Correlation among urinary eosinophil protein X, leukotriene E4, and 11-dehydrothromboxane B2 in patients with spontaneous asthmatic attack

Urinary eosinophil protein X in childhood asthma: relation with changes in disease control and eosinophilic airway inflammation

The aim of this study was to assess cross-sectional and longitudinal correlations between uEPX and other markers of asthma control and eosinophilic airway inflammation. Methods. We measured uEPX at baseline, after 1 year and after 2 years in 205 atopic asthmatic children using inhaled fluticasone. At the same time points, we assessed symptom scores (2 weeks diary card), lung function (forced expiratory volume in one second (FEV(1))), airway hyperresponsiveness (AHR), and percentage eosinophils in induced sputum (% eos). Results. We found negative correlations between uEPX and FEV(1) at baseline (r = -0.18, P = 0.01), after 1 year (r = -0.25, P < 0.01) and after 2 years (r = -0.21, P = 0.02). Within-patient changes of uEPX showed a negative association with FEV(1) changes (at 1 year: r = -0.24, P = 0.01; at 2 years: r = -0.21, P = 0.03). Within-patient changes from baseline of uEPX correlated with changes in % eos. No relations were found between uEPX and symptoms. Conclusion. In this population of children with atopic asthma, uEPX correlated with FEV(1) and % eos, and within-subjects changes in uEPX correlated with changes in FEV(1) and % eos. As the associations were weak and the scatter of uEPX wide, it seems unlikely that uEPX will be useful as a biomarker for monitoring asthma control in the individual child.

CD203c expression on human basophils is associated with asthma exacerbation

BACKGROUND

CD203c is a basophil cell surface marker used to diagnose and monitor various allergic diseases, but its relationship to asthma is not clear.

OBJECTIVE

We determined whether CD203c expression levels are associated with stable and exacerbated asthma.

METHODS

We used flow cytometry to compare spontaneous expression levels of surface markers on basophils from patients with stable or exacerbated asthma and from healthy subjects. Longitudinal changes in these expression levels were measured after basophil stimulation by IgE-dependent or IgE-independent mechanisms and compared with patients' asthma status.

RESULTS

Spontaneous expression levels of CD203c were significantly higher on basophils from patients with asthma exacerbation than patients with stable asthma or healthy subjects. In contrast, no differences in spontaneous expression levels of CD63 or CD69 were observed among the 3 groups. Anti-IgE-induced expression of CD203c significantly increased in basophils during asthma exacerbation (P = .005). Low concentrations of Dermatophagoides pteronyssinus or IL-3 induced higher expression levels of CD203c during asthma exacerbation than during clinical improvement; induction of CD203c expression by these antigens therefore correlates with asthma control. In the patients with clinical improvement, there was a correlation between spontaneous CD203c expression levels and the percent predicted values of FEV(1) (r = -0.761; P = .022).

CONCLUSION

Asthma exacerbation was accompanied by increased expression of CD203c on basophils that decreased significantly during remission. Basophil expression levels of CD203c might therefore be used to monitor asthma in patients.

Hyperleukotrieneuria in patients with allergic and inflammatory disease

Cysteinyl leukotrienes (CysLTs: leukotrienes C(4), D(4), and E(4)) have long been implicated in the pathogenesis of asthma and several allergic diseases. LTE(4) has been identified as a major metabolite of LTC(4), and urinary LTE(4) (U-LTE(4)) is considered as the most reliable analytic parameter for monitoring the endogenous synthesis of CysLTs. From recent studies on the U-LTE(4) associated with adult stable asthma we identified four factors for hyperleukotrieneuria, namely, aspirin intolerance, eosinophilic nasal polyposis (ENP), vasculitis, and severe asthma. In ENP, there is prominent infiltration of eosinophils in the sinus and polyp tissues, which is linked to adult asthma and aspirin sensitivity, and ENP is the most important factor for the overproduction of CysLTs in asthmatics. We also demonstrated that anaphylaxis and eosinophilic pneumonia (EP) are associated with a marked increase in the U-LTE(4) concentration. Under these disease conditions, U-LTE(4) may be one of the candidate biomarkers. Moreover, the changes in U-LTE(4) concentrations may provide valuable information concerning therapeutic targets.

A novel antagonist of prostaglandin D2 blocks the locomotion of eosinophils and basophils

BACKGROUND

Chemoattractant receptor homologous molecule of Th2 cells (CRTH2) has been shown to mediate the chemotaxis of eosinophils, basophils and Th2-type T lymphocytes. The major mast cell product prostaglandin (PG) D(2) is considered to be the principal ligand of CRTH2.

MATERIALS AND METHODS

We developed a novel CRTH2 antagonist, AZ11665362 [2,5-dimethyl-3-(8-methylquinolin-4-yl)-1H-indole-1-yl]acetic acid, and characterized its efficacy in binding assay in HEK293 cells, eosinophil and basophil shape change assay and migration assay, platelet aggregation and eosinophil release from guinea pig bone marrow. The effects were compared with ramatroban, the sole CRTH2 antagonist clinically available to date.

RESULTS

AZ11665362 bound with high affinity to human and guinea pig CRTH2 expressed in HEK293 cells and antagonized eosinophil and basophil shape change responses to PGD(2). AZ11665362 was without effect on the PGD(2)-induced inhibition of platelet aggregation. In contrast, AZ11665362 effectively inhibited the in vitro migration of human eosinophils and basophils towards PGD(2). The release of eosinophils from the isolated perfused hind limb of the guinea pig was potently stimulated by PGD(2), and this effect was prevented by AZ11665362. In all assays tested, AZ11665362 was at least 10 times more potent than ramatroban.

CONCLUSIONS

AZ11665362 is a potent CRTH2 antagonist that is capable of blocking the migration of eosinophils and basophils, and the rapid mobilization of eosinophils from bone marrow. AZ11665362 might hence be useful for the treatment of allergic diseases.

Urinary eosinophil protein X in children with atopic asthma

The aim of this study was to investigate the relationship between urinary eosinophil protein X (uEPX) and asthma symptoms, lung function, and other markers of eosinophilic airway inflammation in asthmatic school children.

METHODS

A cross-sectional study was performed in 180 steroid dependent atopic children with stable moderately severe asthma, who were stable on 200 or 500 microg of fluticasone per day. uEPX was measured in a single sample of urine and was normalized for creatinine concentration (uEPX/c). Symptom scores were kept on a diary card. FEV1 and PD20 methacholine were measured. Sputum induction was performed in 49 and FE(NO) levels measured in 24 children.

RESULTS

We found an inverse correlation between uEPX/c and FEV1 (r = -.20, P = .01) and a borderline significant correlation between uEPX/c and PD20 methacholine (r = -.15, P = .06). Symptom score, %eosinophils and ECP in induced sputum and FE(NO) levels did not correlate with uEPX/c.

CONCLUSION

uEPX/c levels did not correlate with established markers of asthma severity and eosinophilic airway inflammation in atopic asthmatic children.

A preliminary study towards downregulation of murine bone marrow eosinophilopoiesis mediated by small molecule inhibition of interleukin-5 receptor alpha gene in vitro

BACKGROUND

Bone marrow eosinophilopoiesis induced by IL-5 makes a major contribution to eosinophilic airway inflammation in asthma. Bone marrow CD(34)(+) cells expressing IL-5Ralpha may be eosinophil progenitors. However, research on the effect of blocking IL-5Ralpha expression on bone marrow eosinophilopoiesis has seldom been reported.

OBJECTIVE

To explore the effect of inhibiting IL-5Ralpha expression with IL-5Ralpha short hairpin RNA-expressing vector on murine bone marrow eosinophilopoiesisin vitro.

METHODS

We constructed 4 kinds of plasmid vectors that could express small molecule inhibition, short hairpin RNA, which targeted IL-5Ralpha (P-IL-5Ralpha), and selected an effective one by transfecting B lymphoma cells in vitro. We also constructed an adenovirus vector which was inserted into an effective template sequence (Ad-IL-5Ralpha). The bone marrow cells were obtained from healthy Balb/c mice, and cultured and transfected by Ad-IL-5Ralpha in vitro. The expression of IL-5Ralpha and the count of newly produced eosinophils were detected in the cultured bone marrow cells.

RESULTS

We found that P-IL-5Ralpha-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed the IL-5Ralpha expression in the B lymphoma cellsin vitro. Ad-IL-5Ralpha could suppress the IL-5Ralpha expression of murine bone marrow cellsin vitro and it could also significantly decrease the IL-5-induced eosinophilia in the cultured bone marrow cells.

CONCLUSION

These results indicate that the blocking of IL-5Ralpha expression by small molecule inhibition can help to effectively decrease murine bone marrow eosinophilopoiesis, and that bone marrow may be used as a critical target organ in the diseases involved in eosinophilia, such as asthma.

Effect of interleukin-5 receptor-alpha short hairpin RNA-expressing vector on bone marrow eosinophilopoiesis in asthmatic mice

Bone marrow eosinophilopoiesis induced by interleukin (IL)-5 is a major contributor to eosinophilic airway inflammation in asthma. However,research on the use of IL-5 receptor alpha (IL-5Ralpha) as the target has seldom been reported. This study was undertaken to explore the effects of inhibition of IL-5Ralpha expression through an IL-5Ralpha short hairpin RNA-expressing vector on bone marrow eosinophilopoiesis and airway inflammation in an asthmatic mouse model. An effective plasmid vector was selected that could express short hairpin RNA targeted at IL-5Ralpha (P-IL-5Ralpha). An adenovirus vector (Ad) was then constructed that was inserted in an effective template sequence (Ad-IL-5Ralpha). An animal model of asthma was established by sensitizing and challenging Balb/c mice with ovalbumin. Animals were treated intravenously with Ad-IL-5Ra and changes in bone marrow eosinophilopoiesis and airway inflammation were detected in asthmatic mice. Investigators found that P-IL-5Ra-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed IL-5Ralpha expression in B lymphoma cells in vitro. In addition, Ad-IL-5Ralpha could suppress IL-5Ralpha expression in murine bone marrow cells in vitro and in vivo, and it could significantly decrease IL-5-induced eosinophilia in cultured bone marrow cells. Additional studies indicated that intravenously injected Ad-IL-5Ralpha not only selectively reduced the number of eosinophils in the bone marrow, peripheral blood, and bronchoalveolar lavage fluid, it also relieved airway inflammation in asthmatic mice. Results reported here show that blocking of IL-5Ralpha expression through RNA interference can enhance effective treatment of asthma, and that bone marrow can be used as a key targeted organ in the treatment of asthmatic mice.

11-Dehydro-thromboxane B2, a stable thromboxane metabolite, is a full agonist of chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) in human eosinophils and basophils

Thromboxane (TX) A(2), a cyclooxygenase-derived mediator involved in allergic responses, is rapidly converted in vivo to a stable metabolite, 11-dehydro-TXB(2), which is considered to be biologically inactive. In this study, we found that 11-dehydro-TXB(2), but not the TXA(2) analogue U46,619 or TXB(2), activated eosinophils and basophils, as assayed by flow cytometric shape change. 11-Dehydro-TXB(2) was also chemotactic for eosinophils but did not induce, nor inhibit, platelet aggregation. Chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) is an important chemoattractant receptor expressed by eosinophils, basophils, and TH2 lymphocytes, and prostaglandin (PG)D(2) has been shown to be its principal ligand. 11-Dehydro-TXB(2) induced calcium flux mainly from intracellular stores in eosinophils, and this response was desensitized after stimulation with PGD(2) but not other eosinophil chemoattractants. Shape change responses of eosinophils and basophils to 11-dehydro-TXB(2) were inhibited by the thromboxane (TP)/CRTH2 receptor antagonist ramatroban, but not the selective TP antagonist SQ29,548, and were insensitive to pertussis toxin. The phospholipase C inhibitor U73,122 attenuated both 11-dehydro-TXB(2)- and PGD(2)-induced shape change. 11-Dehydro-TXB(2) also induced the chemotaxis of BaF/3 cells transfected with hCRTH2 but not naive BaF/3 cells. At a threshold concentration, 11-dehydro-TXB(2) had no antagonistic effect on CRTH2-mediated responses as induced by PGD2. These data show that 11-dehydro-TXB(2) is a full agonist of the CRTH2 receptor and hence might cause CRTH2 activation in cellular contexts where PGD-synthase is not present. Given its production in the allergic lung, antagonism of the 11-dehydro-TXB(2)/CRTH2axis may be of therapeutic relevance.

Leukotriene C4 synthase promoter polymorphism in Japanese patients with aspirin-induced asthma

BACKGROUND

The A to C transversion in the promoter region of the gene encoding leukotriene C4 synthase (LTC4S) is proposed to be associated with the development of aspirin-induced asthma (AIA).

OBJECTIVE

We investigated the frequency of the polymorphism in Japanese population and its association with clinical characteristics and cysteinyl leukotriene production.

METHODS

Genotyping of LTC4S gene promoter was performed on 60 patients with AIA, 100 patients with aspirin-tolerant asthma (ATA), and 110 control subjects. We assessed the basal levels of urinary LTE4, the increment of urinary LTE4 on venous aspirin challenge, and LTC4S activity in peripheral blood eosinophils.

RESULTS

The frequency of the variant C allele was significantly higher in patients with AIA (frequency of allele [q] = 0.192) than in patients with ATA (q = 0.110, P =.042). Variant C-allelic carriers experienced asthma at a significantly younger age (31.8 +/- 2.9 years [mean +/- SEM]) than wild-type A homozygotes (41.3 +/- 2.2 years, P =.007). Basal levels of LTE4 and the increment of urinary LTE4 on venous aspirin challenge did not show a difference between wild-type A homozygotes and variant C-allelic carriers. There was no relationship between the polymorphism and the LTC4S activity in eosinophils, although LTC4S activities were significantly higher in patients with AIA than in patients with ATA.

CONCLUSION

Our findings reveal the lack of functionality of the polymorphism in the LTC4S gene, whereas this polymorphism might have some effect on the development of AIA, probably in linkage disequilibrium with another causatively important mutation.

Eosinophil granule proteins in serum and urine of patients with helminth infections and atopic dermatitis

Eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EPX) are cytotoxic molecules involved in helminth infections and allergic reactions. Hitherto most clinical chemical studies have been concerned with the analysis of serum ECP in allergic diseases. The aim of this study was to examine whether serum as well as urine levels of these proteins are useful clinical chemical parameters in helminthiases and allergic diseases such as atopic dermatitis. Comparing these diseases under the same methodological conditions, levels of ECP and EPX were generally higher in helminthiases than in atopic dermatitis and non-helminth, non-allergic diseases. The highest levels of both proteins occurred in tropical worm diseases, in particular hookworm disease and onchocerciasis. When comparing helminthiases with allergic disorder, only hookworm disease (ECP and EPX) and onchocerciasis (EPX) exhibited significantly higher eosinophil cationic protein serum levels than atopic dermatitis. In patients with schistosomiasis mansoni and egg loads of > 1000-10 000 eggs/g stool (epg) EPX serum levels were significantly higher than in patients exhibiting loads < 1000 epg. Urinary analyses revealed only EPX to be present in measurable amounts. Levels of this protein were much higher in urine of patients with hookworm disease and onchocerciasis than in those with atopic dermatitis and in healthy controls. The results suggest that besides serum EPX, urinary EPX may be a useful clinical chemical parameter in eosinophilia of helminth and allergic aetiology.

Systemic activation of basophils and eosinophils: markers and consequences

Basophils and eosinophils are important effector cells in human allergic diseases; they play a significant role in promoting allergic inflammation through the release of proinflammatory mediators (such as histamine, leukotriene C(4), major basic protein, eosinophil cationic protein, IL-4, and IL-13, among others). Notably, in allergic subjects, these cells exist in higher numbers and in a more activated state compared with nonatopic control subjects. Evidence for the greater activation state includes increased expression of intracellular and surface markers and hyperreleasability of allergy mediators. We have been interested in the phenotypic markers of effector-cell activation for many years. There is considerable overlap among activation markers, and few activation markers have been found that define a unique phenotype that is quantifiable in the assessment of the presence and severity of allergic disease. This review summarizes the existing evidence for systemic activation of human basophils and eosinophils in allergic diseases. The potential mechanisms responsible for functional and morphologic alterations in these effector cells and the specificity and utility of surface markers in the assessment of allergic disease activity or severity are also discussed.

Inflammatory mediators in blood and urine

Inflammation plays a major role in the pathophysiology of asthma. Therefore, monitoring of the disease and its management preferably should include assessment of mediators of airways inflammation. Much interest has been focused on using eosinophil granule proteins in blood and urine as markers of asthma inflammation. The eosinophil granule proteins are important mediators in allergic inflammation. They often function well as inflammatory markers when used in controlled clinical studies, and are therefore useful research tools. With urinary eosinophil-derived protein X (EPX) venous blood sampling is avoided. Disadvantages which limit usefulness in clinical practice are overlap between values in patients and controls, a rather weak correlation to traditional lung function variables, elevation of levels by concurrent allergic disease, and the delay between sampling and test results. Urinary excretion of leukotriene E4 (LTE(4)) reflects the production of cysteinyl leukotrienes, which are major mediators in asthma. The excretion of LTE4 possibly reflects lung function better than serum ECP. In the future, monitoring of cytokines may be used in clinical asthma to monitor control and aid in the prognosis of the disease in the young child. Techniques for simple and rapid monitoring of key type 1 and type 2 cytokines are needed.

Urinary eosinophil protein X and serum eosinophil cationic protein in infants and young children with atopic dermatitis: correlation with disease activity

BACKGROUND

Eosinophil cationic protein (ECP) and eosinophil protein X (EPX) or eosinophil-derived neurotoxin (EDN) are released by eosinophil granulocytes in allergic diseases. Serum ECP (s-ECP) levels have been correlated with disease activity in atopic dermatitis (AD) in adults and young patients, and high urinary EPX (u-EPX) levels in asthmatic patients seem to reflect active disease. A relationship between AD severity and u-EPX concentration in young children has not been previously studied.

OBJECTIVE

This study was performed to evaluate whether the severity of AD in infants and young children was correlated with s-ECP and u-EPX levels.

METHODS

Fifty-four infants and children (mean age, 17.7 months; range, 4-48 months) with AD and without other allergic conditions were evaluated. The severity of AD was measured by using the SCORAD index. S-ECP, serum total IgE, serum-specific IgE for common allergens, and peripheral blood eosinophil counts (PBECs) were determined. In forty-two children u-EPX was also measured. Seven age-matched control patients underwent the same determinations.

RESULTS

S-ECP and u-EPX were significantly higher in children with AD than in control children (mean, 23.9 vs 3.5 microg/dL [P <.001] and 57.7 vs 6.0 microg/mmol creatinine [P <.001]). A significant correlation was found between SCORAD and s-ECP (P =.002), u-EPX (P =.01), and PBECs (P =.01) and between symptom index and uEPX (P =.0004). PBECs were strongly correlated to s-ECP and u-EPX (P <.0001). However, 5 patients with moderate and severe AD (11.9%) showed low levels of s-ECP, u-EPX, and PBECs.

CONCLUSION

S-ECP and u-EPX were useful markers of AD activity in infants and young children. When taken together, the two determinations could give more information about the clinical course of the illness. Some patients seemed to have clinical exacerbations without an involvement of eosinophils and their products.