Integrated Biosensor for Rapid and Point-of-Care Sepsis Diagnosis.

Sepsis is an often fatal condition that arises when the immune response to an infection causes widespread systemic organ injury. A critical unmet need in combating sepsis is the lack of accurate early biomarkers that produce actionable results in busy clinical settings. Here, we report the development of a point-of-care platform for rapid sepsis detection. Termed IBS (integrated biosensor for sepsis), our approach leverages (i) the pathophysiological role of cytokine interleukin-3 (IL-3) in early sepsis and (ii) a hybrid magneto-electrochemical sensor for IL-3 detection. The developed platform produces test results within 1 h from native blood samples and detects IL-3 at a sensitivity of <10 pg/mL; this performance is >5-times faster and >10-times more sensitive than conventional enzyme-linked immunoadsorbent assays, the current gold standard. Using clinical samples, we show that elevated plasma IL-3 levels are associated with high organ failure rate and thus greater risk of mortality, confirming the potential of IL-3 as a sepsis diagnostic biomarker. With further system development ( e. g., full automation, data security measures) and rigorous validation studies, the compact and fast IBS could be a practical clinical tool for timely diagnosis and proactive treatment of sepsis.

Loss of cooperativity of secreted CD40L and increased dose-response to IL4 on CLL cell viability correlates with enhanced activation of NF-kB and STAT6.

Chronic lymphocytic leukemia (CLL) cells fail to enter apoptosis in vivo as opposed to their non-malignant B-lymphocyte counterparts. The ability of CLL cells to escape apoptosis is highly dependent on their microenvironment. Compared to non-malignant B cells, CLL cells are more responsive to complex stimuli that can be reproduced in vitro by the addition of cytokines. To understand the molecular mechanism of the environment-dependent anti-apoptotic signaling circuitry of CLL cells, we quantified the effect of the SDF-1, BAFF, APRIL, anti-IgM, interleukin-4 (IL4) and secreted CD40L (sCD40L) on the survival of in vitro cultured CLL cells and found IL4 and sCD40L to be most efficient in rescuing CLL cells from apoptosis. In quantitative dose-response experiments using cell survival as readout, the binding affinity of IL4 to its receptor was similar between malignant and non-malignant cells. However, the downstream signaling in terms of the amount of STAT6 and its degree of phosphorylation was highly stimulated in CLL cells. In contrast, the response to sCD40L showed a loss of cooperative binding in CLL cells but displayed a largely increased ligand binding affinity. Although a high-throughput microscopy analysis did not reveal a significant difference in the spatial CD40 receptor organization, the downstream signaling showed an enhanced activation of the NF-kB pathway in the malignant cells. Thus, we propose that the anti-apoptotic phenotype of CLL involves a sensitized response for IL4 dependent STAT6 phosphorylation, and an activation of NF-kB signaling due to an increased affinity of sCD40L to its receptor.