Elevated Interleukin-6 Levels in Irritable Bowel Syndrome and Non-Ulcerative Dyspepsia

Plasma Interleukin-13 Levels Correlate With the Severity of Symptoms Induced by Functional Dyspepsia

OBJECTIVE

Functional dyspepsia (FD) is a gastrointestinal functional disorder of the upper gastrointestinal tract that affects the quality of life of patients and poses a significant economic burden. It has been proposed that the local inflammatory immune response at the duodenum is associated with an increase in intestinal permeability, favoring the recruitment of Th2 cells and granulocyte degranulation. Moreover, systemic immune response could also be related to the symptoms of FD. The objective of this study was to evaluate the systemic immune response in Uruguayan patients with FD by analyzing the cytokine levels in plasma and the frequency of circulating T cells associated with duodenal recruitment.

PATIENTS AND METHODS

An analytic and cross-sectional study in 30 patients with FD and 15 healthy controls (HCs) was carried out. Patients were diagnosed with FD according to the Roma IV Committee definition. Cytokine levels were measured in plasma by a specific assay. Expression of α4β7 and CC chemokine receptor9 in circulating T cells was evaluated by flow cytometry.

RESULTS

Higher levels of interleukin (IL)-5, IL-13, and IL-8 and lower levels of IL-10 and IL-12p70 were detected in patients with FD than in HC. Furthermore, a positive linear correlation between IL-13 and the severity of FD symptoms was found. CD4+ T cells from patients with FD expressed higher levels of α4β7 and CC chemokine receptor9 than those from HC.

CONCLUSIONS

An increase of Th2-like cytokines and a positive correlation between the levels of plasma IL-13 and the severity of symptoms in patients with FD from Uruguay were detected.

Ultra-Sensitive and Semi-Quantitative Vertical Flow Assay for the Rapid Detection of Interleukin-6 in Inflammatory Diseases

The inflammation biomarker Interleukin 6 (IL-6) exhibits a concentration of less than 7 pg/mL in healthy serum but increases 10–100-fold when inflammation occurs. Increased serum IL-6 has been reported in chronic diseases such as rheumatoid arthritis (RA), as well as in life-threatening acute illnesses such as sepsis and cytokine release syndrome (CRS). This work seeks to meet the demand for rapid detection of serum IL-6 both for rapid monitoring of chronic diseases and for triaging patients with acute illnesses. Following the optimization of several types of gold nanoparticles, membrane pore sizes, and buffer systems, an ultra-sensitive vertical flow assay (VFA) was engineered, allowing the detection of recombinant IL-6 in spiked buffer with a limit of detection (LoD) of 10 pg/mL and a reportable range of 10–10,000 pg/mL with a 15-min assay time. The detection of IL-6 in spiked pooled healthy serum exhibited an LoD of 3.2 pg/mL and a reportable range of 10–10,000 pg/mL. The VFA’s stability was demonstrated over 1-day, two-week, four-week, and six-week storage durations at room temperature. The inter-operator CV and intra-operator CV were determined to be 14.3% and 15.2%, respectively. Three reference zones, high, low, and blank, were introduced into the cartridge to facilitate on-site semi-quantitative measurements across a 6-point semi-quantitative range. Finally, the performance of the IL-6 VFA was validated using 20 RA and 20 healthy control (HC) clinical serum samples, using ELISA as the gold standard platform. The ultra-sensitive, rapid IL-6 VFA could potentially be used to triage patients for intensive care, treatment adjustments, or for monitoring disease activity in inflammatory conditions.

Micro-inflammation in functional dyspepsia: A systematic review and meta-analysis

Functional dyspepsia (FD) is a gastrointestinal disorder of unknown etiology. Although micro-inflammation appears to be important in the pathogenesis, studies evaluating immune activation in FD have been inconsistent. A systematic review of literature and meta-analysis was performed to compare immunologic cell counts and cytokine levels in the mucosa and peripheral blood of individuals with FD and healthy controls. PubMed, Embase, and the Cochrane library were searched. Data on immunologic cell counts and cytokines levels among individuals with FD and control groups were extracted and compared by calculating standard mean differences (SMD). Thirty-seven studies met the inclusion criteria. Mast cell (SMD = 0.94, 95%CI 0.26-1.62, P = .007) and eosinophil counts (SMD = 0.36, 95%CI 0.06-0.68, P = .03) in the stomach were increased, among individuals with FD compared to controls. Similarly, mast cell (SMD = 0.66, 95%CI 0.20-1.13, P = 0.005) and eosinophil (SMD = 0.95, 95%CI 0.66-1.24; P < .001) counts in the duodenum were also increased in those with FD compared to controls. In a subgroup analysis, elevated eosinophil counts in the duodenum were observed in both post-prandial distress syndrome (SMD = 0.97, 95%CI 0.46-1.47, P = .0002) and epigastric pain syndrome subtypes (SMD = 1.16, 95%CI 0.48-1.83, P = .0008). No differences in mucosal intraepithelial lymphocyte, enterochromaffin cell, and neutrophil counts, as well as, peripheral interlukin-6 (IL-6) and IL-10 levels were observed among individuals with FD and controls. Micro-inflammation in the form of local immune cell infiltration, particularly eosinophils and mast cells, characterizes the pathogenesis of FD.