Mutations in latent membrane protein 1 of Epstein-Barr virus are associated with increased risk of posttransplant lymphoproliferative disorder in children.

Epstein-Barr virus (EBV)-positive posttransplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at an increased risk of EBV-positive PTLD could influence clinical management of immunosuppression and other therapies, improving posttransplant outcomes. A 7-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at positions 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk of EBV-positive PTLD (clinical trials: NCT02182986). DNA was isolated from peripheral blood of EBV-positive PTLD case patients and matched controls (1:2 nested case:control), and the cytoplasmic tail of LMP1 was sequenced. Thirty-four participants reached the primary endpoint of biopsy-proven EBV-positive PTLD. DNA was sequenced from 32 PTLD case patients and 62 matched controls. Both LMP1 mutations were present in 31 of 32 PTLD cases (96.9%) and in 45 of 62 matched controls (72.6%) (P = .005; OR = 11.7; 95% confidence interval, 1.5, 92.6). The presence of both G212S and S366T carries a nearly 12-fold increased risk of development of EBV-positive PTLD. Conversely, transplant recipients without both LMP1 mutations carry a very low risk of PTLD. Analysis of mutations at positions 212 and 366 of LMP1 can be informative in stratifying patients for risk of EBV-positive PTLD.

Discovery and Validation of a Biomarker Model (PRESERVE) Predictive of Renal Outcomes After Liver Transplantation.

BACKGROUND AND AIMS: A high proportion of patients develop chronic kidney disease (CKD) after liver transplantation (LT). We aimed to develop clinical/protein models to predict future glomerular filtration rate (GFR) deterioration in this population. APPROACH AND RESULTS: In independent multicenter discovery (CTOT14) and single-center validation (BUMC) cohorts, we analyzed kidney injury proteins in serum/plasma samples at month 3 after LT in recipients with preserved GFR who demonstrated subsequent GFR deterioration versus preservation by year 1 and year 5 in the BUMC cohort. In CTOT14, we also examined correlations between serial protein levels and GFR over the first year. A month 3 predictive model was constructed from clinical and protein level variables using the CTOT14 cohort (n = 60). Levels of ß-2 microglobulin and CD40 antigen and presence of hepatitis C virus (HCV) infection predicted early (year 1) GFR deterioration (area under the curve [AUC], 0.814). We observed excellent validation of this model (AUC, 0.801) in the BUMC cohort (n = 50) who had both early and late (year 5) GFR deterioration. At an optimal threshold, the model had the following performance characteristics in CTOT14 and BUMC, respectively: accuracy (0.75, 0.8), sensitivity (0.71, 0.67), specificity (0.78, 0.88), positive predictive value (0.74, 0.75), and negative predictive value (0.76, 0.82). In the serial CTOT14 analysis, several proteins, including ß-2 microglobulin and CD40, correlated with GFR changes over the first year. CONCLUSIONS: We have validated a clinical/protein model (PRESERVE) that early after LT can predict future renal deterioration versus preservation with high accuracy. This model may help select recipients at higher risk for subsequent CKD for early, proactive renal sparing strategies.

Discovery and validation of a novel blood-based molecular biomarker of rejection following liver transplantation.

Noninvasive biomarker profiles of acute rejection (AR) could affect the management of liver transplant (LT) recipients. Peripheral blood was collected following LT for discovery (Northwestern University [NU]) and validation (National Institute of Allergy and Infectious Diseases Clinical Trials in Organ Transplantation [CTOT]-14 study). Blood gene profiling was paired with biopsies showing AR or ADNR (acute dysfunction no rejection) as well as stable graft function samples (Transplant eXcellent-TX). CTOT-14 subjects had serial collections prior to AR, ADNR, TX, and after AR treatment. NU cohort gene expression (46 AR, 45 TX) was analyzed using random forest models to generate a classifier training set (36 gene probe) distinguishing AR vs TX (area under the curve 0.92). The algorithm and threshold were locked and tested on the CTOT-14 validation cohort (14 AR, 50 TX), yielding an accuracy of 0.77, sensitivity 0.57, specificity 0.82, positive predictive value (PPV) 0.47, and negative predictive value (NPV) 0.87 for AR vs TX. The probability score line slopes were positive preceding AR, and negative preceding TX and non-AR (TX + ADNR) (P ≤ .001) and following AR treatment. In conclusion, we have developed a blood biomarker diagnostic for AR that can be detected prior to AR-associated graft injury as well a normal graft function (non-AR). Further studies are needed to evaluate its utility in precision-guided immunosuppression optimization following LT.

Development and clinical validity of a novel blood-based molecular biomarker for subclinical acute rejection following kidney transplant.

Noninvasive biomarkers are needed to monitor stable patients after kidney transplant (KT), because subclinical acute rejection (subAR), currently detectable only with surveillance biopsies, can lead to chronic rejection and graft loss. We conducted a multicenter study to develop a blood-based molecular biomarker for subAR using peripheral blood paired with surveillance biopsies and strict clinical phenotyping algorithms for discovery and validation. At a predefined threshold, 72% to 75% of KT recipients achieved a negative biomarker test correlating with the absence of subAR (negative predictive value: 78%-88%), while a positive test was obtained in 25% to 28% correlating with the presence of subAR (positive predictive value: 47%-61%). The clinical phenotype and biomarker independently and statistically correlated with a composite clinical endpoint (renal function, biopsy-proved acute rejection, ≥grade 2 interstitial fibrosis, and tubular atrophy), as well as with de novo donor-specific antibodies. We also found that <50% showed histologic improvement of subAR on follow-up biopsies despite treatment and that the biomarker could predict this outcome. Our data suggest that a blood-based biomarker that reduces the need for the indiscriminate use of invasive surveillance biopsies and that correlates with transplant outcomes could be used to monitor KT recipients with stable renal function, including after treatment for subAR, potentially improving KT outcomes.

Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3'untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

Weight-based loading of vancomycin in patients on hemodialysis.

We evaluated weight-based loading doses of vancomycin and resulting initial prehemodialysis concentrations. Modeling demonstrated modest correlation between dose administered, age, and initial concentration achieved. Actual body weight-based loading of vancomycin predictably achieves therapeutic initial concentrations in patients who receive hemodialysis.

Polymorphisms in apoptosis and cell cycle control genes and risk of brain tumors in adults.

Despite the potential importance of the cell cycle and apoptosis pathways in brain tumor etiology, little has been published regarding brain tumor risk associated with common gene variants in these pathways. Using data from a hospital-based case-control study conducted by the National Cancer Institute between 1994 and 1998, we evaluated risk of glioma (n = 388), meningioma (n = 162), and acoustic neuroma (n = 73) with respect to 12 single nucleotide polymorphisms from 10 genes involved in apoptosis and cell cycle control: CASP8, CCND1, CCNH, CDKN1A, CDKN2A, CHEK1, CHEK2, MDM2, PTEN, and TP53. We observed significantly decreased risk of meningioma with the CASP8 Ex14-271A>T variant [odds ratio (OR)(AT), 0.8; 95% confidence interval (95% CI), 0.5-1.2; OR(AA), 0.5; 95% CI, 0.3-0.9; P(trend) = 0.03] and increased risk of meningioma with the CASP8 Ex13+51G>C variant (OR(GC), 1.4; 95% CI, 0.9-2.1; OR(CC), 3.6; 95% CI, 1.0-13.1; P(trend) = 0.04). The CT haplotype of the two CASP8 polymorphisms was associated with significantly increased risk of meningioma (OR, 1.7; 95% CI, 1.1-2.6), but was not associated with risk of glioma or acoustic neuroma. The CCND1 Ex4-1G>A variant was associated with increased risk for glioma, and the Ex8+49T>C variant of CCNH was associated with increased risk of glioma and acoustic neuroma. The MDM2 Ex12+162A>G variant was associated with significantly reduced risk of glioma. Our results suggest that common variants in the CASP8, CCND1, CCNH, and MDM2 genes may influence brain tumor risk. Future research in this area should include more detailed coverage of genes in the apoptosis/cell cycle control pathways.

Variation in genes relevant to aromatic hydrocarbon metabolism and the risk of adult brain tumors.

Genes involved in phase I and phase II regulation of aromatic hydrocarbon-induced effects exhibit sequence variability that may mediate the risk of adult brain tumors. We evaluated associations between gene variants in CYP1A1, CYP1B1, GSTM3, EPHX1, and NQO1 and adult brain tumor incidence. Cases were patients with glioma (n = 489), meningioma (n = 197), or acoustic neuroma (n = 96) diagnosed from 1994 to 1998 at three U.S. hospitals. Controls were 799 patients admitted to the same hospitals for nonmalignant conditions. DNA was extracted from blood samples collected from 1277 subjects, and genotyping was conducted for CYP1A1 I462V, CYP1B1 V432L, EPHX1 Y113H, GSTM3 *A/*B (intron 6 deletion), and NQO1 P187S. The CYP1B1 V432L homozygous variant was associated with decreased risk of meningioma (odds ratio [OR] = 0.6; 95% CI, 0.3-1.0) but not the other tumor types. The GSTM3 *B/*B genotype was associated with increased risk of glioma (OR = 2.3; 95% CI, 1.0-5.2) and meningioma (OR = 3.6; 95% CI, 1.3-9.8). Increased risks associated with GSTM3 *B/*B were observed in younger subjects (age < 50) and older subjects (age > or = 50), in men and women, and within each study site. The magnitude of association for GSTM3 with glioma and meningioma was greater among ever-smokers than among those who had never smoked. None of the other genotypes showed consistent associations with any tumor type. The association with the GSTM3 *B allele, while intriguing, requires replication, and additional research is needed to clarify the function of the GSTM3 alleles studied here.