Role of peripheral and tissue eosinophils and eosinophil cationic protein in pediatric inflammatory bowel disease

OBJECTIVES

Inflammatory bowel disease (IBD), eosinophilic gastrointestinal disease (EGID), and functional abdominal pain disorder (FAPD) present with nonspecific gastrointestinal (GI) symptoms clinically and also have some similarities in pathogeneses associated with eosinophils. Therefore, we aimed to evaluate the role of eosinophils in IBD compared to EGID and FAPD by investigating eosinophils in peripheral blood and GI tissue and eosinophil cationic protein (ECP).

METHODS

Pediatric patients with chronic GI symptoms who underwent endoscopic biopsies were enrolled. Complete blood cell counts, inflammatory markers, immunoglobulin E (IgE), serum ECP levels, and endoscopic and histopathologic findings were retrospectively reviewed.

RESULTS

A total of 387 patients were included: 179 with EGID, 107 with IBDs, and 82 with FAPD. Peripheral absolute eosinophil count (AEC), total IgE, and serum ECP were significantly higher in both IBD and EGID than in FAPD (all p < 0.05). Statistically significant differences were noted among the three groups in tissue eosinophil counts in each segment of GI tract except for the esophagus (p < 0.05). Significant differences were observed in tissue eosinophil counts in the ascending, sigmoid colon, and rectum between EGID and IBD (p < 0.05). Peripheral and tissue eosinophils in the stomach and duodenum revealed positive correlation in both EGID and IBD (both p < 0.001).

CONCLUSION

Elevated eosinophil-related markers, as well as increased tissue eosinophilic infiltration in the affected areas of the GI tract in both IBD and EGID compared to FAPD, suggest that eosinophils might play a common important role in the pathogeneses of both diseases.

Role of serum eosinophil cationic protein in distinct endotypes of chronic rhinosinusitis

BACKGROUND

Serum eosinophil cationic protein (ECP) levels affect the surgical outcome of chronic rhinosinusitis (CRS) with nasal polyps. Primary CRS can be classified into type 2 (T2) and non-T2. We aimed to differentiate the role of serum ECP levels in surgical outcomes between the distinct endotypes of primary CRS.

METHODS

We prospectively enrolled patients with bilateral primary CRS who underwent surgical treatment with postoperative follow-up for at least 12 months. Endotyping and serum parameter measurements were completed within 1 week before surgery.

RESULTS

In total, 113 patients were enrolled, including 65 with T2 CRS and 48 with non-T2 CRS. Patients in the T2 CRS group with uncontrolled CRS had significantly higher serum ECP levels than those in patients in the non-T2 CRS group. An optimal cut-off value was obtained at 17.0 μg/L using the receiver operating characteristic curve, attaining a sensitivity of 91.7% and specificity of 56.6%. Multivariate logistic regression analysis showed that a higher serum ECP level was an independent factor for postoperative uncontrolled disease. The hazard ratio was 11.3 for the T2 group, with serum ECP levels over 17.0 μg/L. In the non-T2 group, no parameters were significantly correlated with postoperative uncontrolled CRS.

CONCLUSIONS

Serum ECP levels appear to be a feasible predictor of postoperative uncontrolled disease in patients with T2 CRS as preoperative serum ECP levels >17.0 μg/L in these patients have an approximately 16.7-fold increased risk of postoperative uncontrolled disease and should be closely monitored.

Predictive Value of Eosinophil Cationic Protein in Nasal Secretions in Eosinophilic Chronic Rhinosinusitis

OBJECTIVES

To investigate the value of secretions Eosinophilic cationic protein (ECP) detection in the diagnosis of endotypes of Chronic rhinosinusitis (CRS) and its correlation with clinical symptoms, so as to provide guidance for the clinical application of EOS and ECP detection in secretions.

METHODS

Patients' nasal secretions and polyps (or middle turbinate for control) were collected and their EOS% and ECP levels were measured. Correlation analysis was performed for EOS% and ECP levels in secretions and tissues, respectively. The correlation between secretions EOS% and ECP and clinical symptom scores (symptomatic visual analog scale (VAS) scores, Lanza-kennedy scores from nasal endoscopy and Lund-Mackay scores from sinus CT) was further analyzed. Receiver operating characteristic curves were used to assess the predictive potential of EOS% and ECP in nasal secretions.

RESULTS

Eosinophilic chronic rhinosinusitis (ECRS) patients had higher concentrations of ECP in nasal secretions than healthy subjects and NECRS (non-eosinophilic CRS) (p < 0.0001;0.0001); EOS% in nasal secretions was higher in ECRS than healthy subjects (p = 0.0055), but the differences between ECRS and NECRS were not statistically significant (p = 0.0999). Correlation analysis showed that tissue EOS% was correlated with ECP concentration and EOS% in nasal secretions (R = 0.5943;0.2815). There was a correlation between EOS% in secretions with a total LM score (R = 0.3131); ECP concentration in secretions with a total LK score (R = 0.3792). To diagnose ECRS, the highest area under the curve (0.8230) was determined for ECP in secretions; the highest area under the curve (0.6635) was determined for EOS% in secretions.

CONCLUSION

Measurement of ECP in nasal secretions is useful for non-invasive diagnosis of ECRS.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:3304-3312, 2023.

Variants of IL6, IL10, FCN2, RNASE3, IL12B and IL17B loci are associated with Schistosoma mansoni worm burden in the Albert Nile region of Uganda

BACKGROUND

Individuals genetically susceptible to high schistosomiasis worm burden may contribute disproportionately to transmission and could be prioritized for control. Identifying genes involved may guide development of therapy.

METHODOLOGY/PRINCIPAL FINDINGS

A cohort of 606 children aged 10-15 years were recruited in the Albert Nile region of Uganda and assessed for Schistosoma mansoni worm burden using the Up-Converting Particle Lateral Flow (UCP-LF) test detecting circulating anodic antigen (CAA), point-of-care Circulating Cathodic Antigen (POC-CCA) and Kato-Katz tests. Whole genome genotyping was conducted on 326 children comprising the top and bottom 25% of worm burden. Linear models were fitted to identify variants associated with worm burden in preselected candidate genes. Expression quantitative trait locus (eQTL) analysis was conducted for candidate genes with UCP-LF worm burden included as a covariate. Single Nucleotide Polymorphism loci associated with UCP-LF CAA included IL6 rs2066992 (OR = 0.43, p = 0.0006) and rs7793163 (OR = 2.0, p = 0.0007); IL21 SNP kgp513476 (OR 1.79, p = 0.0025) and IL17B SNP kgp708159 (OR = 0.35, p = 0.0028). A haplotype in the IL10 locus was associated with lower worm burden (OR = 0.53, p = 0.015) and overlapped SNPs rs1800896, rs1800871 and rs1800872. Significant haplotypes (p<0.05, overlapping significant SNP) associated with worm burden were observed in IL6 and the Th17 pathway IL12B and IL17B genes. There were significant eQTL in the IL6, IL5, IL21, IL25 and IFNG regions.

CONCLUSIONS

Variants associated with S. mansoni worm burden were in IL6, FCN2, RNASE3, IL10, IL12B and IL17B gene loci. However only eQTL associations remained significant after Bonferroni correction. In summary, immune balance, pathogen recognition and Th17 pathways may play a role in modulating Schistosoma worm burden. Individuals carrying risk variants may be targeted first in allocation of control efforts to reduce the burden of schistosomiasis in the community.

Conformational exchange divergence along the evolutionary pathway of eosinophil-associated ribonucleases

The evolutionary role of conformational exchange in the emergence and preservation of function within structural homologs remains elusive. While protein engineering has revealed the importance of flexibility in function, productive modulation of atomic-scale dynamics has only been achieved on a finite number of distinct folds. Allosteric control of unique members within dynamically diverse structural families requires a better appreciation of exchange phenomena. Here, we examined the functional and structural role of conformational exchange within eosinophil-associated ribonucleases. Biological and catalytic activity of various EARs was performed in parallel to mapping their conformational behavior on multiple timescales using NMR and computational analyses. Despite functional conservation and conformational seclusion to a specific domain, we show that EARs can display similar or distinct motional profiles, implying divergence rather than conservation of flexibility. Comparing progressively more distant enzymes should unravel how this subfamily has evolved new functions and/or altered their behavior at the molecular level.

Prognostic factors for polyp recurrence in chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps is frequently managed with endoscopic sinus surgery (ESS). Prior studies describe individual clinical variables and eosinophil density measures as prognostic for polyp recurrence (PR). However, the relative prognostic significance of these have not been extensively investigated.

OBJECTIVES

We sought to evaluate the impact of PR on measures of disease severity post-ESS and quantify the prognostic value of various clinical variables and biomarkers.

METHODS

Ninety-four patients with chronic rhinosinusitis with nasal polyps and prospectively biobanked polyp homogenates at the time of ESS were recruited 2 to 5 years post-ESS. Patients were evaluated with patient-reported outcome measures and endoscopic and radiographic scoring pre- and post-ESS. Biomarkers in polyp homogenates were measured with ELISA and Luminex. Relaxed least absolute shrinkage and selection operator regression optimized predictive clinical, biomarker, and combined models. Model performance was assessed using receiver-operating characteristic curve and random forest analysis.

RESULTS

PR was found in 39.4% of patients, despite significant improvements in modified Lund-Mackay (MLM) radiographic and 22-item Sinonasal Outcomes Test scores (both P < .0001). PR was significantly associated with worse post-ESS MLM, modified Lund-Kennedy, and 22-item Sinonasal Outcomes Test scores. Relaxed least absolute shrinkage and selection operator identified 2 clinical predictors (area under the curve = 0.79) and 3 biomarkers (area under the curve = 0.78) that were prognostic for PR. When combined, the model incorporating these pre-ESS factors: MLM, asthma, eosinophil cationic protein, anti-double-stranded DNA IgG, and IL-5 improved PR predictive accuracy to area under the curve of 0.89. Random forest analysis identified and validated each of the 5 variables as the strongest predictors of PR.

CONCLUSIONS

PR had strong associations with patient-reported outcome measures, endoscopic and radiographic severity. A combined model comprised of eosinophil cationic protein, IL-5, pre-ESS MLM, asthma, and anti-double-stranded DNA IgG could accurately predict PR.

Performance of Eosinophil Cationic Protein as a Biomarker in Asthmatic Children

BACKGROUND

Although blood eosinophils are a frequently used marker of type 2 inflammation in children with asthma, their sensitivity is relatively poor. Additional markers of type 2 inflammation are needed.

OBJECTIVE

We hypothesized that plasma concentrations of eosinophil cationic protein (ECP), a marker of eosinophil activation, would be useful for detection of type 2 inflammation and would predict poorer asthma outcomes over 1 year.

METHODS

Children and adolescents 6 through 17 years (N = 256) with confirmed asthma completed a baseline visit and a follow-up visit at 12 months. A subset also underwent systemic corticosteroid responsiveness testing with intramuscular triamcinolone. Outcome measures at 12 months included uncontrolled asthma, lung function, and asthma exacerbations treated with systemic corticosteroids.

RESULTS

Plasma ECP concentrations ranged from 0.03 to 413.61 ng/mL (median, 6.95 ng/mL) and were consistently associated with other markers of type 2 inflammation. At baseline, children in the highest ECP tertile had poorer asthma control, more airflow limitation, and more exacerbations, but also had greater symptom improvement with intramuscular triamcinolone. At 12 months, associations between the highest ECP tertile and exacerbations, but not lung function or asthma control, persisted after covariate adjustment. However, the sensitivity of ECP was modest and was not markedly different from that of blood eosinophil counts.

CONCLUSION

Plasma ECP concentrations may be a useful marker of type 2 inflammation in children and may help identify those children at highest risk for recurrent exacerbations who could benefit from corticosteroid treatment. However, additional markers may be needed to improve sensitivity for outcome detection.

Eosinophil cationic protein: A new diagnostic biomarker in coronary slow flow phenomenon

AIM

This study has investigated the role of eosinophil cationic protein (ECP), released by eosinophils, in the coronary slow flow phenomenon.

METHODS

This study included sixty patients with coronary slow flow (CSF) and sixty patients with normal coronary flow. The coronary flow rate was evaluated with TIMI frame count (TFC). ECP level, blood count and biochemical parameters were assessed.

RESULTS

The ECP levels (18.9±7.5 vs 13.1±6.4 ng/ml, p<0.001) and eosinophil counts (0.25±0.14 vs 0.18±0.09 10³/mm³, p=0.001) were higher in the CSF group. Multivariable regression analysis showed that ECP level and eosinophil counts were independent predictors the presence of CSF (p=0.003 and p=0.006). There was a weak but important correlation among the ECP level, eosinophil count and mean TFC (p=0.001, p=0.003, respectively). The ROC analysis showed a cut off value of 14.05 ng/ml for ECP level to diagnose CSF with 73.3 % sensitivity and 66.7 % specificity, and area under the ROC curve was 0.745 (95% CI: 0.657-0.833, p<0.001).

CONCLUSION

ECP levels were increased in CSF patients and this increasing correlated with coronary artery flow rates. The ECP level was independent predictor for the presence of SCF and it may be use as suitable diagnostic biomarker for CSF (Tab. 3, Fig. 3, Ref. 30).

[Relationship between eosinophils in nasal discharge and responses to treatment of inhaled glucocorticosteroid in patients with persistent allergic rhinitis]

OBJECTIVE

To evaluate the treatment responses of persistent allergic rhinitis with and without eosinophils (EOS) in nasal discharge to inhaled glucocorticosteroid (CS), and therefore to verify whether low eosinophil level in nasal discharge can predict poor response to treatment with CS.

METHOD

Forty-two symptomatic allergic rhinitis patients, who had not received CS therapy in three months preceding the study, were examined before and 2 month, 4 months and 6 months after treatment with CS. At each visit, all patients underwent symptom scoring and physical sign scoring. The level of eosinophil cationic protein (ECP) in the nasal discharge supernatants was measured by radioimmunoassay. The patients were divided into 2 groups according to nasal discharge EOS percentages, an EOS group (EOS > or = 3%) and a non-EOS group (EOS < 3%). The response to CS therapy (as measured by symptom and physical sign scores) and the changes of nasal discharge measurements were compared between the 2 groups.

RESULT

In the EOS group, the baseline EOS [0.086 (0.065; 0.176)] and ECP level [(326 +/- 145) microg/L] were significantly higher than EOS [0.016 (0.005; 0.022)] and ECP level [(154 +/- 58) microg/L] of the non-EOS group, t = 4.40, 3.32, respectively, all P < 0.01. After 2 months and 6 months of CS therapy, the nasal discharge EOS, ECP level were 0.038 (0.006; 0.070), 0.019 (0.010; 0.060), (175 +/- 122) microg/L, (175 +/- 153) microg/L, respectively in the EOS group,which were significantly different as compared to baseline values (F = 6.73, 7.38, respectively all P < 0.05). But in the non-EOS group, the nasal discharge EOS and ECP level were 0.014 (0.004; 0.032), 0.015 (0.010; 0.026), (118 +/- 60) microg/L, (112 +/- 60) microg/L, respectively at 2 and 6 months, which showed that the nasal discharge EOS level and the symptom and physical sign scores did not improve significantly (F = 0.82, P > 0.05), but the ECP level did improve (F = 3.78, P < 0.05). The average daily dose of CS was not different between the two groups at any visits.

CONCLUSION

In persistent allergic rhinitis with low EOS in nasal discharge, CS therapy for 6 months failed to improve symptoms and physical signs.

RNase 3 (ECP) is an extraordinarily stable protein among human pancreatic-type RNases

There have been some attempts to develop immunotoxins utilizing human RNase as a cytotoxic domain of antitumor agents. We have recently shown that only human RNase 3 (eosinophil cationic protein, ECP) among five human pancreatic-type RNases excels in binding to the cell surface and has a growth inhibition effect on several cancer cell lines, even though the RNase activity of RNase 3 is completely inhibited by the ubiquitously expressed cytosolic RNase inhibitor. This phenomenon may be explained by that RNase 3 is very stable against proteolytic degradation because RNase 3 internalized through endocytosis could have a longer life time in the cytosol, resulting in the accumulation of enough of it to exceed the concentration of RNase inhibitor, which allows the degradation of cytosolic RNA molecules. Thus, we compared the stabilities of human pancreatic-type RNases (RNases 1-5) and bovine RNase A by means of guanidium chloride-induced denaturation experiments based on the assumption of a two-state transition for unfolding. It was demonstrated that RNase 3 is extraordinarily stabler than either RNase A or the other human RNases (by more than 25 kJ/mol). Thus, our data suggest that in addition to its specific affinity for certain cancer cell lines, the stability of RNase 3 contributes to its unique cytotoxic effect and that it is important to stabilize a human RNase moiety through protein engineering for the design of human RNase-based immunotoxins.

Serum Eosinophilic Cationic Protein (ECP) in Asthmatic Malaysian Children

Eosinophilic inflammation in the airways is important in the pathogenesis of childhood asthma. Serum eosinophilic cationic protein (ECP), a marker of eosinophil activation was measured in 20 asthmatic children and 19 non-asthmatic controls. There was no difference in the socio-demography, passive smoke exposure, urinary cotinine levels and family history of asthma between the 2 groups. The median serum ECP in asthmatic children was 27.0 mcg/L (IQ1 8.8, IQ3 59.0); which was higher than in non-asthmatic controls [5.9 mcg/L (IQ1 3.0, IQ3 11.9), p=0.002]. An elevated serum ECP level can be helpful as supportive evidence in the diagnosis of bronchial asthma in Malaysia children.

Sequence variation at two eosinophil-associated ribonuclease loci in humans

Host defense against invading pathogens is of great importance to the survival of higher organisms. We have been studying the evolution of mammalian eosinophil-associated ribonucleases (EARs), which are members of the ribonuclease A superfamily with known antipathogen activities. Earlier studies showed that positive selection promoted rapid diversification of paralogous EAR genes in both primates and rodents. Intraspecifically, however, it is unknown whether these genes also have divergent alleles. The recent discovery that the gene repertoire of the EAR family is much larger in rodents than in primates has led us to consider the possibility that primates maintain a large number of polymorphic alleles to compensate for a smaller gene repertoire. Here we present sequences of 2417 nucleotides at the two EAR loci, the eosinophil-derived neurotoxin (EDN, RNase 2) and eosinophil cationic protein (ECP, RNase 3), from >50 human individuals. Our data demonstrate that the nucleotide diversities (0.06-0.11%) at these loci are typical for human nuclear genes, thus permitting us to reject this polymorphism hypothesis. No significant departure from neutrality is noted and no signs of overdominant selection are observed. Similar patterns were observed in a preliminary study of chimpanzees. In summary, our results suggest that the antipathogen functions of the primate EARs are conserved after they are established and that these proteins are not currently undergoing rapid diversification in response to challenge from invading microorganisms.

Three-dimensional crystal structure of human eosinophil cationic protein (RNase 3) at 1.75 A resolution

Eosinophil cationic protein (ECP; RNase 3) is a human ribonuclease found only in eosinophil leukocytes that belongs to the RNase A superfamily. This enzyme is bactericidal, helminthotoxic and cytotoxic to mammalian cells and tissues. The protein has been cloned, heterologously overexpressed, purified and crystallized. Its crystal structure has been determined and refined using data up to 1. 75 A resolution. The molecule displays the alpha+beta folding topology typical for members of the ribonuclease A superfamily. The catalytic active site residues are conserved with respect to other ribonucleases of the superfamily but some differences appear at substrate recognition subsites, which may account, in part, for the low catalytic activity. Most strikingly, 19 surface-located arginine residues confer a strong basic character to the protein. The high concentration of positive charges and the particular orientation of the side-chains of these residues may also be related to the low activity of ECP as a ribonuclease and provides an explanation for its unique cytotoxic role through cell membrane disruption.