Human Saliva as a Diagnostic Specimen for Early Detection of Inflammatory Biomarkers by Real-Time RT-PCR

Abstract

Nowadays human saliva is more frequently studied as a non-invasive, stress-free, and preferable diagnostic material than blood. Supporting evidences acknowledge saliva as a mirror that reflects the body's physical state. Numerous studies have also demonstrated the presence and use of RNA derived from saliva in the early diagnosis of disease by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Assessing the host inflammatory response in patients and its resolution at an early stage can serve as a prognostic and predictive method in determining therapeutic response or disease progression. In this context, the potential of saliva as a specimen to diagnose early inflammatory biomarkers using RT-PCR seems fascinating and useful. Here, we review inflammatory biomarkers within the saliva, focusing on early detection of these biomarkers using RT-PCR and the factors influencing the quality of saliva specimen.

Saliva as a Potential Specimen to Monitor IL-6, TNF-α and IL-10 in COVID-19 Patients

“…All cytokine profile studies performed to date were based on protein level analysis from serum/plasma of subjects, none of the studies emphasized on gene level analysis and the use of easy to procure and non-invasive salivary diagnostics in this context. Saliva has been regarded as a potential specimen in both diagnosis and prognosis of numerous diseases by investigators around the world [ 14 ]. Also, saliva sample collection is relatively much easier, non-invasive, requires less stress and promotes low-cost storage than any other body fluid.…”

“…Moreover, salivary analysis makes frequent monitoring easy, especially in infants, children and elderly patients, as well as in conditions where urine or blood sampling is not practical. However, despite its numerous advantages, saliva is not yet considered to be an established analytical specimen due to the insufficient information about its biochemical composition and correlation with plasma levels [ 14 , 20 ]. In our study, we have tried to fill this gap area by analysing the inflammatory genes, IL-6, TNF-α and IL-10 from blood and saliva samples of 64 subjects who were tested positive for SARS-CoV-2 not more than 2 days before enrolling to study,out of the total study population, all 64 (100% patients expressed IL-6 gene and TNF-α, whereas 7 (5.19% patients expressed IL-10 in both blood and saliva samples.…”

“…A nurse received the tubes wearing gloves and deposited it into a cooler containing ice packs for transport to the laboratory. Quality control of saliva specimen and other preparations before saliva collection was ensured by following the recommended guidelines [ 14 ]. All samples were processed within the same day.…”

“…Though human saliva is reported to be used for detection of numerous inflammatory markers such as IL-1, IL-6, TNF, arachidonate 5-lipoxygenase (5-LOX), chemokines, vascular endothelial growth factor (VEGF), prostaglandin-endoperoxide synthase 2 (COX-2), matrix metalloproteinases (MMPs), twist-related protein (TWIST) and cell surface adhesion molecules in patients affected with chronic diseases [ 14 , 15 ], we could not find any study reporting the detection of salivary inflammatory markers in COVID-19 patients.…”

Quantitative Detection of Mastitis Factor IL-6 in Dairy Cow Using the SERS Improved Immunofiltration Assay

“…Cytokines play important roles in the immune system of dairy cows by regulating various cell physiological functions. In addition, they act as transmitters of cell communication in the process of inflammation and immune response [ 7 , 8 ]. As a multifunctional cytokine, interleukin-6 (IL-6) is a kind of glycoproteins produced and secreted by activated macrophages, lymphocytes, and epithelial cells.…”