Dynamics of circulating follicular helper T cell subsets and follicular regulatory T cells in rheumatoid arthritis patients according to HLA-DRB1 locus.

B cells, follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are part of a circuit that may play a role in the development or progression of rheumatoid arthritis (RA). With the aim of providing further insight into this topic, here we evaluated the frequency of different subsets of Tfh and Tfr in untreated and long-term treated RA patients from a cohort of Argentina, and their potential association with particular human leukocyte antigen (HLA) class-II variants and disease activity. We observed that the frequency of total Tfh cells as well as of particular Tfh subsets and Tfr cells were increased in seropositive untreated RA patients. Interestingly, when analyzing paired samples, the frequency of Tfh cells was reduced in synovial fluid compared to peripheral blood, while Tfr cells levels were similar in both biological fluids. After treatment, a decrease in the CCR7loPD1hi Tfh subset and an increase in the frequency of Tfr cells was observed in blood. In comparison to healthy donors, seropositive patients with moderate and high disease activity exhibited higher frequency of Tfh cells while seropositive patients with low disease activity presented higher Tfr cell frequency. Finally, we observed that HLA-DRB1*09 presence correlated with higher frequency of Tfh and Tfr cells, while HLA-DRB1*04 was associated with increased Tfr cell frequency. Together, our results increase our knowledge about the dynamics of Tfh and Tfr cell subsets in RA, showing that this is altered after treatment.

The HLA-B*51 allele is strongly associated with Behçet Disease in an Argentinean population / El alelo HLA-B*51 se asoció fuertemente a la Enfermedad de Behçet en la población argentina

OBJECTIVE: To assess the association between the HLA-B*51 allele and Behçet Disease (BD) in Argentinean patients. METHODS: We enrolled 34 consecutive Argentinean patients with definitive diagnosis of BD between October 2016 and March 2017. None of the patients had the HLA-B*51 allele determined at study entry. Unrelated controls (n=240) were randomly obtained from the national cadaveric donor database. Demographic and clinical features of the patients were recorded by attending physicians through a questionnaire. RESULTS: Mean age of cases was 42 years old. Nineteen (55.8%) were male, and the mean age at diagnosis was 35 years old; twenty (58.8%) were Mestizos, 8 (23.5%) were Caucasian, and 6 (17.6%) were Amerindians. Thirteen (38.2%) of 34 cases were HLA-B*51 allele positive; 11 were heterozygous and 2 homozygous for the allele. Thirty-four (14.2%) of 240 controls were positive for the HLA-B*51 allele. The association between BD and HLA-B*51 allele was greater than that of control group (OR=3.75; p = 0.0012). CONCLUSIONS: The HLA-B*51 allele is strongly associated with BD in Argentinean patients. Our finding is consistent with previous studies indicating that the HLA-B*51 allele is an important susceptibility gene in BD regardless the geographical region and ethnicity

OBJETIVO: Evaluar la asociación entre el alelo HLA-B*51 y la enfermedad de Behçet (EB) en pacientes argentinos. MÉTODOS: Incluimos en forma consecutiva 34 pacientes argentinos con diagnóstico definitivo de EB entre los meses de octubre de 2016 y marzo de 2017. Ninguno de los pacientes tenía el alelo HLA-B*51 determinado al inicio del estudio. Los controles no relacionados (n=240) se obtuvieron al azar de la base nacional de datos de donantes cadavéricos. Las características demográficas y clínicas de los pacientes fueron registradas por los médicos asistentes a través de un cuestionario. RESULTADOS: La edad promedio de los casos fue de 42 años. Diecinueve (55,8%) fueron varones, y la edad promedio en el momento del diagnóstico fue de 35 años; 20 (58,8%) fueron mestizos, 8 (23,5%) caucásicos y 6 (17,6%) amerindios. Trece (38,2%) de los 34 casos fueron positivos para el alelo HLA-B*51; 11 de ellos fueron heterocigotas y 2 homocigotas para dicho alelo. Treinta y cuatro (14,2%) de los 240 controles fueron positivos para el alelo HLA-B*51. La asociación entre la EB y el alelo HLA-B*51 fue mayor que en el grupo control (OR=3,75; p = 0,0012). CONCLUSIONES: El alelo HLA-B*51 está fuertemente asociado con la EB en pacientes argentinos. Nuestro hallazgo es consistente con estudios previos que indican que el alelo HLA-B*51 es un gen de susceptibilidad importante en la EB independientemente de la región geográfica y la etnia

The HLA-B*51 Allele is strongly associated with Behçet Disease in an Argentinean population.

OBJECTIVE: To assess the association between the HLA-B*51 allele and Behçet Disease (BD) in Argentinean patients. METHODS: We enrolled 34 consecutive Argentinean patients with definitive diagnosis of BD between October 2016 and March 2017. None of the patients had the HLA-B*51 allele determined at study entry. Unrelated controls (n=240) were randomly obtained from the national cadaveric donor database. Demographic and clinical features of the patients were recorded by attending physicians through a questionnaire. RESULTS: Mean age of cases was 42 years old. Nineteen (55.8%) were male, and the mean age at diagnosis was 35 years old; twenty (58.8%) were Mestizos, 8 (23.5%) were Caucasian, and 6 (17.6%) were Amerindians. Thirteen (38.2%) of 34 cases were HLA-B*51 allele positive; 11 were heterozygous and 2 homozygous for the allele. Thirty-four (14.2%) of 240 controls were positive for the HLA-B*51 allele. The association between BD and HLA-B*51 allele was greater than that of control group (OR=3.75; p=0.0012). CONCLUSIONS: The HLA-B*51 allele is strongly associated with BD in Argentinean patients. Our finding is consistent with previous studies indicating that the HLA-B*51 allele is an important susceptibility gene in BD regardless the geographical region and ethnicity.

Frequency of human leukocyte antigens class II-DR alleles (HLA-DRB1) in Argentinian patients with early arthritis.

Patients with rheumatoid arthritis (RA) or undifferentiated arthritis (UA) in the CONAART database (Argentine Consortium for Early Arthritis) were assessed for genetic risk factors for RA, specifically for HLA-DRB1 alleles and the PTPN22 rs2476601 polymorphism associated with progression to RA. This is a case-control study. Blood samples were obtained to determine HLA-DRB1 genotypes by PCR-SSO Luminex and PTPN22 (rs2476601) polymorphism by allelic discrimination. A control group of individuals from the general Argentinian population were obtained from the national register of cadaveric organ donors. A total of 1859 individuals were included in this analysis: 399 patients from the CONAART database (347 patients with RA at study end and 52 patients with UA at study end, mean follow-up time 25 ± 18 months) and 1460 individuals from the general Argentinian population. Compared with the controls, the HLA-DRB1*04 and DRB1*09 alleles were more commonly detected in patients with RA diagnosis (OR (95% CI) 2.23 (1.74-2.85) and 1.89 (1.26-2.81)) respectively. Both patients with UA and the general population showed higher frequency of DRB1*07, DRB1*11 and DRB1*15 alleles than patients with RA. PTPN22 rs2476601 polymorphism frequency was higher in RA and UA vs the general population; however, this was significantly different only for RA vs control group (OR [95% CI] = 1.81 [1.10-3.02], P = 0.018. HLA-DRB1 typing and PTPN22 allelic discrimination could distinguish between patients with UA, patients with early RA, and the general population in Argentina. This is the first study of HLA-DRB1 alleles and PTPN22 polymorphism associations with progression to early RA in an Argentinian population.

Chagas disease and liver transplantation: Experience in Argentina using real-time quantitative PCR for early detection and treatment.

BACKGROUND: Chagas disease (CD) is an endemic zoonosis that occurs in Latin America and is caused by the parasite Trypanosoma cruzi. Early detection of T. cruzi in liver transplant recipients at risk may avoid complications from CD. The aim of this study was to examine the pre-operative evaluation and follow-up of CD after liver transplantation (LT) of patients at risk of CD using real-time quantitative polymerase chain reaction (qPCR) for T. cruzi. METHODS: Between January 2009 and June 2016, 13 (12.7%) of 102 LTs performed in recipients at risk for CD without specific postoperative prophylaxis were prospectively evaluated using qPCR for T. cruzi. Four seronegative patients received livers from seropositive donors (R-/D+) and 9 seropositive recipients received livers from seronegative donors (R+/D-). A cohort of 89 patients without risk for CD during the same time period was analyzed as controls. RESULTS: A positive qPCR for T. cruzi prior to LT was found in 2/9 (22.2%) seropositive recipients, and both achieved early response after therapy. The cumulative incidence of positive parasitemia after LT was higher in R+/D- than R-/D+ (37.7% vs 0%, P = .17). R+/D- transplant patients with positive qPCR achieved therapeutic response without manifestations of acute CD. LT outcomes at 1 year were similar in patients at risk of CD and in controls not at risk for CD. CONCLUSION: A small proportion of T. cruzi-seropositive candidates presented positive parasitemia before LT. After LT, qPCR allowed detection of parasitemia leading to use of preemptive therapy in all R+/D- with T. cruzi replication. No cases of T. cruzi parasitemia occurred in R-/D+.

Detection of Trypanosoma cruzi and Treatment Monitoring by PCR from Dried Blood Spot Samples in Children.

BACKGROUND: Parasitic infections by Trypanosoma cruzi (T. cruzi) are frequent in children from endemic areas. Specific therapies have been successfully used in pediatric populations to treat this disease. T. cruzi diagnosis should be optimized and become available for any clinical environment. OBJECTIVE: To study T. cruzi prevalence in children from an area of active transmission and carry out a posttreatment follow-up. To verify the feasibility of detecting DNA of T. cruzi from dried blood spot. METHODS: We analyzed presence of T. cruzi in 78 Aboriginal children (Toba community) that attended to a rural school of Chaco province, Argentina. Serum and whole blood (dried blood spot) were assessed by means of serological techniques and PCR. Positive children received Benznidazole. Diagnosis and post treatment follow-up of T. cruzi infection were performed. RESULTS: The serology assay showed infection in 34 of 78 (43.5%) children studied; PCR was positive in 5/34, displaying parasitemia. Serology remained positive in 28/28 children 120 days post-treatment, while PCR was positive in 18/28 (6/34 children were lost in follow-up). No adverse effects during the treatment were reported. CONCLUSIONS: We were able to establish T. cruzi prevalence in the studied population and also to prove the usefulness of dried blood spot for T. cruzi detection using PCR in isolated areas. This method allowed us to verify early treatment failure. Possible causes of this failure are discussed below.

Reactivation of Chagas Disease in a Patient With Follicular Lymphoma Diagnosed by Means of Quantitative Real-Time Polymerase Chain Reaction.

We report a case of Chagas disease reactivation in a patient with stage IIb follicular lymphoma in the cecum. He was admitted to the hospital with neutropenia and fever. He had a history of right hemicolectomy 6 months earlier and had received the sixth cycle of chemotherapy with cyclophosphamide/doxorubicin/vincristine/prednisone/rituximab. Blood and urine cultures were negative, but the fever persisted. Reactivation of Chagas disease was confirmed by means of quantitative real-time polymerase chain reaction (qRT-PCR). Parasitic load was 577 950 parasite equivalents/mL. The patient began treatment with benznidazole 5 mg/k per day every 12 hours. After 1 month, the qRT-PCR control was undetectable. The patient completed 60 days of treatment and is currently asymptomatic. Trypanosoma cruzi qRT-PCR may become a useful diagnostic method for reactivation of Chagas disease.

Immune thrombocytopenia with antiphospholipid antibodies in monozygotic twins.

We describe monozygotic twins with immune thrombocytopenia (ITP) associated to antiphospholipid antibodies with a dissimilar clinical expression. The first patient was diagnosed to have ITP at 63 years old and was treated with corticosteroids. She presented ulterior exacerbations of thrombocytopenia requiring intravenous immunoglobulin and subsequent treatment with rituximab. She ultimately had a favorable response without thrombotic events during follow-up. The second patient who had a history of three spontaneous abortions and endometrial adenocarcinoma in complete remission was evaluated for severe thrombocytopenia, ITP was diagnosed at the age of 63. She was treated with steroids and had a favorable response. After few months she developed deep venous thrombosis and pulmonary embolism requiring anticoagulation therapy without hemorrhagic events. Both patients were found to have antiphospholipid antibodies and HLA DR4 (DRB1*04) and HLA DR5 (DRB1*12). The association of those two entities in monozygotic twins could support the presence of common predisposing genes. However, with both patients being genotipically identical, the clinical expression was different. Those cases highlight the possibility that environmental factors may affect the expression of those disorders.

Splenic autoimplantation in omentum and stomach, hematoimmunological follow-up and B-cell repertoire in the graft.

INTRODUCTION: Splenic autoimplantation appears to be the only alternative to preserve splenic tissue after splenectomy; however, its relevance is still controversial We intended to study splenic autoimplantation in the greater omentum and stomach wall of rabbits and analyze its hematoimmunological performance and the preservation of original structures. METHODS: New Zealand rabbits were divided in two groups: autoimplanted (A) (n=13) and splenectomized (S) (n=4). The animals of group A underwent autoimplantation of splenic fragments in the greater omentum and gastric wall Both groups were evaluated by hemocytological tests, scintigraphy, immunoglobulin and C3 dosages, before the surgery and 2 and 4 months afterwards. After 4 months, the grafts were removed and histological examination and gen rearrangement of B-lymphocytes receptors by polymerase chain reaction (PCR) were performed to assess the cellular diversity of clones. RESULTS: The histological analysis demonstrated the presence of splenic tissue in 10 of the 13 cases (77%) with evident size reduction. The gastric location did not develop complications and demonstrated higher morphological correspondence to the autoimplanted tissue. Both groups showed significant decrease of IgM and increase of C3, without considerable differences between both of them during follow up. From the 8 grafts studied with PCR, 3 cases presented polyclonality and 5 oligoclonality. CONCLUSIONS: The revascularized grafts evidenced splenic regenerating tissue, probably associated to the oligoclonality detected by PCR. Consequently, we consider that autoimplantation is a reasonable alternative for splenectomized patients, even though the stomach placement and the high frequency of oligoclonality justify further investigation.

Using polymerase chain reaction in early diagnosis of re-activated Trypanosoma cruzi infection after heart transplantation.

BACKGROUND: Heart transplantation is an effective treatment for patients with end-stage Chagas' heart disease. Re-activation of Chagas' disease in transplant recipients is frequent, triggered by immunosuppression level. Therefore, highly sensitive methods for early diagnosis of Chagas' disease relapse are necessary to initiate appropriate therapy. We analyzed the use of polymerase chain reaction (PCR) in the clinical follow-up of heart transplant recipients. METHODS: We prospectively evaluated 4 heart transplant recipients at the Hospital Privado, Cordoba, Argentina, who had terminal Chagas' disease. The parameters analyzed were presence of parasites in the blood (blood culture, Strout) and in endomyocardial biopsy (EMB) samples, and PCR was performed with oligonucleotides directed to a nuclear repetitive sequence of Trypanosoma cruzi. We evaluated these parameters weekly from the day of transplantation until results were negative and then during regular follow-up visits. RESULTS: In 2 patients, we detected T cruzi using PCR in peripheral blood 30 days before clinical evidence of re-activation. In the 3rd case, PCR results in peripheral blood were positive from the day before transplantation, followed by positive results in EMB and sub-cutaneous chagomas biopsy specimens. Only 1 patient had positive Strout results for parasites in skin lesions, and none showed amastigotes in the biopsy specimens. After clinical diagnosis, all patients received 5 mg/kg/day benzimidazole for 6 months, with acceptable tolerance and good clinical outcome. All patients had negative peripheral blood PRC results after 30 days of treatment. One patient had intermittent positive PCR results during follow-up, with no evidence of clinical re-activation. CONCLUSION: Polymerase chain reaction detection of T Cruzi in heart transplant recipients is a more sensitive and specific procedure in diagnosing Chagas' disease re-activation.

Molecular and clinical response to angiotensin II receptor antagonist in kidney transplant patients with chronic allograft nephropathy.

Chronic allograft nephropathy (CAN) represents an important cause of graft loss after kidney transplantation. TGF-beta1 is a key factor in fibrogenesis, and the angiotensin II receptor antagonist losartan may decrease the intra-graft synthesis of TGF-beta1. The aim of this study was to determine the clinical and molecular effect of losartan in kidney transplant patients (KTPs) with CAN. We studied nine KTPs, after the first year of transplantation, with proteinuria (more than 500 mg/24 h), stable renal function, and histological signs of CAN. Immunosuppression was cyclosporine, azathioprine, and corticoids. Kidney biopsy was performed in all patients at the beginning of the study and 12 weeks after treatment with 50 mg/day of losartan. Quantitation of intra-graft expression of TGF-beta1 was performed in all biopsies, by real-time PCR. After losartan treatment there were no differences in patients' BP and blood creatinine level. The proteinuria significantly dropped to 414.2+/-377 mg/24 h, P=0.001. Intra-graft expression of TGF-beta1 was decreased after treatment. In conclusion, losartan significantly decreases the intra-graft expression of TGF-beta1 and proteinuria in KTPs with CAN.

Morbimortalidad de los pacientes con miocardiopatía chagásica y trasplante cardíaco. Experiencia inicial / Morbidity and mortality in heart transplanted patients with chagasic cardiomyopathy. Initial experience

Introducción: La miocardiopatía chagásica durante el período crónico es una causa frecuente de insuficiencia cardíaca avanzada, pero la indicación de trasplante cardíaco aún es controversial en algunos centros. Objetivos: Evaluar en estos pacientes la mortalidad, las complicaciones postrasplante, la frecuencia de reactivación de T. Cruzi (TC) y la utilidad de su detección a través de la reacción en cadena de la polimerasa (PCR). Material y métodos: Se evaluaron 27 pacientes trasplantados desde el año 1997: 4 pacientes chagásicos (grupo A) y 23 en el grupo control (grupo B). El análisis de PCR se realizó con empleo de la secuencia de oligonucleótico TCZ1 y TCZ2. El diagnóstico de reactivación de T. Cruzi se realizó en base a la visualización histopatológica de amastigotas en muestra de tejidos. Resultados: El seguimiento promedio fue de 28,75 ± 23,38 meses en el grupo A y de 28,04 ± 16,84 meses en el grupo B. La sobrevida a los 3 años fue del 75 por ciento y el 65 por ciento respectivamente (p = 0,59). La reactivación de TC ocurrió en los 4 pacientes chagásicos. La infección por CVM (p = 0,05) fue más frecuente en el grupo A. La PCR positiva precedió en 30-60 días a la aparición de los síntomas en 3 pacientes y se negativizó en todos los pacientes luego del tratamiento. Conclusiones: Los pacientes trasplantados chagásicos tienen una mortalidad similar a los no chagásicos a pesar de la reactivación de TC. La parasitemia detectada por PCR es de utilidad para el diagnóstico precoz y el monitoreo terapéutico de la reactivación de la tripanosomiasis.

Morbimortalidad de los pacientes con miocardiopatía chagásica y trasplante cardíaco. Experiencia inicial / Morbidity and mortality in heart transplanted patients with chagasic cardiomyopathy. Initial experience

Introducción: La miocardiopatía chagásica durante el período crónico es una causa frecuente de insuficiencia cardíaca avanzada, pero la indicación de trasplante cardíaco aún es controversial en algunos centros. Objetivos: Evaluar en estos pacientes la mortalidad, las complicaciones postrasplante, la frecuencia de reactivación de T. Cruzi (TC) y la utilidad de su detección a través de la reacción en cadena de la polimerasa (PCR). Material y métodos: Se evaluaron 27 pacientes trasplantados desde el año 1997: 4 pacientes chagásicos (grupo A) y 23 en el grupo control (grupo B). El análisis de PCR se realizó con empleo de la secuencia de oligonucleótico TCZ1 y TCZ2. El diagnóstico de reactivación de T. Cruzi se realizó en base a la visualización histopatológica de amastigotas en muestra de tejidos. Resultados: El seguimiento promedio fue de 28,75 ± 23,38 meses en el grupo A y de 28,04 ± 16,84 meses en el grupo B. La sobrevida a los 3 años fue del 75 por ciento y el 65 por ciento respectivamente (p = 0,59). La reactivación de TC ocurrió en los 4 pacientes chagásicos. La infección por CVM (p = 0,05) fue más frecuente en el grupo A. La PCR positiva precedió en 30-60 días a la aparición de los síntomas en 3 pacientes y se negativizó en todos los pacientes luego del tratamiento. Conclusiones: Los pacientes trasplantados chagásicos tienen una mortalidad similar a los no chagásicos a pesar de la reactivación de TC. La parasitemia detectada por PCR es de utilidad para el diagnóstico precoz y el monitoreo terapéutico de la reactivación de la tripanosomiasis. (AU)

Una técnica de PCR-ELISA cuantitativa para el diagnóstico de enfermedad por citomegalavirus (CMV) en pacientes transplantados renales / A technique of cuantitative PCR-ELISA for diagnosis of cytomegalovirus disease in renal transplanted patients

Introducción: El citomegalovirus (CMV) es el agente causal de la enfermedad viral de mayor prevalencia en pacientes transplantados. La detección del ADN de CMV por medio del PCR es común entre los pacientes receptores de ri±ones, dando resultados falsos positivos en pacientes que no tienen enfermedad. Hemos desarrollado una técnica de PCR-ELISA cuantitativa y competitiva para identificar pacientes que padecen la enfermedad por CMV. Métodos: Analizamos 350 muestras provenientes de 65 receptores de transplantes renales cadavéricos no seleccionados. Se extrajo ADN de CMSP semanalmente hasta el día de la alta hospitalaria y se lo estudio por PCR cualitativa. Los casos positivos se analizaron por PCR-ELISA cuantitativa y competitiva también. Esta técnica usa un estßndar interno(SI) heterólogo que contiene la misma secuencia de oligonucleótido para el 4to exon del gen del antigeno temprano inmediato (ATI) utilizado en una PCR cualitativa. La detección y cuantificación se realizó en placas de 96 pozo cubiertas con sondas específicas para él SI y CMV. Los resultados se expresaron como copias virales (CV) por 1 millón de CMSP. Resultados: Cuarenta y uno de los pacientes (63,1 por ciento) tuvieron un ensayo cualitativo positivo y 8 de ellos tenían infección clínica por CMV. Los 41 pacientes con PCR (+) fueron re-analizados por ensayo cuantitativo. Los 8 que tenían la enfermedad por CMV presentaron un valor promedio de 219,6+/- 117,2 CV/106 CMSP (P<0,01)Conclusión: La carga viral de CMV es útil para identificar los pacientes transplantados renales que desarrollaron la enfermedad por CMV. Valores mayores a 500 CV/106 CMSP se relacionan altamente con el desarrollo de la enfermedad.ABSTRACT: Background: Cytomegalovirus (CMV)is the most prevalent viral disease in organ transplantation. Detection of CMV DNA in PBMC by PCR occurs frequently in renal allograft recipients, yielding false positive patient not having the CMV disease. We have developed a quantitative and competitive PCR-ELISA assay to identify patients with CMV disease. Methods: Three hundred and fifty sample from 65 non-selected cadaveric renal transplant recipients were studies. DNA was extracted from PBMC weekly up to day of discharge and tested by qualitative PCR. The positive samples were studied by quantitative competitive PCR-ELISA

Una técnica de PCR-ELISA cuantitativa para el diagnóstico de enfermedad por citomegalavirus (CMV) en pacientes transplantados renales / A technique of cuantitative PCR-ELISA for diagnosis of cytomegalovirus disease in renal transplanted patients

Introducción: El citomegalovirus (CMV) es el agente causal de la enfermedad viral de mayor prevalencia en pacientes transplantados. La detección del ADN de CMV por medio del PCR es común entre los pacientes receptores de ri±ones, dando resultados falsos positivos en pacientes que no tienen enfermedad. Hemos desarrollado una técnica de PCR-ELISA cuantitativa y competitiva para identificar pacientes que padecen la enfermedad por CMV. Métodos: Analizamos 350 muestras provenientes de 65 receptores de transplantes renales cadavéricos no seleccionados. Se extrajo ADN de CMSP semanalmente hasta el día de la alta hospitalaria y se lo estudio por PCR cualitativa. Los casos positivos se analizaron por PCR-ELISA cuantitativa y competitiva también. Esta técnica usa un estßndar interno(SI) heterólogo que contiene la misma secuencia de oligonucleótido para el 4to exon del gen del antigeno temprano inmediato (ATI) utilizado en una PCR cualitativa. La detección y cuantificación se realizó en placas de 96 pozo cubiertas con sondas específicas para él SI y CMV. Los resultados se expresaron como copias virales (CV) por 1 millón de CMSP. Resultados: Cuarenta y uno de los pacientes (63,1 por ciento) tuvieron un ensayo cualitativo positivo y 8 de ellos tenían infección clínica por CMV. Los 41 pacientes con PCR (+) fueron re-analizados por ensayo cuantitativo. Los 8 que tenían la enfermedad por CMV presentaron un valor promedio de 219,6+/- 117,2 CV/106 CMSP (P<0,01)Conclusión: La carga viral de CMV es útil para identificar los pacientes transplantados renales que desarrollaron la enfermedad por CMV. Valores mayores a 500 CV/106 CMSP se relacionan altamente con el desarrollo de la enfermedad.ABSTRACT: Background: Cytomegalovirus (CMV)is the most prevalent viral disease in organ transplantation. Detection of CMV DNA in PBMC by PCR occurs frequently in renal allograft recipients, yielding false positive patient not having the CMV disease. We have developed a quantitative and competitive PCR-ELISA assay to identify patients with CMV disease. Methods: Three hundred and fifty sample from 65 non-selected cadaveric renal transplant recipients were studies. DNA was extracted from PBMC weekly up to day of discharge and tested by qualitative PCR. The positive samples were studied by quantitative competitive PCR-ELISA