Cytomegalovirus infection after organ transplantation: an update with special emphasis on renal transplantation

Predictors of mortality in autoimmune disease patients with concurrent cytomegalovirus infections detected by quantitative real-time PCR

Objective

Cytomegaloviruses (CMV) can have a significant impact on the prognosis of immunocompromised patients. Unlike in the transplantation and AIDS fields, only a few studies on CMV infections have been published in the field of autoimmunity. In this study, we examined the clinical outcomes of CMV infections in patients with autoimmune diseases at a single tertiary medical institution.

Methods

A retrospective study was performed to identify the mortality risk factors associated with CMV infections in patients with autoimmune diseases. We reviewed the medical records of patients with autoimmune diseases who were diagnosed with CMV infections using real-time quantitative polymerase chain reaction between December 2005 and March 2016. Clinical and laboratory parameters as well as treatment outcomes were analyzed.

Results

Seventy-three CMV infected patients were separated into survivors and non-survivors. Non-survivors had significantly higher median CMV-DNA copy numbers than survivors (95,500 vs 6,700 copies/mL, p = 0.005) and demonstrated significantly more frequent incidents of CMV pneumonitis (69.2 vs 36.2%, p = 0.007). After adjusting for multiple confounding covariates, the log CMV-DNA copies/mL (hazard ratio, 1.48; 95% confidence interval, 1.14–1.92; p = 0.003) and the presence of concurrent infections (hazard ratio, 22.00; 95% confidence interval, 2.75–175.97, p = 0.004) were identified as independent mortality risk factors. Furthermore, patients with high CMV copy numbers (> 60,000 copies/mL) had higher in-hospital mortality than those with low CMV copy numbers (p < 0.05).

Conclusions

CMV-DNA copy numbers and concurrent infections are predictors of in-hospital mortality in CMV-infected patients with autoimmune diseases. Therefore, serial measurements of CMV-DNA copy numbers and close observation for signs of other infections are recommended for patients with autoimmune diseases who have concurrent CMV infection.

Determination of human cytomegalovirus pp65 antigenemia among renal transplant patients

Human cytomegalovirus (HCMV) is an important cause of morbidity and mortality in immunosuppressed transplant recipients. Isolation of HCMV from peripheral blood leukocytes (PBLs) is considered a reliable marker of disseminated HCMV infection. HCMV pp65 antigenemia is widely used for monitoring CMV infection and guiding preemptive therapy. The aim of this study was to compare pp65 antigenemia with culture technique for detection of HCMV in PBLs among kidney transplant patients and also to determine the threshold value of significant pp65 antigenemiat. Fifty-one peripheral blood samples from post-renal transplant patients collected during August 2009 to March 2011 were processed for pp65 antigenemia assay. These were also tested for isolation of the virus by inoculation into human corneal fibroblast cells. The results of pp65 antigenemia and culture were compared to determine the clinical significance of pp65 antigenemia. HCMV was isolated in 21 cases. On comparing the pp65 antigenemia results with that of the viral isolation, a mean of 23 cells was determined to yield a positive isolation of HCMV. The values of pp65 antigenemia and isolation results were correlated (paired t-test, P = 0.0029). A pp65 count of 23 and above was considered significant in our clinical settings since we found that these clinical specimens yield positive culture result.

Guillain-Barré Syndrome due to CMV Reactivation after Cardiac Transplantation

A 40-year-old male patient suffered from end-stage heart failure due to ischemic cardiomyopathy and received orthotopic cardiac transplantation in June 2005. The instantaneous postoperative course was uneventful, but, seven months later, he suffered from paralysis in the lower extremities finally resulting in quadriplegia and was admitted to hospital. After laboratory testings the diagnosis of a Guillain-Barré syndrome due to cytomegalovirus reactivation was confirmed.

Long-term results of CMV hyperimmune globulin prophylaxis in 377 heart transplant recipients

BACKGROUND

Cytomegalovirus (CMV) has emerged as the most important pathogen to affect the post-operative course after heart transplantation. We performed a retrospective analysis to evaluate the efficiency of CMV hyperimmune globulin (CMVIG) prophylaxis in preventing CMV disease in aggressively immunosuppressed patients after heart transplantation.

METHODS

We studied 377 heart transplant recipients who received quadruple-immunosuppressive therapy and CMVIG as sole CMV prophylaxis. The study population was categorized into 4 groups according to donor and recipient CMV serology at the time of transplantation (D+/R+, D+/R-, D-/R+, D-/R-) and was monitored for CMV immediate early antigen in peripheral blood cells, in urine sediments, and in throat washings; for the presence of serum CMV immunoglobulin M and CMV immunoglobulin G; and for clinical evidence of CMV-related symptoms. In addition, we compared the incidence of cardiac allograft vasculopathy and infection among the groups.

RESULTS

During the first 5 years after transplantation, CMV disease developed in 79 patients (20.96%). Comparison among the groups showed significantly increased risk for CMV disease in allograft recipients of organs from seropositive donors (D+, 27.31%; D-, 11.33%; p = 0.0003). We observed 6 CMV-associated deaths, all in CMV-antibody-negative recipients. Additionally CMV-positive recipients had a greater incidence of cardiac allograft vasculopathy (p = 0.048), and a greater overall infection rate (p = 0.0034).

CONCLUSIONS

Cytomegalovirus hyperimmune globulin administration prevents CMV disease and infection in aggressively immunosuppressed heart transplant recipients. Because fatal CMV disease in CMV-negative recipients of organs from seropositive donors could not be prevented with CMVIG alone, we recommend the additional use of prophylactic ganciclovir in this CMV-mismatched population.

Detection of human cytomegalovirus DNA by real-time quantitative PCR

A real-time PCR assay was developed to quantify human cytomegalovirus (CMV) DNA. This assay was used to demonstrate a higher CMV DNA load in plasma of bone marrow transplant patients than in that of blood donors. The CMV load was higher in CMV antigen-positive patients than in antigen-negative patients.

Highly altered V beta repertoire of T cells infiltrating long-term rejected kidney allografts

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 +/- 10% of area infiltrate) may thus be instrumental in this phenomenon, which is likely to be dependent on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the V beta chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR V beta usage for the majority of V beta families and also a very high percentage (55%) of V beta families exhibiting common and oligoclonal V beta-C beta rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, V beta 8 and V beta 23 families exhibited common and oligoclonal V beta-J beta rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal V beta 8-J beta 1.4 rearrangement. Quantitative PCR showed that biased V beta transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.

A sensitive method for quantifying cytomegalic endothelial cells in peripheral blood from cytomegalovirus-infected patients

A sensitive method has been developed for the quantification of cytomegalic endothelial cells (CEC) in peripheral blood (PB) of patients with active cytomegalovirus (CMV) infections. The three subsequent key steps of this method are density centrifugation to enrich endothelial cells (EC) in the mononuclear cell (MNC) fraction, EC-specific staining, and fluorescence-activated cell sorting (FACS) of EC onto adhesion slides. The FACS method was compared with the conventional method of cytocentrifugation of the MNC fraction onto slides, followed by EC-specific staining. The main advantage of the additional steps for the isolation and quantification of CEC in PB by FACS is a 10-times-greater sensitivity than by cytocentrifugation of the MNC fraction alone. The recovery percentages of EC from whole blood were comparable for both methods. Recoveries of EC obtained after FACS were 53% +/- 16.5%, (mean +/- standard deviation), and recoveries of EC obtained after cytocentrifugation of the MNC fraction were 43% +/- 4.3%. In patients with active CMV infection, 5 to 72 CEC were detected by FACS, equivalent to 0.8 to 9.0 CEC/ml of blood. With this method for isolation and quantification, the characterization of CEC in PB of patients with CMV-associated clinical symptoms, as well as the quantification of EC in PB of patients with pathophysiological manifestations involving endothelial damage that are different from those caused by CMV infections, can be performed.

Comparative study of cytomegalovirus (CMV) antigenemia assay, polymerase chain reaction, serology, and shell vial assay in the early diagnosis and monitoring of CMV infection after renal transplantation

BACKGROUND

Early diagnosis of cytomegalovirus (CMV) infection, which is an important cause of morbidity and mortality in renal transplant recipients, remains of great importance. This prospective study was performed in kidney transplant recipients to determine the diagnostic value of the CMV antigenemia assay in comparison with polymerase chain reaction (PCR), serology, and shell vial assay.

METHODS

Seventy-five consecutive renal transplant recipients were enrolled in this study and monitored by both antigenemia assay and serology. The initial 34 of the 75 patients were subjected to PCR and shell vial assay.

RESULTS

Antigenemia, PCR, and shell vial assay became positive before the onset of CMV-related symptoms in 31/34 (89%), 13/16 (81%), and 2/16 (13%), respectively. None of the 34 patients who had symptomatic CMV disease showed a significant increase in IgG or IgM before the onset of symptoms. Antigenemia and PCR assays turned positive, 7 and 11 days (median), respectively, before the onset of clinical symptoms. Serology and shell vial assay became positive 21 and 25 days (median), respectively, after the onset of CMV-related clinical symptoms. To examine the clinical value of these assays, "good correlation" was defined based on the correlation between the clinical course and the results of the assays. Good correlation with the antigenemia assay was observed in 33 (96%) out of 34 renal transplant recipients who recovered from their CMV disease after ganciclovir therapy. Only one of 16 (7%) patients showed good correlation by shell vial assay, whereas PCR and serology did not show a good correlation. Consequently, antigenemia was considered the best way to monitor CMV infections after kidney transplantation.

CONCLUSIONS

Only the CMV antigenemia assay can be successfully employed after renal transplantation for the early diagnosis and extensive monitoring of active CMV infection.

Factors influencing the occurrence of active cytomegalovirus (CMV) infections after organ transplantation

In this study, several factors influencing the occurrence of active CMV infection after organ transplantation (Tx) are analysed. For this purpose, 105 heart, kidney and lung transplant recipients who were CMV-positive or had a CMV-positive donor, were closely monitored for active CMV infection by antigenaemia, cultures, CMV serology and lymphocyte proliferation (LP) to CMV. Univariate and multivariate regression analysis were performed. As pretransplant risk factors the HLA-type and numbers of HLA mismatches between recipients and their donors, and the CMV serology of the recipient and donor were analysed. A new finding was that recipients of donors positive for HLA-B7 were especially at risk for developing active CMV infection (P = 0.03) and CMV disease (P = 0.03). This was not due to increased rejection treatment in these patients. Post-transplant risk factors for development of active CMV infection were absence of detectable cellular immunity to CMV (lymphocyte proliferation) after Tx (P < 0.01) and rejection treatment with OKT3 or ATG (P = 0.05). High levels of IgG anti-CMV did not prevent occurrence of active CMV infection or CMV disease in the CMV+ recipients.

Cytomegalovirus-specific antibodies to an immediate early antigen and a late membrane antigen and their possible role in controlling secondary cytomegalovirus infection

In 24 renal transplant recipients who had a secondary cytomegalovirus (CMV) infection, the magnitude and development of CMV-specific antibodies directed against two different antigens were studied in relation to the presence of CMV-immediate early antigen-positive peripheral blood leucocytes (CMV antigenaemia). These antibodies were measured in an antigen-capture ELISA using two monoclonal antibodies: one directed against the major immediate early antigen (IEA) and a second one directed against the CMV-encoded glycoprotein B (gB). A statistically significant inverse relationship between the level of anti-IEA antibodies present at the time of transplantation as well as the magnitude of the increase of these antibodies during CMV infection and the maximum number of IEA-positive cells during infection was shown. In contrast, both anti-gB and anti-total CMV antibodies did not give any correlation with the CMV antigenaemia. This may indicate that the anti-IEA immune response plays a role in defence mechanisms against a CMV infection.

Early detection of active cytomegalovirus (CMV) infection after heart and kidney transplantation by testing for immediate early antigenemia and influence of cellular immunity on the occurrence of CMV infection

To determine the incidence of active cytomegalovirus (CMV) infection after organ transplantation and its relationship with the immune system, 55 renal and 14 cardiac transplant recipients were closely monitored for active CMV infection (expression of CMV immediate early antigen in granulocytes--antigenemia--and positive cultures) and immune parameters. All 19 CMV-seronegative recipients with seronegative donors remained seronegative, showing that no CMV transmission occurred by leukocyte-depleted blood products. Primary CMV infection occurred in 4 of 11 (36%) patients with positive donors and was symptomatic in 1 (9%) patient. Active CMV infection was found in 29 of 39 (74%) seropositive patients and was symptomatic in 3 (8%) patients. CMV antigenemia was always the first indication of active CMV infection (antigenemia, on average, at day 45 +/- 15; immunoglobulin G rise at day 71 +/- 36; and positive cultures at day 70 +/- 17). Cellular immunity, as measured by lymphocyte proliferation (LPT), proved to be of importance in the prevention of active CMV infection, as 14 of 15 patients with negative LPT obtained active CMV infections with antigenemia and positive cultures, whereas 1 of 10 patients with positive LPT did so (P less than 0.0001).