Increased levels of S100A8/A9, IL-1ß and IL-18 as a novel biomarker for recurrent tonsillitis

Serum Levels of Selected Cytokines and Chemokines and IgG4 in Children With Recurrent Respiratory Tract Infections

Background: Respiratory tract infections are a common health problem. Cytokines/chemokines play a critical role in the regulation of the immune system. Their defective production may predispose to recurrent respiratory tract infections (RRIs), and an excessive immune response may lead to chronic inflammation and cause damage to the respiratory tract. Another biomarker of respiratory infections may be immunoglobulin-IgG4. Its meaning has still been little explored. We wanted to assess the suitability of the levels of biomarkers tested: interleukin (IL)-17A, IL-18, IL-23, normal T cells expressed and secreted (RANTES), and induced protein (IP)-10, as well as immunoglobilun G4 (IgG4) to predict recurrent infections. Methods: The study group (SG) included a total of 130 children (68 girls, 62 boys) between 3 and 17 years of age with RRI. The control group (CG) included 86 healthy children with no symptoms of inflammatory or allergic diseases (44 girls and 42 boys) of the same age. Blood samples were collected in fasting state and then serum samples were frozen and stored until biomarker assay. Results: Serum RANTES, IL-18, IL-23, and IgG4 concentration were higher in all children with recurrent infections vs. those in the CG (p  < 0001). Serum levels of IL-17A and IP-10 were also significantly higher in the SG than in the CG, but only in the youngest children. Among the six serum markers, RANTES demonstrated the highest area under the receiver operating characteristic curve (area under curve) value (0.998, 95% confidence interval [CI]: 0.98-1.0, p < 0.001) for the diagnosis of RRIs, followed by IL-23 (0.99, 95% CI 0.966-0,999, p < 0.001) and IL-18 (0.957, 95% CI 0.921-0.980, p < 0.001). Conclusions: RANTES, IL-23, and IL-18 could be strong predictors of respiratory infections recurrence in children.

Immediate and Delayed Salivary Cytokine Responses during Repeated Exposures to Cold Pressor Stress

INTRODUCTION

Excessive stress is increasingly recognized as an important trigger of many diseases prevalent in modern societies, and monitoring such stress-related effects could aid prevention. The measurement of salivary markers of inflammation is emerging as a promising tool to non-invasively quantify stress' effects on immune processes in everyday life and thereby detect early aberrations before the manifestation of serious health problems. However, more laboratory-controlled research is needed in order to establish the timescale and determinants of salivary cytokine responses to acute stress.

METHODS

We repeatedly exposed participants to Cold Pressor Stress Test (CPT) or a control procedure and measured a wide array of salivary cytokines as well as subjective, cardiovascular, and cortisol stress reactions. CPT exposure was repeated every 15 min, 3 times in total, with a duration of 3 min each. Saliva was sampled immediately after the first two exposures as well as in 15-min intervals until 60 min after the onset of the first intervention.

RESULTS

We found that many cytokines were detectable in saliva. Specific stress effects were limited to IL-8 and IL-6, however, which decreased immediately or 15 min after stress onset, respectively. Moreover, IL-8 was negatively correlated to cortisol output in the stress but not in the control group. Significant increases were also observed in salivary TNFα and IFNγ; however, these effects were similar under both stress and control conditions.

DISCUSSION

Our results show that particular salivary cytokines may be sensitive to immediate effects of acute CPT-induced stress and also highlight the importance of employing control procedures to discern stress effects from unrelated variations in salivary cytokines.