Irene Rebollo-Mesa

Development of a cross-platform biomarker signature to detect renal transplant tolerance in humans.

Identifying transplant recipients in whom immunological tolerance is established or is developing would allow an individually tailored approach to their posttransplantation management. In this study, we aimed to develop reliable and reproducible in vitro assays capable of detecting tolerance in renal transplant recipients. Several biomarkers and bioassays were screened on a training set that included 11 operationally tolerant renal transplant recipients, recipient groups following different immunosuppressive regimes, recipients undergoing chronic rejection, and healthy controls. Highly predictive assays were repeated on an independent test set that included 24 tolerant renal transplant recipients. Tolerant patients displayed an expansion of peripheral blood B and NK lymphocytes, fewer activated CD4+ T cells, a lack of donor-specific antibodies, donor-specific hyporesponsiveness of CD4+ T cells, and a high ratio of forkhead box P3 to alpha-1,2-mannosidase gene expression. Microarray analysis further revealed in tolerant recipients a bias toward differential expression of B cell-related genes and their associated molecular pathways. By combining these indices of tolerance as a cross-platform biomarker signature, we were able to identify tolerant recipients in both the training set and the test set. This study provides an immunological profile of the tolerant state that, with further validation, should inform and shape drug-weaning protocols in renal transplant recipients.

Prophylactic antibiotics after acute stroke for reducing pneumonia in patients with dysphagia (STROKE-INF): a prospective, cluster-randomised, open-label, masked endpoint, controlled clinical trial

BACKGROUND Post-stroke pneumonia is associated with increased mortality and poor functional outcomes. This study assessed the effectiveness of antibiotic prophylaxis for reducing pneumonia in patients with dysphagia after acute stroke. METHODS We did a prospective, multicentre, cluster-randomised, open-label controlled trial with masked endpoint assessment of patients older than 18 years with dysphagia after new stroke recruited from 48 stroke units in the UK, accredited and included in the UK National Stroke Audit. We excluded patients with contraindications to antibiotics, pre-existing dysphagia, or known infections, or who were not expected to survive beyond 14 days. We randomly assigned the units (1:1) by computer to give either prophylactic antibiotics for 7 days plus standard stroke unit care or standard stroke unit care only to patients clustered in the units within 48 h of stroke onset. We did the randomisation with minimisation to stratify for number of admissions and access to specialist care. Patient and staff who did the assessments and analyses were masked to stroke unit allocation. The primary outcome was post-stroke pneumonia in the first 14 days, assessed with both a criteria-based, hierarchical algorithm and by physician diagnosis in the intention-to-treat population. Safety was also analysed by intention to treat. This trial is closed to new participants and is registered with isrctn.com, number ISRCTN37118456. FINDINGS Between April 21, 2008, and May 17, 2014, we randomly assigned 48 stroke units (and 1224 patients clustered within the units) to the two treatment groups: 24 to antibiotics and 24 to standard care alone (control). 11 units and seven patients withdrew after randomisation before 14 days, leaving 1217 patients in 37 units for the intention-to-treat analysis (615 patients in the antibiotics group, 602 in control). Prophylactic antibiotics did not affect the incidence of algorithm-defined post-stroke pneumonia (71 [13%] of 564 patients in antibiotics group vs 52 [10%] of 524 in control group; marginal adjusted odds ratio [OR] 1·21 [95% CI 0·71-2·08], p=0·489, intraclass correlation coefficient [ICC] 0·06 [95% CI 0·02-0·17]. Algorithm-defined post-stroke pneumonia could not be established in 129 (10%) patients because of missing data. Additionally, we noted no differences in physician-diagnosed post-stroke pneumonia between groups (101 [16%] of 615 patients vs 91 [15%] of 602, adjusted OR 1·01 [95% CI 0·61-1·68], p=0·957, ICC 0·08 [95% CI 0·03-0·21]). The most common adverse events were infections unrelated to post-stroke pneumonia (mainly urinary tract infections), which were less frequent in the antibiotics group (22 [4%] of 615 vs 45 [7%] of 602; OR 0·55 [0·32-0·92], p=0·02). Diarrhoea positive for Clostridium difficile occurred in two patients (<1%) in the antibiotics group and four (<1%) in the control group, and meticillin-resistant Staphylococcus aureus colonisation occurred in 11 patients (2%) in the antibiotics group and 14 (2%) in the control group. INTERPRETATION Antibiotic prophylaxis cannot be recommended for prevention of post-stroke pneumonia in patients with dysphagia after stroke managed in stroke units. FUNDING UK National Institute for Health Research.

The Murcia Twin Registry: A Population-Based Registry of Adult Multiples in Spain

The Murcia Twin Registry (MTR) was created in 2006, under the auspices of the University of Murcia and the regional Health Authority, aiming to develop a research resource in Spain intended to stimulate current research and new investigation on the analysis of genetic factors related to health and health-related behaviors. The MTR development strategy was designed as a step-by-step process. Initially, it was focused on womens health but nowadays it includes males and opposite-sex twins. The database comprises 2,281 participants born between 1940 and 1966 in the region of Murcia, in Spain. There have been three waves of data collection and today the MTR databases include questionnaire and anthropometric data as well as biological samples. The current main areas of research interest are health and health-related behaviors, including lifestyle, health promotion, and quality of life. Future short-term development points to the completion of the biobank and continuing the collection of longitudinal data.

Familial Resemblance for Loneliness

Social isolation and loneliness in humans have been associated with physical and psychological morbidity, as well as mortality. This study aimed to assess the etiology of individual differences in feelings of loneliness. The genetic architecture of loneliness was explored in an extended twin-family design including 8,683 twins, siblings and parents from 3,911 families. In addition, 917 spouses of twins participated. The presence of assortative mating, genetic non-additivity, vertical cultural transmission, genotype–environment (GE) correlation and interaction was modeled. GE interaction was considered for several demographic characteristics. Results showed non-random mating for loneliness. We confirmed that loneliness is moderately heritable, with a significant contribution of non-additive genetic variation. There were no effects of vertical cultural transmission. With respect to demographic characteristics, results indicated that marriage, having offspring, more years of education, and a higher number of siblings are associated with lower levels of loneliness. Interestingly, these effects tended to be stronger for men than women. There was little evidence of changes in genetic architecture as a function of these characteristics. We conclude that the genetic architecture of loneliness points to non-additive genetic influences, suggesting it may be a trait that was not neutral to selection in our evolutionary past. Sociodemographic factors that influence the prevalence of loneliness do not affect its genetic architecture.

Familial Resemblance of Borderline Personality Disorder Features: Genetic or Cultural Transmission?

Borderline personality disorder is a severe personality disorder for which genetic research has been limited to family studies and classical twin studies. These studies indicate that genetic effects explain 35 to 45% of the variance in borderline personality disorder and borderline personality features. However, effects of non-additive (dominance) genetic factors, non-random mating and cultural transmission have generally not been explored. In the present study an extended twin-family design was applied to self-report data of twins (N = 5,017) and their siblings (N = 1,266), parents (N = 3,064) and spouses (N = 939) from 4,015 families, to estimate the effects of additive and non-additive genetic and environmental factors, cultural transmission and non-random mating on individual differences in borderline personality features. Results showed that resemblance among biological relatives could completely be attributed to genetic effects. Variation in borderline personality features was explained by additive genetic (21%; 95% CI 17–26%) and dominant genetic (24%; 95% CI 17–31%) factors. Environmental influences (55%; 95% CI 51–60%) explained the remaining variance. Significant resemblance between spouses was observed, which was best explained by phenotypic assortative mating, but it had only a small effect on the genetic variance (1% of the total variance). There was no effect of cultural transmission from parents to offspring.

Biomarkers of Tolerance in Kidney Transplantation: Are We Predicting Tolerance or Response to Immunosuppressive Treatment?

We and others have previously described signatures of tolerance in kidney transplantation showing the differential expression of B cell–related genes and the relative expansions of B cell subsets. However, in all of these studies, the index group—namely, the tolerant recipients—were not receiving immunosuppression (IS) treatment, unlike the rest of the comparator groups. We aimed to assess the confounding effect of these regimens and develop a novel IS‐independent signature of tolerance. Analyzing gene expression in three independent kidney transplant patient cohorts (232 recipients and 14 tolerant patients), we have established that the expression of the previously reported signature was biased by IS regimens, which also influenced transitional B cells. We have defined and validated a new gene expression signature that is independent of drug effects and also differentiates tolerant patients from healthy controls (cross‐validated area under the receiver operating characteristic curve [AUC] = 0.81). In a prospective cohort, we have demonstrated that the new signature remained stable before and after steroid withdrawal. In addition, we report on a validated and highly accurate gene expression signature that can be reliably used to identify patients suitable for IS reduction (approximately 12% of stable patients), irrespective of the IS drugs they are receiving. Only a similar approach will make the conduct of pilot clinical trials for IS minimization safe and hence allow critical improvements in kidney posttransplant management.

Public knowledge, attitudes, social distance and reported contact regarding people with mental illness 2009–2015

To investigate whether public knowledge, attitudes, desire for social distance and reported contact in relation to people with mental health problems have improved in England during the Time to Change (TTC) programme to reduce stigma and discrimination 2009–2015.

Sex Differences in Sum Scores May Be Hard to Interpret: The Importance of Measurement Invariance

In most assessment instruments, distinct items are designed to measure a trait, and the sum score of these items serves as an approximation of an individual’s trait score. In interpreting group differences with respect to sum scores, the instrument should measure the same underlying trait across groups (e.g., male/female, young/old). Differences with respect to the sum score should accurately reflect differences in the latent trait of interest. A necessary condition for this is that the instrument is measurement invariant. In the current study, the authors illustrate a stepwise approach for testing measurement invariance with respect to sex in a four-item instrument designed to assess disordered eating behavior in a large epidemiological sample (1,195 men and 1,507 women). This approach can be applied to other phenotypes for which group differences are expected. Any analysis of such variables may be subject to measurement bias if a lack of measurement invariance between grouping variables goes undetected.

Symptom Burden and Associated Factors in Renal Transplant Patients in the U.K.

CONTEXT Renal transplantation is gold standard care in end-stage kidney disease, but little is known about symptom prevalence in transplanted patients. OBJECTIVES This study assesses symptom prevalence in this population. METHODS This was a U.K.-based, cross-sectional symptom survey of end-stage kidney disease patients transplanted more than one year previously. Patient-reported data were collected using the renal Patient Outcome Scale. Demographic/clinical data also were collected, including estimated glomerular filtration rate (eGFR), renal diagnosis, and comorbidity. RESULTS One hundred ten patients participated; mean age was 47 years (SD 13.6), and mean eGFR was 46 mL/min (SD 16.8, range 14-101). Symptom burden was high, with a mean of seven symptoms, but marked variance (SD 5.2, range 0-22). The most prevalent symptoms were weakness (56%, 95% CI 47-65), difficulty sleeping (46%, 95% CI 37-56), dyspnea (42%, 95% CI 33-51), feeling anxious (36%, 95% CI 28-46), and drowsiness (36%, 95% CI 28-46). Certain symptoms-weakness, difficulty sleeping, dyspnea, and drowsiness-were commonly reported as severe. A significant inverse relationship between renal function, as measured by eGFR, and number of symptoms (P<0.05) emerged. CONCLUSION For renal transplant recipients, symptom burden is similar to dialysis, although with less pain, anorexia, and immobility. Routine symptom assessment should be undertaken in transplant patients to identify these often undisclosed symptoms.

Personality: Possible effects of inbreeding depression on sensation seeking.

The target paper demonstrates the value of evolutionary genetics for personality research. Apart from a summing-up of concepts, the authors validate their theory with evidence from studies on both human- and animal personality. In this commentary, I want to show the need for inter-disciplinary research to answer questions on personality in psychology and biology.