Gleich, Gerald J.

Abstract Accumulation of eosinophils in the lung with concomitant tissue damage are defining histopathologic features of human asthma. Through degranulation and the release of proinflammatory proteins such as major basic protein (MBP), eosinophils may perpetuate this inflammatory response. We investigated the extent of eosinophil degranulation in a murine model of allergic pulmonary inflammation. In this paradigm, the mice develop pulmonary eosinophilia, mucus hypersecretion, tissue damage, and airway edema and hyperreactivity. To evaluate the degree of eosinophil degranulation, we used a polyclonal antibody to murine MBP (mMBP) to perform dot blot analysis of bronchoalveolar lavage (BAL) cells and fluids, and immunohistochemical fluorescent analysis of lung tissue sections. After ovalbumin antigen challenge, we were unable to detect immunoreactive mMBP in the BAL fluids from either nonsensitized or sensitized mice. However, after lysis of the recoverable BAL cells, we were able to detect mMBP by immunoblot analysis, with the levels of immunoreactive mMBP directly related to the number of recoverable eosinophils. We also examined paraffin-embedded, lung tissue sections for patterns of mMBP deposition. Whereas lung sections from allergic mice revealed prominent peribronchial eosinophilia after antigen challenge, tissue sections from nonsensitized animals rarely displayed eosinophils. Despite the presence of numerous eosinophils, no immunohistologic evidence of extracellular mMBP could be found in antigen-challenged allergic mice. Furthermore, rechallenged allergic mice displayed a significant increase in the number of recruited pulmonary eosinophils but all immunoreactive mMBP was still intracellular. We conclude that the recruited pulmonary eosinophils have not substantially degranulated. These results suggest that, in this murine model of allergic inflammation, eosinophil degranulation and release of mMBP does not contribute to the observed pulmonary inflammation and airway hyperreactivity.

Abstract We evaluated the ability of eosinophil granule major basic protein (MBP) to stimulate interleukin (IL)-8 production by neutrophils. MBP over the concentration range of 0.1 to 10 μM stimulated the release of up to approximately 8 ng/ml IL-8. Incubation with 2 μM MBP showed that, after a 1 h lag, the level of IL-8 release increased with time for approximately 10 h. At the 2 μM concentration, eosinophil cationic protein, eosinophil-derived neurotoxin, and eosinophil peroxidase did not stimulate significant levels of IL-8 production. MBP stimulated 2-fold increases in IL-8 messenger RNA (mRNA) after 1 and 3 h of incubation, which were blocked by pretreatment with actinomycin D. However, stimulation with MBP did not produce an increase in the binding activity of nuclear factor (NF)-κB or activator protein-1. No NF–IL-6 binding activity was detected in the same nuclear extracts. In addition, stimulation with MBP prolonged the stability of IL-8 mRNA. MBP also induced transient increases in mRNA for macrophage inflammatory protein (MIP)-1α and MIP-1β, but did not stimulate the release of either chemokine. These findings indicate that MBP is selective among the eosinophil granule proteins as a stimulus for neutrophil IL-8 release and, further, that stimulation of neutrophil IL-8 release by MBP involves both transcriptional and posttranscriptional regulation. We postulate that MBP-induced release of IL-8 by neutrophils may contribute to the pathophysiology of acute asthma and other inflammatory lung diseases.

Abstract To determine the histologic differences in the airways of patients who died from sudden-onset asthma and the more common slow-onset asthma, we studied seven cases of fatal asthma. The numbers of eosinophilsand neutrophils, as well as extracellular deposition of their respective granule contents in the airway mucosa and submucosa, were determined and statistically analyzed. Four of the seven patients had slow-onset asthma attacks in which the time interval between onset of asthma and death was more than 2.5 h. In contrast, three patients had sudden-onset asthma in which the time interval between onset of asthma attack and death was less than 1 h. The four patients with slow-onset fatal asthma had more eosinophils (34.1 ± 6.3 in slow-onset; 9.7 ± 3.5 in sudden-onset; p = 0.002) and fewer neutrophils (4.8 ± 2.0 in slow-onset; 16.8 ± 5.4 in sudden-onset; p = 0.008) in the airway submucosa than did patients with sudden-onset fatal asthma. In addition, within the slow-onset fatal asthma group, eosinophils exceeded neutrophils in the airway submucosa (eosinophils > neutrophils, p = 0.002). By contrast, within the sudden-onset fatal asthma group, neutrophils exceeded eosinophils (neutrophils > eosinophils, p = 0.04). We suggest that sudden-onset fatal asthma is immunohistologically distinct from slow-onset fatal asthma and that it is characterized by a relative paucity of eosinophils in the face of an excess of neutrophils in the airway submucosa. These observations raise the possibility that the mechanism of airway inflammation as well as that of airway narrowing in sudden-onset fatal asthma may be quite distinct from those in slow-onset fatal asthma.

SUMMARYThe participation of eosinophils in the Spanish toxic oil syndrome (TOS) was investigated. Eosinophil infiltration and degranulation in tissues from 52 patients with the TOS were examined by immunofluorescence staining for the eosinophil granule major basic protein (MBP). Serum MBP levels were determined in sera from 323 patients. Eosinophil infiltration and degranulation were found in several tissues, especially during the acute phase of the TOS, and serum MBP was significantly elevated during all phases of the disease, suggesting that eosinophils play a role in the pathogenesis of the TOS.

Abstract Eosinophil granule proteins are deposited in cutaneous lesions in many human diseases, but how these proteins contribute to pathophysiology is obscure. We injected eosinophil cationic protein (ECP or RNase 3), eosinophil-derived neurotoxin (EDN or RNase 2), eosinophil peroxidase (EPO), and major basic protein-1 (MBP1) intradermally into guinea pig and rabbit skin. ECP and EDN each induced distinct skin lesions at ≥2.5 μM that began at 2 days, peaking at ∼7 days and persisting up to 6 wk. These lesions were ulcerated (ECP) or crusted (EDN) with marked cellular infiltration. EPO and MBP1 (10 μM) each produced perceptible induration and erythema with moderate cellular infiltration resolving within 2 wk. ECP and EDN localized to dermal cells within 2 days, whereas EPO and MBP1 remained extracellular. Overall, cellular localization and RNase activity of ECP and EDN were critical for lesion formation; differential glycosylation, net cationic charge, or RNase activity alone did not account for lesion formation. Ulcerated lesions from patients with the hypereosinophilic syndrome showed ECP and EDN deposition comparable to that in guinea pig skin. In conclusion, ECP and EDN disrupt skin integrity and cause inflammation. Their presence in ulcerative skin lesions may explain certain findings in human eosinophil-associated diseases.

Epidemiologic studies strongly associate eosinophilia-myalgia syndrome (EMS) with ingestion of tryptophan containing a contaminant ("peak E"). Prior reports have suggested that peak E is the di-tryptophan Nα-animal of acetaldehyde. Spectral and chemical studies now demonstrate that peak E is 1,1′-ethylidenebis[tryptophan]. This novel amino acid may be the etiological agent responsible for EMS, or it may be a marker of a still unidentified causal agent.

The quantities of immunoglobulin E (IgE) antibodies to grass or ragweed allergens were measured by an immunoabsorption in the serums of patients sensitive to one of these allergens. IgE antibodies to grass or ragweed allergens accounted for means of 30 and 29 percent of the total IgE protein. After the ragweed pollination season, the levels of serum IgE antibodies to ragweed allergens rose dramatically and in postpollination serums they accounted for 39 percent of the total IgE protein with a range from 13 to 50 percent.

The titers of antibodies to the benzylpenicilloyl antigenic determinant are increased with specific antiserum to immunoglobulin D, as shown by the enhancement method. This increase in titer is blocked by purified immunoglobulin D protein but not by immunoglobulins of the other four classes.

Objective.Eosinophil-associated proteins, especially eosinophil-derived neurotoxin, may be important contributors to the neurologic pathology and symptoms caused byBaylisascaris procyonis infection.Methods.Two cases of severe B procyonisencephalitis with evidence of marked eosinophil degranulation in the central nervous system are presented. Serial cerebrospinal fluid (CSF) specimens were collected from each patient during the course of their illness. Antibodies against B procyonis were measured in the patients' serum and CSF. Levels of the eosinophilopoietin interleukin-5 (IL-5) and 2 important eosinophil proteins, eosinophil-derived neurotoxin and major basic protein, were assayed in the CSF.Results.Both patients had rapidly progressive central nervous system disease with evidence of eosinophilic meningoencephalitis. Both tested positive for antibodies to B procyonis in serum and CSF and had progressively worsening deep white matter changes on magnetic resonance images of the brain. CSF levels of IL-5, eosinophil-derived neurotoxin, and major basic protein were markedly elevated over controls.Conclusions.This is the first report of the measurement of IL-5, eosinophil-derived neurotoxin, and major basic protein in human CSF. In addition to traumatic damage and necrosis caused by migrating larvae, eosinophil-derived neurotoxin from associated eosinophilic inflammation may be an important contributory factor in the pathogenesis of B procyonis encephalitis. parasite, eosinophil-derived-neurotoxin, major basic protein, eosinophilia, hypereosinophilia, interleukin-5, encephalitis, child.