Christer Peterson

Eosinophil cationic protein (ECP): molecular and biological properties and the use of ECP as a marker of eosinophil activation in disease.

Eosinophil cationic protein (ECP): A review on molecular and biological properites and the use of ECP as a marker of eosinophil activation in disease

Radioimmunoassay of human eosinophil cationic protein (ECP) by an improved method. Establishment of normal levels in serum and turnover in vivo

A radio immunoassay was developed allowing measurement of the cytotoxic cationic ECP. The assay, which has a total incubation time of 3.5 hr, is a double antibody assay with radiolabelled ECP. covering the concentration range of 2–200 μ/l. Performance data show a detection limit of < 2 μg/1 and a cross‐reactivity with eosinophil protein X (EPX/EDN) of <0.06%. The coefficient of variation (%) within the measuring range was, within assay 4.8–10.4, and total 6.6–12.0. The assay is useful for measurement in various body fluids including serum, nasal secretions and bronchoalveolar lavage fluid, and dilution of samples prior to analysts was generally not required. Sera from 100 apparently healthy individuals revealed a geometric mean of 6.0 μg ECP/1 and a range (95%) of 2.3–15.9 μg/1. The elimination rate of ECP, t12. in vivo was estimated to be 65 min when ECP was measured in serum. Comparisons between this assay and a method previously described showed that the new method is superior with regard to precision and assay procedure.

Indirect evidence of bronchial inflammation assessed by titration of inflammatory mediators in BAL fluid of patients with asthma

Bronchial inflammation is a characteristic of asthma that may be examined indirectly by bronchoalveolar lavage (BAL). Nine normal individuals were compared with 38 age-matched adults with asthma of variable severity to appreciate the importance of cell activation in the severity of asthma. The severity of asthma was appreciated by the clinical score of Aas and the pulmonary function of the patients. FEV1 ranged between 35% and 130% of predicted. The indirect activation of eosinophils (EOSs), mast cells, fibroblasts, and neutrophils was examined by the titration of eosinophil cationic protein (ECP), tryptase, hyaluronan (HA), and myeloperoxidase (MPO) by radioimmunoassay in BAL fluid (BALF) and cytology of BALF. In the adults with asthma, there was a significantly increased number of EOSs and a significantly increased level of all mediators but MPO. MPO levels were increased in seven patients only; three of these patients were previous smokers. Only ECP and HA levels were significantly correlated with the severity of asthma. These results demonstrate EOSs, mast cells, and fibroblasts are activated in asthma, whereas the involvement of neutrophils is less clear. There was a significant correlation between ECP and HA levels, suggesting a common activation of EOSs and fibroblasts.

Blood eosinophil number and activity in relation to lung function in patients with asthma and with eosinophilia

Blood eosinophil count, serum concentrations of eosinophil cationic protein (ECP), eosinophil protein X (EPX), myeloperoxidase (MPO), and peak expiratory flow (PEF) rate were studied in 23 patients with severe labile asthma characterized by eosinophilia at the start and end of a treatment period of 5 weeks. The mean blood eosinophil count was 808 x 10(6)/L at the start of the treatment period. Serum ECP and EPX were significantly raised compared with that of the references, whereas the mean serum MPO level was normal. The mean PEF was significantly and negatively correlated to both blood eosinophil count and serum ECP and EPX, but the predominant correlation was that between blood eosinophil count and PEF. At the end of the treatment period, PEF had increased and the blood eosinophil count and serum ECP and EPX were reduced when these values were compared with the values at the start of the treatment period. There was a significant and negative correlation of mean PEF to serum ECP but not to the blood eosinophil count. In individual subjects, the decreases in the blood eosinophil counts and serum EPX were significantly correlated to the individual increases of mean PEF. In conclusion, the present investigation indicates that in patients with asthma and pronounced eosinophilia, the lung function of the patients was principally related to the number of circulating eosinophils, whereas, when their eosinophilia was reduced to moderate levels, the patients lung function was closer related to the activity of the eosinophils.

Secretion of granule proteins from eosinophils and neutrophils is increased in asthma.

The activity of eosinophil and neutrophil granulocytes with respect to secretion of granule proteins was studied in 30 patients with asthma and with varying severity of their disease. Granulocytes were stimulated with serum-opsonized Sephadex particles, and the released amount of eosinophil cationic protein (ECP), eosinophil protein X (EPX), and myeloperoxidase was measured by means of specific radioimmunoassays. Eosinophils from patients with asthma released significantly more (p less than 0.001) ECP and EPX after 20 minutes of incubation than cells from control subjects without asthma. The release of myeloperoxidase from neutrophils was also somewhat higher (p less than 0.03). The serum concentrations of ECP and EPX were also significantly increased (p less than 0.001) in the group with asthma. No significant relationships were found between clinical variables and the secretory activity of either eosinophils or neutrophils. We conclude that eosinophils and, to some extent, neutrophils from subjects with asthma have an increased propensity to release their granule proteins, which we suggest is a consequence of priming of these cells.

Purification and characterization of a human neutrophil lipocalin (HNL) from the secondary granules of human neutrophils

A 45 kDa-protein was purified from the granules of human neutrophils. The protein consists of two apparently identical subunits. The isoelectric point was pH 8.40, and the molecular weight 45 kDa (unreduced) or 24 kDa (reduced). Treatment of the protein with Endoglucosidase F resulted in a reduction in the molecular weight to 20 kDa, indicating the presence of N-linked carbohydrate. The extinction coeffient was E1%,1cm = 13.76 at 280 nm. The 60 amino acid sequence revealed up to 65% sequence homology with rat alpha 2-microglobulin-related protein, which belongs to the lipocalin family. The protein co-sedimented with secondary (specific) granule marker proteins and correlated to the neutrophil content of Lactoferrin (r = 0.81, p < 0.001) and was estimated to be 0.59 microgram 10(-6) cells. Release studies showed that the neutrophils released 51.4 +/- 9.0% of the total cellular content of the protein when they were exposed to serum-opsonized particles, which was much higher than the release of Myeloperoxidase (12.7 +/- 3.5%) and Lactoferrin (22.9 +/- 4.7%). The N-terminal and four tryptic fragment amino acid sequence of the protein was identical with an N-formyl peptide binding 24 kDa protein and gelatinase associated protein of human neutrophils. In conclusion, we have purified and characterized a protein, human neutrophil lipocalin (HNL), from the secondary granules of human neutrophils and shown that it is readily mobilized from the neutrophils upon stimulation.

Indirect evidence of nasal inflammation assessed by titration of inflammatory mediators and enumeration of cells in nasal secretions of patients with chronic rhinitis

Pathophysiologic mechanisms of perennial rhinitis are poorly understood. The characterization of inflammation was studied in nasal lavage of patients with perennial rhinitis by the enumeration of cells involved in the allergic inflammation and the measurement of six mediators released in nasal secretions to determine whether some mediators were relevant for the etiologic diagnosis and the occurrence of symptoms. Ten healthy subjects and 57 patients with perennial rhinitis were placed into four groups according to the symptoms they presented at the time of the study and the origin of the allergy. Allergy was characterized by the history, skin prick tests to standardized allergens, and RAST. Eosinophil protein X (EPX), tryptase, histamine, myeloperoxidase, prostaglandin D2, and leukotriene C4/D4 (LTC4/D4) were measured in nasal lavage by enzyme assay or radioimmunoassay. Eosinophils and neutrophils were enumerated after cytocentrifugation of the lavage fluid and May Grunwald Giemsa staining. Tryptase, myeloperoxidase and EPX but not histamine levels were increased in all four patient groups. Eosinophils, LTC4/D4, and prostaglandin D2 were significantly (p < 0.001, p < 0.03, and p < 0.01) increased in allergic and symptomatic patients. EPX was significantly increased in symptomatic allergic and nonallergic patients. This study suggests the involvement of mast cells, neutrophils, and eosinophils, but the latter cells appear to have a more prominent role. The importance of EPX and LTC4/D4 in the characterization of chronic symptomatic rhinitis was also observed.

Urinary eosinophil protein X in children with atopic asthma: A useful marker of antiinflammatory treatment ☆ ☆☆ ★ ★★

BACKGROUND Bronchial asthma is associated with elevated serum levels of eosinophil products, such as eosinophil protein X (EPX), but the occurrence in urine of this substance in patients with asthma has not previously been studied. OBJECTIVE This study was performed to clarify whether increased amounts of eosinophil granulocyte proteins in urine and serum reflect ongoing asthmatic inflammation and whether decreasing values reflect successful treatment. METHODS Twelve children with a median age of 12.5 years who had mild or moderate atopic asthma were studied for 3 months. At the time of inclusion in the study, treatment with inhaled budesonide was initiated. Nine children of the same age without atopic disease served as control subjects. Levels of EPX, eosinophil cationic protein (ECP), and myeloperoxidase in serum and in urine (urinary EPX) were determined at inclusion and then after 3 months of treatment. Spirometry was performed on the same occasions. RESULTS At the time of inclusion, urinary EPX and serum ECP were significantly higher in children with atopic asthma than in the control subjects (mean, 116.4 vs 43.0 micrograms/mmol creatinine [p = 0.004] and 37.0 vs 14.8 micrograms/L [p = 0.004]). In the asthma group urinary EPX, as well as serum ECP, decreased significantly after 3 months of treatment with budesonide (116.4 to 68.4 micrograms/mmol creatinine [p = 0.005] and 37.0 to 24.0 micrograms/L [p = 0.04]). At the same time, peak expiratory flow values increased significantly in the children with asthma (76.0% to 87.8% of predicted value [p = 0.005]) but not in the control subjects (87.0% to 90.1%). In the asthma group the levels of myeloperoxidase were similar to those in the control group, both at inclusion and after 3 months. CONCLUSION Increased urinary EPX and serum ECP levels seem to reflect active atopic asthma, whereas decreased levels after antiinflammatory treatment probably reflect normalization of airway inflammation, and indirectly, improved lung function.

Eosinophil Activation in Allergic Disease

The eosinophil granulocyte is a pro-inflammatory cell which in its granules contains an abundance of highly cytotoxic proteins such as eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase, eosinophil protein X and major basic protein. Upon stimulation of the cell, these proteins as well as a number of lipid mediators such as leukotriene C4, prostaglandin and platelet-activating factor are released to the exterior. The molecules which are produced during inflammatory reactions of the allergic type attract eosinophils to the target organ and stimulate them to liberate their products. The physiological meaning of this reaction is probably to combat invading parasites; however, in their absence accumulation and activation of eosinophils may cause disease, and one such disease may be chronic asthma.

Degranulation of eosinophils from pollen-atopic patients with asthma is increased during pollen season†

The secretion of granule proteins from eosinophils and neutrophils was studied in isolated cells, obtained from 11 pollen-atopic patients with asthma, twice during and twice outside pollen season. Granulocytes were stimulated with serum-opsonized Sephadex particles, and the released amount of eosinophil cationic protein (ECP), eosinophil protein X (EPX), and myeloperoxidase (MPO) were measured by means of specific radioimmunoassay (RIA). Eosinophils from the pollen-atopic patients obtained during pollen season released significantly more (p less than 0.02) ECP and EPX than cells from the same patients obtained before pollen season. The released amount of ECP and EPX was correlated (r = 0.54; p less than 0.003) to the total pollen count. The release of MPO from neutrophils was only raised (p less than 0.01) at the end of the pollen season. Serum concentrations of ECP and EPX and blood eosinophil counts were significantly raised (p less than 0.002, p less than 0.001, and p less than 0.009, respectively) before pollen season and increased further at the end of the pollen season. There were no changes in lung function during pollen season and consequently no discernible relationships to eosinophil and neutrophil degranulation. We conclude that eosinophils and, to some extent, neutrophils from birch pollen-atopic subjects have an increased propensity to secrete their granule proteins during a pollen season. We suggest that these cells have been primed as a consequence of allergen exposure.