YKL-40 in serum: a promising biomarker of juvenile SLE and strongly correlated with disease duration.

BACKGROUND: The biological function of YKL-40 is not well determined in different inflammatory and autoimmune diseases; however, some data highlighted its possible connection with disease activity. AIM: We investigated the diagnostic utility of serum YKL-40 in patients with SLE and examined its correlation with disease activity. Additionally, we examined any differences in serum YKL-40 levels between juvenile and adult SLE patients. METHODS: We included 78 female patients with SLE and 42 controls. The level of YKL-40 in serum was measured by ELISA. RESULTS: The serum YKL-40 level in SLE patients was significantly higher compared to the control group (9 (3) ng/mL vs. 5.5 (0.1) ng/mL; p < 0.001). YKL-40 showed excellent diagnostic utility with an AUC of 1 (p < 0.001) and a cutoff point of 5.6, providing sensitivity and specificity of 100%. YKL-40 was higher in adolescents and those with a positive family history of SLE (p = 0.01 for both) and positively correlated with disease duration (r = 0.45, p < 0.001). YKL-40 level was significantly higher in patients with photosensitivity, fever, vasculitis, blood disorders, positive anti-dsDNA, and APL ab (p < 0.05 for all). Conversely, patients with skin manifestations had a significantly lower YKL-40 (p = 0.004). In juvenile SLE, the AUC was 0.65 and a p-value of 0.01, and at a cutoff value of (8.7) ng/mL, the sensitivity and specificity were 72% and 60%, respectively. CONCLUSION: YKL-40 in serum could be a promising biomarker in patients with SLE, especially in adolescent-onset cases. It is independently influenced by disease duration, anemia, thrombocytopenia, positive anti-dsDNA, and APL ab features.

A Vapor Based Microfluidic Flow Regulator.

We introduce a flow regulating technology that uses trapped air bubbles in a hydrophobic microfluidic channel. We present basic designs for flow regulators and flow valves using trapped air. Experiments have successfully demonstrated the capability of this technique for delivering constant and varying flow rate, and for on-off valving. This approach to valving provides a simple, yet effective way to monolithically integrate flow and valve control on polymer Lab-on-Chip devices.

Droplet screens in nanovolumes using static conditions.

Microfluidic droplet systems have shown great promise in high throughput chemical assays to minimize chemical consumption and increase process efficiency. We report a droplet system that forms nanovolume drops under static conditions. The programmability of drop sizes is determined by geometric configurations and surface tension, and not particularly sensitive to flow rates. The geometry of the device predetermines locations of drops, and thus it is easy to identify the locations of drops and the volumes of the drops within them. Further integration can be made to generate screening assays and utilized in various applications such as crystallization screening and solubility studies. This technology makes hand-operated systems a possibility, since precision control of flow rates is not necessary.