European perspective on human polyomavirus infection, replication and disease in solid organ transplantation

Human polyomaviruses (HPyVs) are a growing challenge in immunocompromised patients in view of the increasing number of now 12 HPyV species and their diverse disease potential. Currently, histological evidence of disease is available for BKPyV causing nephropathy and haemorrhagic cystitis, JCPyV causing progressive multifocal leukoencephalopathy and occasionally nephropathy, MCPyV causing Merkel cell carcinoma and TSPyV causing trichodysplasia spinulosa, the last two being proliferative skin diseases. Here, the current role of HPyV in solid organ transplantation (SOT) was reviewed and recommendations regarding screening, monitoring and intervention were made. Pre-transplant screening of SOT donor or recipient for serostatus or active replication is currently not recommended for any HPyV. Post-transplant, however, regular clinical search for skin lesions, including those associated with MCPyV or TSPyV, is recommended in all SOT recipients. Also, regular screening for BKPyV replication (e.g. by plasma viral load) is recommended in kidney transplant recipients. For SOT patients with probable or proven HPyV disease, reducing immunosuppression should be considered to permit regaining of immune control. Antivirals would be desirable for treating proven HPyV disease, but are solely considered as adjunct local treatment of trichodysplasia spinulosa, whereas surgical resection and chemotherapy are key in Merkel cell carcinoma. Overall, the quality of the clinical evidence and the strength of most recommendations are presently limited, but are expected to improve in the coming years.

A case of primary JC polyomavirus infection-associated nephropathy

A 15-year-old boy with a posterior urethral valve received a deceased donor kidney transplant (KT) in March 2011. Basiliximab induction followed by tacrolimus-based triple medication was used as immunosuppression. Eleven months after KT, the graft function deteriorated and the biopsy demonstrated interstitial nephritis suggestive of acute rejection. BK polyomavirus (BKPyV) surveillance in urine and plasma was negative. The patient received methylprednisolone pulses and anti-thymocyte globulin. Immunohistochemistry was positive for simian virus 40 (SV40) large T-antigen (LTag) in the biopsies, and quantitative polymerase chain reaction for JC polyomavirus (JCPyV) indicated high viral loads in urine and borderline levels in plasma. Immunosuppression was reduced and follow-up biopsies showed tubular atrophy and interstitial fibrosis. Two years after KT, antibody-mediated rejection resulted in graft loss and return to hemodialysis. Retrospective serologic work-up indicated a primary JCPyV infection with seroconversion first for IgM, followed by IgG, but no indication of BKPyV infection. In the SV40 LTag positive biopsies, JCPyV deoxyribonucleic acid (DNA) with archetype noncoding control region was detected, while BKPyV DNA was undetectable. To the best of our knowledge, this is the first reported case of primary JCPyV infection as the cause of PyV-associated nephropathy in KT.

Diffuse gastrointestinal bleeding and BK polyomavirus replication in a pediatric allogeneic haematopoietic stem cell transplant patient

Patients undergoing haematopoietic stem cell transplantation (HSCT) are at high risk of severe gastrointestinal bleeding caused by infections, graft versus host disease, and disturbances in haemostasis. BK polyomavirus (BKPyV) is known to cause hemorrhagic cystitis, but there is also evidence of BKV shedding in stool and its association with gastrointestinal disease. We report putative association of BKPyV replication with high plasma viral loads in a pediatric HSCT patient developing hemorrhagic cystitis and severe gastrointestinal bleeding necessitating intensive care. The observation was based on chart review and analysis of BKPyV DNA loads in plasma and urine as well as retrospective BKPyV-specific IgM and IgG measurements in weekly samples until three months post-transplant. The gastrointestinal bleeding was observed after a >100-fold increase in the plasma BKPyV loads and the start of hemorrhagic cystitis. The BKPyV-specific antibody response indicated past infection prior to transplantation, but increasing IgG titers were seen following BKPyV replication. The gastrointestinal biopsies were taken at a late stage of the episode and were no longer informative of BK polyomavirus involvement. In conclusion, gastrointestinal complications with bleeding are a significant problem after allogeneic HSCT to which viral infections including BKPyV may contribute.

Current characteristics and outcome of cytomegalovirus infections after kidney transplantation

INTRODUCTION

The clinical course of cytomegalovirus (CMV) infections in the current era is poorly described. We characterized the symptoms and outcome of all CMV infections in a large cohort of kidney transplant recipients. Among 1129 kidney transplant recipients transplanted between 2004 and 2011 in Charité Universitätsmedizin Berlin and Helsinki University Hospital, 297 patients with CMV infection were characterized.

RESULTS

CMV disease occurred in 217/1129 patients (19.2%), and CMV infection in 297/1129 (26.3%). Gastrointestinal symptoms were recorded in 58% and fever in 47% patients with primary CMV disease, compared to 46% and 27% patients with symptomatic CMV reactivation, whereas leukopenia or thrombocytopenia were seen in only 17-28% patients, and malaise in 9-10%. Tissue-invasive CMV gastroenteritis was confirmed in 11% and CMV pneumonia in only 1% of patients with CMV disease. Only 1 patient died because of CMV infection (mortality 0.3%). Virus-related factors or the use of secondary prophylaxis did not predict the risk of recurrence, which occurred in 33% patients.

CONCLUSION

In conclusion, CMV disease remains a common problem after kidney transplantation. Gastrointestinal symptoms were common, especially in patients with primary CMV infection, whereas bone marrow suppression, hepatopathy, or malaise were seen less frequently.

Detection of HHV-6-specific mRNA and antigens in PBMCs of individuals with chromosomally integrated HHV-6 (ciHHV-6)

After inheritance of chromosomally integrated HHV-6 (ciHHV-6), viral DNA is found in every nucleated cell. The prevalence of ciHHV-6 is estimated to be 0.2-5% of humans. There are conflicting data on the potential for replication, possibly leading to clinical implications. We analysed peripheral blood mononuclear cells (PBMCs) from individuals with ciHHV-6 proven by fluorescence in situ hybridization (FISH) for HHV-6-specific mRNA (U94, U42, U22) and antigens by means of reverse transcription PCR and an indirect immunoperoxidase staining. U94 transcripts indicative of latent infection were detected in six (54.5%) out of 11 individuals at least once. Transcripts indicative of lytic infection (i.e. U42 and U22) were detected in four (36.4%) out of 11 individuals at least once. HHV-6 antigen was detected in seven (70%) out of 10 individuals at least once. The presence of viral mRNA and proteins supports virus gene expression from ciHHV-6, which may lead to virus replication. Considering the properties of active HHV-6 infection together with obvious replicative activity in individuals with ciHHV-6, pathophysiological effects leading to clinical consequences of chromosomally integrated viral DNA might be considered.

Primary CMV infections are common in kidney transplant recipients after 6 months valganciclovir prophylaxis

Prolonging cytomegalovirus (CMV) prophylaxis in CMV seronegative recipients of a kidney from CMV seropositive donor (D+/R-) may reduce the incidence of late infections. We analyzed late-onset primary CMV infections after 6 months valganciclovir prophylaxis. Data from all CMV D+/R- kidney transplant recipients between January 2004 and December 2008 at our center were analyzed. Patients with a functioning graft at 6 months after transplantation who received 6 months of valganciclovir prophylaxis 900 mg once daily were included (N = 127). CMV was diagnosed with quantitative PCR. Prophylaxis was completed in 119 patients. Prophylaxis was stopped at 3-5 months due to leukopenia or gastrointestinal side effects in eight patients. Late-onset primary CMV infection developed in 47/127 (37%) patients median 244 days after transplantation (range 150-655) and median 67 days after the cessation of prophylaxis (range 1-475). Four infections were asymptomatic. In others, symptoms included fever (N = 28), gastrointestinal symptoms (nausea, vomiting, diarrhea) (N = 24), respiratory tract symptoms (N = 12), and hepatopathy (N = 6). Median peak viral load was 13500 copies/mL (range 400-2,831,000). Recurrent CMV infection developed in 9/47 (19%) patients. No significant risk factors for CMV infection were identified. Symptomatic primary CMV infections were commonly detected also after prolonged valganciclovir prophylaxis.

Quantitative HHV-6B antigenemia test for the monitoring of transplant patients

Human herpesvirus-6 (HHV-6) infection, mostly caused by variant B, is common after transplantation. Here, we report a new modified method using an HHV-6B glycoprotein IgG antibody, OHV-3, and attempt to quantify the HHV-6 antigenemia after liver transplantation. Twenty-four liver transplant recipients were frequently monitored by the HHV-6 antigenemia test, which detects the HHV-6B virion protein in peripheral blood mononuclear cells (PBMC). HHV-6B antigens were now retrospectively demonstrated using a glycoprotein OHV-3 IgG antibody in the immunoperoxidase staining from the same specimens and quantified as positive cells/10,000 PBMC. The results were confirmed and quantified by DNA hybridization in situ. Altogether, 206 blood specimens were analyzed. During the first six months, HHV-6 antigenemia was detected in 17/24 (71%) recipients by using the HHV-6B virion antibody. In total, 37% (77/206) of specimens were positive with the virion antibody and 39% (78/201) by the OHV-3 antibody. The peak number of OHV-3-positive cells in the PBMC varied from 5 to 750/10,000 (mean 140/10,000). The OHV-3 antibody was useful to quantify the HHV-6B antigenemia. The findings of the HHV-6B quantitative antigenemia using the OHV-3 antibody correlated well with the previous qualitative HHV-6 antigenemia assay, and can be used as an alternative quantitative method in the monitoring of HHV-6 in transplant patients.

Case report: human herpesvirus 6 reactivation associated with colitis in a lung transplant recipient

Whereas human herpesvirus 6 (HHV-6) reactivation is frequent in solid organ transplant recipients, symptomatic disease is rare. A case of colitis associated with HHV-6B reactivation was observed in a lung transplant recipient. This case report suggests that symptomatic HHV-6 infection may occur in the absence of detectable viremia.

Inhibition of Semicarbazide-Sensitive Amine Oxidases Decreases Lymphocyte Infiltration in the Early Phases of Rat Liver Allograft Rejection

Vascular adhesion protein-1 (VAP-1) has been shown to mediate lymphocyte adhesion to endothelia at sites of inflammation in vitro and in vivo. VAP-1 is also an ectoenzyme with semicarbazide-sensitive amine oxidase (SSAO) activity. In this study we investigated whether inhibition of SSAO influences the inflammatory infiltration in acute rat liver allograft rejection. BN recipients of DA liver allografts were treated with 50 mg/kg/d semicarbazide, an inhibitor of SSAO, or similar volumes of saline. 10 rats/group were followed for graft survival, and 10 rats/group were sacrificed on day 7 post-transplantation for histology and T-lymphocyte isolation. The area percentage of portal inflammatory infiltrates in the grafts was assessed from digital photomicrographs. The proportion of CD4-, CD8- and IL2-receptor positive lymphocytes in the graft was quantified with flow cytometry. On day 7, semicarbazide treatment significantly decreased the inflammatory infiltrate area in the grafts. CD4-, CD8- and IL2-receptor positive cells were equally affected. However, animal survival was not affected. Blockade of the enzymatic activity of VAP-1 has a significant effect on lymphocyte infiltration early in acute liver rejection. Later, activation of other adhesion pathways can by-pass the blockade caused by VAP-inhibition.

Cytomegalovirus infection of the liver transplant: virological, histological, immunological, and clinical observations

The most common organ-specific manifestation of cytomegalovirus (CMV) infection after liver transplantation is hepatitis. Here we retrospectively describe the detailed virological, histological, immunological, and clinical findings associated with CMV infection in 229 consecutive adult liver transplantation patients. CMV infection was diagnosed by pp65 antigenemia. From 439 liver biopsies, CMV antigens were demonstrated by immunohistochemistry and CMV DNA by hybridization. The Banff criteria were used for histology. The expression of various adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], endothelial leukocyte adhesion molecule-1 [ELAM-1]), their ligands (leukocyte function antigen-1 [LFA-1], very late antigen-4 [VLA-4], Sialyl-LewisX-molecule [SLeX]), and lymphoid activation markers (major histocompatibility complex [MHC] Class II, interleukin-2-receptor [IL-2R]) was demonstrated by immunohistochemistry. CMV infection of the transplant occurred in 26 patients (11% of all 229 patients and 17% of the 151 patients with liver biopsy). The incidence was higher among seronegative (26%) than in seropositive recipients (9%), but most cases 18/26 (70%) were reactivations. The CMV pp65 antigenemia levels were usually high in primary infections (893+/-1069, range 50-3000 pp65+cells), but varied widely in reactivations (388+/-740, range 3-3000). The histological Banff score was slightly increased (2.3+/-0.9). Microabscesses, lymphocytic infiltration, Kupffer cell reaction, and parenchymal alterations were common but viral inclusions rare. CMV significantly (P<0.05) increased ICAM-1 and VCAM-1 expression and the number of LFA-1, VLA-4, and Class II-positive lymphocytes in the graft. All CMV infections were successfully treated with antivirals. Intragraft CMV infection had no influence on the long-term outcome, but biliary complications were common. In conclusion, CMV infection of the liver transplant occurred both in primary infection and in reactivation, and also in the cases with low pp65 antigenemia levels. Microabscesses and other histological alterations were common but viral inclusions rare. Increased adhesion molecule expression was associated with lymphocyte infiltration. Successfully treated CMV hepatitis had no influence on the long-term clinical outcome.

Cytomegalovirus and Proliferative Signals in the Vascular Wall of CABG Patients

OBJECTIVE

To further elucidate the mechanism by which cytomegalovirus (CMV) may promote atherosclerosis, we studied the expression pattern of cellular inflammatory and proliferative signals in the aortic wall of CMV(+) and CMV(-) patients undergoing coronary artery bypass grafting (CABG).

METHODS

Aortic biopsies and blood samples of 68 CABG patients were investigated for CMV-DNA by PCR and IN SITU hybridisation. Expression of pp65 antigen, adhesion molecules (ICAM-1, VCAM-1, E-selectin), growth factors (PDGF-AA, TGF-beta), and the cellular proliferation factor Ki-67 was studied by immunohistochemistry. Logistic regression was used to test the correlation between the presence of CMV, vascular inflammation, and traditional noninflammatory risk factors for atherosclerosis.

RESULTS

CMV-DNA was detected in the aortic tissue of 52 (76%) patients, and was localised predominantly in vascular smooth muscle cells. In CMV(+) patients, the expression of adhesion molecules and growth factors in the aortic endothelium was increased compared with CMV(-) patients. A positive correlation of elevated CRP, the induction of adhesion molecules and growth factors and CMV(+) was found. Female gender, smoking, and hyperlipidaemia were identified as risk factors for CMV(+).

CONCLUSIONS

CMV-DNA in smooth muscle cells induces local growth factor expression as well as endothelial activation, both of which can promote the progression of atherosclerosis. Since traditional atherogenic risk factors increase the likelihood of aortic CMV manifestation, we suggest that CMV plays a crucial role in mediating the progression of atherosclerosis.

HHV-6-DNAemia Related to CMV-DNAemia After Liver Transplantation

In addition to cytomegalovirus (CMV), activation of other betaherpesviruses, especially human herpesvirus 6 (HHV-6), has been reported in liver transplant patients. The purpose of this study was to investigate the posttransplant HHV-6-DNAemia in relation to CMV-DNAemia in liver transplant patients. Thirty-one adult liver allograft recipients were regularly monitored for CMV and HHV-6 during the first 3 months after transplantation. For the diagnosis of CMV infections, pp65-antigenemia assay and quantitative DNA-PCR were used. HHV-6 was demonstrated by using quantitative DNA-PCR and HHV-6 antigenemia test. Altogether 253 blood specimens of 31 recipients were analyzed. In addition, CMV and HHV-6 specific antigens were demonstrated by immunohistochemistry in liver biopsy specimens in the case of graft dysfunction. Thirteen patients (40%) developed a clinically significant CMV infection, at a mean of 33 days (range 5 to 62 days) after transplantation and were treated with intravenous ganciclovir. The peak viral loads of these symptomatic CMV infections were high (CMV-DNA 34210 +/- 37557 copies/mL plasma). Six additional asymptomatic patients demonstrated significantly lower CMV-DNAemia levels (1020 +/- 1008 copies/mL, P < .05), and were not treated. Concurrently with CMV, HHV-6 DNAemia and antigenemia were detected in 17 of 19 patients, mean 11 days (range 6 to 24 days) after transplantation. HHV-6 appeared prior to CMV in most cases (12 of 17). However, the peak viral loads were low (HHV-6-DNA <1500 copies/mL blood), even in the five patients who demonstrated HHV-6 antigens on liver biopsy. All CMV infections were successfully treated with ganciclovir and the CMV DNAemia/antigenemia subsided. HHV-6 also responded to the antiviral treatment, but more slowly and less clearly. In conclusion, HHV-6 activations were common and usually associated with CMV infection in liver transplant patients. Further investigation of the clinical significance of HHV-6 DNAemia/antigenemia is necessary.

DNA Microarray-Based Gene Expression Profiles of Cytomegalovirus Infection and Acute Rejection in Liver Transplants

An association between cytomegalovirus (CMV) infection and alloresponse has been suggested. CMV increases inflammation and adhesion molecule expression in graft, and induces cytokines and growth factors, linked with transplant vasculopathy and chronic rejection. We have investigated the gene expression of various inflammatory factors in the CMV-associated immune response and compared this with the immune response of acute rejection in liver transplants by using DNA microarray technology. Gene expression was studied at mRNA level in biopsies from liver transplant patients experiencing CMV infection or acute rejection. RNA extracted from liver grafts after reperfusion was used as control material. Among the strongly upregulated genes in the specimens obtained from liver transplants during CMV infection were IFN-gamma, caspases 1 and 3, granzymes A and B, TGF-beta receptors II and III, IL-10 receptor alpha, VCAM-1, TNF receptor, IL-4, TNF-alpha, IL-10, IL-2 receptor beta, IL-1beta, PDGF-receptor beta, vascular adhesion protein-1, TGF-beta2, and ICAM-1. In biopsies with acute liver allograft rejection, the most significantly upregulated genes were MHC class II, IFN-gamma, caspases 1 and 3, IL-2R beta and gamma, granzymes A and B, VLA-4, L-selectin, E-selectin, VCAM-1, and IL-1beta. Upregulated genes common for CMV and alloresponse were granzyme A and B, E-selection, IFN-gamma, VCAM-1, VLA-4, TNF, caspases 1, 3, and 8, and PDGF. Microarray analysis defined different entities in the immune responses of CMV infection and acute rejection. The differences and similarities of the gene expression profiles related to those in CMV infection and rejection may help to understand the intragraft immunologic events.

Quantitative PCR in the diagnosis of CMV infection and in the monitoring of viral load during the antiviral treatment in renal transplant patients

Cytomegalovirus (CMV) infection is a significant problem in transplantation. In this study, a quantitative PCR test was compared with the CMVpp65 antigenemia assay not only in the diagnosis CMV infections but especially in the monitoring of viral loads during ganciclovir treatment of CMV disease in individual renal transplant patients. Altogether 342 blood specimens were obtained from 116 patients. Blood specimens were used for Cobas Amplicor Monitor plasma PCR and for the pp65 assay. Also shell vial culture was performed. The patients with a positive pp65 finding were monitored for CMV weekly during ganciclovir treatment and/or until the antigenemia subsided. CMV was detected in 31/116 (27%) patients, of whom 14 (12%) developed CMV disease and were treated with ganciclovir. CMV was found by shell vial culture in 13/14 cases, but by PCR and pp65 test in all 14 patients. CMV was detected in 156 (45%) samples; by PCR in 121/156 (range 344-103,000 copies/ml) and by pp65 test in 138/156 (range 1-1,000 positive cells/50,000 leukocytes) and by culture in 59/156 (38%) only. The peak viral loads were significantly (P<0.0001) higher in CMV disease than in untreated infections (19,650 vs. 379 copies/ml, and 100 vs. 5pp65 positive cells). In the monitoring of individual patients, the time-related CMV-DNAemia and pp65 antigenemia correlated well during the treatment of CMV disease. In conclusion, Cobas Amplicor Monitor plasma PCR and CMVpp65 antigen assays can be equally used in the diagnosis CMV infection and in the monitoring of viral load during antiviral treatment.

Comparison of two quantitative CMV PCR tests, Cobas Amplicor CMV Monitor and TaqMan assay, and pp65-antigenemia assay in the determination of viral loads from peripheral blood of organ transplant patients

BACKGROUND

Quantitative PCR assays have become the most common methods in the determination of viral load during cytomegalovirus (CMV) infection of transplant patients. However, usually these tests are still quite time-consuming and labor-intensive which diminishes their utility of these tests in routine diagnostic laboratories.

OBJECTIVES

The objective of this study was to develop a quantitative CMV PCR test which is time-saving and easy to perform for the detection and monitoring of CMV infection of transplant patients.

STUDY DESIGN

The quantitative real time CMV PCR assay using TaqMan chemistry and an automated sample preparation system, MagNA Pure LC, was developed. The designed quantitative CMV test was compared to commercial quantitative PCR test, Cobas Amplicor Monitor, in the determination of CMV DNA loads in plasma samples of liver and kidney transplant patients. The results were also correlated with the CMV pp65-antigenemia test. The clinical material of 270 blood specimens of transplant patients were tested using these two PCR methods and pp65-antigenemia test in parallel. Plasma samples were used for PCR assays and leucocytes for the antigenemia test.

RESULTS

The TaqMan assay described was easy to perform, it was rapid (3-4 h) and hands-on time needed for performing the test was short. The detection limit of the assay was 250 copies/ml (cps/ml) plasma and the linear range up to 25,000,000 cps/ml. TaqMan assay was the most sensitive test detecting 92% of the CMV positive findings. Cobas Monitor detected 80% and pp65 test 88% of the positive findings. The correlations between TaqMan and antigenemia assays, and between Cobas Amplicor and antigenemia were statistically significant and high, R = 0.84 (P < 0.0001) and R = 0.80 (P < 0.0001), respectively. Also correlation between two PCR tests was statistically significant (R = 0.64, P < 0.0001). Of the 27 patient studied, 19 demonstrated CMV antigenemia and DNAemia in their blood during the post transplant monitoring. Thirteen of these patients developed a symptomatic CMV infection and were treated with ganciclovir. The peak viral loads of symptomatic patients were statistically higher by all three methods than those of asymptomatic patients.

CONCLUSIONS

The developed real time TaqMan assay was rapid and easily performed and could be the best alternative for the diagnosis of CMV infection and monitoring of liver and kidney transplant patients.

Detection of CMV-DNA in peripheral blood leukocytes of liver transplant patients after ganciclovir treatment

Cytomegalovirus (CMV) infections are common after transplantation, but usually successfully treated with antivirals. In this study, the detection of CMV-DNA in peripheral blood leukocytes was monitored and compared with CMVpp65-antigenemia in liver transplant patients receiving ganciclovir treatment. Twenty adult liver transplant recipients were frequently monitored for CMV up to 6 months after transplantation. CMV infections were diagnosed by pp65-antigenemia and the same specimens were used for CMV-DNA in situ hybridization. Altogether 202 blood specimens were analyzed. During the first 6 months, 14/20 patients developed CMV antigenemia and 11 were treated with ganciclovir. In all patients, CMV-DNA was detected before antigenemia (mean 15 days earlier). All patients responded to ganciclovir and pp65-antigenemia disappeared. However, 8/11 demonstrated persistence of CMV-DNA for up to 6 months. Recurrences appeared in 6/11 patients. In conclusion, detection of CMV-DNA preceded pp65-antigenemia. Persistence of CMV-DNA demonstrates that the virus is not eliminated by ganciclovir and recurrences can be expected.

CMV infection is usually associated with concurrent HHV-6 and HHV-7 antigenemia in liver transplant patients

Human herpesvirus 6 and 7 (HHV-6, HHV-7) have been recently reported in liver transplant patients. HHV-6 may cause fever, neurological disorders and hepatitis. The clinical significance of HHV-7 is less clear. HHV-6 and -7 are closely related to cytomegalovirus (CMV), and interactions between the viruses have also been suggested. In this study, we investigated the post transplant HHV-6 and -7 antigenemia was in relation to symptomatic CMV disease after liver transplantation. Consecutive 34 adult liver allograft recipients transplanted during 1999-2000 were included in the study. CMV infections were diagnosed by the frequent monitoring of pp65-antigenemia and by viral cultures. HHV-6 and -7 were demonstrated, by using immunoperoxidase staining and monoclonal antibodies against the virus specific antigens, in the mononuclear cells from the same blood specimens which were obtained for CMV pp65 monitoring. Altogether 322 blood specimens were analyzed. CMV disease was diagnosed in 12 (35%) patients during the first 3 months (first pp65 positive specimen mean 25 days, range 8-61 days) after transplantation. Concurrent HHV-6 antigenemia was detected in 10/12 (mean 14 days, range 6-22 days) and HHV-7 antigenemia in 9/12 patients (mean 25 days, range 10-89 days) after transplantation. HHV-6 usually appeared slightly before CMV. All CMV infections were successfully treated with ganciclovir and the CMV-antigenemia subsided. HHV-6 and -7 antigenemia also responded to the antiviral treatment, but more slowly than CMV. In conclusion, CMV infection was usually associated with HHV-6 and -7 antigenemia in liver transplant patients. The results support the suggestion that CMV, HHV-6 and -7 may have interactions. The clinical symptoms of CMV infection, may also be linked with HHV-6 or -7.

Comparison of plasma polymerase chain reaction and pp65-antigenemia assay in the quantification of cytomegalovirus in liver and kidney transplant patients

BACKGROUND

Cytomegalovirus (CMV) is a significant problem in transplantation. The antiviral treatment is based on the clinical symptoms and the rapid laboratory diagnosis. Although polymerase chain reaction (PCR) methods have already been widely used, the clinical correlation of the findings is not clear.

OBJECTIVE

The objective of this study was to investigate the usefulness of a quantitative plasma PCR test and compare it with the pp65-antigenemia test in the detection of clinically significant CMV infections in liver and kidney transplant patients.

STUDY DESIGN

The clinical material consisted of 253 consecutive blood samples was tested using a quantitative polymerase chain reaction test, Cobas Amplicor CMV Monitor (Roche) and pp65 antigenemia assay. Plasma was used for PCR and leucocytes were used for the antigenemia test.

RESULTS

CMV was detected in 89 out of 253 blood samples by one or both methods. PCR detected 78 (range 274-165000 copies/ml) and pp65 antigenemia test 79 (range 1-1500 positive cells/50000) of the positive findings. The sensitivity and specificity of PCR test was 86 and 94%, respectively. The PCR detected all clinically significant CMV infections (>10 positive cells in pp65 test) and infections which required antiviral treatment. In addition, the correlation between the two tests was almost linear.

CONCLUSIONS

The quantitative PCR appears to be a suitable alternative to diagnose and monitor CMV infections in transplant patients.

Expression of the cytomegalovirus genome in kidney allografts during active and latent infection

Cytomegalovirus (CMV) infection is suggested to be a risk factor for chronic rejection. Here we investigated whether CMV can persist in renal allografts, and in which structures the viral genome is found during an acute infection and a latent period after an active infection. CMV infection was diagnosed in 72/157 patients by CMV antigenemia tests and by viral cultures. CMV antigens were demonstrated in 38 available biopsies by immunohistochemistry, and CMV genome by DNA hybridization in situ. Standard histology was also performed. CMV antigens were detected in 7/15 biopsies obtained during acute infection, in three with acute rejection, and chronic changes in the other biopsies. CMV genome was located in inflammatory cells, in tubuli and in the capillary endothelium. During a latent period without a positive finding in blood or urine, CMV antigens were still found in 6/31 biopsies. CMV DNA was found in inflammatory cells, tubular and glomerular structures and in the endothelium of the arterioles. During the latent period with persistent CMV in the graft, in most cases (10/12) mild to moderate chronic changes were recorded.

HHV-6 reactivation is often associated with CMV infection in liver transplant patients

Human herpesvirus 6 (HHV-6) infection has been recently reported in liver transplant patients. HHV-6 is closely related to cytomegalo-virus (CMV), and some interaction between the viruses has been suggested. In this study, the post-transplant HHV-6 antigenemia was investigated in relation to symptomatic CMV infections in adult liver transplant patients. CMV infections were diagnosed by the pp65 antigenemia test and by viral cultures. HHV-6 infections were demonstrated by the HHV-6 antigenemia test and by serology. Significant symptomatic CMV infection was diagnosed in 42 of 75 patients during the first 6 months after transplantation. All CMV infections were successfully treated with ganciclovir. Concurrent HHV-6 antigenemia was detected in 21 (50%) of 42 patients with CMV infection. All HHV-6 infections were reactivations. HHV-6 also responded to the antiviral treatment, but with less clear effect. In conclusion, HHV-6 reactivation is often associated with CMV infection in liver transplant patients. The results support the suggestion that CMV and HHV-6 may have interactions.

Induction of class II molecules by cytomegalovirus in rat heart endothelial cells is inhibited by ganciclovir

Cytomegalovirus (CMV) has been demonstrated to induce class II antigen expression in endothelial cells. To study whether ganciclovir (DHPG) has an effect on CMV-induced class II expression, cultured rat heart endothelial cells were infected with rat CMV (RCMV) and treated with different DHPG concentrations. Class II antigens in endothelial cells were detected by a monoclonal antibody and immunoperoxidase technique. Control cells did not express class II antigen, but during RCMV infection 92% of cells were class II-positive. DHPG treatment (1, 10, 100 and 1000 microg/ml) decreased RCMV-induced class II expression from 73% to 59%, 6% and 0%, respectively. As DHPG inhibits CMV DNA polymerase, our present results suggest that DHPG affects RCMV-induced class II expression via the inhibition of RCMV DNA replication.

Good and impaired response to ganciclovir treatment of severe CMV infections in liver transplant recipients

In this study we investigated good and impaired clinical responses to ganciclovir treatment of severe CMV disease in 23 adult liver transplant patients. CMV episodes were diagnosed by direct immunodetection of CMV-specific antigens in blood leukocytes and by viral cultures. The patients were monitored weekly for CMV antigenemia during the antiviral treatment. Sixteen out of 23 patients recovered from CMV episodes with the standard ganciclovir therapy of 2 weeks. Seven patients demonstrated an impaired response to ganciclovir and had to be treated for longer than 2 weeks (29 +/- 9 days). The patients with an impaired response to ganciclovir also demonstrated higher CMV antigenemia levels compared to those with good a response, and all still had antigenemia after 2 weeks' therapy. Thus, most severe CMV infections in liver transplant patients subsided with ganciclovir treatment of 2 weeks, but impaired responses also occurred and patients had to be treated for several weeks with ganciclovir before they recovered from CMV.

Sequential analysis of adhesion molecules and their ligands in rat renal allografts during the development of chronic rejection

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are important in endothelial cell-leukocyte interactions. In this sequential study, the expression of ICAM-1 and VCAM-1 and their ligands LFA-1 and VLA-4 as well as major histocompatibility complex class II antigens (MHC class II), and interleukin-2-receptor (IL-2R) were investigated during the development of chronic renal allograft rejection in a rat model. The time-related expression of adhesion molecules and their ligands in the graft was correlated to the chronic allograft damage index (CADI). In association with an initial short immune activation, there was a significant ICAM-1 and VCAM-1 induction in the vascular endothelium and the tubular epithelium. In the interstitium, there was infiltration of lymphocytes expressing ligand molecules VLA-4 and LFA-1, as well as activation markers MHC class II and IL-2R. Thereafter, the expression declined together with the increase of CADI-values. In end-stage chronic rejection, there was practically no expression of ICAM-1 and VCAM-1. In the interstitium, there were only few ligand-expressing leukocytes. In conclusion, adhesion molecules and their ligands are involved in the induction phase of the process but no longer in the later stages of chronic rejection.

Diagnostic implications of human cytomegalovirus immediate early-1 and pp67 mRNA detection in whole-blood samples from liver transplant patients using nucleic acid sequence-based amplification

Nucleic acid sequence-based amplification (NASBA) was used for detection of the human cytomegalovirus (CMV) immediate early-1 (IE) and the late pp67 mRNA in 353 blood samples collected from 34 liver transplant patients. The diagnostic value of these assays was compared to that of the pp65 antigenemia assay. Overall, 95 and 42% of the antigenemia-positive samples were IE NASBA and pp67 NASBA positive, respectively. Although the results from pp67 NASBA and the antigenemia assay appeared to correspond poorly, a clear correlation was seen between pp67 NASBA-negative results and low numbers of pp65 antigen-positive cells. Twenty patients (59%) were treated with ganciclovir after the diagnosis of symptomatic CMV infection. Before initiation of the antiviral therapy, the antigenemia assay detected the onset of symptomatic infection in all patients, whereas 95 and 60% of these patients were IE NASBA and pp67 NASBA positive, respectively. Although the sensitivity of IE NASBA was very high, the positive predictive value (PPV) of this assay for the onset of a symptomatic infection was only 63%. The PPV of the antigenemia assay as well as pp67 NASBA was considerably higher (80 and 86%, respectively). Thus, the detection of IE mRNA using NASBA appears to be particularly useful as a marker for early initiation of antiviral therapy in patients at high risk for the development of a symptomatic infection. Also, IE NASBA was found to be more sensitive than the antigenemia assay for monitoring CMV infection during antiviral therapy. On the contrary, pp67 NASBA did not appear to have additional diagnostic value compared to the antigenemia assay.

Induction of vascular adhesion protein-1 during liver allograft rejection and concomitant cytomegalovirus infection in rats

Vascular adhesion protein-1 (VAP-1) is an adhesion molecule controlling lymphocyte recirculation through high endothelial venules of the lymph nodes. It has also been shown to be induced and to mediate lymphocyte adhesion at sites of inflammation. We studied the expression of VAP-1 and two other inducible adhesion molecules ICAM-1 and VCAM-1 in our experimental model of rat liver allograft rejection and, in addition, the effect of concomitant rat cytomegalovirus (RCMV) infection on this expression. Expression of VAP-1, ICAM-1, and VCAM-1 was studied in rat liver allografts with or without RCMV infection, isografts, and normal rat liver. Immunoperoxidase technique and monoclonal antibodies including a novel anti-VAP-1 reagent were used. VAP-1 expression was induced by acute rejection in sinusoids, hepatocytes, and also in bile ducts, when compared to the isografts or normal liver, where only blood vessels were consistently positive. Sinusoidal and hepatocyte expression of VAP-1 was prolonged by the presence of RCMV. ICAM-1 and VCAM-1 expression was also induced by acute rejection. However, RCMV increased sinusoidal VCAM-1 expression compared to uninfected grafts. The present experimental study shows that VAP-1 is up-regulated in acute rejection of liver allografts, and that this up-regulation is prolonged by RCMV infection.

Human herpesvirus-6 antigenemia after liver transplantation

BACKGROUND

Human herpesvirus (HHV)-6 has recently been reported in liver transplant patients. It infects and causes dysfunction in hepatic transplants, which provides serious differential diagnostic problems between allograft rejection and viral infection. The diagnosis of posttransplantation HHV-6 infection is usually based on serology or on polymerase chain reaction detection of viral DNA in peripheral blood specimens. However, serology does not tell the exact time of the infection, and detection of viral DNA by polymerase chain reaction may also indicate a latent infection in seropositive patients. Here we report the diagnostic use of frequent monitoring of HHV-6 antigenemia after liver transplantation.

METHODS

Altogether 622 blood specimens from 51 consecutive adult liver transplant patients were analyzed. The diagnosis was based on demonstration of HHV-6-specific antigens in peripheral blood mononuclear cells using immunoperoxidase staining and monoclonal antibodies and on serology.

RESULTS

During the first year (7-280 days) after transplantation, HHV-6 infection was diagnosed in 11 (22%) of 51 patients. HHV-6 early antigens, as well as HHV-6 variant B antigens, were detected in all 11 patients. HHV-6 diagnosis was confirmed by serology. The episode of HHV-6 antigenemia usually lasted for several weeks together with mild, if any, clinical signs of the infection. A significant graft dysfunction was associated with HHV-6 antigenemia in 8 of 11 patients, and viral antigens were also detected in the liver biopsy specimens of 3 of these patients.

CONCLUSIONS

An active HHV-6 infection can be diagnosed from peripheral blood by detection of virus-specific antigens in mononuclear cells. HHV-6 antigenemia correlated with seroresponse.

Time-related effects of cytomegalovirus infection on the development of chronic renal allograft rejection in a rat model

Cytomegalovirus (CMV) infection is a risk factor for chronic allograft rejection. The histological findings of chronic renal allograft rejection include inflammation, vascular intimal thickening, glomerulosclerosis, tubular atrophy and fibrosis. We have developed a rat model of renal transplantation in which transplants, after an early inflammatory episode, end up with chronic rejection within 60 days. During the early phase of the process in this model, CMV increased and prolonged the inflammatory response, the expression of adhesion molecules, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 and their ligands, lymphocyte function antigen-1 and very late antigen-4 in the graft. Simultaneously, the production of various growth factors, such as transforming growth factor beta, platelet-derived growth factor and connective tissue growth factor was upregulated, which induce smooth muscle cell proliferation in the vascular wall and collagen synthesis by fibroblasts. Chronic rejection developed within 20 days in CMV-infected grafts. In summary, CMV infection accelerated and enhanced the early immune response, the induction of growth factors and collagen synthesis, and the development of chronic rejection in renal allografts.

Diagnostic value of nucleic-acid-sequence- based amplification for the detection of cytomegalovirus infection in renal and liver transplant recipients

To evaluate the diagnostic value of nucleic-acid-sequence-based amplification (NASBA) for the detection of cytomegalovirus (CMV) infection in transplant recipients, we compared immediate early 1 (IE1) and late pp67 mRNA detection by NASBA with the antigenemia assay, PCR and viral culture in 72 renal transplant (RTx) recipients and with antigenemia and serology in 25 liver transplant (LTx) recipients. Antigenemia, viral culture and pp67 NASBA were almost equivalent for the detection of CMV in RTx recipients. In LTx recipients, antigenemia detected more positive samples and more positive recipients compared to pp67 NASBA. In RTx recipients, PCR detected more positive samples and positive recipients compared to pp67 NASBA, antigenemia and viral culture. Also the first day of detection was slightly earlier for PCR. However, IE1 NASBA was the most sensitive test and detected 96% of all positive samples and positive transplant recipients. In addition, IE1 NASBA preceded PCR and all other positive results. This makes IE1 NASBA a very attractive screening test for the early detection of CMV infection.

Infections in pediatric kidney and liver transplant patients after perioperative hospitalization

BACKGROUND

Infectious complications are a major cause of morbidity and mortality after organ transplantation. There are several reports on infections during the first months after transplantation, but there are very few data regarding infections in long-term survivors of pediatric organ transplantation.

METHODS

The incidence and type of infections were retrospectively analyzed in 56 children who underwent 59 liver or renal transplantations. Follow-up was begun when the patient was sent home after a successful operation. All of the children received triple immunosuppression.

RESULTS

During a mean follow-up of 4.8 years (total, 286 patient years), 1540 episodes of infection were recorded. The median incidence was 4.8 episodes/patient year. The greatest number was seen in the smallest children, 3 to 6 months after transplantation. Viral upper respiratory tract infections were the most common problem, accounting for half of the episodes (2.7 episodes/patient year). Gastroenteritis was the second most common viral infection. Only 45 episodes of infection with herpesviruses were recorded, and seven of those were caused by cytomegalovirus. Otitis media and sinusitis were the most common bacterial infections and complicated upper respiratory infection in 23% of episodes. Thirty-nine episodes of urinary tract infections were diagnosed, thirty-one in children with renal transplants. Other bacterial infections were rare, and only three episodes of verified bacterial sepsis were diagnosed.

CONCLUSION

The frequency and type of infections in children with liver and renal transplants who are on triple immunosuppression are quite similar to those in age-matched healthy children.

Antiviral and immunomodulatory effects of desferrioxamine in cytomegalovirus-infected rat liver allografts with rejection

BACKGROUND

Cytomegalovirus (CMV) infection is associated with acute and chronic allograft rejection. We have recently shown that rat CMV increases portal inflammation and bile duct destruction in a model of rat liver allograft rejection. Desferrioxamine (DFO), an iron chelator and antioxidant, has recently been demonstrated to have antiviral as well as immunomodulatory effects in vitro. We therefore investigated whether DFO inhibits (a) CMV infection and (b) graft destruction in our rat model.

METHOD

One day after liver transplantation, PVG (RT1c) into BN(RT1n), the rats were infected with rat CMV (RCMV, Maastricht strain; 10(5) plaque-forming units i.p.). The effects of 100 mg/kg body weight and 200 mg/kg body weight DFO were examined.

RESULTS

In the untreated group, the grafts were uniformly RCMV culture-positive. In the group receiving 200 mg/kg DFO, RCMV replication was effectively inhibited. Inflammatory response in the graft, and especially the number of macrophages, was significantly reduced by DFO. Portal inflammation and bile duct destruction were also significantly reduced. In the untreated group, the bile duct epithelial cells were found to be strongly positive for tumor necrosis factor-alpha and this expression was clearly decreased by DFO. In addition, DFO significantly inhibited vascular cell adhesion molecule-1 expression on sinusoidal endothelial cells.

CONCLUSIONS

Our in vivo transplant study strongly supports the inhibitory effects of metal chelators on CMV infection and their possible usefulness in the treatment of CMV-induced pathogenic changes.

Effect of desferrioxamine (DFO) and calcium trinatrium diethylenetriaminepentaacetic acid (DTPA) on rat cytomegalovirus replication in vitro and in vivo

Cytomegalovirus (CMV) infection is a major problem in the immunosuppressed patient. It is thought that besides direct CMV induced cell lysis, immunological damage is part of CMV pathogenesis. New antiviral drugs, which combine immunomodulating and antiviral qualities, could be beneficial. Recently, it has been described that desferrioxamine (DFO) and calcium trinatrium diethylenetriaminepentaacetic acid (DTPA) exhibit both properties. In this report the antiviral effects of both compounds against rat CMV (RCMV) are described in vitro and in vivo using a generalised and local infection model. In vitro, both compounds exhibited a significant antiviral effect, DTPA being more potent than DFO. However, in the generalised infection model no effect was seen on mortality, morbidity or presence of virus in internal organs. In rats infected subcutaneously in the hind paw, no effect was seen locally on paw thickness, presence of viral antigens and inflammatory response. In addition, these rats suffered from a generalised infection of low magnitude at 15 days post infection, although both DFO and DTPA were able to lower the level of viral replication. In conclusion, our data indicate that despite in vitro activity, in vivo usage of DFO or DTPA for acute CMV infection is not warranted.

Complement membrane attack complex and protectin (CD59) in liver allografts during acute rejection

BACKGROUND/AIMS

The complement system is important in the rejection of xenografts, but very little is known about its activation in the rejection of allografts. Complement lysis is induced by the membrane attack complex (MAC), an aggregate of C5b, C6, C7, C8 and C9 molecules. The main defender against MAC is the CD59 molecule, also called protectin. In this study, the aim was to analyze the possible deposition of MAC and the fate of CD59 on distinct cell populations during liver allograft rejection.

METHODS

Liver allografts were monitored by frequent fine-needle aspiration biopsies (FNAB) to demonstrate the immunoactivation of rejection. To examine MAC and CD59 in the FNAB, in relation to the activation markers of rejection, IL2-receptor, MHC class II and ICAM-1 expression, specific monoclonal antibodies and immunoperoxidase staining were used.

RESULTS

Ten out of 21 consecutive liver transplants underwent a histologically confirmed episode of reversible acute rejection. In the FNAB, a significant increase of the activation markers IL2-receptor, class II and ICAM-1 correlated with the peak of inflammation during the episode. In association with inflammation, a significant deposition of MAC was recorded in neutrophils and lymphocytes infiltrating the graft and in the parenchymal cells. MAC deposition subsided together with the inflammation. A significant decrease in CD59 expression was seen in neutrophils during rejection, but CD59 expression on other inflammatory cells and hepatic tissue cells varied greatly.

CONCLUSIONS

Complement activation was seen in association with acute rejection of liver allografts and it led to MAC assembly on leukocytes and tissue cells. A decrease in CD59 expression was less clear-cut, but it may predispose the cells to complement-mediated elimination.