The development of urinary neopterin immunoassays and their clinical applications for non-invasive detection of cellular immune activation.

摘要

Due to the fundamental changes in societies and healthcare systems, infections have returned as a major threat to global societies. Screening of infected patients allows immediate and proper medical actions and minimizes the risk of disease transmission. Although appropriate and prompt medical actions such as isolation and/or treatment to the patients should be taken, they are frequently delayed due to slow identification methods for finding out particular pathogens. Also, the pitfall of existing specific pathogen screening is that potential hazardous pathogens may remain undetected, either because they are known but not screened or they are unknown. There is an imperative need to develop a rapid screening tool which reflects general immunity conditions for gatekeeping. In view of that, rapid and non-invasive urinary neopterin immunoassays are developed. Urinary neopterin is a sensitive indicator for cellular immune activation. The accelerated production of neopterin is enforced by the stimulation of interferon-gamma. In diseases involving intensified activities of monocytes and macrophages including infections and inflammations, significant elevation of urinary neopterin concentration is observed. It is a powerful screening tool for infections, as it reacts to a broad variety of known and hitherto not-characterized pathogens.;A rapid ELISA has been developed for high-throughput measurements of urinary neopterin concentrations. It is more competitive than the existing neopterin ELISAs by offering much higher analytical sensitivity (limit of detection down to 0.76 nmol/L) and shorter assay time (40 minutes) with minimal experimental steps.;A novel lateral-flow immunochromatography has been developed for quantitative detection of neopterin concentrations in urine. It is a portable device in point-of-care testing format allowing decentralized applications. It is a single step immunoassay using colloidal gold particles for signal generation. It demonstrates high analytical sensitivity (limit of detection down to 1.1 nmol/L) and provides rapid results in 5 minutes. To the best of our knowledge, it is the fastest immunoassay ever reported for quantitative measurements of urinary neopterin concentration.;The clinical study using acute respiratory tract infections (ARTIs) patients as the disease population proved the superior diagnostic value of the developed immunoassays applying for infection screening, supported by exclusively high AUCs (>0.96, P<0.001) in ROC curve analysis achieved by using both tests. For differentiation of viral and bacterial aetiology, high AUCs (>0.71, P<0.001) are achieved. It is believed that applications of the developed simple, rapid and sensitive urinary neopterin immunoassays will be versatile.