Incidence of enterovirus in patients with acute gastroenteritis.

Enteroviruses (EV) have been linked to lymphocytic meningitis and exanthems, but they may also be involved in acute gastroenteritis (AGE), a condition whose aetiological agent often remains unidentified. In this work 1214 samples from individuals with AGE were studied with the aim of establishing the incidence of EV. The samples were collected between September and December in three different years and subjected to real-time genomic amplification in order to determine the viral load (VL). Of the 1214 samples studied, infection by a single virus was found in 328 cases (27%) and coinfection in 69 (5.7%). While adenoviruses (AdV) were the most frequent (14.8% of total), EV were present in 126 (10.4%) of the individuals tested. Of the 126 EV-positive samples, this virus was found as a single infection and coinfection in 76 (6.3%) and 50 (4.1%) cases, respectively. VL for EV was 5.58±1.51 log copies/ml (range 3.73-9.69) in the former and 6.27±1.75 (range 3.73-10.5) (p=0.02) in the latter. EV were identified in 97 children under 5 (16.9%) and in 29 (4.5%) patients over 5. Patients less than 5 years showed a higher VL that those more than 5 years age [6.08±1.57 (range 3.82-9.69) vs. 5.07±1.53 (range 3.73-10.58); (p=0.002)]. There was a high incidence of EV in AGE patients, and they were more frequent in those under 5, where they were found to replicate more efficiently. These results therefore indicate that testing for EV should be included in the diagnosis of AGE.

Viral infections of the central nervous system in Spain: a prospective study.

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

A novel real-time genotyping assay for detection of the E6-350G HPV 16 variant.

It has been suggested that some E6 human papillomavirus (HPV) type 16 variants could be involved in viral persistence and progression of HPV infection. A novel one-step allelic discrimination real-time PCR was evaluated for E6-350G variant detection in 102 endocervical HPV 16 positive samples. This assay was also used to assess the distribution of this variant in Spanish women with cervical cancer related to HPV 16. The detection limit for the allelic discrimination assay was 50 copies per reaction, even where the E6-350G variant represents only 20% of the variants in the sample. Complete concordance was observed between DNA sequencing and the novel AD RT-PCR assay. Fourteen E6-350T reference strains and 18 E6-350G variants were detected out of 32 endocervical samples from women with cervical cancer. The average age of women who were infected by the E6-350G HPV 16 variant was 10 years lower in these samples than in women who were infected by the reference strain. This novel allelic discrimination assay is a fast, sensitive and specific method for detection of the E6-350G HPV 16 variant.

Effect of killer immunoglobulin-like receptors in the response to combined treatment in patients with chronic hepatitis C virus infection.

Killer immunoglobulin-like receptors (KIRs) are related to the activation and inhibition of NK cells and may play an important role in the innate response against infection with viruses such as hepatitis C virus (HCV). We examined whether the different combinations of KIRs with their HLA class I ligands influenced the response to combined treatment (pegylated alpha interferon and ribavirin) of patients infected by HCV. A total of 186 consecutive patients diagnosed with chronic HCV infection were analyzed. Seventy-seven patients exhibited HCV RNA levels at 6 months posttreatment and were called nonresponders (NR), while 109 cleared viral RNA and were named sustained viral responders (SVR). Patients were typed for HLA-B, HLA-Cw, KIR genes, and HCV genotype. In our study, the frequency of the KIR2DL2 allele was significantly increased in NR (P < 0.001; odds ratio [OR] = 1.95), as was the frequency of the KIR2DL2/KIR2DL2 genotype (P < 0.005; OR = 2.52). In contrast, the frequencies of the KIR2DL3 genotype (P < 0.001) and KIR2DL3/KIR2DL3 genotype (P < 0.05; OR = 0.54) were significantly increased in the SVR. Different combinations of KIR2DL2 and KIR2DL3 alleles with their ligands were analyzed. The frequency of the KIR2DL2/KIR2DL2-HLA-C1C2 genotype was significantly increased in the NR (P < 0.01; OR = 3.15). Additionally, we found a higher frequency of the KIR2DL3/KIR2DL3-HLA-C1C1 genotype in the SVR group (P < 0.05; OR = 0.33). These results were not affected by the HCV genotype. In conclusion, patients who carried the KIR2DL2/KIR2DL2-HLA-C1C2 genotype were less prone to respond to treatment. However, the KIR2DL3/KIR2DL3-HLA-C1C1 genotype clearly correlated with a satisfactory response to treatment, defined by the clearance of HCV RNA.

Molecular identification of two genotypes of mumps virus causing two regional outbreaks in Asturias, Spain.

BACKGROUND: In spite of universal vaccination, several sporadic cases of mumps infection, which could produce outbreaks, are detected every year in different countries. OBJECTIVE: Mumps virus strains causing two regional outbreaks in Asturias (Spain) were phylogenetically characterized. STUDY DESIGN: Mumps virus strains, which were detected in samples from patients belonging to two regional outbreaks in Asturias, were characterized by sequencing of the SH gene and further alignment to homologous sequences of representative strains of the different mumps genotypes. RESULTS: Two different strains (Ast/SP02 and Ast/SP07) were isolated. Sequence analysis revealed that while Ast/SP02 belonged to genotype H, Ast/SP07 was phylogenetically close to UK02-19, a reference strain for a new genotype. Both strains belonged to different genotypes from those used in the vaccination (Jeryl-Lynn strain is genotype A). CONCLUSION: Mumps virus strains different from those used in vaccination program can cause mumps outbreaks even in vaccinated patients.

Hepatitis C virus reactivation in anti-hepatitic C virus-positive renal transplant recipients.

From 1992 to 2001 hepatitis C virus (HCV) viremia was studied in 53 renal transplant recipients anti-HCV+ with at least 3 months follow-up posttransplant using a quantitative retrotranscriptase-PCR method. HCV-RNA was detected in 45 (85%): 29 of the 34 recipients treated with azathioprine-based therapy and 15 of 18 treated with mycophenolate mofetil. Immunosuppressive therapy type did not affect HCV replication. Three different patterns of HCV-RNA evolution were detected: 13 (28.8%) patients with high RNA-HCV levels; 21 (46.7%) patients with low levels; and 11 (24.4%) patients with viremia elevation. In 10 (90%) of 11 of the last group, HCV viremia was detected before 15 days posttransplantation, significantly earlier than in the other two groups. Thus, replication during the first 15 days after transplantation leads to a high RNA-HCV viral load. No clinical symptoms were related to HCV.

Influence of ganciclovir prophylaxis on citomegalovirus, human herpesvirus 6, and human herpesvirus 7 viremia in renal transplant recipients.

In order to know the influence of ganciclovir (GCV) prophylaxis on cytomegalovirus (CMV) human herpesvirus (HHV)-6 and HHV-7 replication in renal transplant recipients, three groups were studies: 54 patients without GCV; 29, with short-term GCV prophylaxis (less than 30 days); and 51, with long-term GCV prophylaxis (more than 60 days). CMV viremia was more prevalent in the first group (74%, 55%, and 29%, respectively), but CMV replication was also found in 14 patients during therapy, in the other two groups. The antiviral did not affect the prevalence of HHV-6 (67.2%) or HHV-7 (76%), but HHV-6 viremia appeared later (42 +/- 31 vs 21 +/- 25/38 +/- 29 days posttransplant) and was shorter (29 +/- 30 vs 62 +/- 34/41 +/- 33 days) among patients with long-term GCV prophylaxis. On the other hand, CMV viremia was longer when HHV-6 replication was present (40 +/- 25 days vs 18 +/- 16 days). In addition, HHV-7 DNA was detected in all patients with CMV disease.

Involvement of adenovirus in clinical mononucleosis-like syndromes in young children.

Although Epstein-Barr virus (EBV) commonly causes infectious mononucleosis (IM) or IM-like syndromes, other agents can be implicated. In this study, viral and parasitic screening was performed to determine the etiological agent of pediatric IM-like syndromes in 38 children. Adenovirus was the agent most frequently detected (47.3%), followed by EBV (31.5%) and cytomegalovirus (2.6%). Although the statistically significant difference between viral detection rates observed in patients who fulfilled clinical and hematological criteria and detection rates in those who presented clinical symptoms only (91.6% vs. 64.3%) indicates that hematological abnormalities are common in viral IM-like syndromes, the existence of syndromes of viral etiology without hematological criteria cannot be discarded. A further analysis showed an absence of lymphocytosis in adenovirus infections as well as a low number (14.3%) of EBV infections associated with increased neutrophils. These data suggest the usefulness of appropriate virological techniques for the detection of adenovirus in pediatric IM-like syndromes.

[Parvovirus B9 infection in a renal transplant recipient. Diagnosis by detection of viral genome in peripheral blood]. / Infección por parvovirus B19 en trasplante renal. Diagnóstico por detección del genoma viral en sangre periférica.

Parvovirus B19 can produce a picture known as pure red blood aplasia in recipients of solid organ. Occasionally the viruses cause decrease of the other blood cells, and various extra-hematologic manifestations. Common diagnosis is realised by bone marrow examination. The diagnostic value of the viral genome in the blood stream is not well defined. We reported the case of a male of 17 years of age, whose diagnosis was done by repeated determinations of the viral parvovirus B19 genome in peripheral blood. It was confirmed by a biopsy of the iliac crest. The patient was treated with unspecific IgG immunoglobulins, with complete recovery from the symptoms and signs. It did not have any recurrence of the disease. This case suggests that the realisation of PCR of Parvovirus B19 in renal transplant patients with pure red cell aplasia could be of greater interest in the diagnosis and monitoring of the disease. The detection of the viral genome could avoid the administration of unnecessary blood transfusions, and possibly the realization of bone marrow biopsy.

Infección por parvovirus B19 en trasplante renal. Diagnóstico por detección del genoma viral en sangre periférica / Parvovirus B19 infection in a renal transplant recipient. Diagnosis by detection of viral genome in peripheral blood

El parvovirus B19 puede producir un cuadro de anemia conocido como aplasiapura de células rojas en los receptores de trasplantes de órganos. A veces se asocia adisminución de las otras series sanguíneas y a variada patología extrahematológica. Eldiagnóstico se suele hacer mediante examen de la médula ósea. El valor de la deteccióndel genoma viral en sangre no está bien delimitado. Se describe el caso de unvarón de 17 años que presentó fiebre, anemia recitulocipénica y hepatitis debida ainfección por parvovirus B19, cuyo diagnóstico se realizó mediante determinaciónseriada del genoma viral en sangre periférica y se confirmó por biopsia de cresta iliaca.El paciente respondió al tratamiento con inmunoglobulinas, recuperándose completamentede los síntomas y no presentando recaídas.Se sugiere que ante la presencia de anemia de origen no filiado en un paciente contrasplante renal se debe realizar una PCR de Parvovirus B19 en sangre periférica, sobretodo si se acompaña de reticulocitopenia. La detección del genoma viral en plasma permiterealizar un diagnóstico y tratamiento precoz, evitando la administración de transfusionessanguíneas innecesarias, y posiblemente la realización de una biopsia ósea

Parvovirus B19 can produce a picture known as pure red blood aplasia in recipientsof solid organ. Occasionally the viruses cause decrease of the other blood cells, and various extra-hematologic manifestations. Common diagnosis is realised by bonemarrow examination. The diagnostic value of the viral genome in the blood stream isnot well defined.We reported the case of a male of 17 years of age, whose diagnosis was done byrepeated determinations of the viral parvovirus B19 genome in peripheral blood. Itwas confirmed by a biopsy of the iliac crest. The patient was treated with unspecificIgG immunoglobulins, with complete recovery from the symptoms and signs. It didnot have any recurrence of the disease.This case suggests that the realisation of PCR of Parvovirus B19 in renal transplantpatients with pure red cell aplasia could be of greater interest in the diagnosis andmonitoring of the disease. The detection of the viral genome could avoid the administrationof unnecessary blood transfusions, and possibly the realization of bonemarrow biopsyParvovirus B19 can produce a picture known as pure red blood aplasia in recipients of solid organ. Occasionally the viruses cause decrease of the other blood cells, and various extra-hematologic manifestations. Common diagnosis is realised by bone marrow examination. The diagnostic value of the viral genome in the blood stream is not well defined. We reported the case of a male of 17 years of age, whose diagnosis was done by repeated determinations of the viral parvovirus B19 genome in peripheral blood. It was confirmed by a biopsy of the iliac crest. The patient was treated with unspecific IgG immunoglobulins, with complete recovery from the symptoms and signs. It did not have any recurrence of the disease. This case suggests that the realisation of PCR of Parvovirus B19 in renal transplant patients with pure red cell aplasia could be of greater interest in the diagnosis and monitoring of the disease. The detection of the viral genome could avoid the administration of unnecessary blood transfusions, and possibly the realization of bone marrow biopsy

Cytomegalovirus replication and "herpesvirus burden" as risk factor of cardiovascular events in the first year after renal transplantation.

Cytomegalovirus (CMV) infection alone or in combination with other pathogens ("pathogen burden") has been postulated as a factor producing arteriosclerosis in some solid organ transplant recipients. The aim of this study was to assess whether the patients with CMV replication and/or "herpesvirus burden" experienced a greater incidence of cardiovascular events during the first year after kidney transplantation. One hundred twenty-one consecutive transplant recipients were prospectively studied for CMV replication using antigenemia and polymerase chain reaction (PCR) weekly during the 4 first months, and monthly thereafter for 1 year. Simultaneously, nested-PCR for human herpes virus (HHV)-6 and HHV-7 were performed to yield a herpesvirus burden (as determined by seropositivity), including CMV, herpes simplex virus (HSV), varicella-zoster virus (VZV), and Epstein-Barr virus (EBV). The following additional parameters were analyzed: gender, age, smoking, duration of dialysis, preexistent diabetes, and preexistent cardiovascular events. After 1 year posttransplantation cardiovascular events, body mass index, arterial hypertension, number of antihypertensive drugs, use of ACE and/or ARBs inhibitors, diabetes, anemia, homocysteine, creatinine, cholesterol, HDLc, LDLc, PTH-i, proteinuria, and immunosuppression with cyclosporine or tacrolimus. CMV replication was present in 79 (65.3%) patients. Among 121 renal transplant recipients, 13 presented cardiovascular events, all associated with CMV replication (P = .004). Neither HHV-6 or HHV-7 replication influenced this complication. All patients with these events were seropositive for CMV, HSV, VZV, and EBV, as opposed to 64.8% without them (P = .009). Other factors that showed differences between patients with versus without events were as follows: preexistent events (76.9% vs 14.8%; P = .000), age (60 +/- 10 vs 49 +/- 14; P = .002), serum triglyceride value (191 +/- 82 vs 135 +/- 72; P = .02), and anemia (23.1% vs 5.6%; P = .05). Multiple logistic regression analysis for statistically significant variables only showed that preexistent events influenced the development of posttransplantation events (odds ratio, 27; 95% confidence interval, 4.7-154; P = .0005). In conclusion, cardiovascular events within 1 year after transplantation were more frequent among patients with CMV replication and seropositivity for other herpesviruses. An important risk factor was the presence of preexistent events.

[Detection of herpes simplex virus and Epstein-Barr virus in squamous cell carcinoma of the upper airways and digestive system]. / Detección del virus herpes simplex y del virus de Epstein-Barr en los carcinomas de células escamosas de vías aerodigestivas superiores.

OBJECTIVE: Previous studies have investigated the role of viruses in tumor origin of head and neck cancer. Despite this, mechanis of viral carcinogenesis remain unclear. The aim of this study is to determine the prevalence of herpes simplex virus (HSV) and Epstein-Barr virus (EBV) in malignant laryngeal and oropharyngeal lesions. MATERIAL AND METHODS: Fresh frozen specimens of 28 laryngeal and oropharyngeal squamous cell carcinomas were studied. The presence or absence of HSV and EBV was determined with polymerase chain reaction (PCR) assays. RESULTS: None of the samples showed evidence for EBV DNA. One tonsilar carcinoma case (3.5%) was positive for HSV DNA detection. CONCLUSIONS: These results do not support HSV and EBV as etiological factors in head and neck cancer.

Comparative study of the efficacy of an induction dose of interferon-alpha2b with ribavirin compared with standard combined treatment in naive patients with chronic hepatitis C.

The efficacy and secondary effects of an induction dose of interferon-alpha2b (IFN-alpha2b) with ribavirin compared with standard combined treatment in naive patients with chronic hepatitis C infection were compared. A prospective study was undertaken between March 1998 and November 2001 in which 84 Spanish hospitals took part. Six hundred and fourteen naive patients (age range 18-65 years) diagnosed with chronic hepatitis C virus (HCV) infection and without cirrhosis or co-infection by other viruses, were included. Patients were divided into two groups. Group A (n = 304) received induction treatment with a daily dose of 5 MU of IFN-alpha2b for 4 weeks, followed by 5 MU three times a week with ribavirin (1000-1200 mg/day, according to weight) until completing 1 year of treatment. Group B (n = 310) received the standard dose of IFN-alpha2b of 3 MU three times per week for 48 weeks together with ribavirin (1000-1200 mg/day, according to weight). Both groups were completely comparable according to age, gender, body weight, transaminase levels, genotype, viral load and hepatic inflammatory activity (Knodell Index). No control group was included for ethical reasons. Pegylated interferon was not available at the time of the study. Serum baseline samples were collected for the determination of genotype. Samples were also collected at baseline, weeks 4, 12, 24, 48 and 72, in order to detect and quantify HCV-RNA. The efficacy of treatment was evaluated by means of sustained viral response (SVR) characterized by persistent negativity of HCV-RNA at the end of the follow-up period. At week 4, the response to treatment was greater in group A (49.6%) compared with group B (34.5%) (P = 0.0002), and was maintained until week 12 (64.1% compared with 55.8% respectively) (P = 0.03). These differences disappeared at week 24, when group A (69%) was compared with group B (65%) (NS). At week 48, the response rate for group A was 50.6% compared with group B 47.4% (NS), and at week 72, the SVR in group A was 46% compared with 40.3% for group B (NS). The global SVR was 43.1%. On analysing the response to treatment according to genotype and viral load, we found that the induction treatment was slightly superior in patients with genotype 1 and an elevated viral load (>2 x 10(6) copies/ml). They achieved a SVR in group A of 39.1% compared with 25.5% in group B (P < 0.05). However, this slight improvement obtained in group A, was achieved at the expense of a greater percentage of dropouts compared with group B (6.4% vs 2.2%, P < 0.01); a greater rate of side effects (58.5 vs 36.7%, P < 0.05) and also a greater percentage of neutropenia (3.1% vs 0.9%, P < 0.05). The induction treatment presented a better initial response, but this was not maintained at the end of treatment, and did not improve the results obtained with the standard treatment. Although the patients with genotype 1 and elevated viral load had a better response with the induction treatment, this was accompanied by a greater percentage of dropouts and secondary effects. It would be interesting to repeat this type of study in the future, using pegylated interferon.

Detección del virus herpes simplex y del virus de Epstein-Barr en los carcinomas de células escamosas de vías aerodigestivas superiores / Detection of herpes simplex virus and Epstein-Barr virus in head and neck squamous cell carcinoma

Objetivo: Diversos estudios han investigado el papel de los virus en la carcinogénesis de los tumores de cabeza y cuello. A pesar de esto, el mecanismo de la carcinogénesis viral permanece poco claro. El objetivo de este estudio es determinar la prevalencia del virus herpes simplex (VHS) y del virus de Epstein-Barr (VE-B) en tumores malignos de laringe y orofaringe. Material y método: Se estudian muestras frescas congeladas de 28 pacientes con tumores de laringe y orofaringe. La presencia o ausencia del VHS y VE-B se determinó mediante la reacción en cadena de la polimerasa (PCR). Resultados: En ninguna de las muestras detectamos el ADN del VE-B. En una muestra de carcinoma de amígdala (3,5 por ciento) detectamos el ADN del VHS. Conclusiones: Nuestros resultados no sugieren que el VHS y el VE-B tengan un papel en la etiología de los tumores de cabeza y cuello (AU)

OBJECTIVE: Previous studies have investigated the role of viruses in tumor origin of head and neck cancer. Despite this, mechanis of viral carcinogenesis remain unclear. The aim of this study is to determine the prevalence of herpes simplex virus (HSV) and Epstein-Barr virus (EBV) in malignant laryngeal and oropharyngeal lesions. MATERIAL AND METHODS: Fresh frozen specimens of 28 laryngeal and oropharyngeal squamous cell carcinomas were studied. The presence or absence of HSV and EBV was determined with polymerase chain reaction (PCR) assays. RESULTS: None of the samples showed evidence for EBV DNA. One tonsilar carcinoma case (3.5%) was positive for HSV DNA detection. CONCLUSIONS: These results do not support HSV and EBV as etiological factors in head and neck cancer (AU)

Remisión de enfermedad severa por citomegalovirus y enfermedad linfoproliferativa post-trasplante en un receptor de trasplante renal tras terapia con ganciclovir y cambio en la medicación inmunosupresora / Remission of severe disease induced by cmv and lymphoproliferative posttransplant disease after changing the immunosuppression regime

Se describe el caso de un receptor de trasplante renal con sobreinmunosupresión inducida por la interacción de tacrolimus y fluconazol que desarrolló dos enfermedades severas producidas por dos virus diferentes del grupo herpes: enfermedad por citomegalovirus (CMV) y enfermedad linfoproliferativa post-trasplante (ELPT). La detección del genoma del virus de Epstein-Barr (VEB) en sangre periférica precede al diagnóstico de ELPT. Ambas enfermedades remitieron con el cambio del régimen inmunosupresor y tratamiento con ganciclovir. Debido a que la infección por CMV es un factor de riesgo para desarrollar ELPT y a que las manifestaciones clínicas y endoscópicas de ambas enfermedades pueden confundirse, en los pacientes con enfermedad por CMV se debe descartar la presencia de una ELPT concomitante, sobre todo si estos pacientes son seronegativos para el virus de Epstein-Barr. La detección del genoma del VEB en sangre periférica puede ser de gran ayuda en el diagnóstico precoz de ELPT en estos pacientes. (AU)

[Remission of severe disease induced by CMV and lymphoproliferative post-transplant disease after changing the immunosuppressive regime]. / Remisión de enfermedad severa por citomegalovirus y enfermedad linfoproliferativa post-trasplante en un receptor de trasplante renal tras terapia con ganciclovir y cambio en la medicación inmunosupresora.

We describe a renal transplant recipient, with overimmunosuppression induced by the interaction of tacrolimus and fluconazole, who developed two severe diseases produced by two different viruses of the herpes group (cytomegalovirus [CMV] disease and posttransplant lymphoproliferative [PTLD] disease EBV-related). Detection of Epstein-Barr virus (EBV) DNA in the blood preceded the histological diagnosis of PTLD. Both diseases improved after changes in the immunosuppressive regime and treatment with ganciclovir. Because CMV infection is a risk factor in developing PTLD, and the clinical and endoscopic manifestations of both diseases could be become confused, PTLD should be excluded in EBV seronegative patients that develop CMV disease. The detection of the EBV genome in blood could help in the early diagnosis of PTLD in these patients.