Viral infection in the renal transplant recipient

Transplantation and the primary care physician

Increasing appreciation of the survival benefits of kidney transplantation, compared with chronic dialysis, has resulted in more patients with kidney disease being referred and receiving organs. The evolving disparity between a rapidly increasing pool of candidates and a smaller pool of available donors has created new issues for the physicians who care for kidney patients and their potential living donors. This article outlines current efforts to address the growing number of patients who await transplantation, including relaxation of traditional donation criteria, maximization of living donation, and donation schemas that permit incompatible donor-recipient pairs to participate through paired donation and transplantation chains. New ethical issues faced by donors and recipients are discussed. Surgical advances that reduce the morbidity of donors are also described, as is the role of the primary physician in medical issues of both donors and recipients.

Leflunomide for cytomegalovirus: bench to bedside

Cytomegalovirus (CMV) remains a major cause of morbidity and mortality among transplant recipients, frequently engaging the clinician in a struggle to balance graft preservation with control of CMV disease. Leflunomide has been shown to have immunosuppressive activity in experimental allograft models together with antiviral activity inhibiting CMV both in vitro and in vivo. Data are emerging about its potential role in ganciclovir-sensitive and -resistant CMV, primarily by virtue of a unique mechanism inhibiting virion assembly, as opposed to inhibition of viral DNA synthesis by current agents. This review aims to put in perspective, the knowledge acquired in the last decade or so on leflunomide for CMV. Evidence suggests that it might have activity against human CMV with good oral bioavailability and, more importantly in the resource-poor setting, is economical. Although the data presented here are not from randomized trials, several relevant observations have been made that could influence future, more structured assessments of the drug. An immune suppressive compound with antiviral features and experimental activity in chronic rejection is an attractive combination for organ transplantation, and it appears that leflunomide may just fit that niche.

[Parvovirus B19 infection after kidney transplantation]

Prevalence for human parvovirus B19 infection is estimated to be between 2% and 30% in renal transplant recipients. In post-transplant settings, parvovirus B19 infection may occur either as a primary infection or a reactivation. Parvovirus transmission most commonly occurs through respiratory tract but may also result from graft or blood packs contamination. Co-infections with HHV-6 and CMV viruses are frequent. The hallmark symptom is anemia, more rarely pancytopenia and hemophagocytic syndrome. In respect to renal involvement, parvovirus B19 infection has been associated with graft dysfunction in 10% of cases. Both thrombotic microangiopathies and collapsing glomerulopathies have been reported concomitantly with parvovirus B19 infection but the causal link remains unclear. Other complications are seldomly reported, including hepatitis, encephalitis, and myocarditis. Diagnosis is based on pre and post-transplant serological status. In addition, the management of parvovirus B19 infection in immunocompromised patients requires quantitative assessment of blood viral load by PCR. The treatment relies primarily on reduction of immunosuppression combined with intravenous immunoglobulin infusions. Relapses occur in 30% of cases.

Post-transplant infections: An ounce of prevention

Infections are the leading cause of hospitalization in transplant recipients. The increased risk of new onset diabetes after transplantation, cardiovascular disease, post-transplant lymphoproliferative disorders adversely affects allograft outcomes. Risk is determined by epidemiologic exposure, immunosuppressive therapy and prophylaxis. The predictable sequence of appearance of infections helps in making management decisions. High likelihood of infections with unusual and multiple organisms necessitates aggressive use of imaging techniques and invasive procedures. Serologic tests depend upon antibody response and are unreliable. Nucleic acid based assays are sensitive, rapid, and allow detection of subclinical infection and assessment of response to therapy. Preventive steps include screening of donors and recipients and vaccination. All indicated vaccines should be administered before transplantation. Inactivated vaccines can be administered after transplantation but produce weak and transient antibody response. Boosters may be required once antibody titers wane. Post-transplant chemoprophylaxis includes cotrimoxazole for preventing urinary tract infections, pneumocystis and Nocardia infections; ganciclovir, valganciclovir, or acyclovir for cytomegalovirus related complications in at-risk recipients; and lamivudine for prevention of progressive liver disease in HBsAg positive recipients. Viral load monitoring and pre-emptive treatment is used for BK virus infection. Infection with new organisms has recently been reported, mostly due to inadvertent transmission via the donor organ.

Update and review: state-of-the-art management of cytomegalovirus infection and disease following thoracic organ transplantation

PURPOSE

Cytomegalovirus (CMV) is among the most important viral pathogens affecting solid organ recipients. The direct effects of CMV (eg, infection and its sequela; tissue invasive disease) are responsible for significant morbidity and mortality. In addition, CMV is associated with numerous indirect effects, including immunomodulatory effects, acute and chronic rejection, and opportunistic infections. Due to the potentially devastating effects of CMV, transplant surgeons and physicians have been challenged to fully understand this infectious complication and find the best ways to prevent and treat it to ensure optimal patient outcomes.

SUMMARY

Lung, heart, and heart-lung recipients are at considerably high risk of CMV infection. Both direct and indirect effects of CMV in these populations have potentially lethal consequences. The use of available treatment options depend on the level of risk of each patient population for CMV infection and disease. Those at the highest risk are CMV negative recipients of CMV positive organs (D+/R-), followed by D+/R+, and D-/R+. More than 1 guideline exists delineating prevention and treatment options for CMV, and new guidelines are being developed. It is hoped that new treatment algorithms will provide further guidance to the transplantation community. The first part describes the overall effects of CMV, both direct and indirect; risk factors for CMV infection and disease; methods of diagnosis; and currently available therapies for prevention and treatment. Part 2 similarly addresses antiviral-resistant CMV, summarizing incidence, risk factors, methods of diagnosis, and treatment options. Parts 3 and 4 present cases to illustrate issues surrounding CMV in heart and lung transplantation, respectively. Part 3 discusses the possible mechanisms by which CMV can cause damage to the coronary allograft and potential techniques of avoiding such damage, with emphasis on fostering strong CMV-specific immunity. Part 4 highlights the increased incidence of CMV infection and disease among lung transplant recipients and its detrimental effect on survival. The possible benefits of extended-duration anti-CMV prophylaxis are explored, as are those of combination prophylaxis with valganciclovir and CMVIG.

CONCLUSION

Through improved utilization of information regarding optimized antiviral therapy for heart and lung transplant recipients to prevent and treat CMV infection and disease and through increased understanding of clinical strategies to assess, treat, and monitor patients at high risk for CMV recurrence and resistance, the health care team will be able to provide the coordinated effort needed to improve patient outcomes.

Cytomegalovirus serostatus pairing and deceased donor kidney transplant outcomes in adult recipients with antiviral prophylaxis

BACKGROUND

The objectives of this study are to investigate the impact of cytomegalovirus (CMV) donor (D)/recipient (R) serostatus on kidney transplant outcomes in recipients who received CMV prophylaxis and to investigate the association of individual antiviral agents (acyclovir, ganciclovir, and valganciclovir) with outcomes in high-risk recipients (D+/R-).

METHODS

By using the Organ Procurement and Transplant Network/United Network for Organ Sharing database, 25,058 deceased donor kidney recipients (≥ 18 years, 2004-2008) who received CMV prophylaxis were stratified into four groups: D+/R+ (11,875), D-/R+ (6046), D+/R- (4555), and D-/R- (2582). The impact of CMV D/R serostatus on acute rejection (6 months and 1 year posttransplant) and long-term outcomes of death-censored graft failure and mortality were compared. The impact of the individual antiviral agent on long-term outcome was further evaluated in the high-risk group (D+/R-).

RESULTS

In multivariate analysis, CMV D/R status was not associated with acute rejection. Compared with D-/R-, D+/R- was associated with an increased risk for death-censored graft failure (hazard ratio=1.28, P=0.01), all-cause mortality(hazard ratio=1.36, P=0.003), and mortality because of viral infection (hazard ratio=8.36, P=0.04). In the D+/R- group, valganciclovir usage was associated with a decreased risk for death-censored graft failure (hazard ratio=0.65, P=0.007) and mortality because of viral infection (hazard ratio=0.22, P=0.03) compared with ganciclovir usage.

CONCLUSIONS

CMV mismatch (D+/R-) was no longer a risk factor for acute rejection in kidney recipients who received antiviral prophylaxis but was still an independent risk factor for death-censored graft failure, all-cause mortality, and viral infection-related mortality.

Cytomegalovirus risk factors in renal transplantation with modern immunosuppression

BACKGROUND

Immunosuppressive regimens have lowered the rate of kidney rejection, but with increasing immunodeficiency-related complications. New cytomegalovirus (CMV) prophylaxis also has become available. The impact of these 2 developments on CMV diseases has not been well evaluated. We conducted a randomized trial comparing a drug regimen common in the 1980s, cyclosporin A (CsA) with azathioprine (Aza), with a drug combination used most today, tacrolimus (Tac) with mycophenolate mofetil (MMF), and we analyzed CMV risk factors in kidney transplant patients.

METHODS

The 300 patients included in the trial underwent the same universal prophylaxis and preemptive therapy. CMV events and risk factors were prospectively recorded.

RESULTS

With preventive and preemptive strategies combined for 3 months, CMV replication was detected in 32.6% and CMV disease in 18.1% of patients. Multivariate analysis on risk factors for CMV disease were CMV donor (D)/recipient (R) matching and first month renal function (risk ratio [95% confidence interval]: 1.02 [1.01; 1.04]; P=0.011), but not the immunosuppressive regimen (P=0.35). The D+/R- combination increased the risk of CMV disease by a factor of 9 (P<0.0001) when compared with D-/R- status, and a factor of 3.5 (P<0.0001) when compared with all CMV-positive recipients. Despite the 50% rate of CMV disease in the D+/R- group, no asymptomatic CMV replication was detected with the preemptive strategy.

CONCLUSIONS

With modern immunosuppression, a sequential quadritherapy with Tac/MMF, and a 3-month CMV prevention strategy, the risk for CMV disease remains close to that with CsA/Aza. A CMV-negative recipient transplanted from a CMV-positive donor (D+/R-) remains a major risk factor, calling for better CMV prophylaxis or matching in negative recipients. Preemptive strategy thus appeared inefficient for this high-risk group. Transplant recipients with altered renal function should also be considered at risk.

Impact of prophylactic versus preemptive valganciclovir on long-term renal allograft outcomes

BACKGROUND

Both prophylactic and preemptive oral valganciclovir therapy are effective for the management of cytomegalovirus (CMV) postrenal transplantation in the short term. The long-term effect of either strategy is less well defined.

METHODS

We analyzed the data on 115 adult recipients previously enrolled in a prospective randomized controlled trial of prophylaxis versus preemptive therapy for CMV. The primary outcome was a composite of freedom from acute rejection, graft loss, or death. Secondary outcomes included individual primary outcomes, posttransplant cardiovascular events, new-onset diabetes mellitus after transplantation, achievement of goal blood pressure, change in body mass index, interstitial fibrosis/tubular atrophy, and change in renal function. The analysis period was a minimum of 48-month posttransplant or a date of death or graft loss, whichever was earlier.

RESULTS

The primary outcome was similar between groups (83% prophylactic vs. 81% preemptive, P=0.754). The secondary outcomes showed similarities between the prophylactic and preemptive groups. Four patients in the prophylactic group (8%) compared with none in the preemptive group (0%) died with a functioning graft, P=0.043.

CONCLUSIONS

Within the limitations of sample size, our data suggest that either strategy for the management of CMV immediately after transplantation seems effective for patient and graft survival in the long term. CMV management is one of the many therapeutic strategies incorporated into a renal transplantation protocol, which often differs among institutions, and the decision as to which approach to use remains center- and resource-specific. The increased incidence of death in the prophylactic group requires further investigation.

Hemorrhagic cystitis secondary to adenovirus or herpes simplex virus infection following renal transplantation: four case reports

Viral infections are common complications following renal transplantation. However, there have been few reported cases of viral cystitis secondary to herpes simplex virus or adenovirus infection. Herein, we have reported four cases of hemorrhagic cystitis secondary to infections with herpes simplex virus and adenovirus following renal transplantation. The etiology was adenovirus in three cases and herpes simplex virus in the remaining case. In all four cases, the primary cause of the renal dysfunction was diabetic nephropathy. All four patients presented with a clinical profile characterized by dysuria, pollakiuria, macroscopic hematuria, and graft dysfunction. Three of the four patients developed these symptoms within the first 3 months after renal transplantation. In all four cases, there was an increase, albeit slight, in creatinine levels, which returned to normal or near-normal values upon resolution of the symptoms. Acute cellular rejection was observed in only one case. Although rare, hemorrhagic cystitis secondary to infection, which typically occurs early in the posttransplant period, causes pronounced symptoms. The infection appears to be self-limiting, resolving completely within 4 weeks.

Defining the risks for cytomegalovirus infection and disease after solid organ transplantation

Cytomegalovirus continues to be one of the most clinically significant infections after solid organ transplantation. Classic definitions of patients at high risk for infection and tissue-invasive disease are focused on recipient-donor serostatus, type of organ transplanted, and overall level of immunosuppression. However, recent trends in clinical practice call for a reevaluation of cytomegalovirus infection risks after solid organ transplantation. Indeed, whereas early-onset cytomegalovirus infection is usually controlled by antiviral prophylaxis with ganciclovir and derivatives, delayed- and late-onset cytomegalovirus infection can develop after the completion of a course of preventive therapy. In addition, indirect effects of cytomegalovirus infection may occur as a result of persistent low-level viremia. Suboptimal dosing of antiviral drugs due to specific drug toxicities may result in the development of ganciclovir-resistant cytomegalovirus disease. The relationship between organ allograft rejection and cytomegalovirus infection and disease has been recognized for some time. Transplantation of increasing numbers of extended-criteria donor organs increases the risk of delayed graft function and acute rejection, prompting the use of more intensive immunosuppression. In addition, the trend to spare long-term exposure to calcineurin inhibitors has contributed to a resurgence in the use of polyclonal T-cell induction immunosuppressive agents, which may reduce host anticytomegalovirus immunity. We discuss the current trends in solid organ transplantation that provide a foundation for defining risks for cytomegalovirus infection and disease, including identification of patients who would benefit from more aggressive cytomegalovirus monitoring and prevention strategies.

Incidence and predictive factors for cytomegalovirus infection in renal transplant recipients

BACKGROUND

Cytomegalovirus (CMV) infection is a common cause of morbidity, graft loss, and mortality among kidney recipients due to its direct and indirect influences on organs and systems, namely, immunomodulation, which favors the appearance of opportunistic infections, vasculopathy, and decreased graft and patient survival. In Mexico the dimensions of this infection are unknown in kidney transplant recipients. We evaluated the incidence and predictive factors for CMV infection among renal transplant recipients of the Mexican Institute of Social Security in Guadalajara.

METHODS

This prospective cohort analysis of patients >or=16 years of age of both genders, included transplantations from May 2006 to July 2007. Two hundred twenty-five patients were followed over 6 months to evaluate CMV infection or disease. We evaluated demographic, clinical, and paraclinical aspects, such as total lymphocyte count and quantitative CMV polymerase chain reactions (PCR).

RESULTS

The overall incidence of CMV infection was 17.8%. CMV infections were associated with lymphopenia (relative risk [RR] 14.75; confidence interval [CI] 95%, 3.46-62.77), serostatus D+/R- (RR 5.53; CI 95%, 2.18-14.05), and fever (RR 4.57; CI 95%, 1.50-13.95). Receiver-operating characteristic (ROC) curves for lymphopenia versus PCR showed a sensitivity of 27% and a specificity of 98%.

CONCLUSION

In our study, lymphopenia, serostatus D+/R-, and fever were good predictors of CMV infections among renal transplant recipients.

BK Polyomavirus in Renal Transplants: Role of Electron Microscopy and Immunostaining in Detecting Early Infection

Reactivation of BK polyomavirus (BKV) is increasingly recognized as a cause of failure of renal allografts. Since no specific treatment is available for this infection, early diagnosis is important, as it allows for early intervention and possible recovery of renal function. Forty-four consecutive renal transplant biopsies performed over a 2-year period were included in the study. In addition to evaluation of renal biopsy tissue sections using routine histochemical stains, CD3, CD20, BK virus immunostains using the specific BK virus and the SV40 antibodies and electron microscopy studies were performed. None of the transplant cases but one exhibited classical histologic viral changes. Viral particles were seen by EM in 19%, and BK-virus positivity was identified in only 43% of these cases. CD20-rich inflammatory infiltrates predominated in cases in which either positive BK stain and/or viral particles were identified ultrastructurally. A combined approach using electron microscopic and immunohistochemical evaluation can be utilized effectively to identify BK virus-associated nephropathy at an early phase facilitating early clinical intervention.

Avoiding pitfalls: what an endoscopist should know in liver transplantation--part II

Over the last decade the number of patients undergoing transplantation has increased. At the same time, effective peri- and postoperative care and better surgical techniques have resulted in greater numbers of recipients achieving long-term survival. Identification and effective management in the form of adequate treatment is essential, since any delay in diagnosis or treatment may result in graft loss or serious threat to patient's life. Various aspects of endoscopic findings that can be commonly encountered among liver transplant recipients are discussed herein. Topics include: persistent and/or recurrent esophageal varices, reflux, Candida or cytomegalovirus (CMV) esophagitis, esophageal neoplasms, posttransplant peptic ulcer, biliary complications, posttransplant lymphoproliferative disorder (PTLD), Kaposi's sarcoma, CMV colitis and inflammatory bowel disease, colonic neoplasms, Clostridium difficile infection, and graft versus host disease (GVHD).

Decreased antibody response to influenza vaccination in kidney transplant recipients: a prospective cohort study

BACKGROUND

Antibody response to the inactivated influenza vaccine is not well described in kidney transplant recipients administered newer, but commonly used, immunosuppression medications. We hypothesized that kidney transplant recipient participants administered tacrolimus-based regimens would have decreased antibody response compared with healthy controls.

STUDY DESIGN

Prospective cohort study of 53 kidney transplant recipients and 106 healthy control participants during the 2006-2007 influenza season. All participants received standard inactivated influenza vaccine.

SETTING & PARTICIPANTS

Kidney transplant recipients administered tacrolimus-based regimens at a single academic medical center and healthy controls.

PREDICTOR

Presence of kidney transplant.

OUTCOMES

Proportion of participants achieving seroresponse (4-fold increase in antibody titer) and seroprotection (antibody titer > or = 1:32) 1 month after vaccination.

MEASUREMENTS

Antibody titers before and 1 month after vaccination by means of hemagglutinin inhibition assays for influenza types A/H1N1, A/H3N2, and B.

RESULTS

A smaller proportion of the transplantation group compared with the healthy control group developed the primary outcomes of seroresponse or seroprotection for all 3 influenza types at 1 month after vaccination. The response to influenza type A/H3N2 was statistically different; the transplantation group had 69% decreased odds of developing seroresponse (95% confidence interval, 0.16 to 0.62; P = 0.001) and 78% decreased odds of developing seroprotection (95% confidence interval, 0.09 to 0.53; P = 0.001) compared with healthy controls. When participants less than 6 months from the time of transplantation were considered, this group had a significantly decreased response to the vaccine compared with healthy controls.

LIMITATIONS

Decreased sample size, potential for confounders, outcome measure used is the standard but does not give information about vaccine efficacy.

CONCLUSIONS

Kidney transplant recipients, especially within 6 months of transplantation, had diminished antibody response to the 2006-2007 inactivated influenza vaccine.

Case of adult mumps infection after renal transplantation

Viruses are the most common cause of opportunistic infections, important complications of transplantation. Mumps infection in renal transplant recipients is uncommon. This report focused on a 23-year-old woman who received immunosuppressive therapy based on tacrolimus, prednisolone, and mycophenolate mofetil for renal transplantation. Sixteen months after transplantation, she was admitted with pain and swelling in both infra-auricular areas. Laboratory findings demonstrated positive mumps IgM and IgG antibodies and an increased serum amylase level. Computed tomography revealed both parotid glands to be diffusely enlarged. After the diagnosis of mumps parotitis, the patient's immunosuppression was reduced and the clinical course was satisfactory.

Viral infection after renal transplantation: surveillance and management

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. 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 post transplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. This review will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Outcome of management strategies for BK virus replication in pediatric renal transplant recipients

Management of BKV infection is not well defined. Eighteen pediatric renal transplant patients with BKV-PCR (+) were divided into three groups; Group 1: Viruria only (6), Group 2: Viremia with stable GFR (4), Group 3: Viremia with >25% decline in GFR and BKVAN on biopsy (8). With initial BKV-PCR(+), Group 1 received no treatment; Group 2 had MMF reduced 30%; Group 3: 6/8 had CNI discontinuation, 2/8 had reduced MMF and cidofovir. BKV, GFR and histology were compared pre- and post-treatment. In Group 1 viruria decreased in all patients; GFR remained stable. Group 2 showed reduced viremia with no GFR change. Group 3 showed reduced viremia in 8/8 patients. Patients with >50% decline in GFR from baseline (6/8) showed worse histology: 2/6 lost grafts despite no BKV on follow-up biopsy. Our results show that with viruria alone no treatment is necessary; with viremia and stable GFR, reduced immunosuppression decreases viremia and maintains GFR. With viremia and reduced GFR, immunosuppression reduction with or without cidofovir decreases viremia and stabilizes GFR in most patients. Greater than 50% reduction in GFR at BKVAN diagnosis correlates with risk for graft loss. Serial monitoring of BKV viremia with early intervention may prevent BKVAN graft loss in children.

Review of nonimmunological causes for deteriorated graft function and graft loss after transplantation

Various factors determine the graft- and patient survival after transplantation. HLA-matching and immunological factors are of importance for the short- and long-term survival. Apart from these obvious determinants, nonimmunological factors play an important role in defining the baseline organ quality as well as the recipients' status. The influence of these parameters on graft- and patient survival is still underestimated and is a topic of debate. On account of the increasing acceptance of marginal-donor organs these events are of increasing importance for graft survival and long-term function. We review nonimmunological causes for deteriorated graft function and graft loss after solid organ transplantation.

[Effects of viral infection on transplant recipients]

Viral infection remains an important cause of morbidity and mortality in transplant recipients. The risk of viral infection in these patients depends on several factors, such as the type of organ transplanted, the intensity of immunosuppression, and the recipient's susceptibility. In additional to direct effects, viral infection cause indirect effects, including greater risk of replication of other viruses, graft rejection, opportunistic infections and other specific entities for each type of transplant. These indirect effects result from the immunomodulatory activity of some viruses, such as cytomegalovirus and human herpes virus-6. For the most part, quantitative molecular tests have replaced serologic testing and in vitro culture for diagnosing infection. This approach is particularly prominent for cytomegalovirus, Epstein-Barr virus, hepatitis B virus, and hepatitis C virus. Despite these diagnostic advances, the development of specific antiviral agents and effective antiviral vaccines is limited. Thus, prophylactic strategies are still essential in transplant recipients.

Decreased Serum Retinol Is Associated with Increased Mortality in Renal Transplant Recipients

Background: Vitamin A plays a central role in epithelial integrity and immune function. Given the risk of infection after transplantation, adequate vitamin A concentrations may be important in patients with a transplant. We assessed whether there was an association between retinol concentration and all-cause mortality in renal transplant recipients.

Methods: We recruited 379 asymptomatic renal transplant recipients between June 2000 and December 2002. We measured serum retinol at baseline and collected prospective follow-up data at a median of 1739 days.

Results: Retinol was significantly decreased in those renal transplant recipients who had died at follow-up compared with those who were still alive at follow-up. Kaplan–Meier analysis showed that retinol concentration was a significant predictor of mortality. In multivariate Cox regression analysis, decreased retinol concentration remained a statistically significant predictor of all-cause mortality after adjustment for traditional cardiovascular risk factors, high-sensitivity C-reactive protein, and estimated glomerular filtration rate.

Conclusions: Serum retinol concentration is a significant independent predictor of all-cause mortality in renal transplantation patients. Higher retinol concentration might impart a survival advantage via an antiinflammatory or anti-infective mechanism.

Virus-induced cellular immune mechanisms of injury to the kidney

Cellular immune systems play an important role in determining renal outcomes in virus-induced kidney diseases. Highlighted briefly are five different locations along the development of adaptive immune responses to viral infection that may promote injury to the renal parenchyma and the loss of renal function. This may occur because adaptive immune cells directly target infected renal parenchymal cells or because the kidney becomes a bystander organ of adaptive immune cell-mediated injury. Examples from recent studies are provided to illustrate how this may lead to clinically relevant renal disease.

Risk Assessment of Immunosuppressive Therapy in Facial Transplantation

BACKGROUND

Immunosuppression-related risks are foremost among ethical concerns regarding facial transplantation. However, previous risk estimates are inaccurate and misleading, because they are based on data from studies using different immunosuppression regimens, health status of the transplant recipients, tissue composition, and antigenicity. This review provides a comprehensive risk assessment for facial transplantation based on comparable data of immunosuppression, recipient health status, and composition and antigenicity of the transplanted tissue.

METHODS

The risk estimates for face transplantation presented here are based on data reported in clinical kidney (10-year experience) and hand transplantation (5-year experience) studies using tacrolimus/mycophenolate mofetil/corticosteroid therapy. Mitigating factors including ease of rejection diagnosis, rejection reversibility, infection prophylaxis, patient selection, and viral serologic status are taken into account.

RESULTS

Estimated risks include acute rejection (10 to 70 percent incidence), acute rejection reversibility (approximating 100 percent with corticosteroid therapy alone), chronic rejection (<10 percent over 5 years), cytomegalovirus disease (1 to 15 percent), diabetes (5 to 15 percent), hypertension (5 to 10 percent), and renal failure (<5 percent).

CONCLUSIONS

A review of these data indicates that previously reported estimates of immunosuppression-related risks are outdated and therefore should no longer be used. These updated risk estimates should be used by facial transplant teams, institutional review boards, and potential recipients when considering the immunologic risks associated with facial transplantation.

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.

Oral Valgancyclovir Versus Intravenous Gancyclovir for Cytomegalovirus Prophylaxis in Kidney Transplant Recipients

BACKGROUND

Prophylaxis against cytomegalovirus (CMV) is a regular practice in organ transplantation. Oral valgancyclovir appears to be an interesting alternative to the usual intravenous form.

PATIENTS AND METHODS

We prospectively compared the response of intravenous gancyclovir for 2 weeks (GAN; n=41) to oral valgancyclovir for 2 weeks (VAL2w; n=23) or 3 months (VAL3m; n=46) in kidney transplant recipients receiving induction immunosuppression. CMV antigenemia assay and/or polymerase chain reaction (PCR) were used for viral detection. Patients were followed for a minimum of 6 months posttransplantation. SPSS software was used for statistical analysis using a cutoff of significance as P<.05.

RESULTS

There was no statistical difference in the demographic features among the study groups. However, human leukocyte antigen (HLA) match was better in the VAL3m group and the patients of this group received less ATG induction immunosuppression (41.3%) compared with the GAN group (100%). The incidence of acute rejection was not different among the study groups. There was a higher incidence of fever with positive CMV tests in the VAL2w group (P=.035) compared with the other groups, while leukopenia with a negative CMV test was significantly higher in the VAL3m group (P=.04). The incidence of CMV disease was higher in the VAL2w group (30.4%) compared with the GAN group (14.6%) or the VAL3m group (8.7%). Renal function was significantly worse in the VAL2w group at 3 and 6 months (P=.011 and .02, respectively).

CONCLUSIONS

Three months oral valgancyclovir prophylaxis for CMV was a more effective regimen compared with intravenous gancyclovir for 2 weeks. Shorter courses were associated with a higher incidence of CMV infection and poorer graft function. Leukopenia observed in patients receiving valgancyclovir may be a drug-related side effect.

Colitis in a renal transplant patient with human herpesvirus-6 infection

A male patient developed colitis and a thrombotic microangiopathy 3 weeks after renal transplantation. Immunosuppression at the time of presentation was with sirolimus, mycophenolate mofetil, and prednisolone, but without a calcineurin inhibitor. Cytomegalovirus infection was excluded. However, human herpesvirus-6 DNA was detected at high copy number in both blood and colonic epithelium. The patient recovered after reduction in immunosuppression, with nutritional support and ganciclovir therapy.

Polyomavirus-associated nephropathy: update on BK virus-specific immunity

The human polyomavirus type 1, also called BK virus (BKV), causes polyomavirus-associated nephropathy (PVAN) in 1-10% of renal transplant recipients, with graft loss in over 50% of cases. The risk factors for PVAN are not conclusively defined and likely involve complementing determinants of recipient, graft, and virus. A central element seems to be the failing balance between BKV replication and BKV-specific immune control, which can result from intense triple immunosuppression, HLA-mismatches, prior rejection and anti-rejection treatment, or BKV-seropositive donor/seronegative recipient pairs. Consistent with this general hypothesis, the timely reduction of immunosuppression in kidney transplant recipients reduced graft loss to less than 10% of cases. However, the BKV-specific humoral and cellular immune response is not well characterized. Recent work from several groups suggest that changes in antibody titers and BKV-specific CD4+ and CD8+ T cells may help to better define the risk and the course of PVAN in renal transplant patients.

Gastrointestinal infections in immunocompromised hosts

PURPOSE OF REVIEW

Gastrointestinal infections in the immunocompromised host continue to have significant morbidity and mortality throughout the world. They all have similar exposures to viruses, bacteria and parasites and respond to these infections in a similar way. This review will summarize the latest reports on the epidemiology, diagnosis and treatment of known and emerging infections over the last 12 months.

RECENT FINDINGS

Highly active antiretroviral therapy has reduced esophageal opportunistic infections in HIV patients compared to patients who are not taking this therapy. Esophageal candidiasis responds to escalating doses of micafungin as effectively as fluconazole. HIV-infected patients with untreated Mycobacterium avium-complex diarrhea are associated with a wasting syndrome that disrupts the somatostatin axis. Polymerase chain reaction testing has improved diagnosis of microsporidial infections. Cytomegalovirus polymerase chain reaction of tissue may improve the diagnosis of cytomegalovirus disease of the gastrointestinal tract in organ-transplant recipients. The treatment of hypogammaglobulinemia in transplant recipients with recurrent cytomegalovirus gastrointestinal disease may resolve their symptoms. Community viruses are an emerging threat to transplant recipients and may affect drug levels. Lastly, anti-tumor necrosis factor alpha therapy in the treatment of inflammatory conditions may cause Listeria monocytogenes to disseminate.

SUMMARY

Immunocompromised hosts remain at risk for severe gastrointestinal and even disseminated infections. Management includes an early rapid diagnosis with rapid restoration of the immune system and appropriate anti-infective therapy. With the immunocompromised population rapidly increasing, prevention of these infections remains the greatest challenge.