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For over 100 years, the eosinophil has been associated with allergic disease. At present, eosinophils appear to be associated pathologically with asthma, atopic dermatitis, allergic rhinitis, eosinophilic gastroenteritis, and certain eye diseases. The effector functions of eosinophils appear to be derived primarily from release of lipid mediators and proteins, including cytokines and granule proteins. Eosinophil degranulation results in the release of several cytotoxic cationic granule proteins. Furthermore, release of cytokines by eosinophils and other cells involved in inflammation amplifies and regulates localized immune responses. Altogether, the eosinophil's capacity to release and be influenced by a variety of mediators, including the granule proteins and cytokines, implicates this cell in the pathology of inflammation and in the perpetuation of the inflammatory response.

In atopic asthma there is strong evidence of eosinophils playing an active role in pathogenesis. Some investigations demonstrated that eosinophil cationic protein (ECP) serum levels increased in atopic patients with asthma during pollen season.The aim of the study was to evaluate the effects of short-term (1 week) beta 2-agonist treatment on lung function and eosinophil activity in asthmatic patients.We used an open, randomized, cross-over design to compare the effects of salbutamol (200 micrograms q.i.d.) and salmeterol (50 micrograms b.i.d.) on peak expiratory flow rate (PEFR), blood eosinophil count and serum levels of ECP as a measure of eosinophil activity in 20 mild atopic asthmatics.Morning and evening PEFR values were both significantly higher during salmeterol treatment than during the salbutamol period. Conversely, both morning and evening daily asthma symptom scores were significantly lower during salmeterol treatment compared with those recorded during the salbutamol period. The mean basal eosinophil blood count on salmeterol treatment (601 +/- 189 mm3) was not higher than the mean count on salbutamol treatment (612 +/- 204 mm3). After both treatments the mean eosinophil blood counts were unchanged (619 +/- 189 mm3 and 576 +/- 212 mm3, respectively). No significant differences in blood eosinophil counts were observed between or within treatments at any time. No significant difference was observed in baseline mean ECP serum concentration (43.8 +/- 26.3 micrograms/L on salmeterol treatment and 41.7 +/- 29.8 micrograms/L on salbutamol treatment, respectively). After salmeterol treatment the mean ECP serum concentration had fallen significantly to 20.9 +/- 18.6 micrograms/L (P0.01), whereas after salbutamol treatment it was unchanged (42.0 +/- 25.1 micrograms/L). Salmeterol treatment produced a decrease in ECP serum levels without any changes in blood eosinophil count.This study demonstrates that salmeterol affords a significant improvement in asthma control during the pollen season, measured by both subjective and objective parameters, compared with salbutamol. This greater efficacy may be related to inhibition of eosinophil degranulation during the pollen season.

Objective. To examine eosinophil activation, as reflected by evidence of eosinophil degranulation in the blood and affected tissues, in patients with diffuse and limited cutaneous forms of systemic sclerosis (SSc). Methods. Levels of the eosinophil-derived major basic protein (MBP), a marker of eosinophil degranulation, were determined in sera from 46 SSc patients, from patients with rheumatoid arthritis and giant cell arteritis, and from healthy volunteers, and in bronchoalveolar lavage fluid from 4 SSc patients. Extracellular tissue deposition of MBP was evaluated in biopsy specimens from affected skin or lung of 11 SSc patients. Results. Patients with diffuse cutaneous SSc (dcSSc) had elevated serum MBP levels compared with normal individuals (mean ± SD 762 ± 271 ng/ml versus 534 ± 144 ng/ml; P = 0.0004). MBP levels were positively correlated with the extent of cutaneous involvement, and negatively correlated with pulmonary function and duration of disease (r = –0.20). By immunohistochemical analysis, modest extracellular MBP deposition could be demonstrated in involved skin in 7 of 10 biopsy specimens, and MBP staining was prominent in affected lung tissues in 2 patients. Conclusion. Eosinophil degranulation appears to be increased in some patients with dcSSc, as indicated by elevated serum levels of MBP and extracellular accumulation of MBP in the lung. Eosinophil granule proteins may contribute to the development of cutaneous and pulmonary fibrosis in SSc.

Background: The eosinophilia-myalgia syndrome, caused by a contaminant or contaminants in epidemiologically implicated L-tryptophan products, is characterized by eosinophilia and eosinophil degranulation. We hypothesized that immune cells are stimulated by implicated L-tryptophan and produce eosinophil-active cytokines. Objectives: This study was designed to identify substances in L-tryptophan causing the eosinophilia-myalgia syndrome. Methods: Peripheral blood mononuclear cells were cultured with L-tryptophan products, and supernatants were tested for their ability to enhance eosinophil degranulation and survival in vitro and for their cytokine content. Subsequently, 46 different L-tryptophan lots were analyzed for their in vitro biologic activities. Results: After peripheral blood mononuclear cells were cultured with implicated L-tryptophan, their supernatants enhanced eosinophil degranulation and survival. These activities were blocked by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody; immunoreactive GM-CSF was measurable in the supernatants. Monocytes, but not T lymphocytes, were the responding cells. However, no correlation was observed between the in vitro biologic activity and lots of epidemiologically implicated L-tryptophan products. This biologic activity in the L-tryptophan products was characterized as endotoxin. Conclusion: Although L-tryptophan products stimulate peripheral blood mononuclear cells to produce GM-CSF, this response is caused by endotoxin contamination of the L-tryptophan products and not by a specific L-tryptophan contaminant. Endotoxin contamination must be considered as a possible cause of eosinophil-active cytokine production by peripheral blood mononuclear cells. (J ALLERGY CLIN IMMUNOL 1995;95:1261-7.)

While eosinophilic gastroenteritis is considered a rare condition, eosinophilic enteritis without gastric involvement is quite common in northeastern Australia. We present 79 patients with biopsy-proven eosinophilic enteritis, 70 seen since 1987. In 10 patients, eosinophilic enteritis was associated with infection by single, sexually immature, adult hookworms, most positively identified as the common dog hookworm Ancylostoma caninum. An additional 22 patients (of 34 tested) had serological evidence of A. caninum exposure. The essential pathology, i.e., edema and eosinophilic infiltration of the gut wall, ascites, and regional lymphadenopathy, was identical to that seen in eosinophilic gastroenteritis. Additional, more specific features included pathological reactions centered on attached worms, mucosal alterations and ulcers considered to be hookworm bite sites, and submucosal and lymph node granulomas with central eosinophil degranulation and degradation products. Since A. caninum has an almost worldwide distribution, it is probable that A. caninum-induced eosinophilic enteritis occurs outside Australia. We show that the worm is easily overlooked in pathological specimens and that care is required to preserve worms intact for specific parasitological identification. The clinical and pathological features were similar to those seen in another human enteric helminthic zoonosis, anisakiasis. The possibility that there are yet other undiscovered intestinal zoonoses remains.

Objective To undertake additional assessment of the possible overlap between bronchiolitis obliterans organizing pneumonia (BOOP) and chronic eosinophilic pneumonia (CEP). Design We retrospectively reviewed open-lung biopsy specimens from six patients with CEP, five patients with idiopathic BOOP, and four patients with secondary BOOP, encountered during the 5-year period 1986 through 1991, for the presence of eosinophils and extent of eosinophil degranulation. Material and methods Using previously described immunofluorescence methods for detection of intact eosinophils and extracellular deposition of eosinophil-derived major basic protein, we counted the number of eosinophils per x160 microscopic field and evaluated the extent of eosinophil degranulation semiquantitatively. Results The median numbers of eosinophils were 221 (range, 26 to 343) in cases of CEP, 7 (range, 1 to 65) in cases of idiopathic BOOP, and 7.5 (range, 1 to 39) in cases of secondary BOOP. More eosinophils were found in CEP than in idiopathic BOOP or all cases of idiopathic and secondary BOOP. We found no differences in the extent of eosinophil degranulation among the three groups, although a tendency for more degranulation was noted in cases of CEP. Conclusion Even though clinical and histologic overlap may exist between CEP and idiopathic BOOP, the exact relationship and the role of the eosinophil in idiopathic BOOP remain to be determined.

This study demonstrated not only the presence of house dust mite antigen (HDM)-specific IgE and IgG antibodies in the sera of 27 patients with atopic dermatitis (AD), but also considerably increased levels of serum eosinophil cationic protein (ECP) and uniformly nadir levels of plasma ECP, which provides evidence for ECP release from eosinophils in vitro. Besides blood eosinophilia, AD patients had an increased number of CD32+ eosinophils and EG2+ "activated" eosinophils; both of which, especially the latter, were significantly correlated with elevated levels of serum ECP. AD-source eosinophils had enhanced sensitivity for IgG-immune complexes corresponding to their increased expression of CD32, whereas neither HDM alone nor IgE/HDM-immune complex induced eosinophil activation. There were no gamma globulin-bearing cells in AD-source eosinophils, indicating that serum ECP levels may be dependent on EG2+ eosinophil numbers rather than the state of CD32-mediated eosinophil degranulation, as shown in vitro. Since HDM can cause an eczematous skin reaction accompanying the eosinophil accumulation and degranulation in sensitized AD, increased numbers of both CD32+ and EG2+ eosinophils according to the extent of AD severity indicates that these eosinophil in vivo generations and their subsequent functioning in the lesional skin may be regulated through HDM-initiated dermatitis events, and then, may form a vicious circle as the AD lesions spread.

The effects of transforming growth factor (TGF) beta 1 on cytokine-enhanced eosinophil survival and degranulation were investigated in vitro to determine whether it is an inhibitory regulator of allergic inflammation. Peripheral blood eosinophils purified by Percoll density gradient centrifugation and the CD16 negative selection technique were incubated in the presence of eosinophil-activating cytokines (interleukin-5 (IL-5), IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-gamma) with and without TFG-beta 1 for 1-3 days. On day 1, eosinophil protein X release was measured by radioimmunoassay. Eosinophil viability on day 3 was determined by staining the cells with fluorescein diacetate and propidium iodide, and on the same day DNA was extracted and subjected to gel electrophoresis to test for fragmentation. TGF-beta 1 significantly inhibited eosinophil survival enhanced by IL-5, IL-3, GM-CSF and IFN-gamma in a dose-dependent manner. The inhibitory effects of TGF-beta 1 on IL-5-enhanced survival was partially reversed by high concentrations of IL-5 and was completely neutralized with anti-TGF-beta antibody. IL-5 inhibited DNA fragmentation of eosinophils in vitro. TGF-beta reversed the effect of IL-5, indicating that TGF-beta 1 activates the pathway of apoptosis. TGF-beta 1 significantly suppressed eosinophil protein X release induced by IL-5. These results suggest that TGF-beta 1 may play a role in the modulation of allergic inflammation.

Prostaglandin D2 (PGD2) plays a key role in many of the physiological markings of allergic inflammation including vasodilation, bronchoconstriction, vascular permeability and lymphocyte recruitment. The action of this molecule is elicited through its two primary receptors, DP and CRTH2. Activation of CRTH2 leads to lymphocyte chemotaxis, potentiation of histamine release from basophils, production of inflammatory cytokines (IL-4, IL-5 and IL-13) by Th2 cells, eosinophil degranulation and prevention of Th2 cell apoptosis. As such, antagonism of CRTH2 has been reported to ameliorate the symptoms associated with various allergen challenge animal models including murine antigen induced lung inflammation, murine cigarette smoke induced lung inflammation, murine allergic rhinitis, guinea pig PGD2-induced airflow obstruction, guinea pig airway hyper-responsiveness, sheep airway hyper-responsiveness and murine contact hypersensitivity. CRTH2 antagonists fall into four broad categories: tricyclic ramatroban analogues, indole acetic acids, phenyl/phenoxy acetic acids and non-acid-containing tetrahydroquinolines. Numerous CRTH2 antagonists have been advanced into the clinic and early reports from two Phase II trials suggest promising activity in the alleviation of atopic symptoms.

Background Thymic stromal lymphopoietin (TSLP) and eosinophils are prominent components of allergic inflammation. Therefore, we sought to determine whether TSLP could activate eosinophils, focusing on measuring the regulation of TSLPR expression on eosinophils and degranulation in response to TSLP, as well as other eosinophil activation responses. Methods Eosinophil mRNA expression of TSLPR and IL-7Rα was examined by real-time quantitative PCR of human eosinophils treated with TNFα and IL-5 family cytokines, and TSLPR surface expression on eosinophils was analyzed by flow cytometry. Eosinophils were stimulated with TSLP (with and without pre-activation with TNFα and IL-3) and evaluated for release of eosinophil derived neurotoxin (EDN), phosphorylation of STAT5, and survival by trypan blue exclusion. A blocking antibody for TSLPR was used to confirm the specificity of TSLP mediated signaling on eosinophil degranulation. Results Eosinophil expression of cell surface TSLPR and TSLPR mRNA was upregulated by stimulation with TNFα and IL-3. TSLP stimulation resulted in release of EDN, phosphorylation of STAT5 as well as promotion of viability and survival. TSLP-stimulated eosinophil degranulation was inhibited by a functional blocking antibody to TSLPR. Pre-activation of eosinophils with TNFα and IL-3 promoted eosinophil degranulation at lower concentrations of TSLP stimulation. Conclusions This study demonstrates that eosinophils are activated by TSLP and that eosinophil degranulation in response to TSLP may be enhanced on exposure to cytokines present in allergic inflammation, indicating that the eosinophil has the capacity to participate in TSLP-driven allergic responses.

Quantitative high throughput assays of eosinophil-mediated activities in fluid samples from patients in a clinical setting have been limited to ELISA assessments for the presence of the prominent granule ribonucleases, ECP and EDN. However, the demonstration that these ribonucleases are expressed by leukocytes other than eosinophils, as well as cells of non-hematopoietic origin, limits the usefulness of these assays. Two novel monoclonal antibodies recognizing eosinophil peroxidase (EPX) were used to develop an eosinophil-specific and sensitive sandwich ELISA. The sensitivity of this EPX-based ELISA was shown to be similar to that of the commercially available ELISA kits for ECP and EDN. More importantly, evidence is also presented confirming that among these granule protein detection options, EPX-based ELISA is the only eosinophil-specific assay. The utility of this high throughput assay to detect released EPX was shown in ex vivo degranulation studies with isolated human eosinophils. In addition, EPX-based ELISA was used to detect and quantify eosinophil degranulation in several in vivo patient settings, including bronchoalveolar lavage fluid obtained following segmental allergen challenge of subjects with allergic asthma, induced sputum derived from respiratory subjects following hypotonic saline inhalation, and nasal lavage of chronic rhinosinusitis patients. This unique EPX-based ELISA thus provides an eosinophil-specific assay that is sensitive, reproducible, and quantitative. In addition, this assay is adaptable to high throughput formats (e.g., automated assays utilizing microtiter plates) using the diverse patient fluid samples typically available in research and clinical settings.

Eosinophilic gastrointestinal diseases are a group of chronic diseases characterized by a range of symptoms caused by eosinophilic inflammation of various parts of the gastrointestinal tract. Other causes for eosinophilia need to be ruled out prior to making the diagnosis of EGIDs. The most common form of EGID is eosinophilic esophagitis (EoE), an antigen-driven disease that afflicts children and adults and has been identified across the world. Histological features include dense eosinophilia of the esophageal mucosa, eosinophil degranulation, eosinophil microabscess formation, and other features of epithelial inflammation including basal zone hyperplasia and rete pege elongation. Treatments include dietary exclusions and topical corticosteroids.

Eosinophil inflammation is essential in many cases of allergic and non-allergic rhinitis. Activated eosinophils release toxic granule proteins. In this study, we compared the degree of local nasal and systemic eosinophil activation by the determination of eosinophil cationic protein (ECP) in serum and native nasal fluid from 119 patients. We found no significant differences in serum ECP levels of the various patient groups. In all patient groups, except in the vasomotor rhinitis group, nasal fluid ECP levels differed significantly from normal controls. We found a nasal fluid ECP (mean +/- SEM) of 32.6 +/- 8.1 ng/ml for normals, 106 +/- 39.7 for non-rhinitic atopics, 87.6 +/- 20.8 ng/ml for patients with chronic non-allergic sinusitis, 101.3 +/- 40.4 ng/ml for patients with a history of pollinosis, 150.5 +/- 35.1 ng/ml for patients with acute pollinosis, 84.7 +/- 24.7 ng/ml for individuals with perennial allergic rhinitis and 112.9 +/- 25.6 ng/ml for patients with both perennial and seasonal allergy. Patients with nasal polyps had mean nasal ECP levels of 146.9 +/- 57.7 ng/ml in absence of allergy and 147.9 +/- 54.9 ng/ml in the presence of allergy. Nasal ECP was 67.0 +/- 22.4 for patients with hyperreactive rhinitis. We found a significant correlation of 0.95 between nasal eosinophils and nasal ECP. Nasal ECP and a subjective symptom score only correlate significantly for chronic sinusitis. We conclude that monitoring native nasal fluid ECP levels may be useful in the diagnosis and management of nasal inflammation. Elevated ECP in nasal secretion may originate from upregulated eosinophil degranulation and thus is a marker for local inflammation although not specific for any particular nasal disease.

101. Laroche D, Chrysanthou S, Lefran~ois C, et al. Evidence of a progressive degranulation of basophil in subjects operated on without adverse reaction. Agents Actions 1992;36(suppl C):C199-C200. 102. De Paulis A, Valentini G, Spadaro G, Lupoli S, Tirri G, Marone G. Human basophil releasability. VIII. Increased basophil releasability in patients with scleroderma. Arthritis Rheum 1991;34:1289-96. 103. Yunginger JW, Nelson DR, Squillace DL, et al. Laboratory investigation of deaths due to anaphylaxis. J Forensic Sci 1991;36:857-65. 104. Takeishi T, Martin TR, Katona IM, Finkelman FD, Galli SJ. Differences in the expression of the cardiopulmonary alterations associated with anti-immunoglobulin E-induced or active anaphylaxis in mast cell-deficient and normal mice: mast cells are not required for the cardiopulmonary changes associated with certain fatal anaphylactic responses. J Clin Invest 1991;88:598-608. 105. Sampson HA, Mendelson L, Rosen JP. Fatal and nearfatal anaphylactic reactions to food in children and adolescents [Comments]. N Engl J Med 1992;327:380-4. 106. Shalit M, Schwartz LB, yon Allmen C, Atkins PC, Lavker RM, Zweiman B. Release of histamine and tryptase during continuous and interrupted cutaneous challenge with allergen in humans. J ALLERCY CLIN IMVnJNOL 1990; 86:117-25. 107. Lavker RM, Schechter NM, Guzzo C, Lazarus GS. Aggressive topical corticosteroid therapy: a novel approach to mast-cell-dependent cutaneous disorders. Dermatologica 1987;175:213-6. 108. Lavker RM, Schechter NM, Lazarus GS. Effects of topical corticosteroids on human dermis. Br J Dermatol 1986;115:101-7. 109. Jarjour NN, Calhoun WJ, Schwartz LB, Busse WW. Elevated bronchoalveolar lavage fluid histamine levels in allergic asthmatics are associated with increased airway obstruction. Am Rev Resp Dis 1991;144:83-7. 110. Broide DH, Gleich GJ, Cuomo AJ, et al. Evidence of ongoing mast cell and eosinophil degranulation in symptomatic asthma airway. J A~LEROY CLlr~ IMMUNOL, 1991; 88:637-48. 111. Liu MC, Bleecker ER, Lichtenstein LM, et al. Evidence for elevated levels of histamine, prostaglandin D2, and other bronchoconstricting prostaglandins in the airways of subjects with mild asthma. Am Rev Respir Dis 1990; 142:126-32. 112. Sedgwick JB, Calhoun WJ, Gleich GJ, et al. Immediate and late airway response of allergic rhinitis patients to segmental antigen challenge: characterization of eosinophil and mast cell mediators. Am Rev Respir Dis 1991; 144:1274-81. 113. Liu MC, Hubbard WC, Proud D, et al. Immediate and late inflammatory responses to ragweed antigen challenge of the peripheral airways in allergic asthmatics: cellular, mediator, and permeability changes. Am Rev Respir Dis 1991;144:51-8. 114. Koshino T, Teshima S, Fukushima N, et al. Identification of basophils by immunohistochemistry in the airways of post-mortem cases of fatal asthma. Clin Exp Allergy 1993;23:919-25.

Eosinophils play a major role in host immunity to parasite infections and allergic reactions such as bronchial asthma. 1 During such inflammatory reactions, soluble mediators released by T cells, macrophages, and other inflammatory cells induce migration of eosinophils from the blood into tissue. Subsequently, appropriate stimuli (e.g., Igcoated helminths) trigger the eosinophils to degranulate, which results in the local release of a series of cytotoxic and proinflammatory proteins such as major basic protein, eosinophil peroxidase, eosinophil cationic protein, and eosinophilderived neurotoxin (EDN)?" 2 Deposition of released granule proteins has been shown in various diseases, including bronchial asthma and parasite infections. ~ Accumulating evidence that eosinophil granule proteins are implicated in tissue damage associated with these diseases has focused interest on the regulation of eosinophil degranulation. However, at present, both the actual physiologic stimuli for eosinophil degranulation and the transmembrane signaling events for triggering degranulation from eosinophils are poorly understood. In numerous receptor systems, ligand binding triggers a rapid increase in phosphoinositide hydrolysis catalyzed by receptor-coupled phospholipase C (PLC) activity? Phosphoinositide breakdown generates at least two second-messenger molecules, inositol 1,4,5-triphosphate and 1,2-diacylglycerol, that in turn ~ increase [Ca2+]i and activate protein kinase C, respectively. 4 In mast cells, platelets, and neutrophils, exocytotic events

Objective: To evaluate the role of the eosinophil granulocyte during hepatic allograft rejection. Design: (a) A retrospective case-control study and (b) a prospective study of consecutive liver transplant recipients. Patients: In the retrospective study, eight patients with severe rejection in the first month after liver transplantation were compared with six patients without rejection. In the prospective study, 20 consecutive patients were studied for the presence of liver allograft rejection between March 1989 and October 1989. Measurements: Absolute eosinophil counts were determined whenever blood was drawn. Serum was analyzed for the presence of two eosinophil granule proteins, major basic protein and eosinophil-derived neurotoxin, on days 7, 14 and 21 after transplantation. Liver biopsy specimens were stained for the presence of major basic protein by means of immunofluorescence using a double-antibody staining technique. The degree of eosinophil infiltration and degranulation was graded using a panel of representative slides. Results: Blood eosinophilia was increased in patients with hepatic allograft rejection (p < 0.05). Serum major basic protein and eosinophil-derived neurotoxin concentrations were similar in patients with and without rejection. Many portal tracts of patients with rejection contained an abundance of eosinophils, and staining for major basic protein revealed the presence of intact eosinophils. In addition, extracellular major basic protein was seen, sometimes in the absence of intact eosinophils or an extensive infiltrate. In patients with severe allograft rejection, major basic protein staining was present in littoral cells lining the sinusoids. Conclusions: Patients with severe rejection in the first month after liver transplantation often have blood eosinophilia and marked infiltration of portal tracts with eosinophils or evidence of eosinophil degranulation. The presence of major basic protein likely is direct evidence of tissue destruction and may indicate active rejection (major basic protein in eosinophils and extracellular major basic protein, presence of portal infiltrate) or the immediate postinflammatory rejection state (extracellular major basic protein and major basic protein inside littoral cells, absence of portal infiltrate and eosinophils, bile ducts damaged or vanished). These findings underline the importance of the eosinophil as an intergral part of the rejection process. We conclude that the presence of eosinophils or their secretion products in the first month after liver transplantation is an indicator of ongoing or recent allograft rejection. (HEPATOLOGY 1994;20:654–662).

We examined the effect of VLA-4-mediated adhesion to purified fibronectin (FN) on the stimulated release of the granular protein, eosinophil peroxidase (EPO), in human peripheral blood eosinophils. In initial studies, optimal time-course and concentration-effect relationships were determined; eosinophil adhesion to FN-coated styrene plates was maximal in wells coated with 10 micrograms/ml FN after incubation in the wells for 60 min (17,097 +/- 3,670 adherent eosinophils/well versus 6,789 +/- 925 adherent eosinophils/well in control wells; P < 0.005). Treatment of eosinophils with 10(-8) to 10(-6) M formylmethionylleucyl-phenylalanine (FMLP) + 5 micrograms/ml cytochalasin B (CYTB) caused a concentration-dependent increase in EPO release, which was augmented by preincubation of eosinophils for 120 min in FN-coated (10 micrograms/ml) styrene wells versus eosinophils preincubated in control wells. At 10(-6) M FMLP+CYTB, initial adhesion to FN for 120 min caused an increase in the secretion of EPO from 367 +/- 26 to 485 +/- 25 ng/10(6) eosinophils (P = 0.0001). Treatment of eosinophils during incubation in FN-coated wells with the anti-VLA-4 monoclonal antibody HP2/1 attenuated stimulated EPO secretion caused by 10(-6) M FMLP+CYTB from 497 +/- 40 to 285 +/- 26 ng/10(6) eosinophils (P < 0.02). Similarly, treatment with HP2/1 caused a decrease in eosinophil adhesion to FN-coated styrene from 12,693 +/- 1,866 to 6,206 +/- 852 adherent cells/FN-coated well (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased numbers of eosinophilic granulocytes and eosinophil degranulation have been observed in various inflammatory conditions. Biopsies from the fallopian tubes of 28 patients were examined for the content of eosinophilic granulocytes. Peritoneal fluids (PF) from 89 patients were analyzed for the concentrations of eosinophilic granulocytes and the granule protein eosinophil cationic protein (ECP). The ECP levels in the PF were substantially elevated during genital inflammation (P < 0.001). Furthermore, one week after laparotomy for adhesiolysis there were both increased PF-ECP levels (P < 0.01) and raised concentrations of eosinophilic granulocytes (P < 0.001) when compared to the reference group. Staining of the biopsies with monoclonal antibodies revealed an increased total number as well as a number of activated eosinophilic granulocytes in specimens from adhesions and sactosalpinx compared to specimens from normal fimbriae. The findings indicate that eosinophilic granulocytes may have a possible role in the fibrotic process of pelvic adhesion disease.

Mouse models of eosinophilic disorders are often part of preclinical studies investigating the underlying biological mechanisms of disease pathology. The presence of extracellular eosinophil granule proteins in affected tissues is a well established and specific marker of eosinophil activation in both patients and mouse models of human disease. Unfortunately, assessments of granule proteins in the mouse have been limited by the availability of specific antibodies and a reliance on assays of released enzymatic activities that are often neither sensitive nor eosinophil specific. The ability to detect immunologically and quantify the presence of a mouse eosinophil granule protein in biological fluids and/or tissue extracts was achieved by the generation of monoclonal antibodies specific for eosinophil peroxidase (EPX). This strategy identified unique pairs of antibodies with high avidity to the target protein and led to the development of a unique sandwich ELISA for the detection of EPX. Full factorial design was used to develop this ELISA, generating an assay that is eosinophil-specific and nearly 10 times more sensitive than traditional OPD-based detection methods of peroxidase activity. The added sensitivity afforded by this novel assay was used to detect and quantify eosinophil degranulation in several settings, including bronchoalveolar fluid from OVA sensitized/challenged mice (an animal model of asthma), serum samples derived from peripheral blood recovered from the tail vasculature, and from purified mouse eosinophils stimulated ex vivo with platelet activating factor (PAF) and PAF + ionomycin. This ability to assess mouse eosinophil degranulation represents a specific, sensitive, and reproducible assay that fulfills a critical need in studies of eosinophil-associated pathologies in mice.

The PI3K pathway plays a major role in many vital cell processes. Our primary aim was to investigate signalling through PI3K for in vitro degranulation from allergen-primed eosinophils and neutrophils in allergic rhinitis and allergic asthma after seasonal and experimental allergen challenge. Nine patients with allergic rhinitis, eight with allergic asthma and four controls were studied during birch pollen season and after nasal and bronchial allergen challenge. Primed blood eosinophils and neutrophils were stimulated for in vitro degranulation with C3b-coated Sephadex particles, after prior incubation with Wortmannin, a PI3K inhibitor. The released amounts of eosinophil cationic protein (ECP), eosinophil peroxidase (EPO) and myeloperoxidase (MPO) were measured by radioimmunoassay. Wortmannin (10(-6) to 10(-9) M) inhibited ECP, EPO and MPO release in a dose-dependent manner in allergic rhinitis and allergic asthma in all three allergen challenge models. Inhibition of ECP release tended to be lower in the asthmatics in all allergen challenge models, statistically significant compared to the controls during season for 10(-8) M Wortmannin (p=0.01). A clear propensity towards less inhibition in the rhinitic patients was seen after nasal and bronchial challenge compared to seasonal exposure, significant for ECP (10(-8) M Wortmannin; p=0.034 and 0.002, respectively). Signalling through PI3K is clearly involved in ECP, EPO and MPO release in allergic rhinitis and allergic asthma irrespective of allergen challenge model. Allergic asthma demonstrated less inhibition of ECP release via PI3K during pollen season, indicating that other pathways play a greater role in eosinophil degranulation in allergic asthma than allergic rhinitis.

Inflammatory reactions to the lung fluke, Paragonimus westermani, in an abnormal host, the rat, were studied by electron microscopy. Inflammatory cells accumulated around the worms in rat muscles, but the reaction varied significantly in intensity as well as distribution of inflammatory cells from worm to worm in the same and different hosts. In an accumulation of inflammatory infiltrates around the worm, eosinophils were more commonly seen, and neutrophils and macrophages were fewer in number. Mast cells appeared rarely. Where inflammatory cells touched to the worms, the tegument of the worms was covered with moderately electron-dense flocculent material which included dense granules. This material, which probably consisted of immune complexes of host antibody and antigen secreted from tegumental granules, seemed to block the inflammatory cells from adhering to the worm surfaces. Inflammatory cells made direct contact with worm surfaces where flocculent material was absent. Dense secretory material was discharged from some eosinophils as a result of degranulation.

Onchocerca ochengi , a filarial parasite of cattle, represents the closest relative of the human pathogen, Onchocerca volvulus . Both species harbour Wolbachia endosymbionts and are remarkable in that adult female worms remain viable but sessile for many years while surrounded by host cells and antibodies. The basis of the symbiosis between filariae and Wolbachia is thought to be metabolic, although a role for Wolbachia in immune evasion has received little attention. Neutrophils are attracted to Wolbachia , but following antibiotic chemotherapy they are replaced by eosinophils that degranulate on the worm cuticle. However, it is unclear whether the eosinophils are involved in parasite killing or if they are attracted secondarily to dying worms. In this study, cattle infected with Onchocerca ochengi received adulticidal regimens of oxytetracycline or melarsomine. In contrast to oxytetracycline, melarsomine did not directly affect Wolbachia viability. Eosinophil degranulation increased significantly only in the oxytetracycline group; whereas nodular gene expression of bovine neutrophilic chemokines was lowest in this group. Moreover, intense eosinophil degranulation was initially associated with worm vitality, not degeneration. Taken together, these data offer strong support for the hypothesis that Wolbachia confers longevity on O. ochengi through a defensive mutualism, which diverts a potentially lethal effector cell response.

Background: eosinophilic esophagitis is an esophageal disor der characterized by esophageal and/or upper gastrointestinal tract symptoms, and by dense esophageal eosinophilia associated with a normal gastric and duodenal mucosa. Prevalently reported in children, eosinophilic esophagitis has recently been reported with increased frequency also in adults. Aims: the purpose of this study was to report our experience with eosinophilic esophagitis in Italy, since there are only very few series of such patients in our country. Patients and methods: we retrospectively reviewed the his tological data of consecutive patients with a diagnosis of esophagitis or reflux disease in the period September 2004-September 2008. Eosinophils were counted where they appeared most nu merous in the biopsy, with a cutoff > 15 eosinophils in more than one high-power field as diagnostic of eosinophilic esophagitis. Pa tients were excluded if gastric or duodenal biopsies showed a prominent eosinophilic infiltrate. Results: twenty two patients (14 adults, 8 children, age range 2-59 years) were identified according to the above criteria. The average eosinophil count was 86/ high-power field (range 31150), associated with other pathologic features (eosinophilic microabscesses eosinophil degranulation, basal zone hyperplasia, papillary elongation). The main clinical complaints were dyspha gia, food impaction, and heartburn, and endoscopic findings con sisted of mucosal thickening and inelasticity, longitudinal shearing, rings, and white specks, without difference between adults and children for both clinical and endoscopic variables. Conclusions: eosinophilic esophagitis is not rare in Italy, and displays clinical, endoscopic, and pathologic features similar to those described in other countries.

Recent evidence confirms that cytokines such as IL-1, IL-4, IL-5, and GM-CSF may enhance or inhibit eosinophil function. Functions that are susceptible to modulation include eosinophil-mediated antibody-dependent damage of helminthic parasites, oxidative metabolism and degranulation. We have employed IgG and IgE-coated Sepharose beads to investigate selective modulation of IgG and IgE-mediated enzyme release by IL-1 beta. Both IgG and IgE-coated beads induced release of granular enzymes beta-glucuronidase and arylsulfatase. Enzyme release from IgG-stimulated eosinophils was inhibited by preincubation with IL-1 beta (100 pg/ml, P less than or equal to 0.05). In contrast, enzyme release by IgE-stimulated eosinophils was enhanced by IL-1 beta (100 pg/ml, P less than or equal to 0.05). These studies support the hypothesis that IL-1 beta has specific selective actions on eosinophil function. Furthermore, these actions on particle-stimulated enzyme release suggest that IgG and IgE mediated processes in eosinophils are differentially regulated.

The syndrome of episodic angioedema and eosinophilia is characterized by cyclic edema, marked peripheral blood eosinophilia, and eosinophil degranulation in the dermis. Using a sensitive immunoenzymetric method, we measured serum interleukin (IL)-5 levels in four patients with this syndrome. We also determined the percentage of activated T cells in the peripheral blood of a new patient before and during an attack. In the patient presented, IL-5 levels peaked several days before maximal eosinophilia and then declined. This patient's lymphocytes showed an increased percentage, 28% (normal 2% to 3%), of activated T cells staining for both CD3 and HLA-DR 10 days before maximal eosinophilia, but no increase at the time of peak eosinophilia. In serum from three previously reported cases, elevated serum IL-5 levels were found during attacks. After glucocorticoid administration, IL-5 levels became undetectable in three of the four patients. Production of IL-5 is likely an important determinant of the pathophysiology of this syndrome.

Eosinophil cationic protein (ECP), a cytotoxic protein contained in the granules of eosinophils, has been suggested as having an important role in the pathogenesis of asthma. To determine whether ECP plays a similar role in bronchiolitis, we tested samples of nasopharyngeal secretions, obtained from a group of 47 children with various forms of illness related to respiratory syncytial virus (RSV) and from 26 children with non-RSV upper respiratory tract illness or bacterial pneumonia, for the presence of ECP by means of a double-antibody radioimmunoassay. Concentrations of ECP in children with RSV bronchiolitis were significantly higher (166.8 ng/ml) than the mean concentration of ECP in both groups of children with RSV upper respiratory tract illness (43.5 ng/ml, p less than 0.002) and RSV lower respiratory tract disease without wheezing (29.1 ng/ml; p less than 0.0002). Children with non-RSV upper respiratory tract illness or bacterial pneumonia had levels of ECP in nasopharyngeal secretions similar to those of children with RSV upper respiratory tract illness or RSV pneumonia. High ECP levels in nasopharyngeal secretions (greater than 50 ng/ml) were predictive of the development of bronchiolitis at the time of RSV infection (p less than 0.001), and the individual ECP levels correlated with severity of the disease as determined by the initial PaO2 concentrations (p less than 0.05). These data suggest that eosinophil degranulation in the respiratory tract occurs during RSV bronchiolitis and may play a significant role in the development of virus-induced airway obstruction.

Activation of human eosinophils by specific extracellular stimuli triggers the cellular degranulation response. Because cellular adhesion is critical for this eosinophil degranulation, we have tested the hypothesis that ligation of the β2 integrin, αMβ2 (Mac-1, CD11b/CD18), leads to intracellular signaling events that contribute to the eosinophil activation response. Recently, we found that engagement of β2 integrin using two different approaches, such as cell adhesion induced by IL-5 or direct ligation of αMβ2, triggered tyrosine phosphorylation of Cbl, the product of the c-cbl proto-oncogene, paxillin, a cytoskeletal protein, an unidentified 115-kD protein, and subsequent cellular degranulation. The results of this study indicate that engagement of αMβ2 on eosinophils triggers an intracellular signaling cascade leading to cellular degranulation. Tyrosine phosphorylation of Cbl, paxillin, and a 115-kD protein may play important roles in adhesion-dependent cellular functions of eosinophils.

Prostaglandin D 2 (PGD 2 ) is derived from arachidonic acid and binds with high affinity to the G protein coupled receptors prostanoid DP 1 and DP 2 . Interaction with DP 2 results in cell chemotaxis, eosinophil degranulation, eosinophil shape change, adhesion molecule upregulation and Th2 cytokine production. In allergic rhinitis and allergic asthma PGD 2 is released from mast cells in response to allergen challenge and may trigger symptoms such as sneezing, rhinorrhea, pruritus, mucus hypersecretion and pulmonary inflammation. In Japan, ramatroban, a dual prostanoid DP 2 /prostanoid TP receptor antagonist, is marketed for allergic rhinitis while selective DP 2 antagonists are currently under investigation as therapeutics for asthma and allergic rhinitis. In the studies described herein, we investigated the efficacy of AM156, a novel selective prostanoid DP 2 receptor antagonist, in murine models of allergic rhinitis and asthma. AM156 inhibited sneezing and nasal rubs in a model of allergic rhinitis. AM156 inhibited pulmonary inflammation and mucus hypersecretion induced by chronic inhalation of house dust mite. These results suggest that selective prostanoid DP 2 receptor antagonists such as AM156 may provide beneficial effects for the clinical treatment of diseases such as allergic rhinitis and asthma.

Background Eosinophils are possibly the most important inflammatory cells in the pathogenesis of rhinosinusitis with nasal polyposis. Eosinophil degranulation is the mechanism by which these cells exert their inflammatory action. Knowledge of eosinophil state and degranulation mode therefore may help us to better understand this disease. A study is made of eosinophil state and degranulation mode using transmission electron microscopy (TEM), attempting to establish correlations with certain clinical variables considered to be of importance in patients with nasal polyposis. Methods A prospective TEM study was made to examine 582 eosinophils under 5000× magnification, classifying them according to their state and degranulation mode. The cells originated from 36 cases of nasal polyposis and were catalogued according to the clinical–radiological presentation of the disorder, the presence of asthmatic disease, or acetilsalicilic acid (ASA) triad syndrome (nasal polyposis, asthma, and nonsteroidal anti-inflammatory drug intolerance), and the degree of nasal tissue eosinophilia of the case of origin. Results A total of 30.75% of the eosinophils were inactive, 41.75% exhibited piecemeal degranulation (PMD), 27.5% exhibited cytolysis, and 0.34% were in apoptosis. The degranulation mode was significantly correlated to the clinical and histological parameters studied. Thus, cytolysis tended to be less pronounced and PMD greater, in the cells from cases with intense eosinophilia or severe polyposis (high clinical stage and ASA triad). Conclusion Cytolysis and PMD are the principal degranulation modes of eosinophils in nasal polyposis—apoptosis being very infrequent. Nasal polyposis shows a correlation between eosinophil degranulation mode and the clinical and radiological stage and the degree of tissue eosinophilia of the case of origin.

Background & Aims Features of eosinophilic esophagitis (EoE) and gastroesophageal reflux disease (GERD) overlap; because they cannot be differentiated on the basis of eosinophil counts alone, it can be a challenge to distinguish these disorders. We aimed to characterize the clinical, endoscopic, and histologic features of EoE and GERD and to identify factors that might be used to differentiate them. Methods We performed a retrospective case-control study on data collected from 2000 to 2007. Cases were patients of any age with EoE, as defined by recent consensus guidelines; controls were patients of any age with GERD. Clinical and endoscopic data were collected, and all esophageal biopsy specimens were reassessed by gastrointestinal pathologists. Cases and controls were compared, unconditional logistic regression was performed to develop a model to predict EoE, and receiver operator characteristic curves were constructed. Results Data from 151 patients with EoE and 226 with GERD were analyzed. Compared with GERD, features that independently predicted EoE included younger age; symptoms of dysphagia; documented food allergies; observations of esophageal rings, linear furrows, white plaques, or exudates by upper endoscopy; an absence of a hiatal hernia, observed by upper endoscopy; a higher maximum eosinophil count; and the presence of eosinophil degranulation observed in biopsy specimens. The area under the curve for this model was 0.934. Conclusions We identified a set of readily available and routinely measured variables that differentiate EoE from GERD. Use of this type of analysis with patients suspected to have EoE might lead to more accurate diagnoses.

SUMMARYSetaria cervi, a bovine filarial parasite contains significant acid phosphatase (AcP) activity in its various life stages. Two forms of AcP were separated from somatic extract of adult female parasite using cation exchange, gel filtration and concavalin affinity chromatography. One form having a molecular mass of 79 kDa was characterized as dual specific protein tyrosine phosphatase (ScDSP) based on substrate specificity and inhibition studies. With various substrates tested, it showed significant activity in the order of phospho-L-tyrosine>pNPP>ADP>phospho-L-serine. Inhibition by orthovanadate, fluoride, molybdate, and zinc ions further confirms protein tyrosine phosphatase nature of the enzyme. Km and Vmax determined with various substrates were found to be 16·66 mM, 25·0 μM/ml/min with pNPP; 20·0 mM, 40·0 μM/ml/min with phospho-L-tyrosine and 27·0 mM, 25·0 μM/ml/min with phospho-L-serine. KIwith pNPP and sodium orthovanadate (IC5033·0 μM) was calculated to be 50·0 mM. Inhibition with pHMB, silver nitrate, DEPC and EDAC suggested the presence of cysteine, histidine and carboxylate residues at its active site. Cross-reactivity withW. bancrofti-infected sera was demonstrated by Western blotting. ScDSP showed elevated levels of IgE in chronic filarial sera using ELISA. Underin vitroconditions, ScDSP resulted in increased effector function of human eosinophils when stimulated by IgG, which showed a further decrease with increasing enzyme concentration. Results presented here suggest thatS. cerviDSP should be further studied to determine its role in pathogenesis and the persistence of filarial parasite.

In this study, mice (nonpermissive hosts) infected with Angiostrongylus cantonensis showed significant worm degeneration and eosinophil degranulation, whereas infected rats (permissive hosts) showed lower worm degeneration and eosinophil degranulation. Pathophysiological changes developed to a lesser extent in rat than in the mouse strains. Neurological evaluation of A. cantonensis-infected mice showed mechanical damage caused by worms migrating to the brain. A significant correlation between the proteolytic enzymes, plasminogen activator (PA) and matrix metalloproteinase-9 (MMP-9), and pathological changes was found in hosts with eosinophilic meningitis or meningoencephalitis. Also, the ratio of cerebrospinal fluid (CSF) to serum albumin was consistently increased in hosts with angiostrongyliasis as compared with control. These data clearly indicate that PA and MMP-9 proteolytic enzymes as well as pathological changes are different in permissive and nonpermissive hosts.

To assess whether mast cell and eosinophil (EOS) degranulation occurs in the airway of subjects with moderately symptomatic asthma, we have measured levels of preformed mast cell-derived mediators (histamine and tryptase) and EOS-derived mediators (major basic protein and EOS-derived neurotoxin) in bronchoalveolar lavage fluid (BALF) obtained from patients with symptomatic (N = 14) and asymptomatic asthma (N = 9) and patients without asthma (N = 6). Both the FEV1 (1.52 +/- 0.33 L:55% +/- 15% of predicted FEV1) and the forced expiratory flow at 50% (FEF50) (1.11 +/- 0.62 L/sec:26% +/- 14% of predicted FEF50) in the patients with symptomatic asthma were significantly lower than the corresponding values for FEV1 (3.16 +/- 0.45 L:86% +/- 10% of predicted FEV1) and the FEF50 (4.04 +/- 1.54 L/sec:71% +/- 25% of predicted FEF50) in the patients with asymptomatic asthma. Levels of histamine (4.8 +/- 5.0 ng/ml versus 0.2 +/- 0.2 ng/ml) (p = 0.05), EOS-derived neurotoxin (420.6 +/- 959.4 ng/ml versus 12.6 +/- 7.7 ng/ml) (p = 0.05), major basic protein (31.4 +/- 46.6 ng/ml versus less than 9 ng/ml) (p = 0.05), and percent EOSs (10.6% +/- 7.0% versus 1.1% +/- 0.9% of BAL cells) (p = 0.0006) were all significantly elevated in BALF from symptomatic compared to asymptomatic patients with asthma. The elevated levels of tryptase (13.2 +/- 14.8 ng/ml versus 3.9 +/- 3.9 ng/ml) in BALF from symptomatic compared to asymptomatic patients with asthma approximated, but did not reach, statistical significance. Spontaneous histamine release from BAL mast cells of symptomatic patients with asthma was 46% +/- 5% compared to 5% +/- 2% in asymptomatic patients with asthma. In response to antihuman IgE, histamine release from BAL mast cells recovered from asymptomatic patients with asthma increased to 25% +/- 10%, whereas in BAL mast cells of symptomatic patients with asthma, no anti-IgE potentiation of histamine release occurred. This study suggests that mast cell and EOS degranulation is ongoing in the airway of patients with moderately symptomatic asthma.

The secretion of preformed granule proteins by eosinophils is an important correlate of eosinophil activation. However, a review of the literature reveals large disparities in the amounts of these substances which were reportedly secreted when eosinophils were activated. In the present study we report that our attempts to quantitate the secretion of eosinophil peroxidase and eosinophil-derived neurotoxin from activated eosinophils by measuring these substances in the incubation supernatants were uniformly unsuccessful. We found that, once they were secreted, both eosinophil peroxidase and eosinophil-derived neurotoxin were promptly lost to assay and presumably destroyed. Thus the measurement of the difference in the concentration of these substances in eosinophils prior to and after activation, revealed that as much as 65% of the eosinophil-derived neurotoxin and 62% of the peroxidase in the eosinophils were lost to assay during activation of the cells whereas the largest amount of these substances which could be measured in the incubation supernatants never exceeded 2%. Evidence is presented that the destruction of eosinophil-derived neurotoxin must occur prior to the release of this substance into the medium. Attempts to inhibit the destruction of eosinophil peroxidase and of eosinophil-derived neurotoxin by incorporating various inhibitors into the incubations were unsuccessful. These results emphasize the need to monitor the overall recoveries of secreted products from activated eosinophils and suggest that meaningful estimates of the secretion of these granule proteins from activated eosinophils can only be obtained by measuring the residual content of these substances in eosinophils after they have been activated and comparing these values to the contents of eosinophils prior to activation.

Eosinophil granules contain cationic proteins, including the major basic protein, which are toxic to mammalian tissue. While eosinophils have been observed to comprise part of the inflammatory reaction in acute Helicobacter pylori gastritis, the role of the eosinophil in the pathogenesis of chronic gastritis is unknown. We evaluated whether eosinophil infiltration and degranulation are associated with chronic gastritis and H. pylori infection. We studied eight patients with chronic H. pylori antral gastritis, three with chronic antral gastritis in the absence of H. pylori, 11 healthy age-matched volunteers without antral gastritis, and eight patients with H. pylori-negative chronic specific gastritis (three Crohn's antral gastritis and five Ménétrier's disease). Serial sections were stained with hematoxylin and eosin, with Giemsa, and by a specific indirect immunofluorescence technique for eosinophil granule major basic protein. Specimens were graded independently by three observers and scores of 0-3 were given for eosinophil infiltration and degranulation (0 = none to 3 = confluent infiltration and/or degranulation). In H. pylori antral gastritis, significantly greater eosinophil infiltration and degranulation were found compared to the normal group, Ménétrier's disease, and chronic H. pylori-negative gastritis. There was no significant difference between gastric Crohn's disease and H. pylori gastritis. The severity of chronic gastritis was significantly correlated with the eosinophil score. Eosinophil degranulation did not appear to be greater at or near sites of bacterial colonization in the H. pylori gastritis specimens. The results suggest that eosinophil infiltration and degranulation may be associated with H. pylori gastritis. We postulate that the release of toxic cationic proteins from eosinophils contributes to the inflammatory changes present in H. pylori gastritis.

Because glucocorticoids are a mainstay in the treatment of asthma and other allergic diseases, we tested the effect of various steroid hormones on secretory IgA- and IgG-induced eosinophil degranulation in vitro. Human normodense eosinophils were purified by discontinuous Percoll density gradient, and hypodense eosinophils were obtained by culture of normodense cells with recombinant human interleukin (rIL)-5. Eosinophils were incubated with various steroids, including dexamethasone, hydrocortisone, methylprednisolone, estradiol, or dihydrotestosterone at concentrations from 10 −9 to 10 −4 mol/L. Sepharose 4B beads coupled to ovalbumin, secretory IgA, or IgG were added as targets of degranulation and incubated at 37 ° C for 4 hours. In some experiments, rIL-5 was added to eosinophils before addition of beads to activate the cells. The release of eosinophil-derived neurotoxin was measured by radioimmunoassay as an index of degranulation. Dexamethasone (10 −9 to 10 −4 mol/L), hydrocortisone (10 −9 to 10 −4 mol/L), estradiol (10 −9 to 10 −7 mol/L), and dihydrotestosterone (10 −9 to 10 −4 mol/L) had no effect on normodense eosinophil degranulation. Methylprednisolone, 10 −5 mol/L, inhibited degranulation of normodense eosinophils up to 20%, whereas 10 −4 mol/L inhibited degranulation of hypodense eosinophils, up to 30%, Overall, no difference in inhibition by steroids was observed between normodense and hypodense eosinophils. rIL-5 enhanced immunoglobulin-induced eosinophil degranulation, but this effect of rIL-5 was not blocked by any of the steroids tested. These results suggest that eosinophil degranulation and rIL-5-mediated eosinophil activation are not direct targets of glucocorticoids and that the beneficial effects of glucocorticoids on allergic inflammation in vivo are not likely due to direct effects on eosinophil degranulation.

Asthma is characterized as a chronic inflammatory disease of the airways. Of the inflammatory cells, macrophages, through IgE receptors, can be activated by allergens and possibly play a role in airway hyperresponsiveness and the late response. Glucocorticoids inhibit the release of mediators from alveolar macrophages, and beta-agonists do not have an effect. Glucocorticoids also inhibit eosinophil degranulation and, therefore, play an important role in decreasing or preventing the inflammation associated with chronic asthma. This report includes a comparison of the characteristics and capabilities of flunisolide, beclomethasone dipropionate, and triamcinolone acetonide, the inhaled glucocorticoids currently available in the United States. Emphasis is placed on this therapeutic category because some current treatment regimens for chronic bronchial asthma rely primarily on bronchodilator therapy, a factor that may be responsible for the observed rise in deaths due to asthma. Aerosol glucocorticoids are an ...

A case of eosinophilic myocarditis following high serum levels of eosinophil cationic protein (ECP) is described. A 27 year old woman was admitted with New York Heart Association (NYHA) class III congestive heart failure. A haematological study showed hypereosinophilia with degranulation and vacuoles; the total eosinophil count was 7980/ml and the ECP serum concentration was noticeably high at 150 ng/ml. Endomyocardial biopsy from the right ventricle showed infiltration of eosinophils and dense deposits of ECP in the endocardium as well as the myocardium. Steroid treatment returned the total eosinophil count and serum ECP to normal, with satisfactory improvement in clinical features. Eosinophilia may cause cardiac damage, and this report confirms that eosinophil degranulation is toxic. Thus, serum ECP seems to be a reliable indicator for diagnosis and for determining treatment parameters of eosinophilic myocarditis. Keywords: eosinophilic myocarditis; eosinophilia; eosinophil cationic protein; endomyocardial biopsy

Eosinophilic esophagitis (EoE) is characterized by medically/surgically-resistant gastroesophageal reflux symptoms and dense squamous eosinophilia. Studies suggest that histologic assessment of esophageal eosinophilia alone cannot reliably separate patients with EoE from those with gastroesophageal reflux disease (GERD). Our goal was to develop an assay to identify EoE patients and perhaps differentiate EoE from other causes of esophageal eosinophilia.A monoclonal antibody specific for an eosinophil secondary granule protein (eosinophil peroxidase [EPX]) was developed and shown to specifically identify intact eosinophils and detect eosinophil degranulation in formalin-fixed specimens. A histopathologic scoring algorithm was developed to analyze data from patient evaluations; the utility of this algorithm was assessed by using archived esophageal tissues from patients with known diagnoses of EoE and GERD as well as controls from 2 tertiary care centers.Intraobserver/interobserver blinded evaluations demonstrated a significant difference (P.001) between scores of samples taken from control subjects, from patients with esophageal eosinophilia who had a diagnosis of EoE, and from patients with GERD (P.001). This algorithm also was able to identify patients whose clinical course was suggestive of a diagnosis of EoE, but that nonetheless failed to reach the critical threshold number ofor =15 eosinophils in a high-power (40x) microscopy field.A novel immunohistochemical scoring system was developed to address an unmet medical need to differentiate histologic specimens from patients with EoE relative to those with GERD. The availability of a unique anti-EPX-specific monoclonal antibody, combined with the ease/rapidity of this staining method and scoring system, will provide a valuable strategy for the assessment of esophageal eosinophilia.

Finding of increased numbers of eosinophils in the muscle in cases of acute appendicitis has led to the hypothesis that it may have an allergic origin. This study aimed to measure the eosinophil degranulation resulting in a rise in the serum of eosinophil granule proteins that would be expected in such cases. The levels of serum eosinophil cationic protein (ECP) measured by chemiluminescence assay in acute appendicitis were compared, with those of appropriate controls. Mean (95% CI) serum ECP (microg/L) levels were: acute appendicitis 45.3 (27.7-63.0); normal appendix 22.7 (16.0-29.3); asthma 24.2 (4.6-43.8); and healthy volunteers 13.2 (8.3-18.1). In cases of acute appendicitis, there is an inverse relationship between duration of symptoms and serum ECP. However, this was not statistically significant. Significant local eosinophil activation and degranulation occurs in acute appendicitis, enough to cause a rise in serum levels of eosinophil chemotactic protein.

Eosinophil degranulation is thought to play a pathophysiological role in asthma. Rab27A is a GTP-binding protein that is known to be essential for the degranulation of several leukocyte subsets and thus may be essential for eosinophil granule exocytosis. Here, we show that Rab27A mRNA and protein are expressed in human eosinophils. We have developed a novel assay to assess Rab27A activation and have found a similar activation pattern of this protein upon stimulation of eosinophils, neutrophils and NK cells suggesting a similar function in these cell types. Interestingly, Rab27A expression was elevated in eosinophils from asthmatic donors. Furthermore, eosinophils from eosinophilic donors displayed more rapid Rab27A activation kinetics than those from donors with lower eosinophil counts. Given that elevated blood eosinophil numbers correlate with increased priming of eosinophils, this pattern of Rab27A activation suggests differential protein expression in activated cells may allow eosinophils to degranulate more rapidly upon stimulation.

Survival of parasitic helminths within a host requires immune evasion and excretorylsecretory (ES) proteins may contribute to this process. Eosinophils are important effector cells in immunity of mice to the nematode Nippostrongylus brasiliensis and eosinophilic interleukin-5 transgenic (IL-5 Tg) mice are highly resistant to the earliest stages of primary infections. In contrast, Toxocara canis is largely resistant to eosinophils, with viable larvae encysted in tissues often surrounded by these and other leucocytes. The aim of this study was to investigate whether T. canis ES (TES) proteins inhibit eosinophil-dependent resistance to N. brasiliensis. Mouse serum pre-treated with TES had reduced capacity to mediate the adherence of leucocytes to N. brasiliensis infective-stage larvae (L3) and this correlated with reduced complement C3 deposition on the parasite. TES did not inhibit eosinophil survival or eotaxin-dependent eosinophil migration in vitro. Cellular inflammation and eosinophil degranulation in the skin in response to injection of L3 was also not impaired by TES. However, when TES was included with L3 in an inoculum given to IL-5 Tg mice, a greatly increased number of parasites migrated to the lung. This suggests that the early eosinophil-dependent resistance in these mice was suppressed, by mechanisms yet to be determined. Refereed/Peer-reviewed

Eosinophils are pleiotropic multifunctional leukocytes involved in initiation and propagation of diverse inflammatory responses, as well as modulators of innate and adaptive immunity. In this review, the biology of eosinophils is summarized, focusing on transcriptional regulation of eosinophil differentiation, characterization of the growing properties of eosinophil granule proteins, surface proteins and pleiotropic mediators, and molecular mechanisms of eosinophil degranulation. New views on the role of eosinophils in homeostatic function are examined, including developmental biology and innate and adaptive immunity (as well as their interaction with mast cells and T cells) and their proposed role in disease processes including infections, asthma, and gastrointestinal disorders. Finally, strategies for targeted therapeutic intervention in eosinophil-mediated mucosal diseases are conceptualized.

We have used fiberoptic bronchoscopy to obtain endobronchial biopsies in which mast cells and eosinophils were enumerated using monoclonal antibodies directed against mast cell tryptase (AA1) and the eosinophil cationic protein (EG2). Eleven symptomatic atopic asthmatics treated with beta 2-agonists alone and six normal subjects were studied. Over a period of 2 wk prior to bronchoscopy, patients recorded asthma symptom scores, bronchodilator usage, and twice-daily peak expiratory flow. Five days before bronchoscopy, methacholine responsiveness was assessed. Two biopsies were taken from the subcarinae, one of which was processed into araldite for immunostaining by the streptavidin biotin immunoperoxidase method and the other into Spurr resin for electron microscopy. The number of AA1 staining mast cells present in the bronchial mucosa was not significantly different in the epithelium or submucosa between the asthmatic and the normal subjects. However, in the biopsies from asthmatics, there were significantly greater numbers of EG2-staining eosinophils in the epithelium (median, 1.2/mm versus zero; p less than 0.005) and in the submucosa (median, 50/mm2 versus 1/mm2; p less than 0.001). Electron microscopy showed morphologic features of mast cell and eosinophil degranulation in the asthmatics. No correlation could be established between mast cell or eosinophil numbers and indices of disease activity of PC20 methacholine, which points to the complexity of mechanisms responsible for the symptoms and the airway hyperresponsiveness of asthma.

We report on a series of three patients with an unusual syndrome of eosinophilia and myalgia associated with the oral ingestion of tryptophan that was recognized in New Mexico in October 1989. All three patients, who were women 37 to 44 years of age, had severe muscle pain, muscle weakness, mouth ulcers, and striking eosinophilia (more than 8 X 10(9) cells per liter). Other manifestations included fever, abdominal pain, dyspnea, skin rash, and elevated serum concentrations of aminotransferase and aldolase. The women had been taking tryptophan in doses of 1.2 to 2.4 g a day for three weeks to 2 1/2 years. The discontinuation of tryptophan and the initiation of glucocorticoid treatment resulted in improvement, but all three women were still symptomatic three to five months later. Tests for trichinosis and other parasites and for allergic and connective-tissues disorders were negative, and serum immunoglobulin concentrations and erythrocyte sedimentation rates were normal. A muscle biopsy in one patient and biopsies of the vagina, liver, and other abdominal organs in another revealed eosinophilic infiltration, as well as the extracellular deposition of eosinophil-granule major basic protein. All three patients had elevated serum and urinary levels of this protein and eosinophil-derived neurotoxin, indicative of eosinophil degranulation. The syndrome of eosinophilia and myalgia in association with the ingestion of tryptophan that was seen in these three patients is a newly recognized adverse effect of tryptophan ingestion. Our identification of this association in these patients led to the discovery of an epidemic of what is now called the eosinophilia-myalgia syndrome.

The wheal-and-flare response to intradermal autologous serum in chronic urticaria offers a model for study of the pathogenesis of the disorder. Serial biopsies of autologous serum induced wheals were performed in 5 chronic urticaria patients to assess the evolution of the cellular inflammatory response and to look for evidence of mast cell degranulation. Perivascular neutrophils and eosinophils were seen as early as 30 min, becoming more intense and diffuse over 2 h. T lymphocyte numbers were increased by 2 h, CD4+ cells outnumbering CD8+ cells at 24 h. By 48 h, the neutrophils were clearing, but eosinophils and lymphocytes persisted. The histology of compound 48/80-induced wheals was similar to serum-induced wheals, but there was little or no response to physiological saline (0.16 M). Stainable mast cells were reduced in compound 48/80- and serum-induced wheals when compared to saline skin tests. Mast cell granules appeared swollen and had lost their characteristic lamellar substructure on electron microscopy of a serum-induced wheal biopsied at 10 min. Eosinophil degranulation was also observed at 2 h. The resemblance of the inflammation to the late phase of IgE-mediated immediate hypersensitivity reactions in atopies supports the concept that a circulating factor causes mast cell degranulation in chronic urticaria and may be important in the pathogenesis of the disorder.

The aims of the current study were to determine the activation states of antral eosinophils and mast cells and to evaluate the interactions of antral inflammatory cells with gastric emptying and electrogastrography (EGG) in 30 pediatric patients with functional dyspepsia. Eosinophil degranulation was moderate in 42% and extensive in 54% of patients. Mast cell degranulation was >50% in 81% of patients. Elevated mast cell density was associated with slower one hour gastric emptying and increased preprandial dysrhythmia. Mast cell density correlated with the preprandial percentage tachygastria. CD3+ cell density correlated with the preprandial percentage tachygastria also, but only in patients with increased eosinophil density. In conclusion, antral eosinophils and mast cells are significantly activated in pediatric functional dyspepsia. Mast cell density is associated with delayed gastric emptying and preprandial dysrhythmia, suggesting that there may be an interaction between antral inflammation and gastric electromechanical dysfunction in the pathophysiology of pediatric functional dyspepsia.

Since diethylcarbamazine at the dosages used to treat filarial infections has little direct toxicity, most of the post-treatment reactions (termed Mazzotti reactions in onchocerciasis) result from the immunological inflammatory mechanisms activated in the process of clearing and killing the skin-swelling or blood-borne microfilariae. These reactions may be either localized to the skin, eyes or lymphatics or generalized systemically (e.g. headache, fever, adenopathy, arthralgia, tachypnoea, tachycardia, hypotension and even death). The occurrence and intensity of such reactions can be shown to be related to the intensity of infection. It had previously been speculated that the best candidates for triggering these post-treatment reactions were activation of complement, immediate hypersensitivity responses mediated by immunoglobulin E, and degranulation of eosinophils with resultant inflammatory reactivity. Recent detailed studies have given little support to the primacy of either complement or immediate hypersensitivity responses in triggering such reactions, but eosinophil degranulation with the release of inflammatory mediators into the tissues and peripheral blood is extremely prominent in all patients undergoing post-treatment reactions and develops with a time course generally consistent with what would be required of an initiator of such reactions. Other inflammatory mediators and pathways may be involved (e.g. kinins, prostaglandins, immune complexes, leukotrienes, platelets and parasite-derived inflammatory molecules), but there is currently no evidence to implicate any of these mechanisms as initiators of the response. Symptomatic treatment of these post-treatment reactions with analgesics, antipyretics, antihypotensive agents etc. has been successful, but their prevention has been achieved only with the broadly anti-inflammatory corticosteroids.