Anti-B2M monoclonal antibody, clone 578DU23.4.2

Introduction: Chronic kidney disease of uncertain etiology (CKDu), an emerging chronic kidney disease (CKD) subtype, contributes to significant morbidity and mortality in certain tropical countries. Although several indicators of CKDu have been previously suggested, sensitive and specific tests to detect early disease or predict disease progression are currently unavailable. This study focused on evaluating 8 renal urinary markers, namely neutrophil gelatinase-associated lipocalin (NGAL), Kidney Injury Molecule-1 (KIM1), cystatin C (CST3), beta 2 microglobulin (B2M), osteopontin (OPN), alpha 1 microglobulin (A1M), tissue inhibitor of metalloproteinase 1 (TIMP1), and retinol binding protein 4 (RBP4), with the hypothesis that these have distinct expression patterns in patients with CKDu. Methods: A cross-sectional study was conducted with 5 study groups comprising subjects from CKDu, endemic CKD, nonendemic CKD, and endemic healthy and nonendemic healthy controls. The urinary levels of the 8 selected renal biomarkers were quantified using multiplex biomarker assay, and the data were subjected to systematic analysis using logistic regression algorithm aiming to extract the best marker combination that could distinctly identify the disease groups noninvasively from the healthy controls. Results: A 3-marker signature panel comprising A1M, KIM1, and RBP4 was identified to represent the best minimum marker combination for differentiating all CKD categories, including CKDu, from healthy controls with an overall sensitivity of >= 0.867 and specificity >= 0.765. The marker combination comprising OPN, KIM1, and RBP4 showed high predictive performance for distinguishing patients with CKDu from patients with CKD with both sensitivity and specificity >= 0.93, which was superior to any existing noninvasive indicator. Conclusion: In all, our systematic evaluation of urinary markers previously linked to CKD, in general, allowed identification of exclusive marker panel combination for early diagnosis and confirmation of CKDu.

BACKGROUND: Liquid biopsy provides important information for the prognosis and treatment of cancer patients. In this study, we evaluated the effects of preanalytical conditions on gene expression and DNA methylation analyses in liquid biopsies. METHODS: We tested the stability of circulating tumor cell (CTC) messenger RNA by spiking MCF-7 cells in healthy donor peripheral blood (PB) drawn into 6 collection-tube types with various storage conditions. CTCs were enriched based on epithelial cell adhesion molecule positivity, and RNA was isolated followed by cDNA synthesis. Gene expression was quantified using RT-quantitative PCR for CK19 and B2M. We evaluated the stability of DNA methylation in plasma under different storage conditions by spiking DNA isolated from MCF-7 cells in healthy donor plasma. Two commercially available sodium bisulfite (SB)-conversion kits were compared, in combination with whole genome amplification (WGA), to evaluate the stability of SB-converted DNA. SB-converted DNA samples were analyzed by real-time methylation-specific PCR (MSP) for ACTB, SOX17, and BRMS1. Quality control was assessed using Levey-Jennings graphs. RESULTS: RNA-based analysis in CTCs is severely impeded by the preservatives used in many PB collection tubes (except for EDTA), as well as by time to analysis. Plasma and SB-converted DNA samples are stable and can be used safely for MSP when kept at -80 degrees C. Down-stream WGA of SB-converted DNA compensated for the limited amount of available sample in liquid biopsies. CONCLUSIONS: Standardization of preanalytical conditions and implementation of quality control steps is extremely important for reliable liquid biopsy analysis, and a prerequisite for routine applications in the clinic. (C) 2018 American Association for Clinical Chemistry