Objective: To evaluate the diagnostic performance of donor-derived plasma cell-free DNA (cfDNA) in discriminating antibody-mediated rejection (ABMR) or de novo donorspecific antibodies (DSA) without histological lesions in kidney allograft recipients. Methods:In this prospective single center observational study, we enrolled kidney allograft recipients between November, 2016 and September, 2017 at the First Affiliated Hospital of Sun Yat-sen University. Kidney allograft recipients with ABMR, de novo DSA but no histological lesions or negative DSA, and stable renal function were included. The plasma cfDNA fraction was measured using a targeted, single nucleotide polymorphism (SNP)-based assay. Pathological diagnosis was made according to the 2015 Banff Kidney Rejection Classification. The area under the ROC curve (AUC-ROC) was determined using the bootstrapping method to estimate median and 95% confidence interval (95% CI). The sensitivity, specificity and Youden index, positive predictive value (PPV), and negative predictive value (NPV) were calculated for specific cfDNA fractions.Results: Totally 37 consecutive patients received kidney allografts, including 18 recipients in the ABMR group and 19 recipients in the stable allograft group (7 DSApositive and 12 DSA-negative). All patients in the ABMR group were DSA positive and 7 patients in the stable group were DSA positive but had no pathologically proven ABMR. The median donor-derived plasma cfDNA fraction was 2.4% (Q1 1.52% -Q3 3.70%) in the ABMR group, and was significantly higher than that of the stable group (0.65%, Q1 Frontiers in Immunology | www.frontiersin.org February 2020 | Volume 11 | Article 342 Zhang et al.Donor-Derived cfDNA in Kidney ABMR 0.57% -Q3 0.97%; P < 0.001), but comparable with that of the DSA-positive patients in the stable allograft group (P = 0.074). The AUC-ROC of cfDNA was 0.90 (95% CI, 0.79-0.98). When a cfDNA threshold of 1% was chosen, it had a sensitivity of 88.9% and a specificity of 73.7%. The PPV was 76.2% and the NPV was 87.5%.Conclusion: Donor-derived plasma cfDNA fraction increased in kidney allograft recipients with ABMR. Detection of donor-derived plasma cfDNA fraction may contribute to the discrimination between ABMR and stable renal allograft function and may aid early recognition of earlier stage antibody-mediated injury.

Background: Donor-derived cell free DNA (ddcf DNA) has been reported as a universal noninvasive biomarker for rejection monitoring in heart, kidney, liver, and lung transplantation. Current approaches based on next-generation sequencing for quantification of ddcf DNA, although promising, may be restricted by the requirement for donor material, as donor samples may not be available. Methods: We proposed a novel next-generation sequencing approach without donor-derived material and compared the non-donor-derived approach and the donor-derived approach using simulation testing and 69 clinical specimens. We also evaluated the performance for acute rejection and infection monitoring in lung transplantation. Results: The non-donor-derived approach reached similar efficacy as the donor-derived approach with a significant linear correlation of R 2 = 0.98. Subsequent validation in clinical specimens demonstrated significant difference between the acute rejection

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Colorectal cancer (CRC) is a leading cause of morbidity and mortality worldwide, with an increasing prevalence. The 5-year relative survival rate for advanced stages is very low, with only 14% for stage IV. However, that of the early stage of CRC is about 90%. Therefore, it is important to screen CRC in the early stage. Epigenetic alterations linked to the carcinogenesis of CRC have been shown to occur earlier and more frequently than genetic alterations in CRC. Here, our study aims to develop a CRC screening methodology by applying the multiplex methylation specific PCR (MMSP) assay to detect CRC-specific methylation biomarkers, which has been pre-selected from public databases and subsequently validated in CRC samples of the Chinese population. Experimentally, cell free DNA (cfDNA) is extracted from ~4ml peripheral blood plasma. Following bisulfite conversion of the cfDNA, MMSP were applied to amplify and detect CRC-specific methylated CpG sites within the cfDNA. From the results of 28 CRCs and 52 control specimens, a sensitivity of 85.7% and the a specificity of 92.3% was achieved. Current standard and most widely used method of detecting CRC is colonoscopy screening. However, colonoscopy requires bowel preparation, and the sedation for patients is a complex and time-consuming procedure with high cost. Additionally, this invasive method also increases the possibility of infection and complications and patient compliance still largely remains a problem. Our non-invasive MMSP assay therefore provides an alternative non-invasive screening option that is cost-effective, meeting the urgent demand of early CRC detection. In addition, because colonoscopy screening currently has low adherence in Chinese population, our method holds great potential for increasing CRC screening rate in China. Citation Format: Lili Ye, Chunting Zheng, Yuan Jie, Bin Li, Yuan Li, Kunling Hu, Liuhong Zeng, Yuying Wang, Mao Mao, Peirong Ding, Taiping Shi, Mingzhi Ye. Non-invasive detection of aberrant DNA methylation in colorectal cancer by multiplex methylation specific PCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3324.

GPX2 has been recognized as a potential candidate gene for feed efficiency in pigs. This article aimed to elucidate polymorphism of GPX2 associated with feed efficiency and its related molecular mechanism. In this study, seven single nucleotide polymorphisms (SNP) of GPX2 were found among 383 Duroc pigs. In addition, seven SNPs and ALGA0043483 (PorcineSNP60 BeadChip data in 600 Duroc pigs), which are near the GPX2 gene, were identified in one haplotypes block. Furthermore, associated studies showed that the genotype of GPX2 has significant association with weaning weight and 100 kg BF in Duroc pigs. In addition, the AG had no effect when the backfat became thinner, and the FCR and RFI traits had a tendency to decrease in the G3 + TT combination genotype, accompanied by an increase of GPX2 expression in backfat and muscle tissues. At the cellular level, the adipocyte proliferation and ability of adipogenic differentiation were reduced, and the lipid degradation increased in 3T3-L1 when there was overexpression of GPX2. In contrast, overexpression of the GPX2 gene can promote the muscle cell proliferation and myogenic differentiation in C2C12 cells. In other words, GPX2 has the effect of reducing fat deposition and promoting muscle development, and it is a candidate gene for backfat and feed efficiency.