Effects of changing immunosuppressive regimen on the incidence, duration, and viral load of cytomegalovirus infection in renal transplantation: a single center report

Cytomegalovirus disease in African-American kidney transplant patients

BACKGROUND

Cytomegalovirus (CMV) disease is a serious infection after kidney transplantation. The risk factors and the impact of CMV disease in African-American (AA) kidney transplant patients have not been well characterized.

METHODS

We performed a retrospective analysis on 448 AA patients transplanted between 1996 and 2005. A 3-month universal chemoprophylaxis with ganciclovir or valganciclovir was administered to CMV donor-positive/recipient-negative (D+/R-) patients and to those treated with anti-thymocyte globulin for rejection, but not routinely to those with other D/R serostatus.

RESULTS

A total of 31 AA patients (7%) developed clinical CMV disease. Compared with other D/R serostatus groups, the D+/R- group had the highest 3-year cumulative incidence of CMV disease (16.9% vs. 6.3% in D+/R+, 4.9% in D-/R+, and 2.4% in D-/R-). The D+/R- group also had the worst 3-year death-censored allograft survival (75% vs. 92% in D+/R+, 94% in D-/R+, and 96% in D-/R-, log-rank P = 0.01). Multivariate analysis found that D+/R- serostatus (odds ratio [OR] 5.4, 95% confidence interval [CI] 0.6-48.2, P = 0.003) and donor age > 60 years (OR 9.1, 95% CI 1.3-65, P = 0.03) were independent risk factors for CMV disease.

CONCLUSION

The D+/R- group has the highest incidence of CMV disease and the worst 3-year renal allograft survival despite 3-month universal prophylaxis. Prolonged chemoprophylaxis may be needed to prevent the late development of CMV disease and to improve allograft survival in the high-risk group of AA kidney transplant recipients.

Incidence, risk factors, and outcomes associated with cytomegalovirus disease in small bowel transplant recipients

Despite improved prophylaxis, monitoring, and more efficient immunosuppression, CMV infection remains a common opportunistic infection in transplant recipients. We assessed the incidence of CMV disease in pediatric SBT recipients, the timing of CMV disease after transplantation, and its impact on patient outcome. The medical records of 98 SBT recipients were reviewed. We performed descriptive analysis, regression analysis, and Kaplan-Meier curves to determine the time-to-event after transplantation. Fifty-three percent patients were male and 47% female, with a mean age of 38.3 months. Thirty-five percent of patients received prophylactic VGC, 55% GCV, 10% a combination of GCV/VGC, and 99% CMV immunoglobulins. A total of 24.5% recipients were CMV D+/R- (CMV serostatus donor positive/recipient negative). Seven (c. 7%) patients developed CMV disease. CMV disease was associated with 2.5 times (0.52-12.1; p = 0.25) higher rate of CMV mismatch and 11.1 times (1.3-95.9; p = 0.03) higher risk of death. CMV prophylaxis increased time-to-death (p = 0.074). Time-to-CMV disease was shorter in patients with enteritis (p < 0.0001), and CMV disease was associated with shorter time-to-death after transplantation (p = 0.001). CMV disease in SBT recipients was associated with an 11-fold mortality increase and a fourfold faster time-to-death. Time-to-death was significantly shorter with CMV enteritis.

Six-month prophylaxis is cost effective in transplant patients at high risk for cytomegalovirus infection

The risk of late-onset cytomegalovirus (CMV) infection remains a concern in seronegative kidney and/or pancreas transplant recipients of seropositive organs despite the use of antiviral prophylaxis. The optimal duration of prophylaxis is unknown. We studied the cost effectiveness of 6- versus 3-mo prophylaxis with valganciclovir. A total of 222 seronegative recipients of seropositive kidney and/or pancreas transplants received valganciclovir prophylaxis for either 3 or 6 mo during two consecutive time periods. We assessed the incidence of CMV infection and disease 12 mo after completion of prophylaxis and performed cost-effectiveness analyses. The overall incidence of CMV infection and disease was 26.7% and 24.4% in the 3-mo group and 20.9% and 12.1% in the 6-mo group, respectively. Six-month prophylaxis was associated with a statistically significant reduction in risk for CMV disease (HR, 0.35; 95% CI, 0.17 to 0.72), but not infection (HR, 0.65; 95% CI, 0.37 to 1.14). Cost-effectiveness analyses showed that 6-mo prophylaxis combined with a one-time viremia determination at the end of the prophylaxis period incurred an incremental cost of $34,362 and $16,215 per case of infection and disease avoided, respectively, and $8,304 per one quality adjusted life-year gained. Sensitivity analyses supported the cost effectiveness of 6-mo prophylaxis over a wide range of valganciclovir and hospital costs, as well as variation in the incidence of CMV disease. In summary, 6-mo prophylaxis with valganciclovir combined with a one-time determination of viremia is cost effective in reducing CMV infection and disease in seronegative recipients of seropositive kidney and/or pancreas transplants.

Impact of immunosuppressive treatment on endothelial biomarkers after kidney transplantation

Endothelial dysfunction occurs in hemodialysis and kidney-transplanted patients and can be enhanced by immunosuppressive therapy. Circulating endothelial cells (CEC), endothelial microparticles (EMP) and sVCAM-1 provide information on endothelium activation and damage. We compared the impact of two immunosuppressive regimens (CsA/Aza vs. Tac/MMF) on the kinetics of CEC, EMP and sVCAM-1 levels in 52 patients, both before graft and 3, 6, 9 and 12 months after graft, in reference to 50 healthy controls. CEC, EMP and sVCAM-1 levels were significantly decreased 1 year after transplantation (M12) as compared to pretransplant values. At M12, CEC and sVCAM-1 levels were significantly higher than those of controls whereas EMP reached normal values. Nine months postgraft, lower CEC and normalized EMP levels were found in patients receiving cyclosporine microemulsion/ azathioprine (CsA/Aza) when compared to patients treated with tacrolimus/ mycophenolate mofetil (Tac/MMF). Multivariate analysis evidenced positive correlations between CEC and history of cardiovascular diseases and between EMP and cytomegalovirus infection at M12. In conclusion, our combined analysis of endothelial injury markers confirms the favorable impact of renal transplantation on endothelium, and show that CEC levels discriminate treatment-associated endothelial toxicity. These results enlighten the potential of these noninvasive blood biomarkers in indexing vascular injury and optimize therapeutic options.

The role of early colonoscopy in CMV colitis of transplant recipients

Cytomegalovirus (CMV)-associated diseases remain a major problem in transplant recipients. Early diagnosis is critical. Presentation of early CMV colitis can be mild and nonspecific in transplant recipients. Although serology is helpful in the diagnosis, sometimes it is inadequate. Because the endoscopic features of CMV colitis are specific, colonoscopy facilitates the histopathologic examination. We present the clinical properties and advantages of early colonoscopy in transplant recipients with CMV colitis. The study group included seven patients (six men, one woman of mean age, 36.7 years (range, 22 to 64 years) whose mean transplant duration was 12.3 months (range, 1 to 72 months). Six of the seven patients experienced an acute graft rejection treated with high doses of steroids; one patient had a herpes simplex virus infection. All patients were on steroid treatment with a various combinations of immunosuppressive agents, including cyclosporine, mycophenolate mofetil, and tacrolimus. All patients presented with mild diarrhea without any blood or mucous discharge. Four patients had fever exceeding 38 degrees C; two had abdominal pain. Stool examinations revealed normal findings in six patients, while one patient had white blood cells and amoebic cysts. Serum CMV IgM and CMV pp65 antigenemia were negative in five of seven patients and two had positive results. All patients showed typical colonoscopic and histopathologic findings compatible with CMV colitis. Standard ganciclovir treatment was successful in all patients. Early and rapid colonoscopy is beneficial for the early diagnosis and management of CMV colitis in transplant recipients.

Tuberculosis After Conversion From Azathioprine to Mycophenolate Mofetil in a Long-Term Renal Transplant Recipient

We report the third case in the literature of a patient with a long-lasting renal allograft who experienced tuberculosis just after the switch from azathioprine to mycophenolate mofetil. The switch was likely responsible for the reactivation of dormant tuberculosis; prophylactic antituberculous treatment should be considered in cases of such a therapeutic change.

Effects of mycophenolate mofetil on donor-specific antibody formation in renal transplantation

BACKGROUND

Mycophenolate mofetil (MMF) is a routinely used immunosuppressive agent that selectively blocks T- and B-lymphocyte proliferation. The present study was designed to investigate the effects of this drug on human leukocyte(HLA) antibody production in general and donor-specific antibody (DSA) formation in particular in 154 recipients of renal allografts.

PATIENTS AND METHODS

Renal allograft recipients were subdivided into three groups. Group 1 patients (n = 60) had received MMF since transplantation in combination with either cyclosporin A or tacrolimus and steroids. Group 2 patients (n = 29) had received an MMF-free immunosuppressive regimen initially followed by addition of MMF some time later. Group 3 patients (n = 65) had received no MMF. Cyclosporin A or tacrolimus in combination with azathioprine and/or steroids were used for immunosuppression. DSA were demonstrated by enzyme-linked immunosorbent assay (ELISA) for detection of panel-reactive antibodies of HLA class I and II specificity.

RESULTS

The HLA antibodies were found in 16.7%, 27.6% and 30.8% of transplant recipients in groups 1, 2 and 3, respectively. DSA were found in 8.3%, 17.2% and 20.0%, and non-DSA in 10.0%, 20.7% and 24.6%, of patients in groups 1, 2 and 3, respectively.

CONCLUSION

The MMF reduces anti-HLA class I and II antibody production and consequently DSA production in renal allograft recipients. Our data indicate this effect to be more pronounced in patients given MMF immediately after transplantation than in those in whom MMF is introduced some time later. The presence of DSA in the serum of renal allograft recipients is associated with poorer graft function (higher serum creatinine and more rejection episodes).

Clinical outcome of chronic immunosuppression in patients with non-infectious uveitis

AIM

To determine the visual outcome and corticosteroid dose requirement in patients with non-infectious uveitis affecting the posterior segment treated with corticosteroids and additional second-line immunosuppression.

METHOD

A retrospective, non-comparative case series was carried out. Seventy-two patients (141 eyes) with uncontrolled non-infectious uveitis on systemic prednisolone were treated with at least one second-line immunosuppressive agent in addition to systemic prednisolone and followed for at least 3 months. Visual acuity (VA), clinical disease activity, corticosteroid-sparing effect, disease relapses requiring corticosteroid dose increase,and side-effects from second-line agents were evaluated.

RESULTS

At the end of the follow-up period (mean: 55.5 months),70 eyes (49.6%) had VA of 6/9 or better. There was a reduction in the mean maintenance dose of prednisolone required before the introduction of the second-line agent (19 mg/day +/- 2 SE)when compared to the mean maintenance dose of prednisolone at the end of the data collection (9 mg/day +/- 1 SE; P <0.001). There was also a significant reduction in the number of disease relapses requiring an increase in prednisolone dose after starting the second-line agents as compared to the year before (P <0.02).

CONCLUSION

In patients with uveitis affecting the posterior segment, the addition of all second-line immunosuppressive therapy was effective in allowing reduction of the dose of systemic prednisolone to 10 mg/day or less, in controlling intraocular inflammation, reducing the number of relapses and in maintaining vision. Because of their side-effects, immunosuppressive treatment should be individualized and monitored closely but its addition is beneficial in the short and longer term.

Optimization of an elispot assay to detect cytomegalovirus-specific CD8+ T lymphocytes

Various arguments suggest that CD8+ T lymphocytes play a major role in the control of cytomegalovirus (CMV) infection. The detection of CMV-specific CD8+ T cells may therefore provide additional information about CMV virus detection to predict the risk of development of CMV disease, especially in immunodepressed transplant recipients. We compared and tested various experimental conditions to optimize an enzyme-linked immunospot assay (Elispot) assay for the detection of CMV-specific CD8+ T lymphocytes. The indirect Elispot assay with one six-day in vitro sensitization step was found to be the most sensitive method to detect CMV-specific CD8+ T cells compared to direct Elispot with unfractionated peripheral blood mononuclear cells or purified CD8+ T cells. We showed that low doses of interleukin-2 during the in vitro culture enhanced the sensitivity of this test, and tetramer staining was performed to verify the high efficiency of this in vitro stimulation step. We directly loaded the specific CMV peptide during the Elispot assay and demonstrated that the use of T2 cells did not improve its sensitivity. Elispot for the detection of interferon-gamma appears to be more sensitive and reliable than measurement of tumor necrosis factor alpha or granzyme B. This technique was successfully applied to detect CMV-specific CD8+ T cells in human leukocyte antigen A2 (HLA-A2) and HLA-B7 healthy patients and in one lymphopenic post-transplant patient with positive CMV serology. This highly sensitive test may be a useful tool to assess T-cell immunity directed against CMV in immunodepressed patients.

Prospective evaluation of the clinical utility of different methods for the detection of human cytomegalovirus disease after liver transplantation

Standardized human cytomegalovirus (HCMV) assays were prospectively evaluated to predict HCMV disease. In 135 consecutive adult liver transplantations, pp65-antigenemia, quantitative HCMV-DNA and qualitative pp67-messenger-RNA were determined weekly. No ganciclovir prophylaxis or preemptive treatment was used. One hundred and ten (81.5%) patients showed no HCMV-infection, 25 patients were positive in at least one of the HCMV-tests (18.5%). Four suffered from HCMV viral syndrome (3.0%) and another four from tissue invasive disease. In total, pp65-antigenemia was detected in 18, HCMV-DNA in 22 and pp67-mRNA in 18 patients. The sensitivity and negative predictive value (NPV) for HCMV-disease was 100% for all tests. The PPV for symptomatic HCMV-infection was 47% for pp67 mRNA. In contrast, the PPV of pp65-antigenemia (using a threshold of > 2/200 000 cells) and quantitative PCR (using a cutoff of > 5000 copies/mL) were 80% and 89%, respectively. A cost analysis revealed symptom-triggered or preemptive treatment was less expensive than general ganciclovir prophylaxis, if the incidence of CMV disease was low (<30%). Quantitative human cytomegalovirus (HCMV)-DNA and pp65-antigen assays have a comparable sensitivity and can therefore predict the onset of HCMV symptoms at an early stage. Compared with general prophylaxis, symptom-triggered or preemptive treatment based on one of these assays might reduce the costs and also the danger of ganciclovir resistance.

The willingness of patients to accept an additional mortality risk in order to improve renal graft survival

BACKGROUND

This study was performed to assess renal transplant patient preferences with respect to the acceptance of an additional mortality risk induced by immunosuppressive therapy in order to prevent graft loss in case of acute rejection.

METHODS

The two decision analysis tools standard gamble and time trade-off were used to interview 155 patients with a functioning renal graft, and 11 on dialysis awaiting transplantation.

RESULTS

Defining the best possible outcome as being alive with a functioning graft (utility value = 1), and the worst outcome as dying (utility value = 0), median utility values of 0.68 (0.59 +/- 0.32, mean +/- SD) with standard gamble and of 0.65 (0.57 +/- 0.32) with time trade-off were obtained for the intermediate outcome (i.e., staying alive but returning to dialysis). Thirteen percent of the patients attributed a utility value of 0 to this intermediate outcome (i.e., they would rather die than return to dialysis), and 8% a utility value of 1 (i.e., they would take absolutely no risk from additional antirejection therapy). Individual utility values for returning to dialysis correlated with time on dialysis before transplantation (R= 0.76, P < 0.005), but no relationship was found between utility values and age, sex, religion, previous methods of dialysis, time with a functioning graft, number of transplantations, or time on the transplantation waiting list.

CONCLUSION

The large interindividual variability of utility values precludes a prediction about the acceptance of a new therapeutic regimen by an individual patient. The assessment of the utility enables, however, a more objective judgment of the general acceptance of any possible risk/benefit ratio induced by a new immunosuppressive regimen in our patient population.

Ex vivo lymphocyte proliferative function is severely inhibited in renal transplant patients on mycophenolate mofetil treatment

Mycophenolate mofetil (MMF) is a recently introduced immunosuppressive drug. Its active form is mycophenolic acid (MPA). MPA specifically inhibits de novo purine synthesis, which is vital for T and B lymphocyte proliferation. We measured lymphocyte subset numbers and mitogen induced proliferation in kidney transplant recipients on different combinations of MMF, cyclosporin A (C), azathioprine (A) and prednisolone (P) (C+A n=70; C+A+P n=15; C+MMF n=45; C+MMF+P n=37) and normals (n=73). Patients on MMF had severely reduced phytohaemagglutinin A (PHA) induced proliferation compared to normals (Nml 2766+/-926 CPM/1000 lymphocytes [mean+/-S.D.]; C+MMF 282+/-406; C+MMF+P 195+/-496); non-MMF patients did not differ from normal. Similar inhibition of Poke Weed Mitogen and Staphylococcal enterotoxin B induced proliferation was observed. Cell cycle studies established that MMF patients had a significantly higher proportion of lymphocytes in the G0/G1 phase following PHA stimulation than the non-MMF patients. All transplant groups had significantly lower B cell numbers than the normal controls but no differences in CD4 and CD8 T cell numbers. All but the C+MMF group had significantly lower CD16+NK cell numbers than normal, while only the non-MMF groups had significantly lower CD56+NK cell numbers. The proliferation assay used was an ex vivo diluted whole blood technique. Removal of residual MPA by washing the plasma out prior to mitogen stimulation led to a significant increase in proliferation in six out of seven cases. In summary we have found that MMF treatment has a strikingly inhibitory effect on patient ex vivo lymphocyte mitogenic function.