Susceptibility of solid organ transplant recipients to viral pathogens with zoonotic potential: A mini-review.

A substantial number of zoonotic diseases are caused by viral pathogens, representing a significant menace to public health, particularly to susceptible populations, such as pregnant women, the elderly, and immunocompromised individuals. Individuals who have undergone solid organ transplantation frequently experience immunosuppression, to prevent organ rejection, and, thus are more prone to opportunistic infections. Furthermore, the reactivation of dormant viruses can threaten transplant recipients and organ viability. This mini-review examines the up-to-date literature covering potential zoonotic and organ rejection-relevant viruses in solid organ transplant recipients. A comprehensive list of viruses with zoonotic potential is highlighted and the most important clinical outcomes in patients undergoing transplantation are described. Moreover, this mini-review calls attention to complex multifactorial events predisposing viral coinfections and the need for continuous health surveillance and research to understand better viral pathogens' transmission and pathophysiology dynamics in transplanted individuals.

Susceptibility of solid organ transplant recipients to viral pathogens with zoonotic potential: A mini-review

ABSTRACT A substantial number of zoonotic diseases are caused by viral pathogens, representing a significant menace to public health, particularly to susceptible populations, such as pregnant women, the elderly, and immunocompromised individuals. Individuals who have undergone solid organ transplantation frequently experience immunosuppression, to prevent organ rejection, and, thus are more prone to opportunistic infections. Furthermore, the reactivation of dormant viruses can threaten transplant recipients and organ viability. This mini-review examines the up-to-date literature covering potential zoonotic and organ rejection-relevant viruses in solid organ transplant recipients. A comprehensive list of viruses with zoonotic potential is highlighted and the most important clinical outcomes in patients undergoing transplantation are described. Moreover, this mini-review calls attention to complex multifactorial events predisposing viral coinfections and the need for continuous health surveillance and research to understand better viral pathogens' transmission and pathophysiology dynamics in transplanted individuals.

Quantitative PCR-Based Diagnosis and Follow-up of Chagas Disease Primary Infection After Solid Organ Transplant: A Multicentre Study.

Chagas disease in solid organ transplant recipients may present as a primary infection (PI). Early detection is crucial for timely treatment. This is the largest observational multicentre study evaluating qPCR for early diagnosis and treatment monitoring of PI in seronegative recipients of organs from seropositive donors. Of 34 patients admitted at 5 health centers, PI was detected by qPCR in 8 (23.5%) within a posttransplant period of 40 days (interquartile range [IQR], 31-50 days). No PI was detected by the Strout test or clinical symptoms/signs. All patients had favorable treatment outcome with negative qPCR 31 days (IQR, 18-35 days) after treatment, with no posttreatment relapse episodes.

Epidemiology, management, and burden of cytomegalovirus in solid organ transplant recipients in selected countries outside of Europe and North America: A systematic review.

BACKGROUND: Cytomegalovirus (CMV) is a frequent infectious complication following solid organ transplantation (SOT). Considering significant differences in healthcare systems, a systematic review was conducted to describe the epidemiology, management, and burden of CMV post-SOT in selected countries outside of Europe and North America. METHODS: MEDLINE, Embase, and Cochrane databases were searched for observational studies in SOT recipients across 15 countries in the regions of Asia, Pacific, and Latin America (search period: January 1, 2011 to September 17, 2021). Outcomes included incidence of CMV infection/disease, recurrence, risk factors, CMV-related mortality, treatment patterns and guidelines, refractory and/or resistant CMV, patient-reported outcomes, and economic burden. RESULTS: Of 2708 studies identified, 49 were eligible (n = 43/49; 87.8% in adults; n = 34/49, 69.4% in kidney recipients). Across studies, selection of CMV preventive strategy was based on CMV serostatus. Overall, rates of CMV infection (within 1 year) and CMV disease post-SOT were respectively, 10.3%-63.2% (9 studies) and 0%-19.0% (17 studies). Recurrence occurred in 35.4%-41.0% cases (3 studies) and up to 5.3% recipients died of CMV-associated causes (11 studies). Conventional treatments for CMV infection/disease included ganciclovir (GCV) or valganciclovir. Up to 4.4% patients were resistant to treatment (3 studies); no studies reported on refractory CMV. Treatment-related adverse events with GCV included neutropenia (2%-29%), anemia (13%-48%), leukopenia (11%-37%), and thrombocytopenia (13%-24%). Data on economic burden were scarce. CONCLUSION: Outside of North America and Europe, rates of CMV infection/disease post-SOT are highly variable and CMV recurrence is frequent. CMV resistance and treatment-associated adverse events, including myelosuppression, highlight unmet needs with conventional therapy.

Tuberculosis treatment without rifampin in kidney/kidney-pancreas transplantation: A case series report.

BACKGROUND: The best approach to tuberculosis (TB) treatment in transplanted patients is still unknown. Current guidelines are based on evidence either extrapolated from other populations or observational. Rifampin-containing regimens have strong pharmacokinetic interactions with immunosuppressive regimens, with high rates of organ dysfunction and ∼20% mortality. This report describes the results obtained using non-rifampin-containing regimens to treat confirmed TB in adult patients with kidney/kidney-pancreas transplantation. METHODS: Retrospective data analysis from confirmed TB cases in adult kidney/kidney-pancreas transplant recipients (2006-2019), treated "de novo" with non-rifampin-containing regimens. RESULTS: Fifty-seven patients had confirmed TB. Thirty patients were treated "de novo" with non-rifampin-containing regimens. These patients' mean age was 49.24 (±11.50) years. Induction immunosuppression was used in 22 patients. Maintenance immunosuppression was tacrolimus-mycophenolate-steroids in 13 (43%), sirolimus-mycophenolate-steroids in 6 (20%), and other immunosuppressive regimens in 11 (36%). Belatacept was used in four patients. TB localizations: pulmonary 43%; disseminated 23%; extrapulmonary 33%. Twenty-seven (90%) patients completed treatment with isoniazid, ethambutol, and levofloxacin (12 months, 23; 9 months, 3; 6 months, 1); 12 of these patients also received pyrazinamide for the first 2 months and were cured with functioning grafts. One patient (3%) lost the graft while on treatment. Two patients (7%) died while on TB treatment. Median (range) follow-up after completion of TB treatment was 32 (8-150) months. No TB relapses were observed. CONCLUSIONS: Results with non-rifampin-containing TB treatments in this case series were better (in terms of mortality and graft dysfunction) than those previously described with rifampin-containing regimens in transplanted patients.

Quantification of torque teno virus (TTV) DNA in saliva and plasma samples in patients at short time before and after kidney transplantation.

BACKGROUND: Several reports have proposed that the viral load of torque teno virus (TTV) in plasma is a biomarker of immune function in solid organ transplantation (SOT) and in allogeneic hematopoietic stem cell transplantation. Additionally, for the latter one, TTV-DNA quantification in saliva has also been suggested. AIM: to investigate the correlation between the TTV viral load and immune function in paired saliva and plasma samples in patients on kidney transplantation. MATERIALS AND METHODS: TTV-DNA viral load was quantified in paired samples of saliva and plasma from 71 patients before and a short-time after renal-transplantation by real-time PCR. RESULTS: The data obtained from 213 paired samples showed a slight consistency in the comparison between saliva and plasma, with prevalence of TTV-DNA being 58%, 52% and 60% in saliva samples and 60%, 73% and 90% in plasma samples before and at 15-20 and 45-60 days after transplantation, respectively. Additionally, a high TTV viral load was observed in plasma at 15-20 and 45-60 days after transplantation compared to that observed in saliva at the same time. CONCLUSIONS: Overall, monitoring TTV-DNA in saliva samples could be an additional fast non-invasive option to assess the immune functionality in SOT populations.

American trypanosomiasis (Chagas disease) in solid organ transplantation.

This review addresses relevant aspects of Chagas disease in the solid organ transplantation setting. This trypanosomiasis was geographically restricted to America, but migration has turned Chagas disease into a global public health concern. Parasite persistence in chronically infected individuals entails the potential of transmission with organ donation and the potential for reactivation under immunosuppression. Prospective monitoring with real-time PCR or direct methods for detection of parasitemia and treatment of documented episodes of transmission/ reactivation (rather than prophylactic treatment) is the recommended approach for managing patients at risk. Chagas disease is an important cause of terminal cardiomyopathy. Clinical results demonstrate that with adequate monitoring and treatment, patients with Chagas cardiomyopathy benefit from heart transplantation, with long-term results even better than patients who underwent heart transplantation due to other conditions. Kidney and liver (and possibly other solid organs) transplantation can be safely performed in chronically infected patients with adequate management. Chronically infected patients are also suitable for organ donation (with the exception of the heart and intestines). Although reactivations and transmissions are observed, serious clinical disease is rare, and they are usually successfully managed with benznidazole or nifurtimox.

Urban Spread of Flaviviruses: A New Challenge in Solid-organ Transplant Recipients.

Yellow fever has never previously been reported in transplant recipients. The first reported case of yellow fever in a kidney transplant recipient in Brazil and the re-emergence of arboviruses in many areas of the world dictate the need of studies aimed to answer multiple unanswered questions.

Seronegativity to polio viruses among previously immunized adult candidates to solid organ transplantation.

In the current effort to eliminate polio from the world, it is important to recognize and vaccinate susceptible groups, especially immunocompromised patients living in countries where attenuated polio vaccine is still used. In this report, we describe the frequency of protective antibodies in a small sample of adult SOT candidates in whom previous vaccination could be ascertained. Patients included in this report were selected among the participants of an ongoing prospective study carried out at the Reference Center for Special Immunobiologicals of the Evandro Chagas National Institute of Infectious Diseases in Rio de Janeiro, Brazil. Among the first 100 patients enrolled in this study, only seven adult SOT candidates had proven polio vaccination at childhood. Three of these seven patients (43%) had no protective antibody titers to one or more poliovirus subtype before solid organ transplant. Proven childhood vaccination against polio does not reliably provide lifelong protective antibody titers for adult SOT candidates and should not be used as a criterion to analyze the need for vaccination in this population.

Seronegativity to polio viruses among previously immunized adult candidates to solid organ transplantation

ABSTRACT In the current effort to eliminate polio from the world, it is important to recognize and vaccinate susceptible groups, especially immunocompromised patients living in countries where attenuated polio vaccine is still used. In this report, we describe the frequency of protective antibodies in a small sample of adult SOT candidates in whom previous vaccination could be ascertained. Patients included in this report were selected among the participants of an ongoing prospective study carried out at the Reference Center for Special Immunobiologicals of the Evandro Chagas National Institute of Infectious Diseases in Rio de Janeiro, Brazil. Among the first 100 patients enrolled in this study, only seven adult SOT candidates had proven polio vaccination at childhood. Three of these seven patients (43%) had no protective antibody titers to one or more poliovirus subtype before solid organ transplant. Proven childhood vaccination against polio does not reliably provide lifelong protective antibody titers for adult SOT candidates and should not be used as a criterion to analyze the need for vaccination in this population.

Transmission of dengue virus from deceased donors to solid organ transplant recipients: case report and literature review.

Dengue fever is a vector-transmitted viral infection. Non-vectorial forms of transmission can occur through organ transplantation. We reviewed medical records of donors and recipients with suspected dengue in the first post-transplant week. We used serologic and molecular analysis to confirm the infection. Herein, we describe four cases of dengue virus transmission through solid organ transplantation. The recipients had positive serology and RT-PCR. Infection in donors was detected through serology. All cases presented with fever within the first week after transplantation. There were no fatal cases. After these cases, we implemented dengue screening with NS1 antigen detection in donors during dengue outbreaks, and no new cases were detected. In the literature review, additional cases had been published through August 2017. Transmission of Dengue virus can occur through organ donation. In endemic regions, it is important to suspect and screen for dengue in febrile and thrombocytopenic recipients in the postoperative period.

Transmission of dengue virus from deceased donors to solid organ transplant recipients: case report and literature review

ABSTRACT Dengue fever is a vector-transmitted viral infection. Non-vectorial forms of transmission can occur through organ transplantation. We reviewed medical records of donors and recipients with suspected dengue in the first post-transplant week. We used serologic and molecular analysis to confirm the infection. Herein, we describe four cases of dengue virus transmission through solid organ transplantation. The recipients had positive serology and RT-PCR. Infection in donors was detected through serology. All cases presented with fever within the first week after transplantation. There were no fatal cases. After these cases, we implemented dengue screening with NS1 antigen detection in donors during dengue outbreaks, and no new cases were detected. In the literature review, additional cases had been published through August 2017. Transmission of Dengue virus can occur through organ donation. In endemic regions, it is important to suspect and screen for dengue in febrile and thrombocytopenic recipients in the postoperative period.

Herpesviruses excretion in saliva of pediatric transplant recipients.

BACKGROUND: Saliva samples could be used for follow-up of herpesviruses infection in pediatric transplant recipients. OBJECTIVE: With the aim of determining the frequency of herpesviral infections in saliva samples after transplantation, and the association with viremia and complications, a pilot longitudinal follow-up of pediatric Cuban transplanted recipients (kidney and liver) was performed. METHODS: Quantitative real-time polymerase chain reaction of cytomegalovirus (CMV), Epstein-Barr virus, herpes simplex virus, human herpesevirus-6 (HHV6), varicella zoster virus, and human herpesvirus-8 were serially assayed in saliva and serum samples from 27 transplanted patients, during 32 weeks after the graft. Samples taken immediately after the graft were used as control samples. RESULTS: Herpesviruses were detected in 88.9% of saliva and in 37.0% of serum samples. HHV6 and CMV were the viruses more frequently detected (70.4%) in saliva and they were significantly more frequent during the follow-up in comparison with control samples (P < .05). Most patients (22/27) had more than one virus shedding concurrently. Patients with CMV in saliva were associated with CMV viremia (P = .009), particularly at the cutoff of 252.5 copies/mL, with a less accurate level of area under the curve. No association between CMV viral load in saliva and viral disease or response to the antiviral treatment was observed. CONCLUSIONS: The association found between CMV shedding in saliva and CMV viremia in this study opens the possibility of future studies of using viral load in saliva as a predictor of viremia. The implementation of herpesviral load in saliva samples for early clinical intervention in pediatric recipients needs a study with a large number of samples for further conclusions.

Response to immunization in children born to renal transplant recipients using immunosuppressive drugs during gestation.

The use of immunosuppressive drugs can impair vaccination responses. When used during pregnancy, they may interfere with the development of the fetus's immune system. However, little is known regarding their influence on infant's response to vaccinations. Twenty-seven children born to renal transplant mothers (Tx) taking immunosuppressive drugs and 31 healthy children had the humoral immune response and reactogenicity to tetanus, Haemophilus influenzae type b (Hib) and 7 pneumococcal serotypes evaluated. The evolution of BCG vaccine scar was also registered. Antibodies were measured by ELISA. Lymphocyte immunophenotyping was performed on cord blood and at 7-8 months of age. Among Tx neonates, 82.4% had low B lymphocyte numbers at birth, and 29.4% had also low numbers of other lymphocyte subpopulations. Nevertheless, all children developed protective antibodies with similar antibody concentrations to the control group. Vaccine reactogenicity was similar in both groups and BCG healing was uneventful.

A first report of leptospirosis after liver transplantation.

Leptospirosis has been rarely reported in solid organ transplant recipients. We report the first case to our knowledge of leptospirosis in a liver transplant recipient who developed jaundice and renal insufficiency. We describe his favorable clinical progression and discuss the possible mechanisms involved in the more benign disease course. We also review the previously published cases of leptospirosis in solid organ transplant recipients. Although this disease does not appear to present any particularities in this context, we highlight the importance of clinical suspicion in this setting, particularly after liver transplantation.

Growth following solid organ transplantation in childhood

One of the ultimate goals of successful solid organ transplantation in pediatric recipients is attaining an optimal final adult height. This manuscript will discuss growth following transplantation in pediatric recipients of kidney, liver, heart, lung or small bowel transplants. Remarkably similar factors impact growth in all of these recipients. Age is a primary factor, with younger recipients exhibiting the greatest immediate catch-up growth. Graft function is a significant contributing factor, with a reduced glomerular filtration rate correlating with poor growth in kidney recipients and the need for re-transplantation with impaired growth in liver recipients. The known adverse impact of steroids on growth has led to modification of the steroid dose and even steroid withdrawal and avoidance. In kidney and liver recipients, this strategy has been associated with the development of acute rejection. In infant heart transplantation, avoiding maintenance corticosteroid immunosuppression is associated with normal growth velocity in the majority of patients. With marked improvements in patient and graft survival rates in pediatric organ recipients, quality of life issues, such as normal adult height, should now receive paramount attention. In general, normal growth following solid organ transplantation should be an achievable goal that results in normal adult height.

Enfermedad inflamatoria intestinal y trasplante de órgano sólido: ¿Qué factores hay que considerar en el manejo? Revisión de la literatura a partir de un caso clínico / Inflammatory bowel disease and solid organ transplant. What factors must be considered for management?: case report and review of the literature

Inflammatory bowel disease (IBD), is a chronic condition, nevertheless its association with solid organ transplantation (SOT) is rare. Its presence stresses decisions on best options dealing with IBD management, immunosuppressive therapy and colorectal cancer (CRC) risks in this group of patients. Literature focused on this topic is scarce. Most of the literature corresponds to retrospective or case series of IBD patients submitted to hepatic orthotropic transplant, due to primary sclerosing cholangitis. The aim of this review is, from an individual clinical case, to tackle the different issues that could be of interest in patients requiring SOT, with or without previous IBD. The interest is focused on IBD evolution, de novo- active IBD and CRC risk. In conclusion, the most important point is that the need to perform a proctocolectomy is more related to the IBD severity than to the transplant itself. The recommendation is that these patients should be managed by a multidisciplinary team on a case by case analysis.

Aunque la enfermedad inflamatoria intestinal (EII) es una condición crónica, la asociación de pacientes con EII y trasplante de órgano sólido (TOS) ocurre de manera muy infrecuente. Sin embargo, su presencia sin duda estresa las decisiones sobre cuáles son las mejores opciones en el manejo de la EII, la terapia inmunosupresora y el riesgo de cáncer colorectal (CCR) en este grupo de pacientes. Hasta la fecha, existe escasa literatura sobre este tema y la mayoría se basa en series retrospectivas y casos clínicos de pacientes con EII que han sufrido un trasplante hepático por colangitis esclerosante primaria. El objetivo de esta revisión es mencionar a partir de un caso clínico, los diferentes aspectos relacionados con pacientes que requieren un TOS con o sin EII previa, destacando la evolución de la EII, el desarrollo de una EII-de novo y el riesgo de CCR. Sin duda, el punto más importante es que la decisión de realizar una colectomía está determinada por la gravedad de la EII y no por el TOS en sí. Es recomendable que estos pacientes sean abordados por un equipo multidisciplinario experto, y analizados caso a caso.

Profilaxis antifúngica en niños y adultos sometidos a trasplante de órganos sólidos y de precursores hematopoyéticos / Prophylaxis against fungal infections in solid organ and hematopoietic stem cells transplantation

Invasive fungal infections are an important cause of morbidity and mortality in SOT and HSCT recipients. The main species involved are Candida spp. and Aspergillus spp, less frequently Cryptococcus spp., causal agents of mucormycosis and Fusarium spp. Usually occur within the first six months post-transplant, but they do it later, especially during episodes of rejection, which maintains the state of immune system involvement. Prophylaxis recommendations are specific to each type of transplant. In liver transplantation use of fluconazole is recommended only in selected cases by high risk factor for invasive fungal infections (A1). If the patient has a high risk of aspergillosis, there are some suggestions for adults population to use amphotericin B-deoxycholate, liposomal amphotericin B or caspofungin (C2) without being validated none of these recommendations in pediatric population. In adult lung transplant patients where the risk of aspergillosis is higher than in other locations, we recommend universal prophylaxis with itraconazole 200 mg/day, nebulised liposomal amphotericin B or voriconazole (C2), no validated recommendations for pediatrics. In HSCT, universal prophylaxis is recommended only in allogeneic and autologous selected cases. The most accepted indication is fluconazole (A1), and posaconazole (A1) or micafungin (A1) in selected cases with high risk of aspergillosis.

Las infecciones fúngicas invasoras constituyen una importante causa de morbilidad y mortalidad en los pacientes receptores de TOS y TPH. Los principales agentes involucrados son Candida spp. y Aspergillus spp, menos frecuentemente Cryptococcus spp., agentes causales de mucormicosis y Fusarium spp. Se presentan habitualmente dentro de los primeros seis meses posttrasplante, pero también lo hacen en forma más tardía, especialmente durante episodios de rechazo, en que se mantiene el estado de compromiso del sistema inmune. Existen recomendaciones de proilaxis especíicas para cada tipo de trasplante. En trasplante hepático se recomienda el uso de fluconazol sólo en casos seleccionados por factores de riesgo (A1). Si existe riesgo de asper-gilosis, hay algunas sugerencias en adultos para el uso de anfotericina B-deoxicolato, anfotericina liposomal o caspofungina (todo en categoría C2), sin estar validada ninguna de estas recomendaciones en pediatría. En trasplante pulmonar en paciente adulto, donde el riesgo de aspergilosis es superior a otras localizaciones, se recomienda proilaxis universal, con itraconazol 200 mg/día, anfotericina liposomal nebulizada o voriconazol (C2), sin recomendaciones validadas para pediatría. En TPH, se recomienda proilaxis universal en trasplante alogénico y sólo para casos seleccionados en trasplantes autólogos. La indicación más aceptada es fluconazol (A1), siendo alternativas a evaluar dependiendo del riesgo de aspergilosis, posaconazol (A1) y micafungina (A1).

Profilaxis de neumonía por Pneumocystis jiroveci en niños y adultos sometidos a trasplante de órganos sólidos y de precursores hematopoyéticos / Prophylaxis against Pneumocystis pneumonia in pediatric and adult patients undergoing solid organ or hematopoietic stem cells transplantation

Pneumocystis jiroveci is an important pathogen in patients undergoing SOT and HSCT. Universal prophylaxis is recommended for all adults and children with SOT and HSCT, considering that its use significantly reduces the occurrence and mortality associated with pneumonia by this agent. The drug of choice is cotrimoxazole (A1) three times a week, low-dose scheme, that has proved equally effective and better tolerated than the daily regimen and/or at high doses. Prophylaxis starts 7 to 14 days post transplant in SOT recipients and post-implant in HSCT, with an average duration of 6 months except in liver and lung transplant as in HSCT with significant degree of immunosuppression, that lasts for 1 year. Alternatives for prophylaxis are dapsone (B2), aerosolized pentamidine (B2) and atovaquone (C2).

Pneumocystis jiroveci es un patógeno importante en pacientes sometidos a TOS y TPH. Se recomienda proilaxis universal a todos los pacientes adultos y niños sometidos a TOS o TPH porque su uso reduce signiicati-vamente la ocurrencia y mortalidad asociada a neumonía por este agente. El medicamento de elección es cotrimoxa-zol (A1) tres veces por semana, en dosis bajas, esquema que ha demostrado igual eicacia y mejor tolerancia que el esquema diario y/o con dosis altas. La proilaxis se inicia 7 a 14 días post trasplante en TOS y posterior al implante en TPH, con una duración promedio de 6 meses salvo en trasplante de hígado y pulmón en que se prolonga por 1 año, al igual que en TPH con grado importante de inmunosupresión. Son alternativas de profilaxis dapsona (B2), pentamidina aerosolizada (B2) y atavacuona (C2).

Profilaxis de citomegalovirus en niños y adultos sometidos a trasplante de órganos sólidos y de precursores hematopoyéticos / Prophylaxis against cytomegalovirus infection in pediatric and adult patients undergoing solid organ and hematopoietic stem cells transplantation

CMV is one of the main infectious problems for SOT and HSCT. The severity of the complications are mainly associated with the type of transplant and immune status against the virus of the transplant donor and the transplant recipient. It is important to prevent exposure, using safe blood transfusion CMV seronegative donors (B1) and/or use of blood leucocytes-depleted by filtration (Al). In addition to preventing exposure, there are two widely used prevention strategies: universal prophylaxis with antiviral therapy or "pre-emptive" strategy based on the use of antivirals only to the early detection of CMV replication in blood. The first option is most used in the SOT management, especially for those identified as the high risk group of CMV disease: R (+), with D (+) or D (-) (Al), where the recommended drug is ganciclovir or valganciclovir . The second approach is preferable for HSCT, which recommends weekly monitoring for CMV viral load from day 10 to 100 post transplant (A3). This strategy requires having a viral laboratory support (A2). The selected antiviral in the case of pre emptive therapy is intravenous ganciclovir (A1).

La infección y enfermedad por CMV son problemas comunes en pacientes con TOS y TPH. La gravedad de las complicaciones asociadas a este virus dependen fundamentalmente del tipo de trasplante y de la experiencia inmunológica previa contra el virus del donante y el receptor. Es importante prevenir la exposición, utilizando transfusiones de sangre segura para CMV con donantes seronegativos (B1) y/o uso de sangre leuco-depletada por iltración (A1). Además de prevenir la exposición, existen dos estrategias de prevención ampliamente utilizadas: La proilaxis universal con antivirales y la terapia adelantada o estrategia "pre-emptive" basada en el uso de antivirales sólo ante la detección precoz de replicación del CMV en sangre. La primera opción es de mayor uso en TOS, especialmente para aquellos binomios identficados como de mayor riesgo de enfermedad por CMV: R (+), con D (+) o D (-) (A1), siendo el medicamento recomendado ganciclovir o valganciclovir. La segunda opción es de elección en TPH, en cuyo caso se recomienda monitoreo semanal con carga viral para CMV desde el día 10 al 100 post trasplante (A3), lo que implica contar con un laboratorio de apoyo en diagnóstico virológico (A2). El antiviral de elección en este caso es ganciclovir iv (A1).