Cytomegalovirus risk factors in renal transplantation with modern immunosuppression

Increased CMV disease and "severe" BK viremia with belatacept vs. sirolimus three-drug maintenance immunosuppression

OBJECTIVES

Belatacept may provide benefit in delayed graft function, but its association with infectious complications is understudied. We aim to assess the incidence of CMV and BK viremia in patients treated with sirolimus or belatacept as part of a three-drug immunosuppression regimen after kidney transplantation.

MATERIALS AND METHODS

Kidney transplant recipients from 01/01/2015 to 10/01/2021 were retrospectively reviewed. Maintenance immunosuppression was either tacrolimus, mycophenolate and sirolimus (B0) or tacrolimus, mycophenolate, and belatacept (5.0 mg/kg monthly) (B1). Primary outcomes of interest were BK and CMV viremia which were followed until the end of the study period. Secondary outcomes included graft function (serum creatinine, eGFR) and acute rejection through 12 months.

RESULTS

Belatacept was initiated in patients with a higher mean kidney donor profile index (B0:0.36 vs. B1:0.44, p = .02) with more delayed graft function (B0:6.1% vs. B1:26.1%, p < .001). Belatacept therapy was associated with more "severe" CMV viremia >25,000 copies/mL (B0:1.2% vs. B1:5.9%, p = .016) and CMV disease (B0:0.41% vs. B1:4.2%, p = .015). However, there was no difference in the overall incidence of CMV viremia >200 IU/mL (B0:9.4% vs. B1:13.5%, p = .28). There was no difference in the incidence of BK viremia >200 IU/mL (B0:29.7% vs. B1:31.1%, p = .78) or BK-associated nephropathy (B0:2.4% vs. B1:1.7%, p = .58), but belatacept was associated with "severe" BK viremia, defined as >10,000 IU/mL (B0:13.0% vs. B1:21.8%, p = .03). The mean serum Cr was significantly higher with belatacept therapy at 1-year follow up (B0:1.24 mg/dL vs. B1:1.43 mg/dL, p = .003). Biopsy-proven acute rejection (B0:1.2% vs. B1:2.6%, p = .35) and graft loss (B0:1.2% vs. B1:0.84%, p = .81) were comparable at 12 months.

CONCLUSIONS

Belatacept therapy was associated with an increased risk of CMV disease and "severe" CMV and BK viremia. However, this regimen did not increase the overall incidence of infection and facilitated comparable acute rejection and graft loss at 12-month follow up.

The Clinical Manifestation of Immunosuppressive Therapy as a Tool to Improve Immune Monitoring in Renal Transplant Recipients

INTRODUCTION

Metrics for posttransplant immune monitoring to prevent over or under immunosuppression in renal transplant recipients (RTRs) are lacking.

METHODS

We surveyed 132 RTRs, 38 in the first year posttransplant and 94 >1-year posttransplant, to study the clinical expression of immunosuppressive therapy. A questionnaire administered to these RTRs was divided into physical (Q physical) and mental (Q mental) symptoms.

RESULTS

In multivariable models for the association between the calculated Q physical and Q mental scores and different clinical and biochemical variables in the 38 RTRs who filled out the questionnaire 130 times during the first year posttransplant, it was found that mycophenolic acid (MPA) and prednisone use increased the mean Q physical score by 0.59 (95% CI: 0.21-0.98, p = 0.002) and 0.53 (95% CI: 0.26-0.81, p = 0.00), respectively, while MPA use increased the mean Q mental score by 0.72 (95% CI: 0.31-1.12, p = 0.001). Among the 94 RTRs who each completed the questionnaire only once, the odds for the mean Q mental score to be above the median value were more than 3 times higher for RTRs treated versus non-treated with MPA (OR 3.38, 95% CI: 1.1-10.3, p = 0.03). MPA-treated RTRs had higher mean scores for questions related to sleep disorders (1.83 ± 1.06 vs. 1.32 ± 0.67 for not treated, p = 0.037), to difficulty falling asleep (1.72 ± 1.11 vs. 1.16 ± 0.5, p = 0.02), and to depression and anxiety.

CONCLUSION

We concluded that prednisone and MPA use are associated with an increased Q physical and Q mental scores in RTRs. Routine monitoring of physical and mental status of RTRs should be implemented to improve the diagnosis of overimmunosuppression. Dose reduction or discontinuation of MPA should be considered in RTRs who report sleep disorders, depression, and anxiety.

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.

Transition from antigenemia to quantitative nucleic acid amplification testing in cytomegalovirus-seropositive kidney transplant recipients receiving preemptive therapy for cytomegalovirus infection

Due to the high costs, the strategy to reduce the impact of cytomegalovirus (CMV) after kidney transplant (KT) involves preemptive treatment in low and middle-income countries. Thus, this retrospective cohort study compared the performance of antigenemia transitioned to quantitative nucleic acid amplification testing, RT-PCR, in CMV-seropositive KT recipients receiving preemptive treatment as a strategy to prevent CMV infection. Between 2016 and 2018, 363 patients were enrolled and received preemptive treatment based on antigenemia (n = 177) or RT-PCR (n = 186). The primary outcome was CMV disease. Secondarily, the CMV-related events were composed of CMV-infection and disease, which occurred first. There were no differences in 1-year cumulative incidence of CMV-disease (23.7% vs. 19.1%, p = 0.41), CMV-related events (50.8% vs. 44.1%, p = 0.20), neither in time to diagnosis (47.0 vs. 47.0 days) among patients conducted by antigenemia vs. RT-PCR, respectively. The length of CMV first treatment was longer with RT-PCR (20.0 vs. 27.5 days, p < 0.001), while the rate of retreatment was not different (14.7% vs. 11.8%, p = 0.48). In the Cox regression, acute rejection within 30 days was associated with an increased the risk (HR = 2.34; 95% CI = 1.12-4.89; p = 0.024), while each increase of 1 mL/min/1.73 m² of 30-day eGFR was associated with a 2% reduction risk of CMV-disease (HR = 0.98; 95% CI = 0.97-0.99; p = 0.001). In conclusion, acute rejection and glomerular filtration rate are risk factors for CMV disease, showing comparable performance in the impact of CMV-related events between antigenemia and RT-PCR for preemptive treatment.

The Clinical and Economic Benefit of CMV Matching in Kidney Transplant: A Decision Analysis

BACKGROUND

The development of cytomegalovirus (CMV) infection after kidney transplant remains a significant cause of posttransplant morbidity, graft loss, and mortality. Despite appropriate antiviral therapy, recipients without previous CMV exposure can currently be allocated a kidney from a donor with previous CMV infection (D+R-) that carries the greatest risk of posttransplant CMV infection and associated complications. Preferential placement of CMV D- organs in negative recipients (R-) has been shown to reduce the risk of viral infection and associated complications.

METHODS

To assess the long-term survival and economic benefits of allocation policy reforms, a decision-analytic model was constructed to compare receipt of CMV D- with CMV D+ organ in CMV R- recipients using data from transplant registry, Medicare claims, and pharmaceutical costs.

RESULTS

For CMV R- patients, receipt of a CMV D- organ was associated with greater average survival (14.3 versus 12.6 y), superior quality-adjusted life years (12.6 versus 9.8), and lower costs ($529 512 versus $542 963). One-way sensitivity analysis demonstrated a survival advantage for patients waiting as long as 30 mo for a CMV D- kidney.

CONCLUSIONS

Altering national allocation policy to preferentially offer CMV D- organs to CMV R- recipients could improve survival and lower costs after transplant if appropriately implemented.

Cytomegalovirus in renal transplant recipients from living donors with and without valganciclovir prophylaxis and with immunosuppression based on anti-thymocyte globulin or basiliximab

BACKGROUND

In our population, anti-thymocyte globulin (ATG) of 1 mg/Kg/day for 4 days is used; which permits not using valgancyclovir (VGC) prophylaxis in some renal transplant recipients (RTR) with moderate risk (R+), to reduce costs. This study aimed to determine the incidence and risk of developing cytomegalovirus (CMV), with or without prophylaxis, when exposed to low doses of ATG or basiliximab (BSL).

PATIENTS AND METHODS

A retrospective cohort included 265 RTR with follow-up of 12 months. Prophylaxis was used in R-/D+ and some R+. Tacrolimus (TAC), mycophenolate mofetil, and prednisone were used in all patients. Logistic regression analysis was performed to estimate the risk of CMV in RTR with or without VGC.

RESULTS

Cytomegalovirus was documented in 46 (17.3%) patients: 20 (43.5%) with CMV infection, and 26 (56.5%) with CMV disease. Anti-thymocyte globulin was used in 39 patients (85%): 32 R+, six D+/R-, and one D-/R-. ATG was used in 90% (27 of 30) of patients with CMV and without prophylaxis. The multivariate analysis showed an association of risk for CMV with the absence of prophylaxis (RR 2.29; 95% CI 1.08-4.86), ATG use (RR 3.7; 95% CI 1.50-9.13), TAC toxicity (RR 3.77; 95% CI 1.41-10.13), and lymphocytes at the sixth post-transplant month (RR 1.77; 95% CI 1.0-3.16).

CONCLUSIONS

Low doses of ATG favored the development of CMV and a lower survival free of CMV compared with BSL. In scenarios where resources for employing VGC are limited, BSL could be an acceptable strategy.

Progress and Challenges in the Prevention, Diagnosis, and Management of Cytomegalovirus Infection in Transplantation

Hosts with compromised or naive immune systems, such as individuals living with HIV/AIDS, transplant recipients, and fetuses, are at the highest risk for complications from cytomegalovirus (CMV) infection. Despite substantial progress in prevention, diagnostics, and treatment, CMV continues to negatively impact both solid-organ transplant (SOT) and hematologic cell transplant (HCT) recipients. In this article, we summarize important developments in the field over the past 10 years and highlight new approaches and remaining challenges to the optimal control of CMV infection and disease in transplant settings.

Cytomegalovirus serologic matching in deceased donor kidney allocation optimizes high- and low-risk (D+R- and D-R-) profiles and does not adversely affect transplant rates

Cytomegalovirus (CMV) is a major cause of infection-related morbidity and mortality in kidney transplantation. The most significant risk for developing CMV infection after transplant depends upon donor (D) and recipient (R) CMV serostatus. In 2012, our Organ Procurement Organization (OPO) began a novel pretransplant CMV prevention strategy via matching deceased kidney donors and recipients by CMV serostatus. Prior to the matching protocol, our distribution of seropositive and seronegative donors and recipients was similar to the United States at large. After the matching protocol, high-risk D+R- were reduced from 18.5% to 2.9%, whereas low-risk D-R- were increased from 13.5% to 24%. There was no adverse effect on transplant rates and no differential effect on waiting times for R+ vs R- after the protocol was implemented. This protocol could be implemented on a regional or national level to optimize low and high-risk CMV seroprofiles and potentially improve CMV-related outcomes in kidney transplantation.

Immunologic Risk Assessment and Approach to Immunosuppression Regimen in Kidney Transplantation

The outcomes of kidney transplantation show a steady improvement with an increasing number of transplantations and decreasing incidence of acute rejection episodes. Successful transplantation begins with a comprehensive immunologic risk assessment and judicious choice of therapeutic agents. In this review, we discuss the trends in transplant immunosuppression practices and outcomes in the United States. We discuss practical testing algorithms for clinical decision making in induction therapy and fine-tuning maintenance immunosuppression. We introduce assessment tools for immune monitoring after transplantation and speculate on future directions in management.

Impact assessment and investigation of factors associated with herpesviruses viremia in the first year of renal transplantation

The increased risk for opportunistic infections after a renal transplant requires monitoring of viral infections to avoid future complications. Our goal was to investigate the impact and factors associated with Epstein-Barr virus (EBV), human cytomegalovirus (HCMV) and human herpesvirus type 6 (HHV-6) viremia in renal transplant recipients. Whole blood samples were collected monthly from 82 patients during the first semester and then quarterly up to 1 year after transplantation. EBV, HCMV, and HHV-6 were detected and quantified by TaqMan real-time polymerase chain reaction. The results showed that EBV and HCMV viremia were detected in 32 patients (39% each), while HHV-6 viremia in only 3 patients (3.7%). EBV was significantly associated with age (P = .050), thymoglobuline induction (P = .019), mTOR inhibitor-based therapy (P = .003), and female gender (P = .044). HCMV was significantly associated with basiliximab induction (P = .015), mycophenolate mofetil (MMF)-based therapy (P = .003) and allograft acute rejection (P = .033). Moreover, HCMV-disease was correlated with MMF-based therapy (P = .021) and female gender (P = .003). In conclusion, EBV and HCMV viremia were associated with different immunosuppressive induction and maintenance strategies. Additionally, higher HCMV viremia (> 10 ⁴ copies/mL) was related to acute allograft rejection.

Risk-stratified approach to anti-viral prophylaxis against cytomegalovirus disease in glomerulonephritis and renal vasculitis treated with potent immunosuppressants

Aim: Cytomegalovirus (CMV) reactivation and disease in immunocompromised individuals is associated with significant morbidity and mortality. Preventive measures such as anti-viral prophylaxis or surveillance and pre-emptive therapy effectively reduced CMV disease in solid organ transplant but have not been evaluated among patients with glomerulonephritis at-risk for CMV disease after immunosuppressive therapy. We evaluated the utility and outcomes of a risk-stratified approach to anti-viral prophylaxis for adults with glomerulonephritis treated with potent immunosuppressants. Methods: Single-center retrospective cohort study of adults with glomerulonephritis and renal vasculitis prescribed methylprednisolone, cyclophosphamide or rituximab in a tertiary referral centre. A risk-stratified approach to CMV anti-viral prophylaxis was implemented in March 2015. We compared the incidence of CMV disease in the pre-implementation (January 2008-December 2014) and post-implementation (June 2015-June 2017) groups. Results: We studied 119 individuals: 85 in the pre-implementation group and 34 in the post-implementation group. The post-implementation group had worse kidney function, greater proteinuria, higher prednisolone dose and more received intravenous methylprednisolone and plasma exchanges but CMV disease within 6 months was similar to the pre-implementation group (2.9% vs. 3.5%, p = 1.00). Among individuals in the post-implementation group who satisfied criteria to receive anti-viral prophylaxis (n = 21), CMV disease was more frequent in the group not given prophylaxis compared to those given prophylaxis as recommended (8.3% versus 0%, p = 1.00). Adverse events related to anti-viral prophylaxis occurred in 40%. Conclusion: This study provided pilot data for future randomized controlled trials to evaluate CMV preventive strategies in selected high-risk patients with glomerulonephritis or renal vasculitis.

Human Vascular Pericytes and Cytomegalovirus Pathobiology

Pericytes are multipotent cells of the vascular system with cytoplasmic extensions proximal to endothelial cells that occur along the abluminal surface of the endothelium. The interactions between endothelial cells and pericytes are essential for proper microvascular formation, development, stabilization, and maintenance. Pericytes are essential for the regulation of paracellular flow between cells, transendothelial fluid transport, angiogenesis, and vascular immunosurveillance. They also influence the chemical composition of the surrounding microenvironment to protect endothelial cells from potential harm. Dysregulation or loss of pericyte function can result in microvascular instability and pathological consequences. Human pericytes have been shown to be targets for human cytomegalovirus (HCMV) infection and lytic replication that likely contribute to vascular inflammation. This review focuses on human vascular pericytes and their permissiveness for HCMV infection. It also discusses their implication in pathogenesis in the blood⁻brain barrier (BBB), the inner blood⁻retinal barrier (IBRB), the placenta⁻blood barrier, and the renal glomerulus as well as their potential role in subclinical vascular disease.

Epidemiology and risk factors for cytomegalovirus infection in glomerular diseases treated with immunosuppressive therapy

AIM

Cytomegalovirus (CMV) infections are associated with morbidity and mortality. We aimed to describe the epidemiology, risk factors and outcomes of CMV infection among patients with glomerulonephritis (GN) who received potent immunosuppressants (IS).

METHODS

Single-centre retrospective study of adults with biopsy-proven GN prescribed methylprednisolone (MP), cyclophosphamide (CYC) or rituximab (RTX). Primary endpoint was CMV infection defined by significant CMV antigenaemia (>10 positive cells in 10⁶ cells) or viraemia (>2000 copies/mL). Death was related to CMV if CMV infection occurred within the same hospitalization as death.

RESULTS

Ninety-four patients were studied. CYC was prescribed in 65% and MP in 71% of the cohort. Only two patients received RTX and 15 patients received plasma exchanges (PEX). Median follow up was 31.9 (IQR: 13.7, 53.6) months. CMV infection occurred in 13 patients (13.8%) at 1.3 (0.6, 3.0) months from biopsy. Patients with CMV infection had higher serum creatinine [404 (272, 619) vs. 159 (93, 317) μmol/L, P < 0.001] and greater proteinuria [UPCR 7.5, (4.8, 11.8) vs. 4.2 (2.3, 8.4) g/g, P = 0.02] than those who did not have CMV infection. Also, more patients received CYC (92% vs. 60%, P = 0.03), RTX (15% vs. 0, P = 0.02) and PEX (38% vs. 12%, P = 0.01) than those who did not have CMV infection. Two patients had CMV-related deaths.

CONCLUSION

Cytomegalovirus infection is common in GN patients receiving potent IS. Surveillance and possibly anti-viral prophylaxis should be considered for high-risk patients.

Cytomegalovirus prophylaxis in seropositive renal transplant recipients receiving thymoglobulin induction therapy: Outcome and risk factors for late CMV disease

BACKGROUND

Anti-thymocyte globulin (ATG) therapy is a risk factor for cytomegalovirus (CMV) disease in renal transplant (RTx) recipients and therefore antiviral prophylaxis is commonly used. We evaluated the outcome of our current policy of 90 days of CMV prophylaxis in seropositive recipients given ATG and the risk factors for the occurrence of CMV disease after prophylaxis.

METHODS

We studied a retrospective cohort of 423 RTx (2010-2014) CMV-seropositive adults given ATG induction therapy.

RESULTS

54 (13%) patients developed CMV disease at a median of 163 days after transplant, of which 29 (54%) had viral syndrome and 25 (46%) had invasive disease. Median prophylaxis time (94 days) and immunosuppressive drugs were similar between groups (CMV vs no-CMV). Those with CMV disease had more deceased donors and higher donor age, lower lymphocyte count, and lower median eGFR at day 90. Multivariable logistic regression analysis at day 90 and 180 found that eGFR ≤40 ml/min/1.73 m² (but not acute rejection) was associated with late CMV disease. In a separate validation cohort of 124 patients with 8% late CMV disease, eGFR ≤45 and lymphocyte count ≤800 cells/mm³ at the end of prophylaxis remained predictive of late CMV disease occurrence.

CONCLUSIONS

These data indicate that antiviral prophylaxis adequately prevented CMV in seropositive recipients given ATG, but late disease still occurred. Low eGFR and low lymphocyte count at the end of prophylaxis may help identify patients at higher risk of CMV disease.

Mesangial cells, specialized renal pericytes and cytomegalovirus infectivity: Implications for HCMV pathology in the glomerular vascular unit and post-transplant renal disease

Background

Human Cytomegalovirus (HCMV) infection is problematic after kidney transplantation. Human mesangial cells along with human glomerular endothelial cells and podocytes constitute the renal glomerular vascular unit (GVU). HCMV infection of the GVU is poorly understood.

Methods

GVU cells infectivity was analysed by microscopy and immunofluorescence. Cytokines profiles were measured by Luminex assays. Renal tissue analysis for HCMV infection was performed by immunohistochemistry.

Results

Mesangial cells and glomerular endothelial cells but not podocytes were permissive for both lab adapted and clinical strains of HCMV. Luminex analysis of cytokines expressed by mesangial cells exposed to the SBCMV clinical strain was examined. A Tricell infection model of the GVU maintains >90% viability with a unique cytokine profile. Finally, we show αSMA stained mesangial cells permissive for HCMV in renal tissue from a transplant patient.

Conclusions

HCMV infection of mesangial cells induces angiogenic and proinflammatory cytokines that could contribute to glomerular inflammation.

Cyclophilin A as a target in the treatment of cytomegalovirus infections

BACKGROUND

Viruses are obligate parasites that depend on the cellular machinery of the host to regenerate and manufacture their proteins. Most antiviral drugs on the market today target viral proteins. However, the more recent strategies involve targeting the host cell proteins or pathways that mediate viral replication. This new approach would be effective for most viruses while minimizing drug resistance and toxicity.

METHODS

Cytomegalovirus replication, latency, and immune response are mediated by the intermediate early protein 2, the main protein that determines the effectiveness of drugs in cytomegalovirus inhibition. This review explains how intermediate early protein 2 can modify the action of cyclosporin A, an immunosuppressive, and antiviral drug. It also links all the pathways mediated by cyclosporin A, cytomegalovirus replication, and its encoded proteins.

RESULTS

Intermediate early protein 2 can influence the cellular cyclophilin A pathway, affecting cyclosporin A as a mediator of viral replication or anti-cytomegalovirus drug.

CONCLUSION

Cyclosporin A has a dual function in cytomegalovirus pathogenesis. It has the immunosuppressive effect that establishes virus replication through the inhibition of T-cell function. It also has an anti-cytomegalovirus effect mediated by intermediate early protein 2. Both of these functions involve cyclophilin A pathway.

CD28 positive, cytomegalovirus specific cytotoxic T lymphocytes as a novel biomarker associated with cytomegalovirus viremia in kidney allorecipients

BACKGROUND

CMV infection remains major complication after kidney transplantation, thus diagnostics tools that would improve identification of individuals at risk of development of CMV - related complications are useful. For this reason, searching for proper immunological biomarkers candidates gives hope to individualize antiviral therapy and minimize side effects of antiviral drugs.

OBJECTIVES

The purpose of this research was to assess immune assays that can be used to predict the likelihood of CMV viremia after kidney allotransplantation.

STUDY DESIGN

In the study, immunological markers of CMV viremia were assessed in 52 kidney transplant recipients during two years lasting follow-up. Immunological markers associated with viral infection, like lymphocytosis, cytotoxic T lymphocytes (CTL) and serum cytokines levels were compared with less common immunological assays, like activated T lymphocytes, CMV-specific CTL stratified according to naïve/memory phenotype. The test to assess expression of CD28 antigen on CTL, as a possible additional marker of CMV-specificity, was developed.

RESULTS

CD28-positive CMV-specific CTL have been found the most useful marker for CMV viremia prediction. Tested value of 3 cells/μl was found to be most suitable for CMV activation assessment with acceptable sensitivity and specificity.

DISCUSSION

This preliminary report suggests that CD28-positive CMV-specific CTL could be put at the first line, as possible novel marker associated with CMV viremia development.

Ongoing higher infection rate in ABO-incompatible kidney transplant recipient: is it a serious problem? A single-center experience

Purpose

Additional clinical experience and knowledge regarding the barrier to transplantation of ABO blood type incompatibility could reduce the higher rate of infectious complications in ABO-incompatible kidney transplantation.

Methods

A total of 79 ABO-incompatible kidney transplantation (ABOiKT) patients were compared with 260 ABO-compatible kidney transplantation (ABOcKT) patients for basic clinical characteristics, infectious complications, rejection episodes, and graft survival.

Results

There were no significant differences in baseline characteristics, rejection rates, or graft survival between the ABOiKT and ABOcKT patients. No significant difference in the infection rate was shown for cytomegalovirus (26.6% vs. 30.0%; P = 0.672), BK virus (19.0% vs. 21.5%; P = 0.752), herpes disease (10.1% vs. 5.0%; P = 0.082), pneumonia (5.3% vs. 3.8%; P = 0.746), or urinary tract infection (8.9% vs. 10.0%; P > 0.999). Female sex (hazard ratio [HR], 2.20; P = 0.003), advanced age (≥60 years) (HR, 2.5; P = 0.019), history of rejection episodes (HR, 2.28; P = 0.016), and history of surgical complications (HR, 4.64; P = 0.018) were significant risk factors for infection. ABO incompatibility demonstrated a tendency toward higher infection risk without statistical significance (HR, 1.74; P = 0.056).

Conclusion

In spite of immunosuppressant protocol modification, the rate of infectious complications following ABOiKT is still higher than with ABOcKT when a modified desensitization protocol is used. However, this was not sufficient to avoid ABOiKT.

Successful treatment of ileal ulcers caused by immunosuppressants in two organ transplant recipients

Although gastroduodenal ulcers are common in solid organ transplant patients, there are few reports on multiple giant ulcers in the distal ileum and ileocecal valve caused by immunosuppressants Herein, we report on a liver transplant recipient and a renal transplant recipient with multiple large ulcers in the distal ileum and ileocecal valve who rapidly achieved ulcer healing upon withdrawal of sirolimus or tacrolimus and administration of thalidomide. In case 1, a 56-year-old man with primary hepatocellular carcinoma had received a liver transplantation. Tacrolimus combined with sirolimus and prednisolone was used as the anti-rejection regimen. Colonoscopy was performed because of severe abdominal pain and diarrhea at post-operative month 10. Multiple giant ulcers were found at the ileocecal valve and distal ileum. The ulcers healed rapidly with withdrawal of sirolimus and treatment with thalidomide. There was no recurrence during 2 years of follow-up. In case 2, a 34-year-old man with end-stage kidney disease received kidney transplantation and was put on tacrolimus combined with mycophenolate mofetil and prednisolone as the anti-rejection regimen. Twelve weeks after the operation, the patient presented with hematochezia and severe anemia. Colonoscopy revealed multiple large ulcers in the ileocecal valve and distal ileum, with massive accumulation of fresh blood. The bleeding ceased after treatment with intravenous somatostatin and oral thalidomide. Tacrolimus was withdrawn at the same time. Colonoscopy at week 4 of follow-up revealed remarkable healing of the ulcers, and there was no recurrence of bleeding during 1 year of follow-up. No lymphoma, tuberculosis, or infection of cytomegalovirus, Epstein-Barr virus, or fungus was found in either patient. In post-transplantation cases with ulcers in the distal ileum and ileocecal valve, sirolimus or tacrolimus should be considered a possible risk factor, and withdrawing them or switching to another immunosuppressant might be effective to treat these ulcers.

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.

Mycophenolic acid versus azathioprine as primary immunosuppression for kidney transplant recipients

BACKGROUND

Modern immunosuppressive regimens after kidney transplantation usually use a combination of two or three agents of different classes to prevent rejection and maintain graft function. Most frequently, calcineurin-inhibitors (CNI) are combined with corticosteroids and a proliferation-inhibitor, either azathioprine (AZA) or mycophenolic acid (MPA). MPA has largely replaced AZA as a first line agent in primary immunosuppression, as MPA is believed to be of stronger immunosuppressive potency than AZA. However, treatment with MPA is more costly, which calls for a comprehensive assessment of the comparative effects of the two drugs.

OBJECTIVES

This review of randomised controlled trials (RCTs) aimed to look at the benefits and harms of MPA versus AZA in primary immunosuppressive regimens after kidney transplantation. Both agents were compared regarding their efficacy for maintaining graft and patient survival, prevention of acute rejection, maintaining graft function, and their safety, including infections, malignancies and other adverse events. Furthermore, we investigated potential effect modifiers, such as transplantation era and the concomitant immunosuppressive regimen in detail.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register (to 21 September 2015) through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

All RCTs about MPA versus AZA in primary immunosuppression after kidney transplantation were included, without restriction on language or publication type.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed risk of bias and extracted data from each study. Statistical analyses were performed using the random-effects model and the results were expressed as risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

We included 23 studies (94 reports) that involved 3301 participants. All studies tested mycophenolate mofetil (MMF), an MPA, and 22 studies reported at least one outcome relevant for this review. Assessment of methodological quality indicated that important information on factors used to judge susceptibility for bias was infrequently and inconsistently reported.MMF treatment reduced the risk for graft loss including death (RR 0.82, 95% CI 0.67 to 1.0) and for death-censored graft loss (RR 0.78, 95% CI 0.62 to 0.99, P < 0.05). No statistically significant difference for MMF versus AZA treatment was found for all-cause mortality (16 studies, 2987 participants: RR 0.95, 95% CI 0.70 to 1.29). The risk for any acute rejection (22 studies, 3301 participants: RR 0.65, 95% CI 0.57 to 0.73, P < 0.01), biopsy-proven acute rejection (12 studies, 2696 participants: RR 0.59, 95% CI 0.52 to 0.68) and antibody-treated acute rejection (15 studies, 2914 participants: RR 0.48, 95% CI 0.36 to 0.65, P < 0.01) were reduced in MMF treated patients. Meta-regression analyses suggested that the magnitude of risk reduction of acute rejection may be dependent on the control rate (relative risk reduction (RRR) 0.34, 95% CI 0.10 to 1.09, P = 0.08), AZA dose (RRR 1.01, 95% CI 1.00 to 1.01, P = 0.10) and the use of cyclosporin A micro-emulsion (RRR 1.27, 95% CI 0.98 to 1.65, P = 0.07). Pooled analyses failed to show a significant and meaningful difference between MMF and AZA in kidney function measures.Data on malignancies and infections were sparse, except for cytomegalovirus (CMV) infections. The risk for CMV viraemia/syndrome (13 studies, 2880 participants: RR 1.06, 95% CI 0.85 to 1.32) was not statistically significantly different between MMF and AZA treated patients, whereas the likelihood of tissue-invasive CMV disease was greater with MMF therapy (7 studies, 1510 participants: RR 1.70, 95% CI 1.10 to 2.61). Adverse event profiles varied: gastrointestinal symptoms were more likely in MMF treated patients and thrombocytopenia and elevated liver enzymes were more common in AZA treatment.

AUTHORS' CONCLUSIONS

MMF was superior to AZA for improvement of graft survival and prevention of acute rejection after kidney transplantation. These benefits must be weighed against potential harms such as tissue-invasive CMV disease. However, assessment of the evidence on safety outcomes was limited due to rare events in the observation periods of the studies (e.g. malignancies) and inconsistent reporting and definitions (e.g. infections, adverse events). Thus, balancing benefits and harms of the two drugs remains a major task of the transplant physician to decide which agent the individual patient should be started on.

Human Leukocyte Antigen Alleles and Cytomegalovirus Infection After Renal Transplantation

Background:

Several studies have been conducted on the relationship between a number of human leukocyte antigen (HLA) alleles and cytomegalovirus infection (CMV), in kidney transplant recipients, after transplantation. However, only a limited number of HLAs have been investigated, so far, and the results have been contradictory.

Objectives:

This study aimed to investigate the relationship between 59 HLA alleles and the CMV infection, in transplant recipients, after kidney transplantation.

Patients and Methods:

This retrospective cohort study was conducted on 200 patients, receiving a kidney transplant, in Baqiyatallah Hospital, in Tehran, during 2013. Throughout a one-year follow-up of kidney transplant recipients, in case of detecting the CMV antigen in patients’ blood, at any time, they were placed in the group of patients with CMV infection, whereas, if no CMV-specific antigen was developed, over a year, patients were placed in the group of patients without CMV infection, after transplantation. This study investigated the relationship between CMV infection in kidney transplant recipients and 59 HLA alleles, including 14 HLA-A, 28 HLA-B, and 17 HLA-DRB1 cases.

Results:

Of all participants, 104 patients (52%) were diagnosed with CMV infection. There was no significant difference between the two groups, with and without CMV infection, in terms of patient’s characteristics. The CMV infection, in patients receiving a transplanted organ from deceased donor, was significantly more prevalent than in those receiving kidney transplant from living donor (63% vs. 39%, respectively, P = 0.001). Recipients with HLA-B44 were more infected with CMV compared with patients without this allele (80% vs. 50%, respectively, P = 0.024); on the contrary, kidney recipients with HLA-DRB1-1 were less infected with CMV than patients without this allele (31% vs. 55%, respectively, P = 0.020). There was no significant relationship between CMV infection and other HLA alleles. Results of multivariate logistic regression analysis showed that deceased donor renal transplantation (OR = 3.018, 95%CI: 1.662 - 5.480, P < 0.001), presence of HLA-B44 (OR = 4.764, 95%CI: 1.259 - 18.032, P = 0.022) and lack of HLA-B8 (OR = 3.246, 95%CI: 1.030 - 10.230, P = 0.044) were the independent risk factors for developing CMV infection, after kidney transplantation.

Conclusions:

The findings of this study showed that deceased donor renal transplantation and the presence of HLA-B44 can make the kidney recipient susceptible to CMV infection after kidney transplantation; on the other hand, the presence of HLA-B8 can have a protective effect.

How to reduce lethal infectious complications in ABO-incompatible kidney transplantation

BACKGROUND

ABO-incompatible organ transplants are good options for expanding the living donor pool; however, the necessary pre-conditioning to remove ABO antibodies before surgery can evoke critical infectious complications after surgery.

METHODS

Between February 2009 and July 2013, we performed ABO-incompatible kidney transplantation on 182 patients. We analyzed the first 85 patients for post-operative infectious complications in a cross-sectional cohort of patients (group 1, n = 85) who had received an ABO-incompatible kidney transplant and, in light of the results, amended the pre-conditioning (lower dose of rituximab, selective use of calcineurin inhibitors, anti-metabolite reduction, and prophylactic strategy) given to a prospective cohort (group 2, n = 97).

RESULTS

The characteristics of the two groups did not differ significantly. Infectious complications decreased significantly in group 2, including cytomegalovirus (anti-genemia 64.7% vs 27.8%, P < .001) and BK viremia (35.2% vs 18.6%, P = .008). The acute rejection rate and death-censored graft survival were similar in both groups. Notably, with the modified protocol, there were no deaths (8.2% vs 0.0%, P = .03).

CONCLUSIONS

Pre-conditioning for ABO-incompatible kidney transplantation is a prerequisite for successful outcome; its drawbacks can be limited with the use of a modified immunosuppressive strategy. If immunosuppression is modified according to host conditions, ABO-incompatible kidney transplantation can be performed safely with a successful graft outcome.

CMV Viremia is associated with a decreased incidence of BKV reactivation after kidney and kidney-pancreas transplantation

BACKGROUND

Cytomegalovirus (CMV) and BK virus (BKV) infections can cause significant morbidity after kidney and kidney-pancreas transplant. There are limited data on the epidemiology and interactions between these two viral pathogens.

METHODS

We prospectively screened 609 kidney or kidney-pancreas transplant recipients from January 2007 to June 2011 for BKV and/or CMV viremia. This included 7453 quantitative BKV polymerase chain reaction and 15,496 quantitative CMV polymerase chain reaction tests. We evaluated risk factors and timing of these infections and the impact of treatment of one infection on the other.

RESULTS

Among 609 recipients, 108 (17.7%) developed CMV viremia, of which 95 (88%) were asymptomatic, 5 (5%) had CMV syndrome, and 8 (7%) developed CMV tissue invasive disease at a median of 5.6 months after transplantation. Risk factors for CMV infection using multivariable analysis were D+R- serogroup (P≤0.0001), donor age >50 years (P=0.013), and higher mean tacrolimus (P=0.0009) and mycophenolate mofetil (P=0.01) blood levels. The incidence of BKV infection in the total population was 163 of 609 (26.7%), of which 150 (92%) occurred in patents without antecedent CMV viremia. Such patients demonstrated a higher rate of subsequent BKV viremia than patients with antecedent CMV viremia (P=0.003; hazard ratio, 2.05; 95% confidence interval, 1.2-3.4). Moreover, we found that only symptomatic CMV viremia had a significant negative impact on graft survival when compared with asymptomatic CMV viremia and those without CMV viremia (relative risk, 3.5; 95% confidence interval, 1.06-8.9; P=0.04).

CONCLUSION

CMV viremia may indirectly protect against subsequent BK viremia possibly due to a reduction of intensity of immunosuppression after diagnosis of CMV viremia.

Effect of maintenance immunosuppressive drugs on virus pathobiology: evidence and potential mechanisms

Recent evidence suggesting a potential anti-CMV effect of mTORis is of great interest to the transplant community. However, the concept of an immunosuppressant with antiviral properties is not new, with many accounts of the antiviral properties of several agents over the years. Despite these reports, to date, there has been little effort to collate the evidence into a fuller picture. This manuscript was developed to gather the evidence of antiviral activity of the agents that comprise a typical immunosuppressive regimen against viruses that commonly reactivate following transplant (HHV1 and 2, VZV, EBV, CMV and HHV6, 7, and 8, HCV, HBV, BKV, HIV, HPV, and parvovirus). Appropriate immunosuppressive regimens posttransplant that avoid acute rejection while reducing risk of viral reactivation are also reviewed. The existing literature was disparate in nature, although indicating a possible stimulatory effect of tacrolimus on BKV, potentiation of viral reactivation by steroids, and a potential advantage of mammalian target of rapamycin (mTOR) inhibition in several viral infections, including BKV, HPV, and several herpesviruses.

Subacute cytomegalovirus appendicitis in a renal transplant recipient

Cytomegalovirus (CMV) infections in transplant patients is a well-known disease. We describe the first case, to our knowledge, documenting CMV appendicitis in a renal transplant patient, and its clinical presentation, diagnosis, and treatment.

Review of cytomegalovirus infection findings with mammalian target of rapamycin inhibitor-based immunosuppressive therapy in de novo renal transplant recipients

Cytomegalovirus (CMV) infection and disease are major complications in the renal transplant recipient. The occurrence of CMV is associated with acute rejection, allograft dysfunction, significant end-organ disease, and mortality. Several clinical studies have indicated that the use of certain immunosuppressive drugs can delay the reconstitution of CMV-specific cell-mediated immune responses, thereby leading to uncontrolled CMV replication. Accumulating evidence indicates, however, that the use of the mammalian target of rapamycin (mTOR) inhibitors, sirolimus, and everolimus, may decrease the incidence and severity of CMV infection in renal transplant recipients. The purpose of this article is to review CMV infection data from randomized clinical trials that investigated the use of sirolimus- and everolimus-based treatment regimens in de novo renal transplantation. The mTOR inhibitor clinical trials included were primarily identified using biomedical literature database searches, with additional studies added at the authors' discretion. This review will summarize these studies to discuss whether mTOR inhibitor-based immunosuppressive therapy can reduce the magnitude of CMV-related complications in the de novo renal transplantation setting.

Human cytomegalovirus and kidney transplantation: a clinician's update

Infection with human cytomegalovirus (CMV) is an important cause of morbidity and mortality in kidney transplant recipients. CMV disease is diagnosed based on the detection of viral replication by phosphoprotein 65 antigenemia or CMV DNA polymerase chain reaction in combination with typical signs and symptoms. Risk factors include CMV-seronegative recipients receiving a CMV-seropositive transplant, older donor age, exposure to cyclosporine and/or antilymphocyte antibody, rejection episodes, and impaired transplant function. Current preventive strategies in kidney transplant recipients include pre-emptive therapy with valganciclovir or intravenous ganciclovir and universal prophylaxis with valacyclovir, valganciclovir, or ganciclovir for 3-6 months after kidney transplantation and for 1-3 months after treatment with antilymphocyte antibody. Established disease should be treated using either intravenous ganciclovir or oral valganciclovir until CMV replication can no longer be detected. In addition to direct effects, CMV infection also induces a wide range of indirect effects, such as decreased transplant and recipient survival and susceptibility to rejection and opportunistic infections. In this review, we highlight the most relevant topics on CMV and kidney transplantation based on current evidence and guidelines.