Purpose: Asthma and chronic obstructive pulmonary disease overlap patients (ACO) have more exacerbations and a worse prognosis than pure asthma or COPD, and it is of great interest to identify differential biomarkers of ACO. We compared blood eosinophil counts, plasma IgE and protein levels among patients with asthma, ACO, COPD, and healthy subjects to identify those associated with ACO. Patients and Methods: 397 adults (age 40– 90 years) were recruited from two Colombian cities: asthma (n=123), COPD (n=100), ACO (n=74) and healthy control (HC, n=100). Plasma protein levels were measured using the Proximity Extension Assay (Olink Proteomics). Results: There were no differences in blood eosinophil counts between the patient groups. Total and specified IgE levels were higher in patients with ACO than in those with COPD. Ten plasma proteins showed significant differences between the patients with ACO and HC. In patients above 60 years old, CXCL9 discriminates ACO from asthma patients with AUC 0.73 (0.63– 0.82, DeLong test p=0.007), and in patients below 60 years old, MCP-3 discriminates ACO from COPD patients with AUC 0.84 (0.62– 1.0, DeLong test p=0.006). CUB domain-containing protein 1 (CDCP1) levels (OR, 0.47; p=0.008) and age > 60 years (OR, 0.25; p=0.001) were negatively associated with ACO. Conclusion: CXCL9 levels could be used to discriminate ACO from asthma patients and MCP-3 to discriminate ACO from COPD. Protein inflammatory signatures in plasma of ACO patients were similar to the COPD group. This study revealed novel biomarkers that may help characterize patients with ACO.

The exhaled fraction of nitric oxide (FeNO) is a biomarker of type 2 inflammation, reflecting the activity of inducible nitric oxide synthase (iNOS) in the bronchial epithelium in response to IL-4 and IL-13. Elevated FeNO levels support asthma diagnosis; however, it is unclear whether active helminth infections and rural environments influence this biomarker. The aim of this study was to compare FeNO levels among subjects naturally infected with helminth parasites and to evaluate their correlation with eosinophil counts and other inflammatory mediators. A total of 275 adult asthmatic patients and 161 healthy controls were involved; also, 223 asthmatic children and 114 healthy controls from the urban area of Cartagena were compared to 90 healthy children from a rural area. We found significant differences in FeNO levels between asthmatic patients and healthy controls in both adult and children’s cohorts (p < 0.0001). There was no difference in FeNO levels between Ascaris-positive and Ascaris-negative adults nor between subjects with active helminth infection and the non-infected. However, FeNO levels were significantly lower in rural healthy children (median 7.50 ppb, [IQR 4–14 ppb]) compared to urban healthy children (median 13.5 ppb, [IQR 10–18.5 ppb], p < 0.0001) and asthmatic children (median 20 ppb, [IQR 11–51 ppb], p < 0.0001). Rural healthy children had the highest total IgE levels (median 508 kU/L, [IQR 168–1020 kU/L]), high eosinophil counts (median 550 eos/μL, [IQR 360–800 eos/μL]) and plasma IL-5 levels (median 0.276 pg/mL, [IQR 0.19–0.53 pg/mL]). In conclusion, FeNO levels are not influenced by either natural exposure to helminth parasites or active infection, which supports its usefulness as a robust asthma biomarker in the tropics. Rural children have the lowest FeNO levels together with the highest total IgE levels, IL-5, and eosinophil counts, suggesting that lung-specific mechanisms are in place controlling iNOS expression during type 2 responses in healthy children.

Desde su descripción inicial en los años noventa, una estructura denominada Urbanorum spp, ha generado controversias en la comunidad científica con respecto a su condición biológica. Por sus características morfológicas observadas bajo microscopia óptica, algunos bioanalistas lo han considerado un organismo protozoario. Sin embargo, no se cuenta con el respaldo científico suficiente para considerar a esta estructura un ser vivo y, aún más, para ser clasificado taxonómicamente como un parásito. En esta reflexión, se reportan por primera vez dos casos sobre la detección en heces de una estructura compatible con Urbanorum spp. en zona rural del departamento de Bolívar, Colombia. Adicionalmente, se analiza la prevalencia de hallazgos similares en países de América del Sur y se resalta la importancia de la aplicación futura de técnicas moleculares y genéticas para el estudio de estos casos.