Infections caused by herpes viruses other than cytomegalovirus in solid organ transplant recipients

Risk factors for colonization and infection by resistant microorganisms in kidney transplant recipients

OBJECTIVES

to assess the prevalence of colonization and infection by multidrug-resistant bacteria in patients undergoing kidney transplantation and identify the rate of infection, morbidity and mortality and associated risk factors.

METHODS

a prospective cohort of 200 randomly included kidney transplant recipients. Epidemiological surveillance of the studied microorganisms was carried out in the first 24 hours and 7 days after transplantation.

RESULTS

ninety (45%) patients were considered colonized. Female sex, hypertension and diabetes (p<0.005), dialysis time (p<0.004), length of stay after transplantation, delayed renal function, and length of stay were identified as risk factors. The microorganisms were isolated from surgical site, bloodstream and urinary tract infections.

CONCLUSIONS

colonization by resistant microorganisms in kidney transplant patients was frequent and risk factors associated with infection were identified. The results should guide the care team in order to minimize morbidity and mortality related to infectious causes in this population.

Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?

During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.

Immunosuppressive Medication and Non-Rejection-Related Complications Following Heart Transplantation

Background: Although the clinical evolution of a patient with heart failure is initially improved by transplantation, a number of potential complications may occur in the post-transplant period, which may be directly related to the effects of chronic immunosuppression. The purpose of this study was to analyze the occurrence and frequency of post-transplant complications related to immunosuppressive treatment in the Institute of Cardiovascular Diseases and Transplantation of Târgu Mureș, Romania.

Material and methods: This is a descriptive study including 53 patients out of a total of 71 patients who underwent cardiac transplantation between 2000 and 2017 in the Institute of Cardiovascular Disease and Cardiac Transplantation in Târgu Mureș, Romania. Data were collected from the patient files and included demographic, clinical and laboratory data, as well as information about post-transplant complications related to immunosuppressive treatment.

Results: The mean age of patients undergoing heart transplantation was 40.72 ± 14.07 years, the majority of patients being male (84.91%) and living in an urban environment (56.60%). The average length of hospital stay was 33.6 days. From the total number of patients, 7 (13.2%) presented post-transplantation bacterial infections, while antibodies indicating the presence or history of B hepatitis, toxoplasma, and cytomegalovirus infection were identified with a relatively high incidence in the study population.

Conclusions: Infections following surgery are probably the most common post-transplant pathology, the primary reason being the administration of immunosuppressive medication.

Evolution of Kaposi sarcoma in the past 30 years in a tertiary hospital of the European Mediterranean basin

BACKGROUND

The incidence of Kaposi sarcoma (KS) has reduced as a result of the introduction of antiretroviral therapy. It is currently considered a rare disease in developed countries, and there has been a paucity of clinical papers on the subject in recent years in Europe.

AIM

To analyse the clinical features and evolution of the different clinical forms of KS in the past 30 years.

METHODS

Patients with cutaneous lesions of KS diagnosed during the period 1987-2016 at Bellvitge Hospital (an 800-bed university referral centre in Barcelona, Spain) were enrolled. Data recorded included age, sex, ethnicity, involved site, number of lesions, extracutaneous involvement, leg oedema, treatment, blood haemoglobin level, and blood cell (leucocyte, lymphocyte and CD4) counts.

RESULTS

Cutaneous lesions of KS were diagnosed in 191 patients (167 men, 24 women, mean ± SD age 51.95 ± 20.16 years). Clinical forms identified were classic KS (n = 53), acquired immunodeficiency syndrome (AIDS)-associated KS (n = 118), immunosuppression-associated KS (n = 18), and African endemic KS (n = 2). The number of patients diagnosed annually reached a maximum in the 1990s because of the AIDS epidemic, and has decreased since 2000. However, both classic KS and immunosuppression-associated KS doubled from the first to the second half of the analysed period. Cutaneous lesions involved the legs in 137 cases, and extracutaneous lesions were detected in 32 patients. In 46 of 118 patients with AIDS, the diagnosis of KS was simultaneous to the detection of human immunodeficiency virus infection.

CONCLUSION

After a decrease in incidence since the middle of the 1990s, AIDS-associated KS continues to occur in Europe, and the number of annual cases of classic KS and immunosuppression-associated KS is increasing.

Oral shedding of human herpesviruses in renal transplant recipients

OBJECTIVE

To describe the shedding profile of human herpesviruses in the saliva of renal transplant recipients.

METHODS

This is a prospective case-control study of 50 renal transplant recipients and control group of 50 individuals (non-transplanted and immunocompetent). Mouthwash samples were collected via oral rinse and then submitted to screening for the presence of eight types of herpesviruses by using multiplex PCR. Fisher's exact, chi-square, and Student t tests were used for statistical analysis, and the significance level was set at 5%.

RESULTS

The mean age of the study group was 49.42 ± 12.94 years, 28/50 (56%) were female, and the time elapsed after transplantation was 68.20 ± 67.19 months. Herpes simplex virus 1 (HSV-1) (P = 0.025) and Epstein-Barr virus (EBV) (P = 0.024) were, statistically, more excreted in the saliva of renal transplant recipients compared to control group. Gender (P = 1.00) and age (P = 0.563) did not influence the salivary shedding of herpesviruses in renal transplant recipients. Individuals who excreted varicella-zoster virus in saliva had a shorter mean time of transplantation (22:00 + 2.82 months) (P < 0.001).

CONCLUSION

Renal transplant recipients excreted herpesviruses more often than controls, especially HSV-1 and EBV, with salivary shedding of herpesviruses being more frequent in patients with recent kidney transplantation.

CLINICAL RELEVANCE

The present findings support other longitudinal studies evaluating the relationship between oral shedding of human herpesviruses and clinical presence of active infection and renal transplant failure.

Metagenomic sequencing complements routine diagnostics in identifying viral pathogens in lung transplant recipients with unknown etiology of respiratory infection

Background

Lung transplant patients are a vulnerable group of immunosuppressed patients that are prone to frequent respiratory infections. We studied 60 episodes of respiratory symptoms in 71 lung transplant patients. Almost half of these episodes were of unknown infectious etiology despite extensive routine diagnostic testing.

Methods

We re-analyzed respiratory samples of all episodes with undetermined etiology in order to detect potential viral pathogens missed/not accounted for in routine diagnostics. Respiratory samples were enriched for viruses by filtration and nuclease digestion, whole nucleic acids extracted and randomly amplified before high throughput metagenomic virus sequencing. Viruses were identified by a bioinformatic pipeline and confirmed and quantified using specific real-time PCR.

Results

In completion of routine diagnostics, we identified and confirmed a viral etiology of infection by our metagenomic approach in four patients (three Rhinovirus A, one Rhinovirus B infection) despite initial negative results in specific multiplex PCR. Notably, the majority of samples were also positive for Torque teno virus (TTV) and Human Herpesvirus 7 (HHV-7). While TTV viral loads increased with immunosuppression in both throat swabs and blood samples, HHV-7 remained at low levels throughout the observation period and was restricted to the respiratory tract.

Conclusion

This study highlights the potential of metagenomic sequencing for virus diagnostics in cases with previously unknown etiology of infection and in complex diagnostic situations such as in immunocompromised hosts.

Genetic variants of innate immune receptors and infections after liver transplantation

Infection is the leading cause of complication after liver transplantation, causing morbidity and mortality in the first months after surgery. Allograft rejection is mediated through adaptive immunological responses, and thus immunosuppressive therapy is necessary after transplantation. In this setting, the presence of genetic variants of innate immunity receptors may increase the risk of post-transplant infection, in comparison with patients carrying wild-type alleles. Numerous studies have investigated the role of genetic variants of innate immune receptors and the risk of complication after liver transplantation, but their results are discordant. Toll-like receptors and mannose-binding lectin are arguably the most important studied molecules; however, many other receptors could increase the risk of infection after transplantation. In this article, we review the published studies analyzing the impact of genetic variants in the innate immune system on the development of infectious complications after liver transplantation.

The role of the clinical microbiology laboratory in solid organ transplantation programs

Infections remain a major complication of solid organ transplantation. For this reason, the clinical microbiology laboratory plays a key role in the success of transplant programs, which must have the support of a qualified laboratory, both technically and professionally. Transplant programs strongly condition the structure and functionality of microbiology laboratories, but at the same time, benefit greatly from the knowledge generated from these programs. The laboratory must make a special effort to implement rapid methods that can respond to the broad spectrum of potential pathogens in solid organ transplant patients. The integration of microbiologists in multidisciplinary teams is highly recommended, as only then can they obtain the highest quality and efficiency in the diagnostic process. This article provides an updated review of the techniques to be used once transplantation has occurred. The role of the microbiologist is also crucial in the pretransplant period, as good microbiological candidate evaluation at this time strongly conditions the success of the transplantation program.