The Impact of Oral Health on Respiratory Viral Infection

Influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2) have caused respiratory diseases worldwide. Coronavirus disease 2019 (COVID-19) is now a global health concern requiring emergent measures. These viruses enter the human body through the oral cavity and infect respiratory cells. Since the oral cavity has a complex microbiota, influence of oral bacteria on respiratory virus infection is considered. Saliva has immune molecules which work as the front line in the biophylactic mechanism and has considerable influence on the incidence and progression of respiratory viral infection. Salivary scavenger molecules, such as gp340 and sialic acid, have been reported to exert anti-influenza virus activity. Salivary secretory immunoglobulin A (SIgA) has potential to acquire immunity against these viruses. Biological features of the oral cavity are thought to affect viral infection in respiratory organs in various ways. In this review, we reviewed the literature addressing the impact of oral conditions on respiratory infectious diseases caused by viruses.

Child Salivary SIgA and Its Relationship to Enteric Infections and EED Biomarkers in Maputo, Mozambique

Characterizing child immunological responses to enteric infections with antibody detection in serum can be challenging in resource-constrained field settings, because sample collection requires trained individuals and its invasive procedure may lead to low response rates, especially among children. Saliva may present a promising non-invasive alternative. The objectives of this research were to compare salivary antibody levels in children to enteric infections and biomarkers of environmental enteric dysfunction (EED). We collected saliva samples from children aged one to six years enrolled in a sanitation trial in Maputo, Mozambique, and characterized salivary secretory immunoglobulin A (SIgA) concentrations with enzyme-linked immunosorbent assays. We used multilevel linear models to analyze cross-sectional associations between salivary SIgA and the number of concurrent enteric pathogen infections, as well as EED biomarkers in matched stool samples. Median salivary SIgA concentrations in this study population were 54 μg/mL (inter-quartile range (IQR): 34, 85 μg/mL), and SIgA levels were similar between children of different ages. SIgA was lower in children experiencing a higher number of concurrent infections −0.04 log μg/mL (95% confidence interval (CI): −0.08 to −0.005 log μg/mL), but was not associated with any of the included EED biomarkers. Contrary to evidence from high-income countries that suggests salivary SIgA increases rapidly with age in young children, the high prevalence of enteric infections may have led to a suppression of immunological development in this study sample and could in part explain the similar SIgA levels between children of different ages.

The Effects of Play Behavior, Feeding, and Time of Day on Salivary Concentrations of sIgA in Calves

The focus of animal welfare science has shifted over the last decades from efforts to avoid negative states to ways of allowing animals the experience of positive emotions. They may influence physiological processes in farmed animals, potentially providing health benefits; in addition, the physiological changes might be used as indicators of emotional states. We investigated calves’ salivary secretory immunoglobulin A (sIgA) concentrations with regard to a possible circadian rhythm and two situations that elicit positive emotions. Ten saliva samples of 14 calves were taken on two consecutive days; within the course of a day we observed a significant decline in salivary sIgA concentrations at 14:00 h. Further, we probed the animals before and after milk feeding and, contrarily to our prediction, detected lower sIgA concentrations 5 min after feeding than 15 min before. A probable explanation might be an increase in salivary flow rate caused by milk ingestion. We also took samples before and after we stimulated play behavior in calves. There was no significant difference in sIgA concentrations between samples taken before and after play. Although there was a significant correlation between the change in sIgA concentrations and the amount of play behavior shown, the correlation depended on an unexpected decrease of sIgA in animals that played little, and thus, does not support our hypothesis. In general, the data showed a large variability that might arise from different factors that are difficult to standardize in animals. Thus, the use of salivary sIgA concentrations as a marker of positive emotions in calves is not supported conclusively by the present data.

Within-Subject Correlation Between Salivary IgA and Measures of Training Load in Elite Football Players

Purpose: To quantify the association between salivary secretory immunoglobulin A (sIgA) and training load in elite football players. Methods: Data were obtained on 4 consecutive days during the preparation camp for the Rio 2016 Olympic Games. Saliva samples of 18 elite male football players were collected prior to breakfast. The session rating of perceived exertion (s-RPE) and external training-load metrics from global positioning systems (GPS) were recorded. Within-subject correlation coefficients between training load and sIgA concentration, and magnitude of relationships, were calculated. Results: sIgA presented moderate to large negative correlations with s-RPE (r = −.39), total distance covered (r = −.55), accelerations (r = −.52), and decelerations (r = −.48). Trivial to small associations were detected between sIgA and distance covered per minute (r = .01), high-speed distance (r = −.23), and number of sprints (r = −.18). sIgA displayed a likely moderate decrease from day 1 to day 2 (d = −0.7) but increased on day 3 (d = 0.6). The training-load variables had moderate to very large rises from day 1 to day 2 (d = 0.7 to 3.2) but lowered from day 2 to day 3 (d = −5.0 to −0.4), except for distance per minute (d = 0.8) and sprints (unclear). On day 3, all training-load variables had small to large increments compared with day 1 (d = 0.4 to 1.5), except for accelerations (d = −0.8) and decelerations (unclear). Conclusions: In elite football, sIgA might be more responsive to training volume than to intensity. External load such as GPS-derived variables presented stronger association with sIgA than with s-RPE. sIgA can be used as an additional objective tool in monitoring football players.

Brief Report: Training Load, Salivary Immunoglobulin A, and Illness Incidence in Elite Paratriathletes

Purpose: To gain an exploratory insight into the relation between training load (TL), salivary secretory immunoglobulin A (sIgA), and upper respiratory tract illness (URI) in elite paratriathletes. Methods: Seven paratriathletes were recruited. Athletes provided weekly saliva samples for the measurement of sIgA over 23 consecutive weeks (February to July) and a further 11 consecutive weeks (November to January). sIgA was compared to individuals’ weekly training duration, external TL, and internal TL, using time spent in predetermined heart-rate zones. Correlations were assessed via regression analyses. URI was quantified via weekly self-report symptom questionnaire. Results: There was a significant negative relation between athletes’ individual weekly training duration and sIgA secretion rate (P = .028), with changes in training duration accounting for 12.7% of the variance (quartiles: 0.2%, 19.2%). There was, however, no significant relation between external or internal TL and sIgA parameters (P ≥ .104). There was no significant difference in sIgA when URI was present or not (101% vs 118% healthy median concentration; P ≥ .225); likewise, there was no difference in sIgA when URI occurred within 2 wk of sampling or not (83% vs 125% healthy median concentration; P ≥ .120). Conclusions: Paratriathletes’ weekly training duration significantly affects sIgA secretion rate, yet the authors did not find a relation between external or internal TL and sIgA parameters. Furthermore, it was not possible to detect any link between sIgA and URI occurrence, which throws into question the potential of using sIgA as a monitoring tool for early detection of illness.

SALIVARY SECRETORY IMMUNOGLOBULIN A LEVEL OF CHILDREN WITH ACUTE LYMPHOBLASTIC LEUKEMIA IN MAINTENANCE PHASE

Objective: The objective of this research is to investigate the differences in salivary secretory immunoglobulin A (sIgA) levels between children with gingivitis who have acute lymphoblastic leukemia (ALL) and are in the maintenance phase of chemotherapy and the levels in healthy children with gingivitis.Methods: This study used cross-sectional and laboratory observation methods with 19 ALL children and 19 healthy children who all had mild gingivitis. Two mL of saliva were collected and stored at −200°C. Then, salivary sIgA levels were measured using the ELISA method.Results: The results indicate an insignificant difference (p>0.05) in salivary sIgA levels between the ALL children in the maintenance phase with the level of 21.38 (7.23–107.26) and 37.26 (11.24–135.63) for the healthy children.Conclusion: There is no significant difference in salivary sIgA levels between the ALL children in the maintenance phase and the healthy children.