CYTOMEGALOVIRUS INFECTION IN ORGAN-TRANSPLANT RECIPIENTS: DIAGNOSTIC VALUE OF PP65 ANTIGEN TEST, QUALITATIVE POLYMERASE CHAIN REACTION (PCR) AND QUANTITATIVE TAQMAN PCR

Refractory pharyngeal ulceration due to cytomegalovirus in a patient with HIV infection: a case report and literature review

BACKGROUND

Cytomegalovirus (CMV) is an important pathogen among immunocompromised hosts. Typically, CMV in human immunodeficiency virus (HIV) infection causes diseases of the retina, digestive tract, lungs and liver, but there are few cases of CMV infection of the pharynx and larynx.

CASE PRESENTATION

A 57-year-old man with HIV infection was admitted because of pharyngeal pain. Before and after admission, pharyngeal biopsies guided by laryngeal endoscopy were performed four times, but pathological examination showed nonspecific inflammation, and the cause of pharyngeal ulceration was unclear. Additionally, the ulceration deteriorated after initiation of retroviral therapy. Laryngomicrosurgery was conducted under general anesthesia to remove tissue, and pathological diagnosis confirmed CMV infection. Pathological features included enlargement of the cytoplasm and nucleus in infected cells, and intranuclear bodies called owl's eye inclusions. Ganciclovir dramatically improved the symptoms and laryngoscopic findings.

CONCLUSIONS

This case was diagnosed as pharyngitis and pharyngeal ulceration caused by CMV infection, related to immune reconstitution inflammatory syndrome. In previous reports of CMV-induced pharyngeal or laryngeal ulceration in HIV infection, we found six cases similar to our present case. All cases were diagnosed by biopsy. The present case indicates the importance of biopsy for definitive diagnosis. CMV infection should be considered as a differential diagnosis of pharyngeal ulceration in patients with HIV infection.

Results of Real-time Multiplex Polymerase Chain Reaction Assay in Renal Transplant Recipients With Sterile Pyuria

Urinary tract infections are a major cause of morbidity and hospitalization after renal transplantation. Patients treated with immunosuppressive drugs suffer not only from common uropathogens but also from opportunistic infections caused by unusual uropathogens. Sterile pyuria is associated with numerous infectious agents including viruses, fungi, and atypical or fastidious organisms. The objective of this study was to investigate the pathogens using real-time multiplex polymerase chain reaction (rtMPCR) assay in sterile pyuria of renal transplant recipients. In this prospective controlled study, pathogen detection was performed with rtMPCR assay on October 2016 in 60 patients with sterile pyuria who had undergone kidney transplantation. A total of 40 renal transplant patients were determined as the control group. Male-to-female ratio was same. The mean age of the subjects with sterile pyuria was 45.7 ± 12.1 (25-74). The mean duration after transplantation was 28.8 ± 3.97 (3-102) months. Pathogens were detected with rtMPCR in 61.7% of sterile pyuria group. This rate was significantly higher compared with the control group (P < .001). Two or more different pathogens were found in 13 (21.7%) patients in sterile pyuria group. The pathogens found included cytomegalovirus in 10 patients (19%), Gardnerella vaginalis and obligate anaerobes in 20 patients (38%), Ureaplasma spp in 17 patients (33%), Candida spp in 2 patients (4%), Mycoplasma hominis in one patient (2%), herpes simplex virus-2 in one patient (2%), and Trichomonas vaginalis in one patient (2%). Sterile pyuria may indicate the presence of genitourinary pathogens that cannot be detected with conventional urine culture method in renal transplantation patients. rtMPCR is an accurate and convenient method for detection of multiple potential pathogens of sterile pyuria in renal transplant patients.

Cytomegalovirus

Cytomegalovirus (CMV), the largest of the herpesviruses, causes a wide range of clinical syndromes, from asymptomatic infection to severe disease in immunocompromised hosts. Laboratory methods for diagnosis include molecular testing, antigenemia, culture, serology, and histopathology. Treatment of CMV infection and disease is indicated in selected immunocompromised hosts, and preventive approaches are indicated in high-risk groups. This chapter reviews the epidemiology, clinical aspects, and the laboratory diagnosis and management of CMV in immunocompromised hosts.

Risk factors, survival, and impact of prophylaxis length in cytomegalovirus-seropositive lung transplant recipients: A prospective, observational, multicenter study

BACKGROUND

The optimal length of cytomegalovirus (CMV) prophylaxis in lung transplantation according to CMV serostatus is not well established.

METHODS

We have performed a prospective, observational, multicenter study to determine the incidence of CMV infection and disease in 92 CMV-seropositive lung transplant recipients (LTR), their related outcomes and risk factors, and the impact of prophylaxis length.

RESULTS

At 18 months post transplantation, 37 patients (40%) developed CMV infection (23 [25%]) or disease (14 [15.2%]). Overall mortality was higher in patients with CMV disease (64.3% vs 10.2%; P<.001), but only one patient died from CMV disease. In the multivariate analysis, CMV disease was an independent death risk factor (odds ratio [OR] 18.214, 95% confidence interval [CI] 4.120-80.527; P<.001). CMV disease incidence was higher in patients with 90-day prophylaxis than in those with 180-day prophylaxis (31.3% vs 11.8%; P=.049). Prophylaxis length was an independent risk factor for CMV disease (OR 4.974, 95% CI 1.231-20.094; P=.024). Sixteen patients withdrew from prophylaxis because of adverse events.

CONCLUSION

CMV infection and disease in CMV-seropositive LTR remain frequent despite current prophylaxis. CMV disease increases mortality, whereas 180-day prophylaxis reduces the incidence of CMV disease.

Clinical utility of viral load in management of cytomegalovirus infection after solid organ transplantation

The negative impact of cytomegalovirus (CMV) infection on transplant outcomes warrants efforts toward improving its prevention, diagnosis, and treatment. During the last 2 decades, significant breakthroughs in diagnostic virology have facilitated remarkable improvements in CMV disease management. During this period, CMV nucleic acid amplification testing (NAT) evolved to become one of the most commonly performed tests in clinical virology laboratories. NAT provides a means for rapid and sensitive diagnosis of CMV infection in transplant recipients. Viral quantification also introduced several principles of CMV disease management. Specifically, viral load has been utilized (i) for prognostication of CMV disease, (ii) to guide preemptive therapy, (iii) to assess the efficacy of antiviral treatment, (iv) to guide the duration of treatment, and (v) to indicate the risk of clinical relapse or antiviral drug resistance. However, there remain important limitations that require further optimization, including the interassay variability in viral load reporting, which has limited the generation of standardized viral load thresholds for various clinical indications. The recent introduction of an international reference standard should advance the major goal of uniform viral load reporting and interpretation. However, it has also become apparent that other aspects of NAT should be standardized, including sample selection, nucleic acid extraction, amplification, detection, and calibration, among others. This review article synthesizes the vast amount of information on CMV NAT and provides a timely review of the clinical utility of viral load testing in the management of CMV in solid organ transplant recipients. Current limitations are highlighted, and avenues for further research are suggested to optimize the clinical application of NAT in the management of CMV after transplantation.

[Lights and shadows of cytomegalovirus infection in solid organ transplantation]

Cytomegalovirus (CMV) develops in 30-80% of patients undergoing solid organ transplantation (SOT). The incidence and presence of symptomatic disease varies depending on the type of transplant, the presence of associated risk factors, the intensity of immunosuppression, and the prevention strategies used. The impact of CMV on SOT is due not only to the effects of CMV disease per se, but also to its multiple indirect effects resulting from its immunomodulatory role and immunoactivation caused by viral latency. The two prophylactic strategies used (universal prophylaxis and preemptive therapy) are equally useful. Both strategies have advantages and disadvantages, and uncertainties remain on the populations that should receive prophylaxis and for how long. Viral monitoring to detect CMV infection is important for diagnosis, prognosis and evaluation of treatment response. The new real-time polymerase chain reaction techniques have provided numerous advantages but standardization remains an issue and common reference values are required. Specific anti-CMV drugs are available but issues such as the role of valganciclovir versus ganciclovir, the development of resistances and optimal treatment length are still being debated. Complementary therapy with mTOR inhibitors and vaccine strategies against CMV are alternatives for which conclusive data are lacking.

The role of the cytomegalovirus antigenemia assay in the detection and prevention of cytomegalovirus syndrome and disease in solid organ transplant recipients: A review of the British Columbia experience

BACKGROUND

The pp65 cytomegalovirus (CMV) antigenemia assay has been used as a means of guiding the pre-emptive therapy of CMV disease in solid organ transplant (SOT) recipients. Recently, concerns have been raised regarding the utility of the test to accurately and precisely detect viral activity early enough to reduce the morbidity and mortality associated with CMV OBJECTIVE: To determine the performance characteristics of the method of antigenemia testing of SOT recipients used at Vancouver General Hospital, Vancouver, British Columbia.

METHODS

All SOT recipients between January 1, 1999, and June 30, 2000, were retrospectively reviewed for six months following transplantation. Physical examination results, laboratory parameters, antigenemia results and treatment information were reviewed.

RESULTS

A total of 134 kidney, liver, lung and kidney-pancreas transplant recipients were included in the analysis. The overall performance characteristics of the antigenemia assay in predicting CMV disease included a sensitivity of 64%, a specificity of 81%, a positive predictive value of 76% and a negative predictive value of 71%. A mean of 18 days passed between the onset of signs and symptoms of CMV disease/syndrome and the first recorded positive antigenemia result, and only 26% of patients had a positive test result before the onset of symptoms. It was found that an antigenemia test breakpoint of at least one positive cell for defining a positive test provided the most sensitive and specific prediction, with increased odds of developing CMV disease.

CONCLUSIONS

Based on performance characteristics, the Vancouver General Hospital's current method of antigenemia testing to guide pre-emptive ganciclovir therapy in SOT patients is not optimal for the early detection of disease. Further study is needed on new molecular testing methods to determine if our ability to predict CMV disease can be improved.

Monitoring of human cytomegalovirus infection in immunosuppressed patients using real-time PCR on whole blood

BACKGROUND

Quantitative monitoring of human cytomegalovirus (HCMV) is currently used in the follow-up of immunosuppressed patients.

OBJECTIVE

To investigate whether real-time PCR quantification (QPCR) of HCMV DNA could replace pp65 antigenemia.

STUDY DESIGN

We compared HCMV QPCR on whole blood (WB) and on plasma with a pp65-antigenemia assay on 192 samples. Afterwards, we tested 1310 samples from 308 immunosuppressed patients both by antigenemia assay and QPCR on WB.

RESULTS

The first study comparison showed that QPCR results on WB and plasma were significantly correlated with antigenemia. QPCR on WB was more sensitive than QPCR on plasma or antigenemia, detecting 31 and 49 additional positive samples, respectively. During the second comparison, QPCR on WB and antigenemia were again correlated (r=0.70; p<0.0001), but QPCR detected 244 additional positive samples. HCMV DNA was detected earlier than pp65 antigen (median difference: 14 days; range: 7-30). One, 5, 10, 50 and 100 pp65-positive cells/200,000 leukocytes corresponded to 439, 1531, 2623, 9150 and 15,671 HCMV DNA copies/mL of WB, respectively, but this equivalence differed according to the sub-group of patients considered.

CONCLUSION

QPCR on WB is the most sensitive method for the monitoring of HCMV infection in immunosuppressed patients.

The use of consensus guidelines for management of cytomegalovirus infection in renal transplantation

Cytomegalovirus (CMV) infection imposes a significant economic burden on susceptible patients after renal transplantation. Our study was conducted to determine the prediction, probability, consequences, and treatment costs of CMV infection under Canadian consensus guidelines in 270 sequential transplant patients. Transplant patients from donors positive (D(+)) for CMV into recipients negative (R(-)) for CMV received antiviral prophylaxis for 14 weeks and all but donor negative (D(-))/R(-) patients were monitored weekly for the CMVpp65 marker expression. Marker-positive patients and patients with CMV infection or disease received antiviral treatment. Within the first 6 months, 27% of the 270 patients tested had incidences of asymptomatic CMV infection, while 9% had CMV syndrome or disease. Only 1% of patients had infection after 6 months. The CMVpp65 marker levels were significantly greater in patients with syndrome or disease; but post-test probabilities and predictive value of the marker assay were low. Mean direct costs for care were $2256 and ranged from $927 for D(-)/R(-) patients to $7069 in the D(+)/R(-) patients. Extension of antiviral prophylaxis to D(+) or D(+)/R(+) patients significantly increased the estimated mean costs for an absolute reduction to 4% in CMV syndrome or disease. Our studies show that current guidelines for treatment enable effective control of CMV infection; however, alternative strategies have different economic impact.

Real-time PCR assay compared with antigenemia assay for detecting cytomegalovirus infection in kidney transplant recipients

Human cytomegalovirus (CMV) infection is a major cause of morbidity and mortality among kidney transplant recipients. The CMVpp65 antigenemia assay has been used for preemptive therapy. Real-time polymerase chain reaction (PCR) technology for CMV DNA quantification in blood has demonstrated a good correlation with the currently employed CMV antigenemia assay. In this study, 90 renal transplant recipients were prospectively enrolled from July 2004 and May 2005. Monitoring of CMV infection was routinely performed with CMV antigenemia and real-time PCR assays. Real-time plasma PCR and CMV antigenemia assays were assessed on 797 samples. CMV antigenemia correlated with a positive CMV PCR (chi(2) = 78.05; P < .0001). Not only the positive rate but also the number of positive cells correlated with the number of PCR DNA copies (F = 26.07, r(2) = .25, P < .0001). To define an optimal cutoff value of CMV DNA load to initiate treatment in kidney transplant patients, we considered a CMV antigenemia titer of >50 positive cells per 400,000 leukocytes as the gold standard in our previous study. The optimal cutoff value for the quantitative real-time PCR assay was predicted to be 86 copies/microL. Thus, we observed that CMV real-time PCR assay would not completely replace antigenemia assay in kidney transplant recipients, but can be used complementarily to screen antigenemia and monitor preemptive therapy.

Immunohistochemically proven cytomegalovirus end-organ disease in solid organ transplant patients: clinical features and usefulness of conventional diagnostic tests

We studied the main clinical features, outcome, and laboratory parameters in a group of solid organ transplant (SOT) patients with immunohistochemically proven cytomegalovirus (CMV) disease. Confirmed CMV cases were obtained through databases. Demographics, clinical data, transplantation type, immunosuppressive regimens, donor and recipient CMV serostatus, therapy, outcome and laboratory results, pp65 antigenemia, and qualitative polymerase chain reaction (PCR) for CMV were analyzed. From 1995 to 2004, 31 cases with complete medical records were identified. Disease appeared between 24 and 2538 days after transplantation but most cases presented in the first 100 days. Gastrointestinal CMV disease was the most frequent form (71%), while thrombocytopenia was present in 50% of cases, and leukopenia was less common (35.5%). CMV pp65 antigenemia was positive in 58% of patients, but its sensitivity increased to 71% if performed during the first 6 months. A qualitative CMV PCR technique gave similar results during this period (71.4%). Most patients were treated with intravenous ganciclovir (n=25; 80.6%). In 4 cases (19.4%), use of foscarnet alone or a sequential regimen with ganciclovir-foscarnet was deemed necessary. Surgical procedures were necessary in 5 patients (16%). The death rate reached 13%. CMV end-organ disease can be a life-threatening infection in SOT patients. Gastrointestinal disease was the most frequent end-organ disease. CMV antigen detection is best suited for the early period after transplantation.

Diagnostic value of reverse transcription-PCR for detection of cytomegalovirus pp67 in samples from solid-organ transplant recipients

We evaluated a highly sensitive quantitative real-time one-step reverse transcription-PCR (RT-PCR) for detection of human cytomegalovirus pp67 transcripts in monitoring of solid-organ transplant recipients. Results were compared with those of pp65 antigen testing and quantitative DNA-PCR. Due to a low clinical sensitivity, the pp67 RT-PCR was not able to replace these assays.

Preventing post-organ transplantation cytomegalovirus disease with ganciclovir: a meta-analysis comparing prophylactic and preemptive therapies

BACKGROUND

Cytomegalovirus (CMV) causes significant morbidity and mortality in transplant recipients, but there is no consensus regarding the most appropriate prevention method. The goal of this meta-analysis was to compare the efficacy of universal prophylaxis and preemption using ganciclovir.

METHODS

Literature searches for randomized and nonrandomized controlled trials of ganciclovir prophylaxis and preemption were conducted. Because of the lack of head-to-head trials, indirect comparisons of meta-analyses of the prevention strategies were performed. Meta-analyses were conducted using a random effects model to estimate the overall risk ratios for various clinical outcomes. We assessed the event rates for control groups across the trials for comparability.

RESULTS

Literature searches identified 17 universal prophylaxis trials and 9 preemption trials with 1560 and 457 subjects, respectively. Overall event rates for CMV disease in control groups across the studies were similar (approximately 26%). The relative risk of CMV disease in prophylaxis trials was 0.34 (95% confidence interval, 0.24-0.48) when trials of patients with prophylaxis of short duration and trials that only evaluated patients with high-risk serostatus were excluded. The relative risk of CMV disease for study subjects in all preemption trials was 0.30 (95% confidence interval, 0.15-0.60), compared with that for control subjects. There was no statistically significant difference in CMV disease between prevention strategies. Similarly, no differences between strategies were found for all-cause mortality or rejection. There were insufficient data to adequately evaluate graft loss and opportunistic infection.

CONCLUSIONS

On the basis of indirect comparisons of meta-analyses of prevention strategies, universal prophylaxis and preemption are equally effective in reducing the incidence of CMV disease.

Comparison of Quantitative PCR and Antigenemia in Cytomegalovirus Infection in Renal Transplant Recipients

Cytomegalovirus infection is a common complication of renal transplantation. Antigen pp65 levels serve as indicators of viral load, although the technique is difficult to perform and interpret. We sought to determine whether quantitative PCR had a higher sensitivity and predictive value in CMV infection.

METHODS

The study included 100 renal transplant recipients who were screened for IgM and IgG at the time of admission. On days 7, 15, 30, 45, 60, 75, 90, 120, 180, and 360, antigenemia tests were performed on blood (pp65) and urine, and a quantitative PCR on blood. Among 59 patients recruited between November 2003 and August 2004 the mean age was 54.5 +/- 12.9 years. Two patients did not reach 90 days follow-up (3%); four patients have not surpassed 90 days (7%); 22, 120 days (37%); and 31, 180 days (53%). Ninety-three percent of patients showed anti-IgG CMV-positive titers with all being IgM CMV-negative at baseline. The patients at risk for infection were given valgancyclovir as prophylaxis throughout the study.

RESULTS

At 474 visits, 8 samples (2.4%) were positive with urine; 5 (1.4%) with pp65, and 15 (4.7%) with PCR. Among the 15 positive samples, two (>100,000 and 3250 copies) revealed agreement of positive IgM and shellvial test on urine; two (15,100 and 5670 copies), antigen pp65 1+; one (17,400 copies) with pp65 2+ and shellvial urine; two (99,400 and 28,300 copies) with pp65 1+ and shellvial urine; and eight remaining determinations, 749, 2250, 686, 928, 2250, 26600, 777, and 2790 copies. The rest of the tests were negative.

CONCLUSION

The preliminary results of this study demonstrated that quantitative PCR was a useful rapid tool for diagnosing and monitoring CMV infections.

Recomendaciones GESITRA-SEIMC y RESITRA sobre prevención y tratamiento de la infección por citomegalovirus en pacientes trasplantados

Cytomegalovirus (CMV) infection remains an important complication of transplantation. The last decade has been characterized by improvements to management that has reduced its morbidity and mortality. The advance has been particularly important in the diagnosis and prevention. Several techniques have been developed that allow the increasingly rapid and sensitive diagnosis. The different preventive strategies include use of appropriate blood products, immune globulin, and antiviral agents either as prophylaxis or pre-emptive therapy. The development of effective oral drugs as valganciclovir also represents a new advance. It is necessary to summarize these advances to facilitate the development of local policies reflecting recent changes. The Group of Study of Infections in Transplantation (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) has therefore produced actual recommendations in the management of CMV infection after transplantation.

Differences in CMV-specific T-cell levels and long-term susceptibility to CMV infection after kidney, heart and lung transplantation

Patients after kidney, heart and lung transplantation differ in their immunosuppressive drug regimens and in susceptibility to infectious complications with cytomegalovirus (CMV). In this study, CMV-specific T-cell responses were characterized in long-term transplant recipients and associated with the frequency of infectious complications. CMV-reactive CD4 T cells from 50 healthy controls, 68 renal, 14 heart and 24 lung transplant recipients were flow cytometrically quantified by the induction of cytokines after specific stimulation. Moreover, the immunosuppressive effect of calcineurin inhibitors on specific T-cell reactivity was quantified in vitro and compared with responses in vivo. Median CMV-specific T-cell frequencies in long-term renal (1.48%; range 0.06-17.26%) and heart transplant recipients (0.90%; 0.13-12.49%) did not differ from controls (1.82%; 0.26-21.00%). In contrast, CMV-specific T-cell levels were significantly lower in lung transplant recipients (0.50%; <0.05-4.98%) and showed a significant correlation with the frequency of infectious episodes (r =-0.57, p = 0.005). The differences within the groups were associated with increasing dosages of immunosuppressive drugs, as exemplified for calcineurin inhibitors that dose dependently reduced specific T-cell reactivity in vitro. In conclusion, monitoring CMV-specific CD4 T cells may serve as a measure for long-term disease susceptibility and may contribute to an improved management of CMV complications after lung transplantation.

Monitoring for human cytomegalovirus infection in solid organ transplant recipients through antigenemia and glycoprotein N (gN) variants: evidence of correlation and potential prognostic value of gN genotypes

Human cytomegalovirus (HCMV) ORF UL73 encodes the envelope glycoprotein gpUL73-gN, which shows seven genotypes (gN-1, gN-2, gN-3a, gN-3b, gN-4a, gN-4b, gN-4c). The goal of this study was to determine retrospectively the distribution of gN variants in solid organ transplant recipients with HCMV infection and to establish an association with parameters important for monitoring post-transplantation clinical course during a follow-up of up to 2 years. Peripheral blood leukocytes from 40 solid organ transplant recipients were analysed for pp65-antigen by immunofluorescence and gN genotyped by sequencing or RFLP analysis. A correlation between gN genotypes and antigenemia peak was found, showing a highly significant difference between gN-1 and gN-4b variants (P<0.005). In particular, gN-1 seems to be associated with patients developing low level antigenemia (<50 pp65-positive cells/2 x 10(5) PBLs; PPV = 90%), whereas gN-4b predicts significantly higher values (>50 pp65-positive cells/2 x 10(5) PBLs; PPV = 80%). Furthermore, the onset of positive antigenemia is significantly earlier in patients infected with a gN-4b strain, compared with those infected by a gN-1 variant. Reported data further support a role for gN genotypes in HCMV pathogenesis. gN-1 and gN-4b show a significantly different virulence and could serve as early predictors for the progression of HCMV infection in transplant patients.

Cytomegalovirus prophylaxis using oral ganciclovir or valganciclovir in kidney and pancreas–kidney transplantation under antibody preconditioning

We investigated retrospectively the risk factors for cytomegalovirus (CMV) infection under ganciclovir or valganciclovir prophylaxis (oral ganciclovir 1 g tid, valganciclovir 450 mg/d) in our kidney and simultaneous pancreas-kidney (SPK) transplant patients undergoing transplantation between July 1, 2001 and February 28, 2003. Two hundred eleven patients receiving prophylactic oral ganciclovir or valganciclovir were included in the study. All patients were given antibody preconditioning (thymoglobulin 178, alemtuzumab 33). Duration of prophylactic treatment was between 3 and 8 months. Fifteen (7.1%) patients developed a positive CMV antigenemia in the first 6 months after transplantation, and 18 of 176 (10.2%) patients developed a positive CMV antigenemia during the first year. No patient developed tissue invasive CMV disease. At 6 months after transplantation, valganciclovir was slightly more effective than ganciclovir prophylaxis (P=.052). Positive donor CMV serology significantly increased the risk of CMV infection compared to CMV-negative donors (P=.014 and P=.003 at 6 and 12 months, respectively). Duration of CMV prophylaxis for more than 3 months decreased the risk of CMV infection (P=.04 and P=.009 at 6 and 12 months, respectively). Either valganciclovir prophylaxis (450 mg/d) or high-dose oral ganciclovir (1 g tid) is effective in preventing tissue-invasive CMV disease, and results in a low incidence of CMV antigenemia in patients undergoing kidney and SPK transplantation.