Blood-Borne RNA Correlates with Disease Activity and IFN-Stimulated Gene Expression in Systemic Lupus Erythematosus.

The loss of tolerance and the presence of circulating autoantibodies directed against nuclear Ags is the hallmark of systemic lupus erythematosus (SLE). Many of these Ags are complexed with short, noncoding RNAs, such as U1 and Y1. The amount of U1 and Y1 RNA complexed with SLE patient Abs and immune complexes was measured in a cross-section of 228 SLE patients to evaluate the role of these RNA molecules within the known biochemical framework of SLE. The study revealed that SLE patients had significantly elevated levels of circulating U1 and/or Y1 RNA compared with healthy volunteers. In addition, the blood-borne RNA molecules were correlated with SLE disease activity and increased expression of IFN-inducible genes. To our knowledge, this study provides the first systematic examination of the role of circulating RNA in a large group of SLE patients and provides an important link with IFN dysregulation.

UltraPrep is a scalable, cost-effective, bead-based method for purifying cell-free DNA.

UltraPrep is an open-source, two-step method for purification of cell-free DNA that entails extraction of total DNA followed by size-selective enrichment of the smaller fragments that are characteristic of DNA originating from fragmentation between nucleosome. The advantages of the two related protocols that are described are that they can easily accommodate a wide range of sample input volumes, they rely on simple, magnetic bead-based technology, the yields of cfDNA are directly comparable to the most popular methods for cfDNA purification, and they dramatically reduce the cost of cfDNA isolation relative to currently available commercial methods. We provide a framework for physical and molecular quality analysis of purified cfDNA and demonstrate that the cfDNA generated by UltraPrep meets or exceeds the quality metrics of the most commonly used procedure. In addition, our method removes high molecular weight genomic DNA (hmwgDNA) that can interfere with downstream assay results, thereby addressing one of the primary concerns for preanalytical collection of blood samples.

Collection of cell-free DNA for genomic analysis of solid tumors in a clinical laboratory setting.

The breadth of diagnostic procedures that utilize cell free DNA (cfDNA) from human plasma has increased dramatically in recent years. Here, we confirm that tumor-derived cfDNA fragments are similar in size distribution to cfDNA derived from normal tissues. Therefore, collection procedures optimized with healthy donor specimens are likely to be applicable to the diagnosis and monitoring of many different cancer types. We verify that the distribution and DNA sequences of fragmentation sites in cfDNA from both normal-germline and tumor-derived cfDNA are non-random. A broad survey of cfDNA from healthy donors suggests that average individuals possess ~6 ng of cfDNA per mL of plasma. Importantly, the cfDNA present in plasma samples that were initially collected as whole blood in K2-EDTA tubes and subsequently processed by centrifugation is stable for several days at ambient temperatures. This observation has the potential to significantly reduce the cost and logistical complexity of shipping clinical samples from the site of collection to centers proficient in diagnostic analysis. Finally, plasma samples collected with high-volume plasma collection devices possess abundant quantities of cfDNA. Since the quantity of analyzed cfDNA is directly proportional to sensitivity of diagnostic assays, this method of plasma collection, where available, could enable highly sensitive post-treatment disease monitoring and early detection of cancer in at-risk individuals.