Cytomegalovirus-related disease and risk of acute rejection in renal transplant recipients: a cohort study with case-control analyses

Detrimental impact of immunosuppressive burden on clinical course in patients with Cytomegalovirus infection after liver transplantation

INTRODUCTION

Cytomegalovirus (CMV)-infection and reactivation remain a relevant complication after liver transplantation (LT). The recipient and donor serum CMV-IgG-status has been established for risk stratification when choosing various pharmaceutical regimens for CMV-prophylaxis in the last two decades. However, factors influencing course of CMV-infection in LT remain largely unknown. In this study, the impact of immunosuppressive regimen was examined in a large cohort of patients.

METHODS

All patients that underwent primary LT between 2006 and 2018 at the Charité-Universitaetsmedizin, Berlin, were included. Clinical course as well as histological and laboratory findings of patients were analyzed our prospectively maintained database. Univariate and multivariate regression analysis for impact of variables on CMV-occurrence was conducted, and survival was examined using Kaplan-Meier analysis.

RESULTS

Overall, 867 patients were included in the final analysis. CMV-infection was diagnosed in 325 (37.5%) patients after transplantation. Significantly improved overall survival was observed in these patients (Log rank = 0.03). As shown by correlation and regression tree classification and regression tree analysis, the recipient/donor CMV-IgG-status with either positivity had the largest influence on CMV-occurrence. Analysis of immunosuppressive burden did not reveal statistical impact on CMV-infection, but statistically significant inverse correlation of cumulative tacrolimus trough levels and survival was found (Log rank < .001). Multivariate analysis confirmed these findings (p = .02).

DISCUSSION

CMV-infection remains of clinical importance after LT. Undergone CMV-infection of either recipient or donor requires prophylactic treatment. Additionally, we found a highly significant, dosage-dependent impact of immunosuppression (IS) on long-term outcomes for these patients, underlying the importance of minimization of IS in liver transplant recipients.

Murine cytomegalovirus promotes renal allograft inflammation via Th1/17 cells and IL-17A

Human cytomegalovirus (HCMV) infection is associated with renal allograft failure. Allograft damage in animal models is accelerated by CMV-induced T helper 17 (Th17) cell infiltrates. However, the mechanisms whereby CMV promotes Th17 cell-mediated pathological organ inflammation are uncharacterized. Here we demonstrate that murine CMV (MCMV)-induced intragraft Th17 cells have a Th1/17 phenotype co-expressing IFN-γ and/or TNF-α, but only a minority of these cells are MCMV specific. Instead, MCMV promotes intragraft expression of CCL20 and CXCL10, which are associated with recruitment of CCR6⁺ CXCR3⁺ Th17 cells. MCMV also enhances Th17 cell infiltrates after ischemia-reperfusion injury, independent of allogeneic responses. Pharmacologic inhibition of the Th17 cell signature cytokine, IL-17A, ameliorates MCMV-associated allograft damage without increasing intragraft viral loads or reducing MCMV-specific Th1 cell infiltrates. Clinically, HCMV DNAemia is associated with higher serum IL-17A among renal transplant patients with acute rejection, linking HCMV reactivation with Th17 cell cytokine expression. In summary, CMV promotes allograft damage via cytokine-mediated Th1/17 cell recruitment, which may be pharmacologically targeted to mitigate graft injury while preserving antiviral T cell immunity.

Clinical consequences of primary CMV infection after renal transplantation: a case-control study

The impact of primary cytomegalovirus infection (pCMV) on renal allograft function and histology is controversial. We evaluated the influence on incidence of acute rejection, allograft loss, allograft function and interstitial fibrosis/tubular atrophy (IF/TA). Retrospective case-control study, recipients transplanted between 2000 and 2014. Risk of acute rejection and allograft loss for those who experienced pCMV infection compared with those who did not, within an exposure period of two months after transplantation. Besides, its influence on allograft function and histology at one to three years after transplantation. Of 113 recipients experienced pCMV infection, 306 remained CMV seronegative. pCMV infection in the exposure period could not be proven as increasing the risk for acute rejection [HR = 2.18 (95% CI 0.80-5.97) P = 0.13] or allograft loss [HR = 1.11 (95%CI 0.33-3.72) P = 0.87]. Combination of pCMV infection and acute rejection posed higher hazard for allograft loss than acute rejection alone [HR = 3.69 (95% CI 1.21-11.29) P = 0.02]. eGFR(MDRD) values did not significantly differ at years one [46 vs. 50], two [46 vs. 51] and three [46 vs. 52]. No association between pCMV infection and IF/TA could be demonstrated [OR = 2.15 (95%CI 0.73-6.29) P = 0.16]. pCMV infection was not proven to increase the risk for acute rejection or allograft loss. However, it increased the risk for rejection-associated allograft loss. In remaining functioning allografts, it was not significantly associated with decline in function nor with presence of IF/TA.

The Interferon-Gamma +874 A/T Polymorphism Is Not Associated With CMV Infection After Kidney Transplantation

The +874 A/T polymorphism in the interferon gamma (IFNG) gene has been associated with Cytomegalovirus (CMV) infection risk in lung and kidney transplant recipients. To replicate this association, we performed a retrospective observational study of this polymorphism and immunosuppressive therapies considering the prophylactic treatment in 600 consecutive kidney transplanted recipients. We found no association of the aforementioned polymorphism with CMV infection in univariate and multivariate analyses regardless of the prophylactic treatment. In addition, the immunosuppressive treatment with mammalian target of rapamycin inhibitors (imTOR) showed a protective effect in all patients independently of prophylaxis. Moreover, in the adjusted model, we found interactions between prophylaxis with high-risk (Donor+/Recipient-, D+/R-) status (p-interaction = 0.01), with thymoglobulin induction therapy (p-interaction = 0.03) and with thymoglobulin anti-rejection therapy (p-interaction = 0.002). Data also revealed that prophylaxis was not an advantage in the not D+/R- and without thymoglobulin therapy group (HR = 0.98, p = 0.95). The benefit of prophylaxis was observed in all groups with thymoglobulin therapy, but it was maximal in the high-risk CMV infection group with both thymoglobulin induction therapy and thymoglobulin anti-rejection therapy (HR = 0.01, p < 0.001). In conclusion, the IFNG +874 polymorphism is not a predictive marker of CMV infection. The protective effect of imTOR is not improved with prophylaxis. Interestingly, the thymoglobulin therapy associated with prophylaxis is not a risk factor for CMV infection, and prophylaxis is not effective in recipients with no high-risk CMV status and without thymoglobulin therapy.

Risk factors for complications and graft failure in kidney transplant patients with sepsis

Immunosuppressive therapies decrease the incidence of acute kidney rejection after kidney transplantation, but also increase the risk of infections and sepsis. This study aimed to identify the risk factors associated with complications and/or graft failure in kidney transplant patients with sepsis. A total of 14,658 kidney transplant patients with sepsis, identified in the National Inpatient Sample (NIS) database (data from 2005-2014), were included in the study and classified into three groups: patients without complications or graft failure/dialysis (Group 1), patients with complications only (Group 2), and patients with complications and graft failure/dialysis (Group 3). Multinomial logistic regression analyses were conducted to evaluate factors associated with kidney transplant recipients. Multivariate analysis showed that, compared to Group 1, patients from Group 2 or Group 3 were more likely to be Black and to have cytomegalovirus infection, coagulopathy, and glomerulonephritis (p ≤ 0.041). Also, Group 2 was more likely to have herpes simplex virus infection, and Group 3 was more likely to have hepatitis C infection and peripheral vascular disorders, compared to Group 1 (p ≤ 0.002). In addition, patients in Group 3 were more likely to be Black and to have hepatitis C infection, peripheral vascular disorders, coagulopathy, and hypertension compared to Group 2 (p ≤ 0.039). Age and female gender were associated with lower odds of complications after kidney transplantation regardless of graft rejection/dialysis (p ≤ 0.049). Hyperlipidemia and diabetes decreased the chance of complications and graft failure/dialysis after kidney transplant (p < 0.001). In conclusion, the study highlights that black race, male gender, and specific comorbidities can increase the risk of complications and graft failure in kidney transplant patients with sepsis.

The effect of cytomegalovirus infection on acute rejection in kidney transplanted patients

Introduction: It is known that cytomegalovirus (CMV) infection is a common problem among kidney transplant patients. This infection can be increased morbidity and decreased graft survival. This problem has been associated with acute rejection too.

Patients and Methods: One hundred and thirty renal transplant patients were included in a prospective, case-control study. The renal transplant patients were divided into two groups; patients group with CMV infection and control group without CMV infection. Serum CMV-IgG in all patients was positive (donor and recipients). None of patients had received anti-thymocyte-globulin and thymoglobulin. CMV infection was diagnosed by quantitative CMV-PCR (polymerase chain reaction) test (more than 500 copies/μg). Rejection episode was defined by kidney isotope scan or biopsy.

Results: In the group of 66 CMV infection patients (41 male [62.1%] and 25 female [37.9%]) the incidence of graft rejection was 36%, however in the group of 64 control patients the incidence of graft rejection was 9.4 % (P < 0.005).

Conclusion: CMV infection is important predisposing factor for acute allograft rejection after kidney transplantation. The results of this study suggests that the control of CMV infection could decrease episodes of acute kidney rejection.

Risk factors in the progression of BK virus-associated nephropathy in renal transplant recipients

BACKGROUND/AIMS

BK virus-associated nephropathy (BKVAN) is an important cause of allograft dysfunction in kidney transplant recipients. It has an unfavorable clinical course, and no definite treatment guidelines have yet been established. Here, we report our center's experience with biopsy-proven BKVAN and investigate factors associated with its progression.

METHODS

From January 2004 to April 2013, 25 patients with BKVAN were diagnosed by biopsy at Seoul St. Mary's Hospital. Of the 25 patients, 10 were deceased-donor transplant recipients and 15 were living-donor transplant recipients. Three of the patients underwent retransplantation. The primary immunosuppressant used was tacrolimus in 17 patients and cyclosporine in eight patients.

RESULTS

BKVAN was observed at a mean duration of 22.8 ± 29.1 months after transplantation. The mean serum creatinine level at biopsy was 2.2 ± 0.7 mg/dL. BKVAN occurred with acute rejection in eight patients (28%). Immunosuppression modification was performed in 21 patients (84%). Additionally, leflunomide and intravenous immunoglobulin were administered to 13 patients (52%) and two (8%), respectively. Allograft loss occurred in five patients (27.8%) during the follow- up period at 0.7, 17.1, 21.8, 39.8, and 41.5 months after the BKVAN diagnosis. Advanced stages of BKVAN, increased creatinine levels, and accompanying acute rejection at the time of BKVAN diagnosis increased the risk of allograft failure.

CONCLUSIONS

The clinical outcomes in patients with biopsy-proven BKVAN were unfavorable in the present study, especially in patients with advanced-stage BKVAN, poor renal function, and acute allograft rejection.

Direct and Indirect Effects of Cytomegalovirus-Induced γδ T Cells after Kidney Transplantation

Despite effective anti-viral therapies, cytomegalovirus (CMV) is still associated with direct (CMV disease) and indirect effects (rejection and poor graft survival) in kidney transplant recipients. Recently, an unconventional T cell population (collectively designated as Vδ2^neg γδ T cells) has been characterized during the anti-CMV immune response in all solid-organ and bone-marrow transplant recipients, neonates, and healthy people. These CMV-induced Vδ2^neg γδ T cells undergo a dramatic and stable expansion after CMV infection, in a conventional “adaptive” manner. Similarly, as CMV-specific CD8+ αβ T cells, they exhibit an effector/memory TEMRA phenotype and cytotoxic effector functions. Activation of Vδ2^neg γδ T cells by CMV-infected cells involves the γδ T cell receptor (TCR) and still ill-defined co-stimulatory molecules such as LFA-1. A multiple of Vδ2^neg γδ TCR ligands are apparently recognized on CMV-infected cells, the first one identified being the major histocompatibility complex-related molecule endothelial protein C receptor. A singularity of CMV-induced Vδ2^neg γδ T cells is to acquire CD16 expression and to exert an antibody-dependent cell-mediated inhibition on CMV replication, which is controlled by a specific cytokine microenvironment. Beyond the well-demonstrated direct anti-CMV effect of Vδ2^neg γδ T cells, unexpected indirect effects of these cells have been also observed in the context of kidney transplantation. CMV-induced Vδ2^neg γδ T cells have been involved in surveillance of malignancy subsequent to long-term immunosuppression. Moreover, CMV-induced CD16+ γδ T cells are cell effectors of antibody-mediated rejection of kidney transplants, and represent a new physiopathological contribution to the well-known association between CMV infection and poor graft survival. All these basic and clinical studies paved the road to the development of a future γδ T cell-based immunotherapy. In the meantime, γδ T cell monitoring should prove a valuable immunological biomarker in the management of CMV infection.

Viral infection in renal transplant recipients

Viruses are among the most common causes of opportunistic infection after transplantation. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or posttransplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections. This paper will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Latent cytomegalovirus infection is an independent risk factor for late graft failure in renal transplant recipients

Background

Cytomegalovirus (CMV) is a risk factor for rejection and mortality soon after renal transplantation. Little is known about its consequences longer after transplantation. We prospectively investigated whether latent CMV infection is a risk factor for graft failure and mortality long after transplantation.

Material/Methods

Our study included 606 renal transplant recipients (RTR) with a functioning graft for >1 year. CMV serology was determined using ELISA. RTRs were divided into CMV-seronegative and latent CMV (seropositive + seroconverted).

Results

We measured CMV IgG at 6.0 [2.6–11.4] years post-transplant. During follow-up (7.0 [6.2–7.5] years), 54 (9%) RTRs experienced graft failure and 137 (23%) RTRs died. Risk for graft failure and mortality was significantly higher in RTRs with latent CMV compared to CMV-seronegative RTRs (HR=3.1, P=0.005 and HR=2.0, P=0.002, respectively). After adjustment for potential confounders, latent CMV infection remained an independent risk factor for graft failure (HR=4.6, P=0.001), but not for mortality (HR=1.4, P=0.2).

Conclusions

Latent CMV is an independent risk factor for graft failure long after renal transplantation and carries a higher risk for graft failure than for mortality. These findings confirm the notion that latent CMV can be harmful in transplanted kidneys.

Shedding light on the elusive role of endothelial cells in cytomegalovirus dissemination

Cytomegalovirus (CMV) is frequently transmitted by solid organ transplantation and is associated with graft failure. By forming the boundary between circulation and organ parenchyma, endothelial cells (EC) are suited for bidirectional virus spread from and to the transplant. We applied Cre/loxP-mediated green-fluorescence-tagging of EC-derived murine CMV (MCMV) to quantify the role of infected EC in transplantation-associated CMV dissemination in the mouse model. Both EC- and non-EC-derived virus originating from infected Tie2-cre(+) heart and kidney transplants were readily transmitted to MCMV-naïve recipients by primary viremia. In contrast, when a Tie2-cre(+) transplant was infected by primary viremia in an infected recipient, the recombined EC-derived virus poorly spread to recipient tissues. Similarly, in reverse direction, EC-derived virus from infected Tie2-cre(+) recipient tissues poorly spread to the transplant. These data contradict any privileged role of EC in CMV dissemination and challenge an indiscriminate applicability of the primary and secondary viremia concept of virus dissemination.

Allograft rejection-related gene expression in the endothelial cells of renal transplantation recipients after cytomegalovirus infection

OBJECTIVE

To explore the effects of cytomegalovirus (CMV) infection on rejection-related gene expression in the endothelial cells of renal transplantation recipients.

METHODS

Endothelial cells (ECs) were cultured and stimulated by a variety of factors: A, normal control group; B, inactivated human cytomegalovirus (HCMV) infection group; C, HCMV infection group; D, HCMV supernatant infection group; and E, ganciclovir HCMV group. Expression of intercellular adhesion molecule-1 (ICAM-1) and major histocompability complex (MHC) class I and class II antigens was detected by flow cytometry (FCM) and immunohistochemistry.

RESULTS

We found characteristic CMV-infected ECs in this study. There were no significant differences among groups A, B and D (P>0.05). Although the expression levels of ICAM-1 were not significantly different between groups C and E (P>0.05), the ICAM-1 expression in these two groups was significantly higher than that in group A (P<0.05). ICAM-1 expression was detected in groups C and E, while there was no expression in groups A, B and D. Furthermore, there was no significant difference of ICAM-1 mRNA expression between groups C and E (P>0.05). Human leucocyte antigen (HLA)-ABC expression was detected in all the groups, while HLA-DR expression was only detected in groups C and E. There were no significant differences of HLA-ABC and HLA-DR expression among groups A, B and D (P>0.05). However, the HLA-ABC and HLA-DR expression levels in groups C and D were higher than those of the remaining groups previously reported (P<0.05). Meanwhile, the HLA-ABC and HLA-DR expression levels in group E were lower than those of group C (P<0.05).

CONCLUSION

CMV could up-regulate the expression levels of ICAM-1 and MHC antigens, which was closely related to allograft rejection.

Expansion of effector memory TCR Vbeta4+ CD8+ T cells is associated with latent infection-mediated resistance to transplantation tolerance

Therapies that control largely T cell-dependent allograft rejection in humans also possess the undesirable effect of impairing T cell function, leaving transplant recipients susceptible to opportunistic viruses. Prime among these opportunists are the ubiquitous herpesviruses. To date, studies are lacking that address the effect of viruses that establish a true latent state on allograft tolerance or the effect of tolerance protocols on the immune control of latent viruses. By using a mixed chimerism-based tolerance-induction protocol, we found that mice undergoing latent infection with gammaHV68, a murine gamma-herpesvirus closely related to human gamma-herpesviruses such as EBV and Kaposi's sarcoma-associated herpesvirus, significantly resist tolerance to allografts. Limiting the degree of virus reactivation or innate immune response did not reconstitute chimerism in latently infected mice. However, gammaHV68-infected mice showed increased frequency of CD8+ T cell alloreactivity and, interestingly, expansion of virus-induced, alloreactive, "effector/effector memory" TCR Vbeta4+CD8+ T cells driven by the gammaHV68-M1 gene was associated with resistance to tolerance induction in studies using gammaHV68-M1 mutant virus. These results define the viral gene and immune cell types involved in latent infection-mediated resistance to allograft tolerance and underscore the influence of latent herpesviruses on allograft survival.

Improvement in long-term renal graft survival due to CMV prophylaxis with oral ganciclovir: results of a randomized clinical trial

Oral ganciclovir prophylaxis and intravenous preemptive therapy are competitive approaches to prevent cytomegalovirus (CMV) disease after renal transplantation. This trial compared efficacy, safety and long-term graft outcome in 148 renal graft recipients randomized to ganciclovir prophylaxis (N = 74) or preemptive therapy (N = 74). Hierarchical testing revealed (i) patients with CMV infection had more severe periods of impaired graft function (creatinine clearance(max-min) 25.0 +/- 14.2 mL/min vs. 18.1 +/- 12.5 mL/min for patients without CMV infection; p = 0.02),(ii) prophylaxis reduced CMV infection by 65% (13 vs. 33 patients; p < 0.0001) but (iii) creatinine clearance at 12 months was comparable for both regimes (54.0 +/- 24.9 vs. 53.1 +/- 23.7 mL/min; p = 0.92). No major safety issues were observed, and patient survival at 12 months was similar in both groups (5 deaths [6.8%] vs. 4 [5.4%], p = 1.0000). Prophylaxis significantly increased long-term graft survival 4 years posttransplant (92.2% vs. 78.3%; p = 0.0425) with a number needed to treat of 7.19. Patients with donor +/recipient + CMV serostatus had the lowest rate of graft loss following prophylaxis (0.0% vs. 26.8%; p = 0.0035). In conclusion, it appears that routine oral prophylaxis may improve long-term graft survival for most renal transplant patients. Preemptive therapy can be considered in low risk patients in combination with adequate CMV monitoring.

Association of the Outcome of Renal Transplantation with Antibody Response to Cytomegalovirus Strain--Specific Glycoprotein H Epitopes

BACKGROUND

Cytomegalovirus (CMV) is the most important pathogen affecting the outcome of renal transplantation. The combination of CMV-seronegative transplant recipients with CMV-seropositive transplant donors places recipients at the highest risk of CMV disease. In cases of congenital CMV infection, existing immunity only partially protected mothers from reinfection with a different genotypic strain. The effect of differences in infected CMV strains between CMV-seropositive transplant donors and CMV seropositive transplant recipients on the outcome of transplantation remains unclear.

METHODS

In this prospective multicenter study, the presence of antibodies against strain-specific glycoprotein H epitopes in 84 CMV-seropositive transplant donor/CMV-seropositive transplant recipient renal transplantation cases were determined, and their relationships to acute transplant rejection, CMV infection, degree of antigenemia, and CMV disease were evaluated.

RESULTS

Among the 84 donor/recipient pairs, 45 and 32 had matched and mismatched strain-specific glycoprotein H antibodies, respectively. Acute transplant rejection in the mismatched group was more frequent than it was in the matched group (63% vs. 22%; P=.005). CMV disease was also more frequently observed in the mismatched group (28% vs. 9%; P=.026). The mismatched group had a higher level of antigenemia (P=.019).

CONCLUSIONS

Our results illustrate more adverse events in the cases with a CMV-seropositive transplant donor and a CMV-seropositive transplant recipient in which the glycoprotein H antibodies are mismatched, suggesting that reinfection with a different CMV strain results in more complications.

Blood glutathione as a marker of cardiac allograft vasculopathy in heart transplant recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) limits survival after heart transplantation (HTx). Between immunologic and non-immunologic factors, reactive oxygen species generation has been proposed as pathogenetic mechanism. This study was aimed at evaluating redox status in HTx recipients and verifying whether it could be independently associated with CAV.

METHODS

Fifty-five consecutive male HTx recipients, median [interquartile range] age 60 yr [50, 64], underwent angiography 67 months [21, 97] after HTx to assess CAV, defined as significant stenosis in >or=1 epicardial vessel or any distal vessel attenuation. All patients underwent blood sampling 89 months [67, 119] after HTx for biochemical (glucose, creatinine, total and LDL cholesterol, and cyclosporin levels) and redox evaluation [plasma reduced and total homocysteine, cysteine, cysteinylglycine, glutathione, blood reduced glutathione (GSH(bl)) and vitamin E]. Univariate Odds Ratios (OR) with 95% confidence interval (95% CI, highest vs. lowest quartile) were estimated on the basis of a logistic regression analysis between clinical, conventional biochemical and redox data. Only the significant variables at univariate entered into multivariate analysis.

RESULTS

CAV was documented in 15 (27%) patients. Univariate analysis showed that time from HTx to angiography (OR 3.97, 95% CI 1.15-14, p = 0.03) and GSH(bl) (OR 0.31, 95% CI: 0.14-0.70, p = 0.005) were significantly associated with CAV. However, multivariate analysis revealed GSH(bl) as the only independent predictor of CAV (OR 0.31, 95% CI: 0.13-0.74, p = 0.008).

CONCLUSIONS

In HTx recipients reduced levels of GSH(bl) are independently associated with CAV. Given its potent intracellular scavenger properties, GSH(bl) may serve as a marker of antioxidant defence consumption, favouring CAV development.

Viral prophylaxis in organ transplant patients

Viral pathogens have emerged as the most important microbial agents having deleterious effects on solid organ transplant (SOT) recipients. Antiviral chemoprophylaxis involves the administration of medications to abort transmission of, avoid reactivation of, or prevent progression to disease from, active viral infection. Cytomegalovirus (CMV) is the major microbial pathogen having a negative effect on SOT recipients. CMV causes infectious disease syndromes, augments iatrogenic immunosuppression and is commonly associated with opportunistic superinfection. CMV has also been implicated in the pathogenesis of rejection. Chemoprophylactic regimens for CMV have included oral aciclovir (acyclovir) at medium and high doses, intravenous and oral ganciclovir, and the prodrugs valaciclovir (valacyclovir) and valganciclovir. CMV prophylactic strategies should be stratified, with the highest-risk patients receiving the most 'potent' prophylactic regimens. Herpes simplex virus (HSV) reactivation in SOT recipients is more frequent, may become more invasive, takes longer to heal, and has greater potential for dissemination to visceral organs than it does in the immunocompetent host. Prophylactic regimens for CMV are also effective chemoprophylaxis against HSV; in the absence of CMV prophylaxis, aciclovir, valaciclovir or famciclovir should be used as HSV prophylaxis in seropositive recipients. Primary varicella-zoster virus (VZV) after SOT is rare and most commonly seen in the paediatric transplant population because of VZV epidemiology. Zoster occurs in 5-15% of patients, usually after the sixth post-transplant month. Prophylactic regimens for zoster are neither practical nor cost effective after SOT because of the late onset of disease and low proportion of affected individuals. All SOT recipients should receive VZV immune globulin after contact with either varicella or zoster. Epstein-Barr virus has its most significant effect in SOT as the precipitating factor in the development of post-transplant lymphoproliferative disorders. Antiviral agents that could be effective are the same as those used for CMV, but indications for and effectiveness of prophylaxis are poorly established. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are important pathogens in the SOT population as indications for transplantation. So-called 'prophylaxis' for recurrent HBV and HCV after liver transplantation is controversial, suppressive rather than preventive, and potentially lifelong. Influenza infection after SOT is acquired by person-to-person contact. During epidemic periods of influenza, transplant populations experience a relatively high frequency of infection, and influenza may affect immunosuppressed SOT recipients more adversely than immunocompetent individuals. Antiviral medications for prevention of influenza are administered as post-exposure prophylaxis to SOT recipients, in addition to yearly vaccine, in circumstances such as influenza epidemics and nosocomial outbreaks, and after exposure to a symptomatic individual during 'flu season'.

Cytomegalovirus ischemic colitis of a diabetic renal transplant recipient

We report a diabetic renal transplant recipient with cytomegalovirus (CMV) disease who presented with tarry stool diarrhea because of multiple colonic ulcerations. Histopathology revealed diffuse colonic ulcers following a process of ischemic vasculitis. The colonic ulcers disappeared dramatically after 2 wk of intravenous ganciclovir therapy. Hyper-immunosuppression was initially suspected but acute rejection (AR) developed after immunosuppressive reduction during the ganciclovir therapy. The AR was successfully reversed and the dosage of cyclosporine was returned to the same level prior to the onset of CMV disease. Our experience suggests that ganciclovir is quite effective for healing colonic ulcers caused by CMV and acute allograft rejection may occur during therapy.

Longitudinal study of herpesviruses in kidney transplant recipients in Cuba

We compared a multiplex polymerase chain reaction assay and a shell vial assay for the detection of herpesviruses infection in 13 Cuban patients who had received kidney transplants. Cytomegalovirus and human herpesvirus 6 were detected in these patients.