Eosinophil involvement in atopic dermatitis as reflected by elevated serum levels of eosinophil cationic protein

Real-World Investigation of Eosinophilic-Associated Disease Overlap (REVEAL): Analysis of a US Claims Database

PURPOSE

The epidemiology of eosinophil-associated diseases (EADs) is not yet fully understood. While some studies have been conducted on stand-alone eosinophilic diseases, there is scarce evidence on the degree of overlap among rarer conditions.

METHODS

The retrospective Real-world inVestigation of Eosinophilic-Associated disease overLap (REVEAL) study used data from the Optum® Clinformatics® insurance claims database to describe and characterize disease overlap among 11 EADs: allergic bronchopulmonary aspergillosis, atopic dermatitis, chronic rhinosinusitis with nasal polyps, eosinophilic gastritis/gastroenteritis, eosinophilic granulomatosis with polyangiitis, eosinophilic esophagitis, bullous pemphigoid, chronic obstructive pulmonary disorder, chronic spontaneous urticaria, and non-cystic fibrosis bronchiectasis. Patient records with EADs of interest were identified between January 1, 2015, and June 30, 2018.

RESULTS

Overall, 1,326,645 patients were included; 74.4% had 1 EAD, 20.5% had ≥ 2 EADs, and 5.1% had ≥ 3 EADs. Higher rates of disease overlap were associated with older age. Higher blood eosinophil counts were also observed in patients with a greater number of overlapping conditions, suggesting a common role for eosinophilic inflammation in the pathogenesis of multiple diseases. Furthermore, greater disease overlap was associated with higher disease severity in most cohorts.

CONCLUSIONS

Results from this study have implications for quantifying unmet needs and can be used to inform treatment guidelines and raise the awareness of eosinophilic inflammation and EAD overlap among healthcare professionals from a range of disease specialties.

Exploration of biomarkers to predict clinical improvement of atopic dermatitis in patients treated with dupilumab: A study protocol

BACKGROUND

Atopic dermatitis (AD) is a common eczematous skin disorder that profoundly reduces the quality of life due to intractable pruritus. Excellent therapeutic success of the anti-interleukin 4 receptor-α antibody dupilumab in clinical trials and a real-world clinical context indicates the crucial roles of interleukin (IL)-4 and IL-13 in the pathogenesis of AD. Along with the clinical improvement in skin scores and pruritus, dupilumab significantly and progressively reduces and normalizes the upregulated expression of T helper type 2 signatures such as Chemokine (C-C motif) ligand (CCL)17, CCL18, CCL22, and CCL26 in the lesional skin of AD. However, no blood/serum biomarkers are known to predict good or poor outcome in patients with AD treated with dupilumab.

METHODS

Patients are at least 18 years of age and have moderate-to-severe AD with Eczema Area and Severity Index (EASI) ≥16, Investigator's Global Assessment ≥3, and body surface area ≥10%. We are going to enroll more than 130 subjects from 18 medical facilities. Clinical objective findings will be evaluated by EASI. Subjective symptoms will be assessed by Patient-Oriented Eczema Measure, Numerical Rating Scale for Pruritus (Pruritus-NRS), Skin Comfort-NRS, and Treatment Satisfaction-NRS. We will measure 18 blood/serum biomarkers including % eosinophils in blood cell count, lactate dehydrogenase, total IgE, soluble interleukin 2 receptor, CCL17, CCL18, CCL22, CCL26, CCL27, IL-13, IL-22, IL-24, IL-25, IL-31, IL-33, thymic stromal lymphopoietin, periostin, and squamous cell carcinoma antigen-2. The clinical evaluation and biomarker sampling will be performed at 0, 2, 4, 8, and 16 weeks of dupilumab treatment. We will also perform proteomic analysis (of roughly 300 proteins) of the patients' sera obtained at 0 and 2 weeks of treatment. The primary endpoint is the association between "baseline levels of 18 biomarkers" and "% change from baseline of EASI at 16 weeks of dupilumab treatment."

DISCUSSION

This is the first clinical trial to explore the biomarkers, including potential proteomic markers, most strongly associated with improvement in EASI in patients with moderate-to-severe AD treated with dupilumab for 16 weeks (B-PAD study). A limitation is that we will only enroll Japanese patients.

Evaluation of Peripheral Blood Eosinophilia in Adolescent and Adult Patients Suffering from Atopic Dermatitis and the Relation to the Occurrence of Allergy to Aeroallergens

Background:

Eosinophils play an important pathogenic role in atopic dermatitis (AD), but its exact function remains to be determined.

Aims and Objectives:

The aim of this study was to correlate the eosinophil count with the manifestations such as asthma bronchiale, rhinitis, level of total IgE, sensitization to mites, animal dander, bird feather, dust, mixture of grass, mixture of trees, mixture of fungi, duration of lesions (persistent or occasional during last year), family history about atopy, and onset of AD (under or above 5 year of age).

Materials and Methods:

Two hundred and seventy-two patients suffering from AD at the age of 14 year or older were examined – 100 men and 172 women with the average age of 26.7±9.5 years and with the average SCORAD index of 32.9±14.1. Complete dermatological and allergological examinations were performed in all patients with the evaluation of monitored manifestations. Mann–Whitney test for difference in medians was used for statistical evaluation.

Results:

The count of eosinophils in peripheral blood was significantly higher in patients with total IgE ≥200 IU/ml, with sensitization to dust, with persistent eczematous lesions and in patients with the onset of AD under 5 year of age. The count of eosinophils above 5% was recorded as well in patients suffering from asthma bronchiale, rhinitis, sensitization to mites, and in patients with positive family history about atopy, but the difference was not significant. On the other hand, the count of eosinophils was under 5% in patients with sensitization to animal dander, bird feather, mixture of grass and trees.

Conclusion:

Our results demonstrated the difference in the count of eosinophils in peripheral blood according to different manifestations in patients suffering from AD.

Probiotics for the treatment or prevention of atopic dermatitis: a review of the evidence from randomized controlled trials

Probiotics are defined as live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. To synthesize the evidence for the effectiveness of probiotics in the treatment or prevention of atopic dermatitis (AD) in children, we reviewed the results of 13 relevant randomized (placebo)-controlled trials (RCTs), 10 of which evaluated probiotics as treatment and 3 for prevention of AD. The main outcome measure in 9 RCTs was the change in SCORAD (SCORing Atopic Dermatitis). Four RCTs suggested that there was a statistically significant decrease in SCORAD after probiotic administration to infants or children with AD for 1 or 2 months compared with that after placebo, while in two RCTs SCORAD was significantly reduced after treatment with lactobacilli only in children with IgE-associated AD. In four of these six RCTs, clinical improvement was associated with a change in some inflammatory markers. In three RCTs, the change in SCORAD was not statistically significant between probiotic- and placebo-treated children, although in one of these trials SCORAD was significantly lower after probiotic than with placebo treatment in food-sensitized children. In most RCTs, probiotics did not cause a statistically significant change in interferon-gamma, interleukin-4, tumor necrosis factor-alpha, eosinophil cationic protein or transforming growth factor-beta compared with placebo. Regarding the effectiveness of probiotics in the prevention of AD, in two RCTs, infants at high risk for atopy who received probiotics developed AD significantly less frequently during the first 2 years of life than infants who received placebo. In these studies, mothers were administered Lactobacillus rhamnosus GG with or without other probiotics perinatally, followed by treatment of the infants with the same probiotics for the first 6 months of life. However, in another trial, neither the frequency nor the severity of AD during the first year of life were significantly different between infants with atopic mothers who received L. acidophilus for the first 6 months of life compared with infants who received placebo.Probiotics, especially L. rhamnosus GG, seem to be effective for the prevention of AD. They were also found to reduce the severity of AD in approximately half of the RCTs evaluated, although they were not found to change significantly most of the inflammatory markers measured in the majority of the RCTs evaluated. More RCTs need to be conducted to elucidate whether probiotics are useful for the treatment or prevention of AD.

Serum eosinophil cationic protein in children with atopic dermatitis

BACKGROUND

Eosinophil cationic protein (ECP) is a cytotoxic agent secreted by activated eosinophils during allergic and inflammatory processes. The aim of the study was to determine the ECP level, absolute and relative eosinophil count and IgE antibodies in children with atopic dermatitis (AD) compared with those of nonatopic children, and to assess the correlation of these laboratory parameters with the clinical severity of AD.

METHODS

This prospective study comprised 70 children. There were 49 children with AD aged 3-36 months, and the control group comprised 21 children with a negative personal and family history for atopic diseases. Detailed history, serum ECP levels (UniCAP FEIA), relative and absolute eosinophil counts and total serum IgE antibodies were determined in both groups. In the children with AD, skin involvement was measured by the SCORAD index.

RESULTS

The calculated SCORAD index was between 16 and 83. IgE antibodies, relative and absolute eosinophil counts showed a significantly wider range of values and a statistically higher median (P < 0.001) in the patients with AD compared with the control group. These laboratory parameters did not correlate with the severity of AD. The serum ECP median level, in the children with AD, was 16.2 microg/L (range 3.01-65.30) compared with 5.92 microg/L (range 2.76-21.90) in the control group. Correlation of the total SCORAD index and the serum ECP levels was negative, weak (r = -0.065) and statistically not significant (P > 0.05). The same was found for the correlation of serum ECP and intensity of skin changes (r = -0.095) and serum ECP and subjective symptoms (r = -0.045). The correlation was positive, but weak and statistically not significant for the serum ECP and extent of the skin lesions (r = 0.079, P > 0.05).

CONCLUSION

Elevated levels of ECP, relative and absolute eosinophil counts, as well as IgE antibodies were determined in the patients with AD. As these laboratory findings did not correlate with the severity of AD, they can be considered only as additional methods in the evaluation of patients with AD.

Manifestation of atopic eczema in children after heart transplantation in the first year of life

Children undergoing heart transplantation in the first year of life appear in clinical observation to develop atopic eczema at an above-chance frequency despite immunosuppressive therapy with cyclosporine A. A clinical study was undertaken to clarify the extent to which those children develop atopic eczema with above-chance frequency. In this cross-sectional study, we examined 41 consecutive children after heart transplantation. Twenty-seven underwent heart transplantation in the first year of life, seven after the first birthday, and seven had cardiac surgery other than heart transplantation in the first year of life and served as a control group. Atopic eczema was diagnosed in 11 out of 27 children with heart transplant in the first year of life. No atopic eczema was diagnosed in the other two groups. Children undergoing heart transplant prior to the first birthday apparently develop atopic eczema more frequently than children whose surgery was performed after the first birthday, and also more frequently than children undergoing organ-preserving procedures, despite immunotherapy. It remains an open question whether a surgical procedure within the first months of life with subsequent immunosuppression causes an alteration in the reactivity of the immune system in these children compared to older children which promotes the occurrence of atopic eczema despite immunosuppression.

Heterogeneity of interleukin 5 genetic background in atopic dermatitis patients: significant difference between those with blood eosinophilia and normal eosinophil levels

BACKGROUND

Blood eosinophil levels in patients with atopic dermatitis vary widely during exacerbation of the disease. We considered that in addition to environmental factors, the genetic background involved with elevating blood eosinophil levels might be heterogeneous among atopic dermatitis patients.

OBJECTIVE

We attempted to determine whether a polymorphism of the interleukin (IL)5 gene plays a role in atopic dermatitis, particularly in those patients with blood eosinophilia. Due to the close relation of blood eosinophilia to high IgE productivity, we also assessed these polymorphisms in patients with high IgE concentrations.

METHODS

We determined the genotype of the IL5 polymorphism -703C/T in 451 atopic dermatitis patients and 116 normal subjects. The patients were classified into three groups by blood eosinophil levels; less than 7%, from 7 to 15%, and more than 15%, as well as by serum IgE concentrations; less than 500 IU/ml, from 500 to 2000 IU/ml, and more than 2000 IU/ml.

RESULTS

IL5 -703C/T was not significantly associated with either total atopic dermatitis patients or individual patients who had both blood eosinophilia and high IgE productivity. However, the distribution of the IL5 -703C/T genotype was significantly different between patients with either blood eosinophilia or high IgE productivity and those without either condition (P=0.0476, P=0.0088, respectively).

CONCLUSION

These results suggest that the IL5 gene may play a role in blood eosinophilia associated with atopic dermatitis. We also considered that the IL5 -703C/T gene polymorphism does not have a direct relationship to disease specificity.

Inhibition of allergic dermal inflammation by the novel imidazopyridazine derivative TAK-427 in a guinea pig experimental model of eczema

Antigen challenge by patch ovalbumin emulsion induced an eczema-like skin lesion in epicutaneously sensitized guinea pigs. Diseased skin sites were macroscopically characterized by manifestations of dermatitis, such as erythema, edema, and papules, and microscopically characterized by acanthosis, spongiosis, and dermal infiltration by eosinophils. Using such lesions as a model of eczema, we evaluated the potential value of TAK-427 [2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino] imidazo[1,2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate] as a therapeutic agent for atopic dermatitis by comparing it with dexamethasone and antihistamines. TAK-427 (0.3-30 mg/kg, p.o.) and dexamethasone (3 and 10 mg/kg, p.o.) inhibited eosinophil infiltration into the skin and ameliorated the dermatitis manifestations and epidermal damage. By contrast, none of the antihistamines tested (azelastine, ketotifen, terfenadine, and cetirizine) suppressed the eosinophil infiltration or dermatitis manifestations. To elucidate the mechanism by which TAK-427 inhibited the development of eczema, we investigated cytokine expression in the affected skin. Both TAK-427 and dexamethasone suppressed the increased mRNA expression of interleukin (IL)-13, granulocyte-macrophage colony-stimulating factor, IL-1alpha, tumor necrosis factor-alpha, interferon-gamma, and IL-8, but not IL-10, suggesting that TAK-427 inhibits allergic inflammation of the skin leading to the development of eczema by inhibiting the expression of proinflammatory cytokines after antigen challenge.

Serum levels of eosinophil cationic protein and eosinophils in asthmatic children during a course of prednisolone therapy

Eosinophils play an important role in the inflammatory events of allergic asthma. Serum eosinophil cationic protein (ECP) is a marker of disease activity and of treatment efficacy in bronchial asthma. To understand the role of ECP concentrations in disease activity of acute asthma, we determined changes in serum concentrations of ECP elaborated by activated eosinophil before and after prednisolone therapy. Circulating levels of ECP in 15 normal control subjects, and in sera of 20 asthmatic children who were allergic to house dust mites, were measured during an acute exacerbation and when the children were in stable condition, using commercially available assay kits. The mean concentrations of serum ECP were significantly higher during an acute asthma exacerbation than when the children were stable (26.41 +/- 21.66 microg/L vs 15.74 +/- 11.36 microg/L P < 0.01) or when compared to control subjects (7.50 +/- 1.42 microg/L; P < 0.001). The mean eosinophil counts (EC) during acute asthma attacks (575 +/- 286/mm3) and when stable (467 +/- 204/mm3) were higher than in the control group (181 +/- 164/mm3). The differences were statistically significant among the three groups (P < 0.05). A significant correlation was found between serum levels of ECP and EC (r = 0.788, P = 0.001) in asthmatic children; there were also significant correlations between ECP and EC in nonallergic normal control subjects (r = 0.662; P = 0.007). In conclusion, this study provides further evidence that changes in serum ECP may serve as an objective indicator for clinical activity and results of treatment in allergic asthmatics.

Fecal tumor necrosis factor alpha, eosinophil cationic protein and IgE levels in infants with cow's milk allergy and gastrointestinal manifestations

Infants with atopic eczema exhibit a specific fecal protein pattern after oral challenge with cow's milk, characterized by an increase in both eosinophil cationic protein (ECP) and tumor necrosis factor (TNF)alpha. The aim of our study was to determine the pattern of these proteins in allergic infants with intestinal manifestations. TNFalpha, ECP and immunoglobulin E (IgE) were measured in stools from 13 infants with intestinal symptoms and 10 healthy infants. The allergic infants underwent two stool collections, one before a cow's milk challenge and the other after the challenge, either at the onset of clinical manifestations (n=6) or 15 days after the challenge if no clinical manifestations occurred (n=7). Baseline TNFalpha, ECP and IgE levels were low in all infants. The concentration of TNFalpha increased after the challenge in infants positive to challenge (p<0.05) but not in those negative to challenge. ECP and IgE levels remained low after the challenge in all the allergic infants. These data confirm that fecal TNFalpha and ECP levels indicate various reaction types of food allergy and that different immunologic disturbances lead to atopic eczema or intestinal symptoms during food allergy. Fecal protein pattern can thus be a useful tool in diagnosing food allergy in infants with intestinal manifestations.

Monitoring of serologic immune parameters in inflammatory skin diseases

This paper deals with the correlation of clinical scoring and serologic markers of inflammation in atopic dermatitis and psoriasis. Serum eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), total serum IgE, IgG and IgM anti-IgE antibodies, and IgE immune complexes were evaluated in monitoring inflammatory skin diseases such as atopic dermatitis and psoriasis. Well-established clinical activity scores were used as standards in recording skin improvement under treatment in a clinical setting. Serum ECP was found to be increased in both atopic dermatitis and psoriasis patients compared to normal controls; sIL-2R and IgE immune complexes were increased only in atopics with increased serum IgE. Anti-IgE antibodies did not show any deviation in both groups of patients. There was a significant elevation of sIL-2R and IgE immune complexes and a nonsignificant elevation of ECP in high-IgE atopics in comparison to those with normal serum IgE. In both groups of patients, there was a significant reduction of ECP and sIL-2R accompanying the improving skin condition. Serum IgE and the other immune parameters failed to respond. In contrast to other studies, serum ECP failed to correspond significantly with disease activity in our study. Our results showed measurable changes of ECP and sIL-2R for atopic dermatitis and/or psoriasis under treatment, but comparison to clinical scores remains difficult due to the different basis of the two systems. The only significant correlation was established for relative changes in sIL-2R and psoriasis area and intensity (PASI), a correlation which might be a useful approach in psoriasis.

Eosinophil cationic protein (ECP) level and its correlation with eosinophil number or IgE level of peripheral blood in patients with various skin diseases

Eosinophil cationic protein (ECP) is a cationic protein derived from eosinophil granulocytes, and has been studied mainly in atopic diseases and considered as a useful marker of disease activity in atopic dermatitis. We measured the serum ECP levels in patients with various skin diseases (n = 875) and in normal healthy controls (n = 79), and evaluated the correlation between ECP level and blood eosinophil number, or ECP and IgE levels. Serum ECP levels were significantly higher in patients with drug eruption (15.8 +/- 1.7 micrograms/l), psoriasis (15.1 +/- 6.0 micrograms/l), acute urticaria (13.9 +/- 1.4 micrograms/l) than in healthy controls (4.5 +/- 0.3 micrograms/l) (P < 0.05) and also significantly elevated in patients with elevated eosinophil numbers (15.2 +/- 1.0 micrograms/l) compared to those in patients with normal eosinophil numbers (8.8 +/- 0.3 micrograms/l) (P < 0.001). Serum ECP level and eosinophil number in peripheral blood were also correlated in patients with psoriasis (gamma = 0.82, P < 0.01), drug eruption (gamma = 0.31, P < 0.01) and acute urticaria (gamma = 0.20, P < 0.05). However, no correlation between ECP and IgE levels in all of the patients was found. Among the patients with chronic urticaria, ECP levels showed an increasing trend in patients with angioedema, cold urticaria and dermographic urticaria as compared with those in healthy controls. Our results suggest that, even though the role of ECP released from activated eosinophils is still unknown, its measurement might be of help to understand the pathogenesis of some skin disorders.

Serum levels of eosinophil cationic protein reflect the state of in vitro degranulation of blood hypodense eosinophils in atopic dermatitis

In patients with atopic dermatitis (AD), serum levels of eosinophil cationic protein (ECP) have been shown to be a good reflector of disease severity. To elucidate what serum levels of ECP actually reflect, ECP levels in serum and plasma and cytological aspects of blood eosinophils were examined in AD patients (n = 27) and compared to healthy subjects (n = 12). Significantly elevated levels of serum ECP were noted in AD patients, while plasma ECP were uniformly recorded at nadir levels in both AD patients and normal subjects. In addition to blood eosinophilia, AD patients had significantly increased numbers of hypodense eosinophils (HEo) with morphological characteristics consistent with an activated state. Serum ECP levels strongly correlated with HEo numbers rather than with total eosinophil counts. These results indicate that elevated levels of serum ECP may be a consequence of in vitro degranulation of "activated" HEo, not of ECP supplementation from lesional skin. In addition, the dynamic correlations of eosinophil-associated parameters (total eosinophil counts, HEo numbers, and serum ECP levels) with AD severity suggest that inflammatory events in lesional skin may be involved in causing not only eosinophilopoiesis in bone marrow, but also development of HEo in the periphery, whose degree in turn may be mirrored in the levels of serum ECP in vitro.

Elevation of serum-soluble E-selectin in atopic dermatitis

Atopic dermatitis (AD) is characterized by alterations in cellular and humoral immunity. The objective of this study is to determine whether soluble E-selectin (sE-selectin) plays a role in AD. We examined the serum sE-selectin levels in patients with atopic dermatitis (n = 23), patients with urticaria (n = 9), and normal healthy individuals (n = 15). The severity of the disease in the AD patients was graded using an established clinical scoring system. We found that sE-selectin levels were significantly higher in atopic dermatitis than in urticaria (P < 0.001) or normal controls (P < 0.0001). In addition, there was a significant correlation between serum sE-selectin and the clinical score (R = 0.73, P < 0.0001). Clinical improvement was associated with a decrease in both the clinical score (P < 0.01) and serum sE-selectin (P < 0.01). E-selectin was recognized on the vascular endothelial cells of the erythematous lesions of AD patients. These results indicate that sE-selectin may play a role in AD.

Zaditen SRO permits once-daily dosing with superior efficacy in the prophylaxis of asthma

This international, multicenter clinical trial was designed to compare the efficacy and safety of two different formulations of ketotifen: Zaditen SRO and Zaditen Standard Form. In a randomized double-blind study over a 12-week treatment period, 3 parallel groups of asthmatic subjects received Zaditen SRO (2 mg once daily), Zaditen SRO (4 mg once daily), or Zaditen Standard Form (1 mg twice daily). Asthmatic subjects (362 evaluable cases, aged 6-29 years) kept daily records of clinical symptoms, use of concomitant medication, and peak flow recordings and were examined at 2-week intervals up to the end of the study. Zaditen SRO 4 mg administered once a day at night showed a statistically significant faster onset of action and was more clinically effective than Zaditen Standard Form. The Zaditen SRO 4-mg and 2-mg formulations were at least as well tolerated as the standard form, with somnolence occurring equally after both formulations. In conclusion, Zaditen SRO (4 mg once daily) was found to be equally safe and more effective in the prophylactic treatment of mild and moderate bronchial asthma than Zaditen Standard Form (1 mg twice daily).

The role of eosinophils and eosinophil cationic protein in monitoring oral challenge tests in children with food-sensitive atopic dermatitis

To investigate the role of peripheral blood eosinophils and eosinophil cationic protein as parameters in monitoring oral food challenges, we monitored 25 infants and children with atopic dermatitis for up to 48 hours after 47 placebo-controlled oral food challenges with cow's milk, hen's egg, cow's milk and hen's egg, or placebo for up to 48 hours. Six healthy young nonatopic adult volunteers served as control subjects. Compared with baseline values, peripheral blood eosinophils decreased significantly immediately after clinical reaction in positive challenges (p < 0.0004), independent of the kind of reaction. Eosinophil cationic protein increased significantly 8 hours after provocation, with a maximum at 24 hours (p < 0.03). This increase was predominantly related to eczematous reactions (p < 0.005). Blood sampling immediately after clinical reaction (for eosinophils) and at 24 hours (for eosinophil cationic protein) seems to be useful in monitoring oral food challenges in children with atopic dermatitis.

Assessment of eosinophil and neutrophil participation in atopic dermatitis: comparison with the IgE-mediated late-phase reaction

We hypothesized that repeated IgE-mediated late-phase reactions are critical in the pathogenesis of atopic dermatitis (AD). Prior studies have shown that extracellular deposition of eosinophil granule major basic protein (MBP) occurs in lesional AD skin, despite a paucity of infiltrating eosinophils, and that deposition of both neutrophil and eosinophil granule proteins occurs in the IgE-mediated late-phase reaction. We evaluated the participation of both eosinophil and neutrophil granule proteins in AD. Cutaneous biopsy specimens and serum and urine samples were obtained from 22 patients with AD. Lesional tissue was examined by means of immunofluorescence for neutrophil elastase and lactoferrin and for eosinophil granule MBP, eosinophil-derived neurotoxin (EDN), and eosinophil cationic protein (ECP). Serum levels of elastase, MBP, EDN, and ECP and urine levels of MBP, EDN, and ECP were measured. Marked extracellular deposition of at least one of the eosinophil granule proteins was present in the dermis of 15 of the 22 AD skin specimens, but minimal or no extracellular neutrophil elastase or lactoferrin deposition was observed in any specimens. Serum and urine levels of MBP, EDN, and ECP in the patients were elevated when compared with those of normal controls, whereas serum levels of neutrophil elastase were not elevated. Serum MPB levels correlated with extent of body surface involvement. These results suggest that eosinophil degranulation occurs in AD but that neutrophil degranulation does not. Although eosinophil degranulation is prominent in both the late-phase reaction and in AD, the lack of neutrophil degranulation in AD demonstrates differences in the inflammatory reactions.

Specific IgE antibodies and serum eosinophil cationic protein in children with atopic dermatitis alone

Both eosinophils and specific immunoglobulin E (IgE) to foods and mites have been considered involved in the pathogenesis of atopic dermatitis (AD). The relationship between eosinophils and specific IgE, however, remains to be elucidated. Blood eosinophil counts, serum eosinophil cationic protein (ECP) and IgE to egg white, cow's milk, soybean, rice and Dermatophagoides pteronyssinus (Dp) were measured in subjects with AD alone or bronchial asthma (BA) alone. Subjects with positive IgE titers (Pharmacia radioallergosorbent test (RAST) units > 0.7) of one or more items were defined as RAST-positive. Immunoglobulin E titers to egg white, cow's milk and soybean of subjects with AD were high in early childhood and declined with aging, whereas the titers of subjects with BA were negative or low. Immunoglobulin E titers to Dp were elevated after 1 year of age in both disease groups. Eosinophil cationic protein (ECP) levels and blood eosinophil counts in the AD and BA groups were significantly higher than those of non-atopic controls. No difference in ECP levels or blood eosinophil counts were observed between RAST-positive and negative groups. It is concluded that IgE to foods such as egg white, cow's milk and soybean might have a role in the pathogenesis of AD of young children, while IgE to mites might be involved in older children. Eosinophils may also participate in AD. However, different mechanisms may be responsible for the rise in specific IgE and high ECP levels and blood eosinophil counts.

Atopic dermatitis: recent trends in pathogenesis and therapy

Emerging concepts in the areas related to the pathogenesis and treatment of atopic dermatitis are reviewed. In particular, recent findings have revealed several key steps in the maintenance of a vicious circle of spongiotic dermatitis associated with elevated T-lymphocyte activation, hyperstimulatory Langerhans cells, defective cell-mediated immunity, and B-cell IgE overproduction. The discovery of specific IgE-binding structures on Langerhans cells provides a mechanism for Langerhans cells to capture and present IgE-targeted allergens to allergen-specific T cells. Furthermore, certain microbial allergens that tend to preferentially elicit IgE-type responses also elicit a T-cell response dominated by the IgE-inducing lymphokine interleukin 4. Repeated stimulation by activated Langerhans cells appears to induce just such a response. Abnormal biochemical responsiveness and mediator release by AD monocytes, mast cells, and eosinophils also participate in the sustainment or initiation of such a vicious circle, and contribute directly to the dermatitis as well. Developments in the areas of neuropeptides, genetics, microbial superantigens, and cytokine networks in the skin also appear to have promise in providing a rational link between immune defects and the inflammatory events in AD. Conventional therapy remains the mainstay of atopic dermatitis management; however, new therapies based upon the above concepts are being tested in clinical trials. Although the difficulty of objectively grading AD lesional activity and the high placebo response of AD patients hampers the interpretation of many reports, several types of approaches are coming into focus. The effectiveness of cyclosporin A, which targets T-cell activation and antigen presentation, indicates that additional agents with such activity should be effective, and verifies the criticality of these cells in AD pathogenesis. Therapy with biologic response modifiers, such as interferon gamma or thymopentin, is oriented toward normalization of imbalanced immune responsiveness, rather than direct suppression of the immune system. The mechanism of action of and toxicities of Chinese herbal mixtures require further investigation, but may reveal hitherto unconsidered avenues. Other recent therapeutic trials have focused on reduction of trigger factors, such as house dust mite exposure, foods, and the abnormal epidermal lipid barrier to irritation.

Immunopharmacology of asthma

Acute symptoms of asthma are largely a consequence of contraction of airway smooth muscle, yet emphasis in asthma pharmacology has shifted away from smooth muscle dysfunction and refocussed upon inflammatory events in the airway mucosa and submucosa. Thus, as described by John Morley existing anti-asthma drugs are used either to suppress inflammatory events (as preventive therapy), or to relieve obstruction to airflow (as symptomatic therapy). There is now a prospect of novel drugs that, by inhibiting phosphodiesterase isoenzymes selectively, will combine preventive and symptomatic therapies within a single molecule. Since atopy is associated with aberrant expression of phosphodiesterase isoenzymes in mononuclear cells, such therapies may belie their pragmatic origins and be envisaged as targeting a specific molecular defect.

Immunopharmacology of asthma

Acute symptoms of asthma are largely a consequence of contraction of airway smooth muscle, yet emphasis in asthma pharmacology has shifted away from smooth muscle dysfunction and refocussed upon inflammatory events in the airway mucosa and submucosa. Thus, as described by John Morley, existing anti-asthma drugs are used either to suppress inflammatory events (as preventive therapy), or to relieve obstruction to airflow (as symptomatic therapy). There is now a prospect of novel drugs that, by inhibiting phosphodiesterase isoenzymes selectively, will combine preventive and symptomatic therapies within a single molecule. Since atopy is associated with aberrant expression of phosphodiesterase isoenzymes in mononuclear cells, such therapies may belie their pragmatic origins and be envisaged as targeting a specific molecular defect.

The role of eosinophils in the pathogenesis of atopic dermatitis--eosinophil granule proteins as markers of disease activity

Currently, there is a large body of evidence that atopic dermatitis (AD) has an immunologic basis. Atopy-specific helper T cells (Th2-like T cells) may play a pathogenetic role by producing and releasing cytokines relevant for the allergic inflammation, such as IL-4, IL-5, and other growth factors. Eosinophils are believed to be of major importance as effector cells mediating the pathogenetically relevant late-phase reaction which is associated with a significant destruction of the surrounding tissue. Accordingly, a significant preactivation of peripheral blood eosinophils was detected in AD patients, leading to an enhanced susceptibility of these cells to distinct stimuli such as IL-5. Toxic proteins, such as eosinophil cationic protein (ECP), contained in the matrix and the core of secondary granules of eosinophils, may play an important role by propagating the allergic inflammatory process and by modulating the immune response. The pathogenetic role of eosinophils in AD is further supported by the detection of these proteins in the eczematous skin of patients. Furthermore, recent data point to a significant correlation between disease activity and deposition of eosinophil granule content: ECP serum levels were significantly increased in AD patients. In addition, ECP levels correlated with the disease activity. Moreover, clinical improvement was associated with a decrease of both the clinical score and serum ECP levels. These data clearly indicate that activated eosinophils may play a major role in the allergic inflammatory process of AD. Therefore, modulation of eosinophil activation could prove to be an important pharmacologic modality for the treatment of AD.