Regular monitoring of cytomegalovirus-specific cell-mediated immunity in intermediate-risk kidney transplant recipients: predictive value of the immediate post-transplant assessment.

OBJECTIVE: Previous studies on monitoring of post-transplant cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) are limited by single-centre designs and disparate risk categories. We aimed to assess the clinical value of a regular monitoring strategy in a large multicentre cohort of intermediate-risk kidney transplant (KT) recipients. METHODS: We recruited 124 CMV-seropositive KT recipients with no T-cell-depleting induction pre-emptively managed at four Spanish institutions. CMV-specific interferon-γ-producing CD4+ and CD8+ T cells were counted through the first post-transplant year by intracellular cytokine staining after stimulation with pp65 and immediate early-1 peptides (mean of six measurements per patient). The primary outcome was the occurrence of any CMV event (asymptomatic infection and/or disease). Optimal cut-off values for CMV-specific T cells were calculated at baseline and day 15. RESULTS: Twelve-month cumulative incidence of CMV infection and/or disease was 47.6%. Patients with pre-transplant CMV-specific CD8+ T-cell count <1.0 cells/µL had greater risk of CMV events (adjusted hazard ratio (aHR) 2.84; p 0.054). When the CMI assessment was performed in the immediate post-transplant period (day 15), the presence of <2.0 CD8+ T cells/µL (aHR 2.18; p 0.034) or <1.0 CD4+ T cells/µL (aHR 2.43; p 0.016) also predicted the subsequent development of a CMV event. In addition, lower counts of CMV-specific CD4+ (but not CD8+) T cells at days 60 and 180 were associated with a higher incidence of late-onset events. CONCLUSIONS: Monitoring for CMV-specific CMI in intermediate-risk KT recipients must be regular to reflect dynamic changes in overall immunosuppression and individual susceptibility. The early assessment at post-transplant day 15 remains particularly informative.

Rural habitat as risk factor for hepatitis E virus seroconversion in HIV-infected patients: A prospective longitudinal study.

Our objective was to determine the incidence and clinical manifestations of acute hepatitis E virus (HEV) in HIV-infected patients. A prospective longitudinal study including HIV-infected HEV-seronegative patients was conducted; HEV seroconversion (to IgG and/or IgM) was the main outcome variable. All patients were tested for HEV antibodies every 3-6 months. For patients who developed HEV seroconversion, a data collection protocol was followed to identify associated clinical manifestations and analytical alterations. A total of 627 patients (89.9%) were followed during a median of 11.96 months (IQR: 8.52-14.52 months) and formed the study population. Forty-one patients developed detectable anti-HEV antibodies (7.2 cases per 100 patients/year). Our study found a high incidence of HEV in HIV-infected patients in southern Spain strongly associated with a rural habitat.

Management of cytomegalovirus infection in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations.

Cytomegalovirus (CMV) infection remains a major complication of solid organ transplantation. Because of management of CMV is variable among transplant centers, in 2011 the Spanish Transplantation Infection Study Group (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) developed consensus guidelines for the prevention and treatment of CMV infection in solid organ transplant recipients. Since then, new publications have clarified or questioned the aspects covered in the previous document. For that reason, a panel of experts revised the evidence on CMV management, including immunological monitoring, diagnostics, prevention, vaccines, indirect effects, treatment, drug resistance, immunotherapy, investigational drugs, and pediatric issues. This document summarizes the recommendations.

Risk of tuberculosis after lung transplantation: the value of pretransplant chest computed tomography and the impact of mTOR inhibitors and azathioprine use.

BACKGROUND: It is necessary to determine the incidence and risk factors for tuberculosis (TB), as well as strategies to assess and treat latent tuberculosis infection (LTBI) in lung transplant recipients. METHODS: A retrospective cohort study of 398 lung transplant recipients was performed. Episodes of TB were studied and the incidence rate was calculated. Logistic regression analysis was used to analyze specific variables as potential risk factors for TB. RESULTS: Median follow-up was 558 days (range 1-6636). Six cases (1.5%) of TB were documented in 398 transplant patients. The incidence density of TB was 406.3 cases/10(5) patient-years (95% confidence interval [CI] 164.7-845), which is higher than in the general population (13.10 cases/10(5) person-years). All cases occurred in the period 1993-2006, when the tuberculin skin test (TST) and treatment of LTBI in positive TST patients were not part of the protocol. Pretransplant computed tomography (CT) showed residual lesions in 50% of patients who developed TB, although the TST was negative and the chest radiograph was inconclusive. Multivariate analysis identified the presence of residual lesions in the pretransplant chest CT (odds ratio [OR] 11.5, 95% CI 1.9-69.1, P = 0.008), use of azathioprine (OR 10.6, 95% CI 1.1-99.1, P = 0.038), and use of everolimus (OR 6.7, 95% CI 1.1-39.8, P = 0.036) as independent risk factors for TB. CONCLUSIONS: Residual lesions in the pretransplant chest CTs and the use of azathioprine and mTOR inhibitors are associated with the risk of TB.

Factors related to the development of CMV-specific CD8+ T cell response in CMV-seropositive solid organ transplant candidates.

This cross-sectional study analyzes factors associated with the development of CMV-specific CD8+ response, measured by IFNg production after cytomegalovirus (CMV) peptide stimulation, in CMV-seropositive solid organ transplantation candidates. A total of 114 candidates were enrolled, of whom 22.8% (26/114) were nonreactive (IFNγ < 0.2 IU/mL). Multivariate logistic regression analysis showed that age, HLA alleles and organ to be transplanted were associated with developing CMV-specific CD8+ immunity (reactive; IFNγ ≥ 0.2 IU/mL). The probability of being reactive was higher in candidates over 50 than in those under 50 (OR 6.33, 95%CI 1.93-20.74). Candidates with HLA-A1 and/or HLA-A2 alleles had a higher probability of being reactive than those with non-HLA-A1/non-HLA-A2 alleles (OR 10.97, 95%CI 3.36-35.83). Renal candidates had a higher probability of being reactive than lung (adjusted OR 8.85, 95%CI 2.24-34.92) and liver candidates (OR 4.87, 95%CI 1.12-21.19). The AUC of this model was 0.84 (p < 0.001). Positive and negative predictive values were 84.8% and 76.9%, respectively. In renal candidates longer dialysis was associated with an increased frequency of reactive individuals (p = 0.040). Therefore, although the assessment of CMV-specific CD8+ response is recommended in all R+ candidates, it is essential in those with a lower probability of being reactive, such as non-renal candidates, candidates under 50 or those with non-HLA-A1/non-HLA-A2 alleles.

Pre-transplant thymic function is associated with the risk of cytomegalovirus disease after solid organ transplantation.

Cytomegalovirus (CMV) disease is an important complication in solid organ transplant recipients. Thymic function in adults is associated with specific T-cell immunity. Pre-transplant thymic function was analysed in 75 solid organ transplant patients by the use of nested PCR. The primary outcome was the incidence of CMV disease 12 months after transplantation. Using multivariable logistic regression, we studied whether pre-transplant thymic function is an independent risk factor for CMV disease after transplantation. Thymic function was related to the risk of CMV disease in CMV-seropositive recipients. In these recipients, pre-transplant thymic function of <9.5 (OR 11.27, 95% CI 1.11-114.43, p 0.040) and the use of thymoglobulin (OR 8.21, 95% CI 1.09-61.84, p 0.041) were independent risk factors for CMV disease at 12 months after transplantation. Patients with pre-transplant thymic function values of <9.5 had a higher subsequent incidence of CMV disease (24%) than patients with values of ≥ 9.5 (3%) (log-rank test: 5.727; p 0.017). The positive and negative predictive values of these pre-transplant thymic function cut-offs were 0.24 (95% CI 0.10-0.45) and 0.97 (95% CI 0.82-1.00), respectively. Pre-transplant thymic function in CMV-seropositive candidates could be useful in determining the risk of post-transplant CMV disease in solid organ transplant patients, selecting a group of low-risk candidates.

Pretransplant interferon-γ secretion by CMV-specific CD8+ T cells informs the risk of CMV replication after transplantation.

In this prospective study we analyzed pretransplant interferon-γ secretion by cytomegalovirus (CMV)-specific CD8+ T cells to assess its possible utility in determining the risk of CMV replication after solid organ transplantation. A total of 113 lung and kidney transplant patients were enrolled in the study but only 55 were evaluable. All CMV-seronegative recipients were pretransplant "nonreactive" (IFNγ <0.2 IU/mL) (11/11), whereas 30/44 (68.2%) CMV-seropositive (R+) recipients were "reactive" (IFNγ ≥0.2 IU/mL) and 14/44 (31.8%) were "nonreactive". In the R(+) "nonreactive" group, 7/14 (50%) developed posttransplant CMV replication, whereas the virus replicated only in 4/30 (13.3%) of the R(+) "reactive" patients (p = 0.021). According to the best multivariate model, pretransplant "nonreactive" recipients receiving an organ from a CMV-seropositive donor had a 10-fold increased risk of CMV replication compared to pretransplant "reactive" recipients (adjusted OR 10.49, 95% CI 1.88-58.46). This model displayed good discrimination ability (AUC 0.80) and calibration (Hosmer-Lemeshow test, p = 0.92). Negative and positive predictive values were 83.7% and 75%, respectively. The accuracy of the model was 82%. Therefore, assessment of interferon-γ secretion by cytomegalovirus (CMV)-specific CD8+ T cells prior to transplantation is useful in informing the risk of posttransplant CMV replication in solid organ transplant patients.

Acyl-acyl carrier protein thioesterase activity from sunflower (Helianthus annuus L.) seeds.

During sunflower (Helianthus annuus L.) seed formation there was an active period of lipid biosynthesis between 12 and 28 days after flowering (DAF). The maximum in-vitro acyl-acyl carrier protein (ACP) thioesterase activities (EC 3.1.2.14) were found at 15 DAF, preceding the largest accumulation of lipid in the seed. Data from the apparent kinetic parameters, Vmax and Km, from seeds of 15 and 30 DAF, showed that changes in acyl-ACP thioesterase activity are not only quantitative, but also qualitative, since, although the preferred substrate was always oleoyl-ACP, the affinity for palmitoyl-ACP decreased, whereas that for stearoyl-ACP increased with seed maturation. Bisubstrate assays carried out at 30 DAF seemed to indicate that the total activity found in mature seeds is due to a single enzyme with 100/75/15 affinity for oleoyl-ACP/stearoyl-ACP/ palmitoyl-ACP. In contrast, at 15 DAF, enzymatic data together with partial sequences from cDNAs indicated the presence of at least two enzymes with different properties, a FatA-like thioesterase, with a high affinity for oleoyl-ACP, plus a FatB-like enzyme, with preference for long-chain saturated fatty acids, both being expressed during the active lipid biosynthesis period. Competition assays carried out with CAS-5, a mutant with a higher content of palmitic acid in the seed oil, indicated that a modified FatA-type thioesterase is involved in the mutant phenotype.

Lipid characterization in vegetative tissues of high saturated fatty acid sunflower mutants.

Modifications of the fatty acid composition of plant vegetative tissues produce deficient plant growth. To determine the expression of the seed high-saturated sunflower (Helianthus annuus L.) mutant character during the vegetative cycle, five sunflower mutant lines (three high-stearic and two high-palmitic) have been studied during their germination and vegetative cycle. No significant variations with regard to the control lines were observed in the mutant vegetative tissue lipids; however, during seed germination important differences between lines were found. Although in the early steps of germination the palmitic and stearic acid levels in the respective mutants seedling cotyledons continued being higher than those of the control lines, they decreased and reached values similar to the controls, except in CAS-3. Variations in the cotyledon palmitic acid content with regard to the control line were also observed in high-stearic mutants, suggesting the expression of a modified acyl-ACP thioesterase or recycling of seed fatty acids during seedling development.

Characterization of polar and nonpolar seed lipid classes from highly saturated fatty acid sunflower mutants.

The seed lipids from five sunflower mutants, two with high palmitic acid contents, one of them in high oleic background, and three with high stearic acid contents, have been characterized. All lipid classes of these mutant seeds have increased saturated fatty acid content although triacylglycerols had the highest levels. The increase in saturated fatty acids was mainly at the expense of oleic acid while linoleic acid levels remained unchanged. No difference between mutants and standard sunflower lines used as controls was found in minor fatty acids: linolenic, arachidic, and behenic. In the high-palmitic mutants palmitoleic acid (16:1n-7) and some palmitolinoleic acid (16:2n-7, 16:2n-4) also appeared. Phosphatidylinositol, the lipid with the highest palmitic acid content in controls, also had the highest content of palmitic or stearic acids, depending on the mutant type, suggesting that saturated fatty acids are needed for its physiological function. Positional analysis showed that mutant oils have very low content of saturated fatty acids in the sn-2 position of triacylglycerols, between the content of olive oil and cocoa butter.