients with end-stage renal disease have prematurely aged T cell systems. We tested whether T cell aging parameters were associated with the risk of infections after renal transplantation (RTx). We studied 188 patients over 1 year. Peripheral T cells were analyzed before and at 3 and 6 mo after RTx for frequency of recent thymic emigrants, relative telomere length and differentiation status. These parameters were related to the occurrence of opportunistic and serious infections. Overall, 84 patients developed an infection. In this group, 50 developed an opportunistic infection and 53 developed a serious infection. T cell aging parameters assessed before RTx were not associated with infection risk. The memory T cells showed a decrease within the first 3 mo in both groups (p < 0.001). The CD4(+) memory T cells increased between 3 and 6 mo within the infection group (p = 0.015). The number of CD8(+) memory T cells increased in both groups (p < 0.001) but reached baseline levels only in the infection group. In the infection group, the CD8(+) CD28(null) T cell percentage increased between 3 and 6 mo (p = 0.024), tending to be higher than at baseline (p = 0.061). These differences in post-RTx dynamics resulted from infections. Parameters of uremia-associated premature aging of peripheral T cells do not predict posttransplant infections.

Cytomegalovirus seroprevalence in organ donors and kidney transplant recipients, Colombia, 2010-2014

INTRODUCTION

Cytomegalovirus infections have gained high importance for individuals that have received organ transplants given the clinical implications this may have in immunocompromised patients. 

OBJECTIVE

To describe the seroprevalence of cytomegalovirus in organ donors and recipients of kidney transplants nationwide from the six regions established by the Red Nacional de Donación y Trasplante. 

MATERIALS AND METHODS

We conducted a descriptive retrospective study that included 1,813 organ donors and 3,313 recipients of kidney transplants, and we calculated IgM and IgG seroprevalence for cytomegalovirus. IgG prevalence was stratified according to sex, age group, and region, and the results were analyzed in each donor-recipient pair and classified according to the risk. Statistical packages IBM SPSS®, Statistics 22, and Epi Info 7 were utilized. 

RESULTS

IgG prevalence for cytomegalivirus was 86.8% in donors and 91.0% in kidney transplant recipients with statistical significance observed for age, geographical location, and between donors and recipients. We analyzed 1,764 pairs of donors and recipients, of which 91.4% were categorized as having intermediate risk. 

CONCLUSIONS

The results of this study showed high cytomegalovirus infection rates in Colombia. Given the risk, categorization of patients undergoing transplants, measures should be adopted by medical teams to minimize risks.

KIR and Human Leukocyte Antigen Genotype Associated Risk of Cytomegalovirus Disease in Renal Transplant Patients

BACKGROUND

Cytomegalovirus(CMV) infections have a significant effect on morbidity and mortality in kidney transplants. We conducted a study to ascertain the association of natural killer cell killer immunoglobulin-like receptors and human leukocyte antigen (HLA) genotype with risk of CMV disease.

METHODS

The 90 CMV-negative patients receiving a first renal transplantation from a CMV-positive donor in this study received triple immunosuppressive therapy and prophylactic CMV treatment for up to 3 months after transplantation.

RESULTS

We observed a 43.3% incidence rate of CMV disease within the first year after transplantation. Twenty-seven recipients experienced a rejection episode, 14 of which had CMV disease, mostly after rejection, suggesting that in this group, CMV disease is not a risk factor for rejection. KIR gene or genotype distribution were similar between the CMV diseased and CMV disease-free group. Twenty-seven recipients (30%) carried KIR-AA genotype, of which nine (33%) had CMV disease. Of the remaining 63 (70%) recipients with KIR-BX genotype, 30 (48%) had CMV disease. There was no significant difference between the two genotype groups with regard to occurrence of CMV disease, although there was a trend toward a lower incidence of CMV disease in recipients carrying the KIR-AA genotype. For CMV disease, we found no significant risk associated with the number of activating or inhibitory KIRs. Neither was missing KIR ligands for the inhibitory KIRs (HLA-C1/C2/Bw4) in recipients associated with lower rates of CMV disease.

CONCLUSION

In CMV-negative recipients, genotypic analysis of KIR repertoire and HLA ligands does not provide risk factors for primary CMV disease after renal transplantation.

Impact of Everolimus and Low-Dose Cyclosporin on Cytomegalovirus Replication and Disease in Pediatric Renal Transplantation

In order to investigate the hypothesis that the mammalian target of rapamycin inhibitor everolimus (EVR) shows anticytomegalovirus (CMV) activity in pediatric patients, we analyzed the impact of EVR-based immunosuppressive therapy on CMV replication and disease in a large cohort (n = 301) of pediatric kidney allograft recipients. The EVR cohort (n = 59), who also received low-dose cyclosporin, was compared with a control cohort (n = 242), who was administered standard-dose cyclosporin or tacrolimus and an antimetabolite, mostly mycophenolate mofetil (91.7%). Multivariate analysis revealed an 83% lower risk of CMV replication in the EVR cohort than in the control cohort (p = 0.005). In CMV high-risk (donor+/recipient-) patients (n = 88), the EVR-based regimen was associated with a significantly lower rate of CMV disease (0% vs. 14.3%, p = 0.046) than the standard regimen. In patients who had received chemoprophylaxis with (val-)ganciclovir (n = 63), the CMV-free survival rates at 1 year and 3 years posttransplant (100%) were significantly (p = 0.015) higher in the EVR cohort (n = 15) than in the control cohort (n = 48; 1 year, 75.0%; 3 years, 63.3%). Our data suggest that in pediatric patients at high risk of CMV, an EVR-based immunosuppressive regimen is associated with a lower risk of CMV disease than a standard-dose calcineurin inhibitor-based regimen.

Effect of delaying prophylaxis against CMV in D+/R- solid organ transplant recipients in the development of CMV-specific cellular immunity and occurrence of late CMV disease

OBJECTIVES

Evaluate the protective effect against late CMV disease of delaying antiviral prophylaxis initiation in D+/R- patients receiving solid organ transplant (SOT).

METHODS

Prospective multicenter study in D+/R- SOT recipients in Spain (Sept/09-Sept/12). Whole blood specimens were prospectively collected after Tx for CMV-specific cell-mediated immunity (CMI) determination. Two prophylaxis strategies were compared: early prophylaxis (EP; starting within the first 3 days after Tx) and delayed prophylaxis (DP; starting 14 days after Tx). Risk factors for the occurrence of CMV disease were determined by survival analysis and proportional risk Cox regression models.

RESULTS

We included 95 patients (50 EP V 45 DP). Twenty six patients (27.4%) developed CMV disease: 32.7% EP vs. 20% DP; (p = 0.2). No cases of CMV disease were reported previously to beginning delayed prophylaxis. The percentage of individuals with detectable CMI response was higher in patients with DP although differences did not reach statistic significance (42% vs 29.6% at day 200 after Tx; p = 0.4). There was a clear trend towards less end-organ CMV disease in patients receiving DP (18.2% EP vs 5% DP; p = 0.09) and DP was the only protective factor in the multivariate analysis (HR: 0.26; CI: 0.05-1.2; p = 0.09).

CONCLUSIONS

A 14-day delay in CMV prophylaxis in D+/R- SOT recipients is safe and may reduce the incidence of late CMV end-organ disease although correlation of this effect with CMI responses was not complete.

CD56+ T cells are increased in kidney transplant patients following cytomegalovirus infection

BACKGROUND

CD56+ T cells previously have been identified as potentially cytotoxic lymphocytes, and relative numbers are increased in some infectious diseases.

PATIENTS AND METHODS

Relative proportions of CD56+ T cells were measured by flow cytometry in groups of renal transplant patients differing in cytomegalovirus (CMV) status of donor (D) and recipient (R). These measurements were related to episodes of CMV viremia.

RESULTS

Patient groups in which recipients (R+) or donors (D+/R-) were CMV+ had significantly higher proportions of CD56+ T cells (5.11 ± 0.69% and 5.42 ± 1.01%, respectively) than the D-/R- group (1.9 ± 0.35%; P = 0.0018 and 0.017, respectively). In the high-risk D+/R- group, it was found that patients who had post-transplant CMV viremia had higher levels than those who remained CMV negative (9.09 ± 2.34% vs. 3.16 ± 1.22%; P = 0.01). CD56+ T cells from R+ and D+/R- groups had higher proportions of both CD4+ and CD8+ cells than the D-/R- group. When activation markers were examined, some CD56+ T cells from both CMV+ groups had a TEM phenotype, with significantly more expressing CD45RO and NKG2C, and less expressing CD28, CD62L, CD127, and CD161 compared to the D-/R- group. Some CD56+ T cells showed specificity for CMV antigens and similar proportions of CD8+ cells were positive for class I HLA-CMV tetramers containing immunodominant CMV peptides compared to the majority CD56- T cells.

CONCLUSION

The results show significant increases in proportions of CD56+ T cells in relation to CMV infection in renal transplant patients and suggest that these cells have a cytotoxic function against CMV-infected cells.

A double-blinded, prospective study to define antigenemia and quantitative real-time polymerase chain reaction cutoffs to start preemptive therapy in low-risk, seropositive, renal transplanted recipients

BACKGROUND

Cytomegalovirus (CMV) disease occurs in 16% to 20% of low-risk, CMV-positive renal transplant recipients. The cutoffs for quantitative real-time polymerase chain reaction (qPCR) or phosphoprotein (pp65) antigenemia (pp65emia) for starting preemptive therapy have not been well established.

METHODS

We measured qPCR and pp65emia weekly from day 7 to day 120 after transplantation, in anti-CMV immunoglobulin G–positive donor and recipient pairs. Patients and physicians were blinded to the test results. Suspicion of CMV disease led to the order of new tests. In asymptomatic viremic patients, the highest pp65emia and qPCR values were used, whereas we considered the last value before diagnosis in those with CMV disease.

RESULTS

We collected a total of 1,481 blood samples from 102 adult patients. Seventeen patients developed CMV disease, 54 presented at least one episode of viremia that cleared spontaneously, and 31 never presented viremia. Five patients developed CMV disease after the end of the study period. The median (95% confidence interval) pp65emia and qPCR values were higher before CMV disease than during asymptomatic viremia (6 [9–82] vs. 3 [1–14] cells/10(6) cells; P<0.001 and 3,080 [1,263–15,605] vs. 258 [258–1,679] copies/mL; P=0.008, respectively). The receiver operating characteristic curve showed that pp65emia 4 cells/10(6) cells or greater showed a sensitivity and specificity to predict CMV disease of 69% and 81%, respectively (area, 0.769; P=0.001), with a positive predictive value of 37% and a negative predictive value of 93%. For qPCR 2,000 copies/mL or higher, the positive predictive value and negative predictive value were 57% and 91%, respectively (receiver operating characteristic area, 0.782; P=0.000).

CONCLUSION

With these cutoffs, both methods are appropriate for detecting CMV disease.

BH3 Profiling Reveals Selectivity by Herpesviruses for Specific Bcl-2 Proteins To Mediate Survival of Latently Infected Cells

Herpesviruses, including human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus, establish latency by modulating or mimicking antiapoptotic Bcl-2 proteins to promote survival of carrier cells. BH3 profiling, which assesses the contribution of Bcl-2 proteins towards cellular survival, was able to globally determine the level of dependence on individual cellular and viral Bcl-2 proteins within latently infected cells. Moreover, BH3 profiling predicted the sensitivity of infected cells to small-molecule inhibitors of Bcl-2 proteins.

Delayed-onset cytomegalovirus disease coded during hospital readmission after kidney transplantation

BACKGROUND

Use of prophylactic anti-CMV therapy for 3 to 6 months after kidney transplantation can result in delayed-onset CMV disease. We hypothesized that delayed-onset CMV disease (occurring >100 days posttransplant) occurs more commonly than early-onset CMV disease and that it is associated with death.

METHODS

We assembled a retrospective cohort of 15,848 adult kidney transplant recipients using 2004 to 2010 administrative data from the California and Florida Healthcare Cost and Utilization Project State Inpatient Databases. We identified demographic data, comorbidities, CMV disease coded during readmission, and inpatient death. We used multivariate Cox proportional hazards modeling to determine risk factors for delayed-onset CMV disease and inpatient death.

RESULTS

Delayed-onset CMV disease was identified in 4.0%, and early-onset CMV disease was identified in 1.2% of the kidney transplant recipients. Risk factors for delayed-onset CMV disease included previous transplant failure or rejection (HR 1.4) and residence in the lowest-income ZIP codes (HR 1.2). Inpatient death was associated with CMV disease occurring 101 to 365 days posttransplant (HR 1.5), CMV disease occurring greater than 365 days posttransplant (HR 2.1), increasing age (by decade: HR 1.5), nonwhite race (HR 1.2), residence in the lowest-income ZIP codes (HR 1.2), transplant failure or rejection (HR 3.2), previous solid organ transplant (HR 1.7), and several comorbidities.

CONCLUSION

These data showed that delayed-onset CMV disease occurred more commonly than early-onset CMV disease and that transplant failure or rejection is a risk factor for delayed-onset CMV disease. Further research should be done to determine if delayed-onset CMV disease is independently associated with death.

Late-Onset Cytomegalovirus Gastritis in Low-Risk Renal Allograft Recipients

OBJECTIVES

Skin grafting has been evolving as an important application in reconstructive surgery. Mixed reports about the survival of allogeneic and xenogeneic keratinocytes require further substantiation to determine the role of these cells in wound healing.

MATERIALS AND METHODS

Rabbit and rat skins were recovered and cultured in vitro. Full-thickness wounds were created on the dorsum of rabbits (2 cm × 2 cm; n = 4). Cultured epithelial autograft, allograft, and xenograft cells were sprayed onto 3 freshly created wounds, with 1 wound acting as a control. The wounds were monitored every 2 days for 4 weeks. After 4 weeks, the rabbits were killed; skin biopsies were taken from each healed wound and stained with hematoxylin and eosin, and epidermal thickness was measured.

RESULTS

All examined grafts showed favorable healing outcomes because the wounds appeared similar to normal skin upon healing. The only observed significant difference was the thickness of the epidermis layer, which was thinner in the xenograft (P = .002) than the autograft or allograft. Morphologic evaluation of the skin surface showed that the rat skin was thinner than the rabbit skin. The graft that achieved the best result was the autograft because the thickness was similar to and mimicked normal skin.

CONCLUSIONS

All 3 grafts (autograft, allograft, and xenograft) have the potential to reconstitute epithelial defects. This approach can overcome the limitation of autologous skin donor sites, especially in burn cases.

Current characteristics and outcome of cytomegalovirus infections after kidney transplantation

INTRODUCTION

The clinical course of cytomegalovirus (CMV) infections in the current era is poorly described. We characterized the symptoms and outcome of all CMV infections in a large cohort of kidney transplant recipients. Among 1129 kidney transplant recipients transplanted between 2004 and 2011 in Charité Universitätsmedizin Berlin and Helsinki University Hospital, 297 patients with CMV infection were characterized.

RESULTS

CMV disease occurred in 217/1129 patients (19.2%), and CMV infection in 297/1129 (26.3%). Gastrointestinal symptoms were recorded in 58% and fever in 47% patients with primary CMV disease, compared to 46% and 27% patients with symptomatic CMV reactivation, whereas leukopenia or thrombocytopenia were seen in only 17-28% patients, and malaise in 9-10%. Tissue-invasive CMV gastroenteritis was confirmed in 11% and CMV pneumonia in only 1% of patients with CMV disease. Only 1 patient died because of CMV infection (mortality 0.3%). Virus-related factors or the use of secondary prophylaxis did not predict the risk of recurrence, which occurred in 33% patients.

CONCLUSION

In conclusion, CMV disease remains a common problem after kidney transplantation. Gastrointestinal symptoms were common, especially in patients with primary CMV infection, whereas bone marrow suppression, hepatopathy, or malaise were seen less frequently.

The impact of early cytomegalovirus infection after kidney transplantation on long-term graft and patient survival

This prospective observational cohort study is an extension of a previous study reporting effects of cytomegalovirus (CMV) on graft and patient survival in 471 patients who underwent kidney transplantation between 1994 and 1997. CMV pp65 antigen was measured every 7-14 d during the first three months after transplantation, given as number of CMV pp65-positive cells per 10(5) leukocytes. A positive test was defined as CMV infection. None of the patients received CMV prophylaxis or preemptive treatment. During a median of 13.7 (7.1-14.9) yr, the number of death-censored graft losses was 118 (25%) and of patient deaths 224 (48%). CMV infection was an independent significant risk factor for mortality in multivariate analysis (HR = 1.453, 95% CI 1.033-2.045, p = 0.032), adjusting for patient and donor age, preemptive transplantation, HLA-DR and -AB mismatches, living donor, acute rejection during the first three months, donor-recipient CMV IgG antibody status and diabetic nephropathy. In univariate analysis, CMV infection was significantly associated with death-censored graft loss but the association was not significant in multivariate model. CMV infection early after kidney transplantation is a predictor of overall mortality but not of death-censored graft loss after a median observation period of 13.7 yr.

Characterization of cytomegalovirus disease in solid organ transplant recipients by markers of inflammation in plasma

Background

While several studies have examined the general inflammatory responses in relation to cytomegalovirus infection, the identification of the various inflammatory mediators as well as their relative importance is far from clear.

Patients and Methods

Solid organ recipients enrolled in an international multicenter trial of cytomegalovirus disease treatment (the VICTOR study) were analyzed (n = 289) (ClinicalTrials.gov NCT00431353). Plasma markers of inflammation and endothelial cell activation were assessed at baseline by enzyme immunoassays.

Results

The major findings were: (i) Plasma levels of the CXC-chemokine interferon-inducible protein-10 (P<0.001) and C-reactive protein (P = 0.046) were independently associated with the presence of cytomegalovirus DNAemia above lower level of quantification. (ii) High levels of CC-chemokine ligand 21 (P = 0.027) and pentraxin 3 (P = 0.033) were independently associated with tissue invasive cytomegalovirus disease as opposed to cytomegalovirus syndrome.

Conclusion

Our findings illustrate the complex interaction between cytomegalovirus and the immune system, involving a wide range of inflammatory mediators that could be associated to disease manifestations in cytomegalovirus related disease.