Eosinophilia

2B4 (CD244) is involved in eosinophil adhesion and chemotaxis, and its surface expression is increased in allergic rhinitis after challenge

A role for the subtypes of CD2 Ig superfamily receptors has been recently demonstrated in eosinophilic inflammation in experimental asthma and atopic asthmatics. We investigated the functions of 2B4 (CD244) molecules in eosinophil adhesion and chemotaxis, and correlated the results to the pathophysiology of allergic rhinitis (AR). Herein, we show that agonistic stimulation of 2B4 by C1.7, the anti-human 2B4 functional grade purified antibody, resulted in significant increase of eosinophils and eosinophil cell line (Eol-1 cells) adhesion to collagen type IV, and random migration. These functions were associated with tyrosine kinase phosphorylation of several protein residues of low molecular weight. Flow cytometry (FACS) experiments demonstrated that Eol-1 cells, normal peripheral blood eosinophils and eosinophils from AR patients, express surface 2B4 molecules. In vitro AR model demonstrated that the CC-chemokine receptor CCR3 stimulation by eotaxin induced significant increase in the expression of surface 2B4 in eosinophils and Eol-1 cells. Immunofluorescence confocal microscopy images showed that eotaxin induces also redistribution of 2B4 molecules towards the pseudopods in eosinophils and Eol-1 cells, changing their shape. Blocking of 2B4 molecules by the corresponding neutralizing antibody inhibited eotaxin induced Eol-1-adhesion, chemotaxis and the cytoskeleton changes. Pretreatment of Eol-1 cells with 1 microM genistein blocked eotaxin-induced Eol-1 adhesion, chemotaxis and 2B4 up-regulated expression. In vivo correlation demonstrated the expression of 2B4 molecules in eosinophils from AR patients to be significantly increased, after nasal provocation challenge. These results identify a novel role for 2B4 molecules in eosinophil functional migratory response and may point to a novel tyrosine kinase-mediated ligation between CCR3 receptor and 2B4 co-receptor in eosinophil chemotaxis. If so, then 2B4 molecules would be a novel target for therapeutic modalities in diseases characterized by eosinophilia such as AR.

Nutritional status according to sensitized food allergens in children with atopic dermatitis

PURPOSE

Food allergies can affect the growth and nutritional status of children with atopic dermatitis (AD). This study was conducted to determine the association between the number of sensitized food allergens and the growth and nutritional status of infants and young children with AD.

METHODS

We studied 165 children with AD, aged 5 to 47 months, and who visited the Atopy Clinic of the Seoul Medical Center. We recorded the birth weight, time at which food weaning began, scoring of atopic dermatitis (SCORAD) index, eosinophil counts in peripheral blood, and total serum IgE and specific IgE to six major allergens (egg white, cow's milk, soybean, peanut, wheat, and fish). The height and weight for age and weight for height were converted to z-scores to evaluate their effects on growth and nutritional status. Specific IgE levels ≥0.7 kUA/L, measured via the CAP assay, were considered positive.

RESULTS

As the number of sensitized food allergens increased, the mean z-scores of weight and height for age decreased (P=0.006 and 0.018, respectively). The number directly correlated with the SCORAD index (r=0.308), time at which food weaning began (r=0.332), eosinophil counts in peripheral blood (r=0.266), and total serum IgE (r=0.394). Inverse correlations were observed with the z-scores of weight for age (r=-0.358), height for age (r=-0.278), and weight for height (r=-0.224).

CONCLUSIONS

A higher number of sensitized food allergens was associated with negative effects on the growth and nutritional status of infants and young children with AD. Therefore, a thorough evaluation of both growth and nutritional status, combined with adequate patient management, is crucial in pediatric AD patients presenting with numerous sensitized food allergies.

[Heart and freezer: about one case of hypereosinophilia and coronary spasm]

We report the case of a 41-year-old woman, non-smoker, without cardiovascular risk, hospitalised for acute ST elevation myocardial infarction. The coronarography showed no significant coronary stenosis and a methylergometrine test performed was positive. After the discovery of a moderate chronic hypereosinophilia, a review of the literature about eosinophile and coronary pathology was realised in order to make a link between hypereosinophilia and coronary spasm.

Leukocytosis and blood eosinophilia in a polyparasitised population in north-eastern Brazil

It has long been known that leukocytosis and blood eosinophilia are common in the tropical environment, but data derived from population-based studies are scarce. A study was undertaken in a fishing village in north-east Brazil where both intestinal helminthiases and parasitic skin diseases are common. Of 409 individuals studied, 128 (31.3%) were infected with one intestinal helminth or ectoparasite species, 93 (22.7%) with two, 61 (14.9%) with three, 25 (6.1%) with four and 11 (2.7%) with more than four species; no parasites were found in 91 (22.2%) individuals. Leukocyte counts ranged between 3,300 cells/microl and 16,100 cells/microl (median, 7,200 cells/microl) and eosinophil counts between 40 cells/microl and 5,460 cells/microl (median, 455 cells/microl). Eosinophilia (>500/microl) was detected in 44.7% of the individuals, and hypereosinophilia (>1,000/microl) in 12.9%. Thirty-six (8.8%) individuals showed leukocytosis. While 75% of individuals with normal eosinophil counts were considered parasite-free, only 14% with eosinophilia and 11% with hypereosinophilia did not have enteroparasites or ectoparasites. Multivariate regression showed that the probability of eosinophilia and hypereosinophilia, but not of leukocytosis, increased with the number of parasite species present. The data show that eosinophilia occurs in almost one-half of the individuals from a resource-poor setting and that it is significantly associated with the presence of intestinal helminths, but not with the presence of ectoparasites.

Clinical evaluation of changes in the morphology of eosinophils

In order to diagnose and monitor patients with allergic diseases, we studied parameters which reflect not only the amount of eosinophils but also their state of activation. Morphologic features reveal additional information on the activity state of eosinophils. The number of nuclear lobes, cell size, amount of vacuoles and density of specific granules are considered characteristic features of eosinophils. We conclude that the size of eosinophils is a useful parameter to distinguish patients with and without eosinophilia. The treatment with corticosteroids did not affect morphological characteristics such as the number of vacuoles, granulation density, cell diameter and the nucleus/cell surface ratio, but the number of lobes per nucleus, a marker of eosinophil maturation, decreased significantly.

Novel association of the src family kinases, hck and c-fgr, with CCR3 receptor stimulation: A possible mechanism for eotaxin-induced human eosinophil chemotaxis

The chemokine eotaxin is a potent and relatively eosinophil-specific chemoattractant implicated in the cell migration to inflammatory sites in allergic diseases. Eotaxin exerts its activity solely through the CCR3 receptor, but the signaling pathways are poorly defined. In this study, we show that eotaxin induces an increase in tyrosine phosphorylation of multiple cellular proteins in normal human eosinophils. Eotaxin-dependent tyrosine phosphorylation was detected 1 min after stimulation and increased for at least 15 min with kinetics similar to those of eotaxin-induced cell shape changes. Herbimycin A, a tyrosine kinase inhibitor, blocked both eotaxin-induced tyrosine phosphorylation and cell shape changes as well as chemotaxis. Immunofluorescence microscopy analyses showed that eotaxin-induced cell shape changes were accompanied by redistribution of tyrosine-phosphorylated proteins and F-actin reorganization that were sensitive to herbimycin A. Coimmunoprecipitation studies revealed that binding of eotaxin to CCR3 greatly enhanced association of the Src family kinases, Hck and c-Fgr, with CCR3 after internalization of CCR3. These results may indicate that recruitment of Hck and c-Fgr to CCR3 in a compartment triggers tyrosine phosphorylation, leading to rapid cell shape changes required for cell migration.

Multiple epithelial cell-derived factors enhance neutrophil survival. Regulation by glucocorticoids and tumor necrosis factor-alpha

We examined the potential of several epithelial-derived factors to enhance neutrophil activation and survival. Neutrophils incubated in the presence of supernatants from nasal-derived primary epithelial cultures had significantly increased survival compared with neutrophils cultured in media alone. Of the cytokines reported to enhance neutrophil survival, transcripts for interleukin (IL)-1alpha, IL-1beta, IL-6, and granulocyte macrophage colony-stimulating factor (GM-CSF) (but not interferon-gamma or granulocyte colony-stimulating factor [G-CSF]) were detected by ribonuclease protection assay in basal and tumor necrosis factor (TNF)-alpha- stimulated epithelial cells. Of the eicosanoid products that enhance neutrophil survival, platelet-activating factor and leukotriene B(4) were not detected in the supernatants, whereas prostaglandin E(2) (PGE(2)) was produced in modest amounts. The levels of IL-6, GM-CSF, and PGE(2) in epithelial supernatants were significantly increased after transient TNF-alpha stimulation. This induction was suppressed if dexamethasone (Dex) was added during TNF-alpha stimulation. Only IL-6, GM-CSF, and PGE(2) promoted neutrophil survival over the range of concentrations detected in the supernatants, and a combination of neutralizing antibodies to GM-CSF and IL-6 completely inhibited the enhanced neutrophil survival in epithelial supernatants. Both the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique and morphologic scoring of apoptotic neutrophils confirmed that epithelial supernatants, as well as purified IL-6, GM-CSF, and PGE(2) all delayed neutrophil apoptosis. Finally, the effects of Dex on neutrophil survival and on epithelial cytokine production were investigated. Dex independently prolonged neutrophil survival but suppressed epithelial production of survival-enhancing factors in a dose-dependent manner. The net effect of Dex appeared to favor neutrophil survival.

IL-4 Induces Eotaxin: A Possible Mechanism of Selective Eosinophil Recruitment in Helminth Infection and Atopy

A common feature of some parasitic infections and allergic and atopic skin diseases is the involvement of Th2 lymphocytes and the dermal appearance of eosinophils (Eos). Because Th2 lymphocytes apparently do not release Eo attractants, we addressed the question of whether the Th2 cytokine IL-4 induces its production in dermal fibroblasts. We therefore stimulated fibroblasts with IL-4. HPLC investigation of supernatants revealed a single Eo chemotactic protein, which was purified to homogeneity giving a single 13-kDa band upon SDS-PAGE analyses. Peptide mapping with subsequent amino acid sequencing revealed an Eo-selective chemotaxin, which consists of a mixture of N-terminally truncated and O-glycosylated forms of the chemokine eotaxin. Other chemokines such as RANTES, MCP-3, MCP-4, or MIP-1α were not detected as Eo chemotaxins under these conditions. Using reverse transcriptase-PCR techniques, we found that IL-4 dose and time dependently induces eotaxin mRNA in dermal fibroblasts. Stimulation with IL-4 and TNF-α caused a 10- to 20-fold increase of the release of three biochemically different eotaxin forms, each consisting of a mixture of N-terminally truncated and O-glycosylated variants having the same backbone amino acid sequence but different specific activities. Our findings support the hypothesis that eosinophil recruitment seen in IL-4-mediated skin reactions, at least in part, may be due to Th2 cytokine-mediated induction of eotaxin in dermal fibroblasts.

Elevated intracellular cyclic AMP inhibits chemotaxis in human eosinophils

Elevated intracellular cyclic AMP is associated with the inhibition of many inflammatory cellular responses. In this study, we examined the effect of cyclic AMP on eosinophil chemotaxis. Eosinophils were isolated from healthy human volunteers using an immunomagnetic method. Eosinophils were treated with agents that elevate intracellular cyclic AMP and evaluated for chemotactic responses to platelet-activating factor (PAF; 10(-6) M) and to complement factor 5a (C5a; 10(-8) M) in microchemotaxis chambers. Forskolin, prostaglandin E1 (PGE1), and a phosphodiesterase (PDE) IV-selective inhibitor inhibited eosinophil chemotactic responses. The mean per cent inhibition of eosinophil chemotaxis in response to PAF by forskolin, PGE1, and the PDE IV-selective inhibitor (10(-5) M) was 16.8 +/- 5.3, 26.6 +/- 9.5, and 35.1 +/- 6.1%, respectively (n = 5). The corresponding values for C5a were 17.5 +/- 7.9, 20.8 +/- 10.7, and 39.5 +/- 5.0%. An exogenous cyclic AMP analogue (dibutyryl cyclic AMP, 10(-3) M) also inhibited eosinophil chemotaxis by 69.4 +/- 12.8 and 66.9 +/- 11.6% in response to PAF and C5a, respectively (n = 5). We conclude that elevated intracellular cyclic AMP inhibits eosinophil chemotaxis.

Host factors and environmental determinants associated with skin test reactivity and eosinophilia in a community-based population study

We examined the relationship of host factors (age, gender) and environmental determinants (smoking status, area of residence) to indicators of allergy (skin test reactivity and eosinophil count) in a random population sample in the Netherlands. Positive skin test reactivity was associated with age (decreasing with increasing age), with male gender (versus female gender), and with urban residence (versus rural residence). Positive skin test reactivity was not associated with smoking. Elevated eosinophil counts were associated with male gender (versus female gender), with urban residence (versus rural residence), and with current smoking (versus never smoking). Elevated eosinophil counts were not clearly associated with age (if adjusted for the age-related effects of skin test reactivity). Additionally, this study specifically demonstrates that skin test reactivity increases with increasing eosinophil count and vice versa, indicating that the two traits are interrelated. Furthermore, this interrelationship was demonstrated to be age-dependent (decreasing with increasing age).

Eosinophilia caused by parasites

Eosinophilia is defined as an absolute count of > 500 eosinophils per mm3 of peripheral blood. Eosinophilia is associated with many disorders, limiting its usefulness as a diagnostic tool in screening expatriates for parasite infections. In addition, only tissue-invasive helminthic parasites cause eosinophilia, which limits its general application as a screening tool for parasitic infections. Because eosinophilia may resolve spontaneously over time, the life cycle of parasites must be considered when evaluating eosinophilic patients, and repeated stool examinations or appropriate serology may be necessary to make the correct diagnosis. Future work on the risks associated with subclinical parasite infections would be helpful to place eosinophilia and other screening tests in proper perspective. Referral of difficult cases to specialists in travel medicine should be considered because detailed information about the geographic distribution and life cycle of helminthic parasites is often crucial to making the correct diagnosis.

Characterization of the non-apparent clinical form in the initial phase of schistosomiasis mansoni

In this paper the history of 115 recruits that had bathed simultaneously in streams contaminated with Schistosoma mansoni, during military maneuvers, is reported. Thirty four of the infected patients presented the initial phase of the infection diagnosed through epidemiologic, clinical and laboratory parameters. Three out of the 34 patients did not reveal the clinical picture of the infection, thus being considered representatives of the non-apparent form of the disease. Differences between the intensity of blood eosinophilia, the area of immediate cutaneous reaction and the number of Schistosoma eggs eliminated in the stools proved not to be statistically significant (p > 0.05) when the non-apparent and acute cases of schistosomiasis were compared. These cases actually may be considered evidences of the non-apparent form hitherto merely taken for granted in the literature.

Ischemia/reperfusion-induced feline intestinal dysfunction: importance of granulocyte recruitment

Although previous studies have reported that neutrophils play an important role in mediating the microvascular injury observed after reperfusion of ischemic intestine, the contribution of these phagocytic cells to the mucosal dysfunction remains unclear. Three series of experiments consisting of an untreated group, a short-term monoclonal antibody (MAb) IB4 treatment group (MAb IB4 given on the day of the experiment), and a long-term MAb IB4 treatment group (3-day pretreatment with MAb IB4) were performed using autoperfused segments of cat ileum exposed to 3 hours of ischemia followed by 1 hour of reperfusion. Mucosal myeloperoxidase activity, an index of mucosal granulocyte levels, increased from 12 to 25 U/g wet wt in the untreated group. In the short-term MAb IB4 experiments, baseline values were very similar to those of the untreated group but no increase in myeloperoxidase activity was observed after ischemia/reperfusion. Long-term pretreatment with MAb IB4 reduced baseline values of myeloperoxidase activity to approximately 1 U/g wet wt; the values remained at this level throughout the experiment. The permeability of the mucosal barrier was quantitated by measuring blood-to-lumen clearance to 51Cr-ethyl-enediaminetetraacetic acid (EDTA). The water absorptive capacity of the intestine was also measured. In the untreated group, mucosal permeability to 51Cr-EDTA increased sixfold and water absorption was abolished after reperfusion. Both short-term and long-term administration of MAb IB4 prevented the net fluid loss into the lumen, but only long-term administration of MAb IB4 blunted the increased mucosal permeability induced by ischemia/reperfusion. These data suggest that interstitial granulocytes contribute significantly to the mucosal dysfunction associated with reperfusion of the ischemic intestine.

Eosinophil cationic protein in peripheral blood of pediatric patients with allergic diseases

We have studied the levels of eosinophil cationic protein (ECP) and tumour necrosis factor (TNF) in peripheral blood obtained from 68 children with bronchial asthma and 11 children with atopic dermatitis. The ECP mean concentrations of the patients were 23.7 +/- 21.4 micrograms/l and 21.2 +/- 18.7 micrograms/l for bronchial asthma and atopic dermatitis respectively, which were significantly higher than the control value, 5.8 +/- 2.3 micrograms/l (P less than 0.005). TNF was unmeasurable in almost all the samples and no significant difference was observed between normal controls and asthmatic children. A significant correlation was observed between serum levels of ECP and blood eosinophil counts in both diseases (r = 0.873; P less than 0.01 and r = 0.740; P less than 0.01, respectively). However, no obvious correlation was observed between serum levels of ECP and IgE levels. ECP levels were significantly reduced by treatment and normalized in parallel with blood eosinophil counts in the patients with total IgE levels less than 800 U/ml. Irrespective of the total IgE levels, the reduction of serum ECP levels was correlated with a decrease in the number of asthmatic attacks and/or improvement of pulmonary function. These results suggest that the ECP levels in peripheral blood indicate an increased activity of eosinophil and would be a more useful marker than eosinophil counts for making clinical analyses and estimating treatment efficacy in paediatric patients with allergic diseases.

Eosinophil colony-stimulating factor induced by administration of interleukin-2 into the pleural cavity of patients with malignant pleurisy

Systemic administration of interleukin (IL)-2 to patients with malignant diseases induces peripheral eosinophilia. In the present study, to clarify the mechanism of eosinophilia induced by IL-2, we examined the changes in the number of eosinophils and eosinophil colony-stimulating factor (Eo-CSF) activity in the pleural fluids of six patients with malignant pleurisy caused by lung cancer or malignant mesothelioma during and after intrapleural administration of IL-2. Results showed that intrapleural administration of IL-2 induced marked eosinophilia in the pleural fluid and moderate eosinophilia in the peripheral blood, and that during IL-2 administration, marked Eo-CSF activity appeared in the pleural fluid before increase in the number of eosinophils, but that this activity did not appear in the peripheral blood. This Eo-CSF activity was inhibited by a combination of anti-IL-5 antibody, anti-IL-3 antibody, and anti-granulocyte/macrophage colony-stimulating factor (anti-GM-CSF) antibody, but not by each antibody alone. Chemotactic activity for eosinophils was also detected in the pleural fluid during IL-2 treatment. These results suggest that eosinophilia in the pleural fluid induced by IL-2 injection into the pleural cavity of patients with malignant pleurisy is due to the Eo-CSF activities of various components, including IL-5, IL-3, and GM-CSF, and chemotactic factors for eosinophils induced locally in the pleural cavity by IL-2.

The relationship of eosinophilia and positive skin test reactivity to respiratory symptom prevalence in a community-based population study

We studied the relationship of the prevalence of a variety of respiratory symptoms to positive skin test reactivity (skin test index greater than or equal to 3) and/or eosinophilia (greater than or equal to 275 eosinophilic cells per cubic millimeter of blood) in a community-based population sample (N = 2805), adjusting for age, gender, area of residence, and cigarette smoking. We considered subjects with neither positive skin test reactivity nor eosinophilia to be the reference group. Positive skin test reactivity without eosinophilia (N = 487; 17.3%) was significantly associated with persistent wheeze (odds ratio value (OR) = 1.6; 95% confidence interval of the odds ratio value (CI) = 1.0 to 2.6) and with asthmatic attacks (OR = 3.2; CI = 2.0 to 5.3). Positive skin test reactivity in combination with eosinophilia (N = 92; 3.3%) was also significantly associated with persistent wheeze (OR = 2.7; CI = 1.2 to 6.0) and with asthmatic attacks (OR = 10.4; CI = 5.3 to 20.2), however, with a stronger association than in subjects with positive skin test reactivity alone. Finally, eosinophilia without positive skin test reactivity (N = 170; 6.1%) was significantly associated with chronic cough (OR = 1.8; CI = 1.2 to 2.7), bronchitis episodes (OR = 2.1; CI = 1.4 to 3.2), dyspnea grade greater than or equal to III (OR = 1.7; CI = 1.0 to 2.8), and asthmatic attacks (OR = 3.0; CI = 1.5 to 6.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Differential sensitivities of purified human eosinophils and neutrophils to defined chemotaxins

Functions of eosinophils and neutrophils isolated from normal human blood were determined by measuring chemotactic migration and release of beta-glucuronidase. Four well-characterized chemotaxins, the complement fragment C5a, formyl-methionyl-leucyl-phenylalanine (FMLP), platelet-activating factor (PAF), and leukotriene B4 (LTB4) were used as stimuli. Neutrophils showed remarkable chemotactic responses to all four chemotaxins. In contrast, eosinophils showed a significant chemotactic response to C5a and PAF, but only weak responses to FMLP and LTB4. Using these chemotaxins we found the following order of chemotactic potency (maximal number of migrated cells): C5a = LTB4 greater than FMLP greater than PAF for neutrophils and PAF = C5a greater than LTB4 = FMLP for eosinophils. Neutrophils elicited a significant beta-glucuronidase release when stimulated by C5a and FMLP, whereas only small amounts were released with PAF and LTB4. On the other hand, an amount of beta-glucuronidase released from eosinophils comparable to that from neutrophils was elicited only with C5a. FMLP, LTB4, and PAF caused the release of small percentages of beta-glucuronidase. The important cellular functions of eosinophils and neutrophils, chemotaxis and enzyme release, are thought to be controlled by differential responsiveness to stimuli.

Induction of interleukin-4-dependent IgE synthesis and interleukin-5-dependent eosinophil differentiation by supernatants of a human helper T-cell clone

The human alloreactive T-cell clone A1 produces interleukin (IL)-4, IL-5, and granulocyte macrophage-colony stimulating factor (GM-CSF), but not IL-2 or interferon-gamma (IFN-gamma), as assessed by probing for mRNA transcripts, immunoassays, or bioassays. Supernatants from clone A1 induced IgE synthesis by normal human peripheral blood mononuclear cells. IL-4 was shown to be necessary and sufficient for the induction of IgE by clone A1 supernatants. In contrast, IgE induction by clone A1 supernatants and recombinant (r) IL-4 was inhibited by IFN-gamma. This suggests that the absence of IFN-gamma from the IL-4-containing A1 supernatants was important for their IgE-inducing ability. Supernatants from clone A1 could also specifically induce the growth of cord blood cell progenitors and their differentiation into eosinophils but not into basophils. rIL-5, but not rIL-4 or rGM-CSF, also induced eosinophil maturation. These data suggest that IL-5 secreted by clone A1 was responsible for its ability to induce eosinophil differentiation. The implications of the concomitant production of IL-4 and IL-5 by a single T-cell clone are discussed.

Inhibitory effect of oral cetirizine on in vivo antigen-induced histamine and PAF-acether release and eosinophil recruitment in human skin

The use of a noninvasive skin chamber technique in vivo in pollen-sensitive patients allowed us to quantify the time-course release of histamine and the recruitment of inflammatory cells (i.e., neutrophils, monocytes, and eosinophils) in skin sites challenged with pollen, histamine, and compound 48/80. The new H1-receptor antagonist, cetirizine 2 HCl, orally administered with 10 mg once a day to pollen-sensitive patients in a double-blind, crossover study versus placebo, induced a significant decrease in the wheal-and-flare cutaneous reaction induced by intradermal injection of pollen, histamine, and compound 48/80. It also significantly inhibited the immediate histamine release occurring in skin chambers after pollen introduction, whereas it did not significantly inhibit the late release. In patients receiving placebo, we detected platelet-activating factor-acether in media collected at the sixth hour from chambers filled with pollen. With cetirizine 2 HCl treatment, platelet-activating factor-acether was not detected in chamber media. Interestingly, cetirizine 2 HCl significantly reduced the eosinophil recruitment observed on the superficial dermis 24 hours after pollen challenge.

Ultrastructural and morphometric analyses of eosinophils from the cerebrospinal fluid of the mouse and guinea-pig infected with Angiostrongylus cantonensis

Guinea-pigs infected with Angiostrongylus cantonensis developed pleocytosis and eosinophilia in the cerebrospinal fluid (CSF) at day 12 post-infection (p.i.), showing a peak response at day 20 p.i., followed by a gradual reduction. Ultrastructural observations on CSF eosinophils from infected mice and guinea-pigs revealed various signs of eosinophil degranulation after day 14 p.i., suggesting the exocytosis of lysosomal material. Morphometric analysis indicated that CSF eosinophils after day 22 p.i. contained fewer granules as well as smaller granules than those at days 14-20 p.i. These data suggest that CSF eosinophils release granule constituents into the outside of the cells and these secretion products could interact with the intracranial worms and are probably related to worm death. As degenerative atrophy or partial loss of Purkinje cells and the spongy vacuolation of the white matter were noted in the cerebellum of infected mice, it was suggested that CSF eosinophils could be a possible cause of neurological disorders in angiostrongyliasis cantonensis.

Comparative study of eosinophil purification on Nycodenz, Metrizamide and Percoll density gradients

Studies on the metabolism of human eosinophils and their interaction with helminthic parasites have been hampered by the difficulty in obtaining these granulocytes in sufficient purity and quantity. In this report, we describe for the first time the application of the density medium Nycodenz for the purification of eosinophils from peripheral blood. Nycodenz density gradient centrifugation is compared with Percoll and metrizamide gradient centrifugation with special emphasis on cell yield, purity of cell suspensions, and functional integrity of separated cells. Percoll gradients provide purer preparations (mean value 94 +/- 15%) of eosinophils from blood with moderate eosinophilia than Nycodenz or Metrizamide (58 +/- 29 and 88 +/- 13%, respectively). The recovery rates of eosinophil-enriched fractions were low after Nycodenz centrifugation (29 +/- 19%) in comparison to Metrizamide (60 +/- 21%) or Percoll (70 +/- 16%). Eosinophils (as neutrophils), prepared by the 3 techniques, function metabolically (superoxide anion generation) and in assays measuring phagocytosis (S. aureus, zymosan particles). Percoll gradient isolated eosinophils (as neutrophils) adhere to and immobilize larvae of Onchocerca volvulus.

The idiopathic hypereosinophilic syndrome

A 14 year old girl with idiopathic hypereosinophilic syndrome is described. In addition to weight loss, anaemia, amenorrhoea, general lethargy, anorexia, mouth ulcers, blisters of hands and feet, and petechial skin rash, she had features of involvement of the cardiovascular system as the major complication. She responded well to treatment. After a comprehensive search of the published reports 18 cases of this syndrome were identified in children under 16 years. Fifteen of these children had involvement of the cardiovascular system as the major source of their morbidity and mortality. Summary of the clinical details and laboratory, biopsy, and necropsy findings of the involvement of the various organ systems of the 18 children is presented.

Classification of myositis. Correlations between morphological and clinical classifications of inflammatory muscle disease

Insufficient clinical data given to pathologists often hamper the differentiation of inflammatory muscle diseases. Thus we proved the value of a classification based only upon morphological criteria. Among 160 biopsies with myositic pattern (4.9% of a series of 3264 muscle biopsies) we could distinguish the following groups: Interstitial inflammation with only few fibre necroses (17.6%), predominance of fibre necroses with few inflammatory infiltrates (38.1%), small vessel vasculitis (20.0%), arteritis (13.1%), granulomatous myositis (8.8%) and polymorphonuclear leukocytic infiltrates (2.6%). This classification is compared with the used clinical diagnoses. Some special morphological aspects (histometric and immunocytologic examinations, tissue calcification, inclusion bodies, neurogenic atrophies) are analysed and so are some clinical peculiarities (e.g. malignoma-association, differentiation of mixed connective tissue syndrome, drug-induced reactions). The diagnostic value of purely morphologic criteria is restricted. For better diagnostic work a great number of clinical informations is required. Nevertheless, certain morphological patterns give important directions, e.g. to occult malignoma.

Platelet-activating factor. A potent chemotactic and chemokinetic factor for human eosinophils

Platelet-activating factor (PAF-acether), an inflammatory mediator with a wide range of biological activities including neutrophil aggregation and chemotaxis, was studied for its effect on human eosinophil locomotion (chemotaxis and chemokinesis). Human eosinophils (25-95% purity) were obtained from donors with a variety of diseases associated with hypereosinophilia. PAF-acether elicited directional locomotion of eosinophils, in a time- and dose-dependent fashion, at concentrations from 10(-5) to 10(-8) M; lyso-PAF had minimal activity over the same dose range. Compared with PAF-acether, the eosinophil locomotory responsiveness of leukotriene B4 (LTB4), histamine, and the valyl- and alanyl-eosinophil chemotactic factor of anaphylaxis (ECF-A) tetrapeptides was negligible. Conversely, neutrophil responsiveness to PAF-acether (optimum 10(-6) M) was comparable in effect to LTB4 (optimum dose 10(-8) M). It was shown that PAF-acether elicited both chemotaxis and chemokinesis of eosinophils. Comparison of normal density and light density eosinophils revealed no qualitative difference in the response to PAF-acether and the other chemoattractants, although the light density cells seemed to demonstrate a greater degree of locomotion to PAF-acether and LTB4. Thus, PAF-acether appears to be a potent eosinophilotactic agent which may play a role in inflammatory reactions characterized by eosinophil infiltration.

Leukotrienes cause eosinophil emigration into conjunctival tissue

The ability of LTB4, LTC4, the 5S,6R and 5R,6S LTD4 stereoisomers, and LTE4 to evoke leukocyte infiltration into the conjunctiva was demonstrated in the guinea pig by histological and light microscopy techniques. LTD4 and LTE4 demonstrated a dose-dependent and predominantly eosinophilic infiltrate over the selected dose range (10 ng to 1000 ng), while there was only a minimal response to LTC4. LTB4 produced marked eosinophil infiltrates only at the highest dose; scattered neutrophil infiltrates were also noted at the high dose of LTB4. The 5R,6S LTD4 stereoisomer did not evoke any leukocyte infiltration. The SRS-A antagonist, FPL 55712, abolished peptidoleukotriene-induced eosinophil emigration, and indomethacin pre-treatment had no inhibitory effect, indicating direct mediation of this response by LTs. Histamine caused a comparable eosinophilia over a dose range of 10 micrograms to 1000 micrograms. LT-induced eosinophil emigration was directed to the conjunctival epithelium; the cells appeared intact and no tissue damage was observed. These results may have relevance in the areas of allergic conjunctivitis and asthma research.

The eosinophilic leukocyte: structure and function

The evidence reviewed here indicates that the eosinophil has the ability to kill many species of helminths and likely does so during worm infection. This toxic ability appears to be regulated by several other cells including mast cells, monocytes, and T lymphocytes. Eosinophils kill helminths through their ability to generate potent oxidants and through their content of cationic proteins, which likely achieve high concentrations at points of granule deposition. Eosinophils also participate in inflammation in human disease especially asthma, skin diseases, and heart disease. Though present concepts hold that the mast cell is the cornerstone of the allergic inflammatory response (450), the findings that eosinophils bind IgE and are activated by antigen-IgE complexes and that the eosinophil can elaborate many inflammatory mediators raise the possibility that the eosinophil might also be involved in the initiation of inflammatory responses. Finally, an eosinophil-related protein appears to play an undefined role in human reproduction.

Effect of zinc and other cations on the release of the eosinophil cationic protein

The eosinophil cationic protein, ECP, is a unique eosinophil granule constituent, which is released extracellularly after exposure of the eosinophils to a non-phagocytosable surface such as complement-coated Sephadex beads. The ECP is released to some extent even in the absence of Ca2+ and Mg2+, though both these cations augment the release reaction tested alone, and an optimal release is observed only in the presence of 2 mmol/l Ca2+ and 2 mmol/l Mg2+ in the medium. Zn2+ at concentrations from 0.25-4.0 mmol/l inhibited the release of ECP in a dose-dependent fashion, with or without Ca2+ and Mg2+ in the medium. Mn2+ had dual effects, stimulating the ECP release in the absence of Mg2+ and Ca2+, and inhibiting the release in the presence of these cations. Li1+ caused minor inhibition of ECP release, but only in the absence of Ca2+ and Mg2+. The inhibitory effect of Zn2+ was immediate and reversible after washing of the cells, suggesting that the inhibition is due to interaction with the plasma membrane functions.

Chronic eosinophilic dermatitis: a manifestation of a multisystemic, eosinophilic, epitheliotropic disease in five horses

A generalized, chronic, progressive, exfoliative dermatitis in five horses is described. Histologically, the lesion is characterized by a superficial and deep perivascular dermatitis which is eosinophil-rich with a marked lymphocytic and plasmacytic component, accompanied by marked acanthosis and hyperkeratosis. More severe cases progress to a lichenoid pattern with the same cellular composition with focal eosinophilic spongiosis and eosinophilic subcorneal pustules. Clinically, the disease is associated with chronic, severe weight loss and is fulminating. The skin lesions are accompanied by lymphoplasmacytic and eosinophilic infiltrates and formation of eosinophilic granulomas in other epithelial organs, most noticeably the pancreas, in which a chronic, fibrosing pancreatitis develops. Other epithelial organs involved to various degrees are salivary glands, the gastrointestinal system, including the oral cavity and esophagus, biliary epithelium and bronchial epithelium. The etiology of this disease is unknown.

Immune responses of CBA/J mice to graded infections with Toxocara canis

The immunological responsiveness of CBA/J mice infected with various numbers of the canine ascarid, Toxocara canis, was characterized after a single infection to ascertain the smallest infection capable of perturbing the immune system of the host. Mice receiving the lowest inoculations (5 eggs per mouse or 0.25 larvae per g of body weight) had detectable alterations in the number of circulating peripheral blood eosinophils and spleen weight-to-body weight ratios. Mice infected with 25 eggs each (1.25 larvae per g of body weight) showed augmented concanavalin A-elicited splenic lymphocyte transformation and a positive lymphocyte transformation in response to a toxocaral antigen preparation in addition to even higher eosinophil counts and heavier spleens. Spleen cells from mice receiving the two largest inocula (125 eggs and 250 eggs per mouse or 6.25 and 12.5 larvae per g of body weight, respectively) had in addition to the above responses a sixfold increase in spontaneous DNA synthesis. An enzyme-linked immunosorbent assay for mouse antibody responses to T. canis indicated that the time of onset as well as the magnitude of the antitoxocaral humoral response is directly proportional to the size of the inoculation used to initiate the infection. Finally, we showed that allowing the infection to become protracted results in some responses increasing somewhat in magnitude, but regardless of length of infection, the magnitude of any of the responses examined is proportional to the size of the infection. The results indicate that different host responses have different thresholds of sensitization and suggest that larvacidal reactions which require intricate interactions among several components of the immune system may not occur in very small infections.

Evaluation of the common conditions associated with eosinophilia

In an eosinophilic population of 47 boys of the same age, a large proportion (92%) were helminth infested or atopic, or both, compared with 36% of 36 controls. The methods used to detect these conditions were not costly or elaborate, except for the radioallergosorbent test, which was used to measure concentrations of circulating IgE antibodies to atopic allergens. It is suggested that an economical approach to detect helminthiasis and atopy in cases of eosinophilia is adopted using the methods employed here, with skin prick tests replacing the radioallergosorbent test.