Human eosinophils have prolonged survival, enhanced functional properties, and become hypodense when exposed to human interleukin 3

Eosinophilic vasculitis in connective tissue disease

BACKGROUND

Neutrophilic and lymphocytic vascular inflammation is common in vasculitis associated with connective tissue disease (CTD). We recently identified eight patients with CTD and eosinophilic vasculitis.

OBJECTIVE

The purpose of this study was to characterize a variant form of vasculitis in CTD with eosinophilic infiltration.

METHODS

Of 98 CTD patients with cutaneous necrotizing vasculitis, eight were found with predominantly eosinophilic vascular infiltration. Nine CTD patients with cutaneous neutrophilic vasculitis were identified for comparison. Clinical and laboratory findings were reviewed and compared. Indirect immunofluorescence for eosinophil granule major basic protein (MBP), neutrophil elastase, and mast cell tryptase was performed on lesional tissue. MBP levels and eosinophil survival enhancing activity were assayed in sera from three patients.

RESULTS

The patients with eosinophilic vasculitis had depressed serum complement levels and peripheral blood eosinophilia; MBP levels were elevated in serum and eosinophil survival was prolonged. Immunofluorescence of tissue showed marked angiocentric eosinophil MBP staining with peripheral neutrophil elastase staining; mast cell tryptase staining was notably absent. The patients with neutrophilic vasculitis were variably hypocomplementemic and did not have peripheral blood eosinophilia. Immunofluorescence showed marked angiocentric neutrophil elastase staining with scattered eosinophil MBP staining; mast cell tryptase staining showed normal mast cell numbers.

CONCLUSION

Patients with eosinophilic vasculitis, CTD, and hypocomplementemia show vessel wall destruction in association with vessel wall deposition of cytotoxic eosinophil granule MBP, which suggests that eosinophils mediate vascular damage in this disease process. In addition, perivascular mast cells appear diminished, thereby suggesting that mast cell degranulation occurs.

Cytokines directly induce degranulation and superoxide production from human eosinophils

BACKGROUND

Cytokines are implicated in allergic diseases and can modulate effector functions of eosinophils stimulated by another agonist. However, little is known about the capacity of cytokines to directly trigger eosinophil degranulation.

OBJECTIVES

We attempted to determine whether cytokines can directly induce degranulation and superoxide production from eosinophils.

METHODS

Eosinophils from normal donors were incubated with various cytokines in albumin-coated tissue culture plates for 4 hours. To quantitate degranulation, the amounts of eosinophil-derived neurotoxin in supernatants were measured by radioimmunoassay. In addition, superoxide production was measured by superoxide dismutase-inhibitable reduction of cytochrome c.

RESULTS

IL-5, IL-3, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor- alpha, and RANTES all induced eosinophil degranulation. Granulocyte-macrophage colony-stimulating factor was the most potent and induced eosinophil-derived neurotoxin release comparable to that induced by secretory IgA beads, one of the most potent secretagogues for eosinophils. In addition, IL-5 and tumor necrosis factor- alpha were synergistic in their induction of eosinophil degranulation. In contrast, IL-1, IL-8, interferon- gamma, and macrophage inflammatory protein-1 alpha did not induce degranulation. Finally, IL-5, IL-3, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor- alpha, but not RANTES, also induced superoxide production from eosinophils.

CONCLUSIONS

Certain cytokines directly induce eosinophil degranulation and superoxide production in vitro. Therefore these cytokines may be important in the release of toxic granule proteins from eosinophils in allergic diseases.

Dot-like focal contacts in adherent eosinophils, their redistribution into peripheral belts, and correlated effects on cell migration and protected zone formation

We have examined the organization of F-actin and focal contacts in eosinophils and the functional consequences correlated with their predistribution. In activated eosinophils adherent to laminin, F-actin is localized in large, uniformly distributed, dot-like structures. Co-localized with the F-actin are a variety of typical components of focal contacts including: the alpha 6 and beta 1 integrins subunits (which mediate eosinophil adhesion to laminin), vinculin, talin, pp125FAK, paxillin, and tyrosine phosphorylated proteins, but not the beta 2 integrin subunit which is not involved in eosinophil adhesion to laminin. In unactivated eosinophils on laminin (which do not adhere well) and in activated eosinophils on non-adhesive surfaces (human serum albumin, tenascin, or a mixture of tenascin and laminin), dot-like accumulations of F-actin do not form. When activated eosinophils are incubated on laminin in the presence of low concentrations of 1,1′-ethylidenebis(L-tryptophan), a remarkable rearrangement occurs. Both conventional and confocal microscopy suggest that the dot-like structures rearrange from a uniform distribution into thick, peripheral belts surrounding each cell with few dot-like structures internal to the belt. Functional consequences occur as a result of this rearrangement of focal contacts and the cytoskeleton. The belt of focal contacts acts as a size-dependent permeability barrier; fluorescent 8 kDa polyethylene glycol does not label the substrate underneath the cells whereas 3.5 kDa polyethylene glycol labels the substrate uniformly. The formation of belts of focal contacts also blocks the ability of eosinophils to migrate on laminin in response to a chemotactic gradient. While the mechanism of 1,1′-ethylidenebis(L-tryptophan) action remains to be determined, experiments indicate that the function of 1,1′-ethylidenebis(L-tryptophan) is distinct from the function of drugs that alter tyrosine kinase and serine/threonine kinase activities. Our observations reveal a novel mechanism for regulating cell behavior in invasive cells in which the rearrangement of focal contacts and the associated cytoskeleton may control cell migration and the sequestration of secreted cytotoxic and degradatory molecules. We propose that 1,1′-ethylidenebis(L-tryptophan) may mimic the function of an endogenous regulator of eosinophil morphology and behavior.

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

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

Molecular cloning of the gene for human leukotriene C4 synthase. Organization, nucleotide sequence, and chromosomal localization to 5q35

Leukotriene C4 (LTC4) synthase catalyzes the conjugation of LTA4 with reduced GSH to form LTC4, the parent of the receptor active cysteinyl leukotrienes implicated in the pathobiology of bronchial asthma. Previous cloning of the cDNA for human LTC4 synthase demonstrated significant homology of its amino acid sequence to that of 5-lipoxygenase activating protein (FLAP) but none to that of the GSH S-transferase super-family. Genomic cloning from a P1 library now reveals that the gene for LTC4 synthase contains five exons (ranging from 71 to 257 nucleotides in length) and four introns, which in total span 2.52 kilobase pairs in length. The intron/exon junctions of LTC4 synthase align identically with those of FLAP; however, the small size of the LTC4 synthase gene contrasts with the > 31-kilobase pair size reported for FLAP. Confirmation of the LTC4 synthase gene size to ensure that no deletions had occurred during the cloning was obtained by two overlapping polymerase chain reactions from genomic DNA, which provided products of the predicted sizes. Primer extension analysis with poly(A)+ RNA from culture-derived human eosinophilic granulocytes or the KG-1 myelogenous cell line revealed multiple transcriptional start sites with prominent signals at 66, 69, and 96 base pairs 5' of the ATG translation start site. The 5'-flanking region revealed a GC-rich promoter sequence consistent with an SP-1 site and consensus sequences for AP-1 and AP-2 enhancer elements, 24, 807, and 877 bp, respectively, 5' from the first transcription initiation site. Southern blot analysis of a genomic DNA (with full-length cDNA as well as 5' and 3' oligonucleotide probes) confirmed the size of the gene and indicated a single copy gene in normal human genomic DNA. Fluorescent in situ hybridization mapped LTC4 synthase to chromosomal location 5q35, which is in close proximity to the cluster of genes for cytokines and receptors involved in the regulation of cells central to allergic inflammation and implicated in bronchial asthma.

Human eotaxin is a specific chemoattractant for eosinophil cells and provides a new mechanism to explain tissue eosinophilia

Eotaxin is an eosinophil-specific chemoattractant that has been recently identified in rodent models of asthma and host response against tumors. To determine whether a similar molecule might play a role in human inflammatory diseases characterized by eosinophilia, we isolated the human eotaxin gene. We demonstrate that human eotaxin is an early response gene of cytokine-stimulated epithelial and endothelial cells, and is induced in peripheral blood eosinophils by interleukin-3. Eotaxin is directly chemotactic for eosinophils, but not mononuclear cells or neutrophils. Eotaxin messenger RNA accumulates markedly in the lesions of patients with inflammatory bowel disease (ulcerative colitis and Crohn's disease), but not in the lesions of patients with diverticulitis. These results now provide a mechanism involving eotaxin to explain the eosinophil infiltration seen in a variety of human disease; as such, an eotaxin antagonist may be a novel therapy for certain human diseases characterized by tissue eosinophilia.

Constitutive production of granulocyte/macrophage colony-stimulating factor by hypodense mononuclear eosinophils developed in vitro from hybrid eosinophil/basophil granulocytes

We recently described the development in vitro of cells with granules characteristic of eosinophils and basophils (hybrid granulocytes) from normal human cord blood mononuclear cells cultured for 14 days with recombinant human (rh) interleukin (IL)-3, rhIL-5, and a soluble basement membrane, Matrigel. Hybrid granulocytes constitutively produced granulocyte/macrophage colony-stimulating factor (GM-CSF) and rapidly developed into eosinophils after the exogenous cytokines and Matrigel were removed. To characterize the developmental progression of hybrid granulocytes, cells were maintained for an additional 14 days in medium containing rhIL-3, rhIL-5, and Matrigel. After 28 days, 73% +/- 1% (mean +/- SEM; n = 6) of the nonadherent cells were mononuclear eosinophils, 13% +/- 3% were eosinophils with two or more nuclear lobes, 13% +/- 4% were hybrid granulocytes, and 0.2% +/- 0.1% were basophils. More than 90% of the mononuclear eosinophils were hypodense as determined by centrifugation through metrizamide gradients. After an additional 5 days of culture in medium without exogenous cytokines, 65% +/- 3% (n = 5) of the 28-day cells excluded trypan blue. In contrast, 2% +/- 1% of freshly isolated peripheral blood eosinophils survived 5 days of culture without exogenous cytokines (n = 5). Fifty percent conditioned medium from in vitro derived 28-day mononuclear eosinophils and 14-day hybrid granulocytes maintained the survival of 60% +/- 7% and 77% +/- 7%, respectively, of freshly isolated peripheral blood eosinophils for 72 h, compared with 20% +/- 8% survival in medium alone (n = 3). The eosinophil viability-sustaining activity of 50% mononuclear eosinophil-conditioned medium was neutralized with a GM-CSF antibody. A total of 88% of the 28-day cells exhibited immunochemical staining for GM-CSF. Thus, during eosinophilopoiesis, both hybrid eosinophil/basophil intermediates and immature mononuclear eosinophils exhibit autocrine regulation of viability due to constitutive production of GM-CSF.

Lymphocytes stimulate expression of 5-lipoxygenase and its activating protein in monocytes in vitro via granulocyte macrophage colony-stimulating factor and interleukin 3

The aim of this study was to examine the role of lymphocytes in regulating expression of the 5-lipoxygenase pathway in monocytes. When monocytes were cultured over a period of days with lymphocytes, calcium ionophore-stimulated 5-lipoxygenase activity was enhanced. If lymphocytes alone were activated with lectins and their supernatants added to monocytes, stimulated 5-lipoxygenase activity was increased, whereas supernatants from lymphocytes cultured without lectins had no effect. Increased immunoreactive protein and mRNA for 5-lipoxygenase and 5-lipoxygenase activating protein were present in cells conditioned with lectin-activated lymphocyte supernatants. The effect of activated-lymphocyte supernatants could be mimicked by either GM-CSF or IL-3, but there was no additive effect with both cytokines. Both GM-CSF and IL-3 were present in the supernatant from lectin-activated lymphocytes at concentrations above their ED50, but were undetectable in the supernatant from nonactivated lymphocytes. The effect of lectin-activated lymphocyte supernatant could be inhibited by neutralizing antibodies to both cytokines, but not to either cytokine alone. We conclude that lymphocytes can regulate the expression of 5-lipoxygenase in monocytes, over a period of days, via the release of soluble factors, primarily GM-CSF and IL-3.

Role of Tumor Necrosis Factor and Granulocyte-Macrophage Colony-Stimulating Factor in the Late Allergic Response in Human Nasal Mucosa

Cytokines play an integral role in the allergic response of the nasal mucosa. The ideal model for analysis of this interaction has yet to be perfected. We present a model for such evaluation and present results of experiments on the release of several cytokines. Freshly harvested human nasal turbinate mucosa was placed on a Gelfoam (Upjohn Co., Kalamazoo, Mich.) raft in a liquid medium to simulate the in situ environment. The allergic response was initiated by exposing the nasal mucosa to various combinations and amounts of human immunoglobulin E and antihuman immunoglobulin E antibody. The supernatants were collected and analyzed by enzyme-linked immunosorbent assay techniques for various cytokines. Histopathologic evaluation of the mucosa was performed throughout the exposure period, confirming normal cellular and tissue architecture and viability. This model was used to monitor the release of interleukin-3, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, and soluble tumor necrosis factor receptors after exposure to immunoglobulin E and immunoglobulin E antibody. Interleukin-3 did not show significant increases during the experiment testing period of 48 hours. Tumor necrosis factor-α and soluble tumor necrosis factor receptors demonstrated time-dependent increases in concentration after immunoglobulin E stimulation. Granulocyte-macrophage colony-stimulating factor showed the greatest time-dependent increases. Their impact on the understanding of the allergic response will be discussed.

IL-3 receptor expression, regulation and function in cells of the vasculature

IL-3 is a haemopoietic growth factor which stimulates the production and functional activity of various blood cell types. Recent evidence suggests that the target cell population of IL-3 is not restricted to haemopoietic cells as previously thought, but vascular cells such as endothelial cells also express receptors for and respond to this cytokine. Interestingly, IL-3 was found to regulate endothelial responses related to inflammation, immunity and haemopoiesis. These findings, summarized in this review, offer new insight into the physiological function of IL-3 and may also be of clinical importance, as IL-3 is used in bone marrow reconstitution following cancer therapy.

Glucocorticosteroid inhibition of cytokine production: relevance to antiallergic actions

We believe that there are the following four classes of glucocorticoid-sensitive cytokines that are involved in cell recruitment: (1) those that activate endothelium nonspecifically; (2) those that activate endothelium specifically; (3) those that activate, prime, and prolong the survival of eosinophils; and (4) those that stimulate movement of cells up into the epithelium. Glucocorticoids inhibit the generation of these cytokines and thereby prevent several different aspects of inflammation, including the activation and recruitment of inflammatory cells (eosinophils, basophils, and lymphocytes) and the release of inflammatory mediators. We believe such pleiotropic actions account for the efficacy and widespread use of glucocorticoids in the treatment of asthma.

Isolation and functional characterization of T cells from human sputum

T cells play a central role in the control of inflammation in the bronchial mucosa through the elaboration of proinflammatory cytokines. This study describes a method for the isolation and cloning of T cells from sputum of adult subjects. In sputum, T cells were of a minor population (< 2% of total cells), and not all expressed activation markers for CD29 (very late antigen-1 (VLA-1)), IL-2R and HLA-DR. When cultured in the presence of rIL-2 for 7 days and then cloned by limiting dilution, the ratios of CD4+ and CD8+ T cell clones (TCC) generated reflected those of CD4+ and CD8+ T cells found in sputum. CD4+ TCC and primary CD4+ T cell populations produced a range of proinflammatory cytokines when stimulated with immobilized anti-CD3 MoAb. Analysis of mRNA messages by reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot showed good correlation with the production of cytokine in culture supernatants. A correlation existed between the pattern of cell infiltrate in sputum and the cytokine profile.

Density of eosinophils reflects activity of disease in allergic asthmatic children

BACKGROUND

Low density eosinophils are more prominent in asthmatic patients compared with healthy subjects. LDE are metabolically more active and produce more tissue-injuring and spasmogenic proteins than normal eosinophils.

OBJECTIVE AND METHODS

With a method providing information about eosinophils of 12 different densities we were able to study eosinophil density characteristics in 24 young patients in detail with allergic asthma in a stable phase, and in 21 patients after a bronchial allergen challenge.

RESULTS

Study of the eosinophil density profile of patients and healthy controls revealed two density populations. Patients had more low density eosinophils than controls. In the patients eosinophil density characteristics and in particular the number of low density eosinophils correlated strongly with both FEV1% predicted (p = -0.66, P < 0.001) and FEV1/FVC (p = -0.47, P < 0.01) as well as with bronchial responsiveness to histamine (p = -0.68, P < 0.001) and house dust mite (p = -0.37, P < 0.05). Allergen induced bronchial reactions were associated with an increase in the number (P < 0.001) and percentage (P < 0.05) of low density eosinophils. A selective rise in the number of eosinophils collected from fractions with a low density accounted for the observed rise in the total number of eosinophils. Density changes did not differ between patients with an isolated early reaction and patients with both an early and a late reaction, nor was there a relation between the severity of the late reaction and the shift in eosinophil density.

CONCLUSION

In conclusion, peripheral blood eosinophil density characteristics and in particular numbers of low density eosinophils are closely related with indicators of the asthma severity under stable conditions. Allergen inhalation induces a further shift towards lower density suggesting additional activation of the eosinophils.

Human eosinophils preferentially survive on tissue fibronectin compared with plasma fibronectin

BACKGROUND

Eosinophil-derived inflammatory mediators including cytokines are considered to be important in the pathogenesis of allergic inflammation. Fibronectin (Fn) has been shown to be a physiological trigger of autocrine cytokine production by human eosinophils. Fn is encoded by a single gene, but alternate splicing of the primary RNA transcript results in polypeptide diversity in a cell type-specific fashion. Thus, tissue Fn contains approximately 50% more of the CS-1 cell binding region recognized by the integrin alpha 4 beta 1 compared with plasma Fn.

OBJECTIVE

Since eosinophils are predominantly tissue-dwelling cells we compared the effect of tissue and plasma Fn on eosinophil survival in culture.

METHODS

The viability and cytokine generation of eosinophils (> 99.9% pure) cultured for up to 4 days in 96 well plates coated with tissue Fn, plasma Fn or BSA was compared.

RESULTS

There was a significant difference in the ability of tissue Fn to support eosinophil survival compared with plasma Fn (P < 0.01). Optimal survival with tissue Fn was seen at 25 micrograms/well (70% +/- 2.0% viability at 3 days vs 7% +/- 2.2% viability on BSA). Significant (P < 0.001) cell viability on tissue Fn was observed for up to 4 days in culture (54% +/- 6.0%) compared with BSA coated wells. Addition of autologous mononuclear cells (final concentration 0.5%, 1% or 2%) resulted in plasma Fn-dependent eosinophil survival comparable to that of 99.9% pure eosinophils adherent to tissue Fn. Tissue Fn-dependent survival was significantly inhibited by anti-interleukin-3, anti-granulocyte macrophage colony stimulating factor (GM-CSF) and anti-IL-5 monoclonal antibodies. Picogram quantities of these three cytokines were detected in supernatants from eosinophils cultured for 3 days on tissue Fn using specific enzyme-linked immunosorbent assays (ELISAs). Eosinophil survival on tissue Fn was significantly inhibited by anti-beta 1 and alpha 4 beta 1 monoclonal antibody (MoAb) and also by a MoAb specific for the CS-1 motif in the IIICS region of Fn.

CONCLUSION

These observations show preferential survival of eosinophils cultured on tissue Fn as a result of alpha 4 beta 1-dependent interaction with the CS-1 region of tissue Fn triggering autocrine cytokine synthesis and release, thereby promoting their survival and persistence within the tissues.

Pharmacokinetic and pharmacodynamic studies of subcutaneously administered recombinant human interleukin-3 following chemotherapy for non-Hodgkin's lymphoma

The pharmacokinetics and the pharmacodynamic profile of subcutaneously administered recombinant human non-glycosylated interleukin-3 (rhIL-3) was studied in lymphoma patients after standard CHOP chemotherapy. 30 patients received 0.5, 1.0, 5.0, 7.5 and 10 micrograms/kg (six patients at each dose level) of rhIL-3 for 14 d. Serum rhIL-3 samples were obtained regularly, during the treatment and serially over a 24 h period on the first (cycle day 2) and the last (cycle day 15) day of rhIL-3 treatment for pharmacokinetic evaluation. Following s.c. injection on cycle day 2. the maximum rhIL-3 serum concentration ranged from 289 pg/ml (0.5 micrograms/kg) to 4690 pg/ml (10 micrograms/kg). Both the maximum serum concentration (R = 0.90. P < 0.0001) and the area under the serum concentration-time curve (R = 0.95, P < 0.0001) were related to dose. The elimination half-life T1/2 beta was 160 min for 0.5 micrograms/kg and 134 min for 10 micrograms/kg, with no apparent dose relationship. The systemic clearance of 3.0-6.0 ml/min/kg was comparable at all dose levels. No significant difference was noted between pharmacokinetic parameters on the first day of rhIL-3 and the last day of treatment, and no accumulation of the drug was noted throughout the study. The pharmacokinetic parameters correlated poorly to the clinical response of the growth factor. where dose in micrograms/kg seemed to be the most important single factor.

Secretion of the eosinophil-active cytokines interleukin-5, granulocyte/macrophage colony-stimulating factor and interleukin-3 by bronchoalveolar lavage CD4+ and CD8+ T cell lines in atopic asthmatics, and atopic and non-atopic controls

Specific eosinophil accumulation and activation within the asthmatic bronchial mucosa are thought to occur at least partly through the actions of cytokines, including interleukin (IL)-5, IL-3 and granulocyte/macrophage colony-stimulating factor (GM-CSF). Although mRNA encoding some of these cytokines has been demonstrated in bronchoalveolar lavage (BAL) fluid cells and bronchial biopsies from asthmatics, it has yet to be established whether these cells produce the translated products and whether expression is associated with CD4+ T helper or CD8+ cytotoxic T cells. We addressed this problem by raising polyclonal CD4+ and CD8+ T cell lines from the BAL fluid of six atopic asthmatics, five atopic non-asthmatics and seven non-atopic non-asthmatic controls. BAL fluid cells obtained at fiberoptic bronchoscopy were depleted of adherent cells, and then T lymphocytes expanded by stimulation with monoclonal anti-CD3 antibody and recombinant human IL-2. When lymphocytes had expanded to sufficient numbers, CD4+ and CD8+ cells were separated by positive selection with magnetic beads coated with anti-CD4 or anti-CD8 monoclonal antibodies and further expanded. Cytokine secretion by standardized cell numbers was measured by enzyme-linked immunosorbent assays. BAL CD4+ T cell lines from the asthmatics secreted significantly elevated quantities of both IL-5 and GM-CSF as compared with lines from the atopic and non-atopic controls (p = 0.023-0.003). In contrast, IL-3 secretion did not significantly differ between the groups. In some subjects, CD8+ T cell lines also secreted significant quantities of these cytokines and there was a trend for IL-5 secretion by these cells to be higher in asthmatics than non-atopic controls (p = 0.035). These data are consistent with the hypothesis that activated T lymphocytes from asthmatics, particularly of the CD4+ subset, are predisposed to release elevated quantities of cytokines relevant to the accumulation and activation of eosinophils.

Increase of activated T-cells in BAL fluid of Japanese patients with bronchiolitis obliterans organizing pneumonia and chronic eosinophilic pneumonia

To study the role of T cells in bronchiolitis obliterans organizing pneumonia (BOOP) and chronic eosinophilic pneumonia (CEP) and to examine the influence of differing racial background, T-cell subsets in bronchoalveolar lavage (BAL) fluid (BALF) and in peripheral blood of 8 Japanese patients with idiopathic BOOP and 5 with CEP were compared with those of 15 normal subjects. The BALF pattern in BOOP was characterized by a significantly high number and percentage of lymphocyte and by a low CD4 to CD8 ratio compared with patients with CEP and healthy volunteers. Patients with CEP showed a significantly higher percentage of BALF eosinophils compared with other groups. There was no significant difference in BALF CD4 to CD8 ratio between patients with CEP and volunteers. Two-color analysis of T-cell subsets revealed that CD3+HLA-DR+ cells (activated T cell) in BALF of patients with BOOP and CEP increased significantly compared with volunteers, while BALF CD3+CD25+ cells (interleukin 2 receptor+ T-cell) did not. In addition, BALF CD8+HLA-DR+ cells (activated suppressor/cytotoxic T cell) in patients with BOOP and CD4+HLA-DR+ cells (activated helper T cell) in patients with CEP were significantly higher than levels detected in healthy subjects. The percentage of CD8+CD57+ cells and the number of CD8+CD11b- cells (cytotoxic T cell) in BALF were significantly higher in patients with BOOP compared with patients with CEP and healthy volunteers. There were no significant differences in the expression of peripheral blood T-lymphocyte surface antigens among the groups. These findings indicate that cytotoxic T cells in Japanese patients with idiopathic BOOP and helper T cells in CEP appear in the lungs is consistent with a previous report in Caucasians, supporting the hypothesis that T cells may play an important role in the pathogenesis of these diseases.

Cyclosporin A inhibits leukotriene production in intact RBL-1 cells without inhibiting leukotriene biosynthetic enzymes

The effects of cyclosporin A (CSA) on arachidonic acid (AA) metabolism were investigated in intact rat basophilic leukemia-1 (RBL-1) cells and cell lysates. Calcium ionophore (A23187)-stimulated synthesis of cysteinyl leukotrienes (LTC4, LTD4, and LTE4), LTB4, and 5-hydroxyeicosatetraenoic acid (5-HETE) in intact cells in the absence or presence of CSA was measured by reversed-phase high-performance liquid chromatography (HPLC). CSA inhibited the production of cysteinyl LTs, LTB4, and 5-HETE in intact cells in a dose-dependent manner. The synthesis of cysteinyl LTs, LTB4, and 5-HETE was also measured after the incubation of cell lysates with free AA in the absence or presence of CSA. CSA did not inhibit synthesis of cysteinyl LTs, but rather stimulated production of LTB4 and 5-HETE in cell lysate. A23187-stimulated release of incorporated [3H]AA from intact cells was not inhibited by CSA. CSA did not inhibit the synthesis of cysteinyl LTs and LTB4 when cells incubated with LTA4 as the substrate. These results indicate that the inhibitory effects of CSA on the synthesis of LTs and 5-HETE in intact cells are attributable to a modulatory action on a step in the series of intracellular events that includes the activation of 5-lipoxygenase, which are initiated by Ca2+ influx and end in the release of metabolites from the cell membrane, rather than to a direct inhibitory action on enzymes in the LT biosynthetic pathway.

In vivo effects of interleukin 3 in HIV type 1-infected patients with cytopenia

OBJECTIVE

To determine the safety, tolerance, and hematological and virological effects of the recombinant hematopoietic growth factor interleukin 3 (IL-3) in HIV-1-infected individuals with cytopenia.

DESIGN AND METHODS

A phase I single-center trial was conducted with patients in cohorts of three receiving one of four dose levels of self-administered, subcutaneously injected IL-3 (0.5, 1.0, 2.5, or 5.0 micrograms/kg/day). Toxicities, hematological effects, and virological effects were recorded. Viral studies included serum HIV p24 antigen levels, quantitative plasma and peripheral blood mononuclear cell cultures, and quantitative, competitive polymerase chain reaction of patient plasma.

RESULTS

Increases in white blood cell counts (WBC) and absolute neutrophil counts (ANC) were noted at the higher dose levels while absolute eosinophil counts (AEC) increased in all patients. The percent changes in WBC from baseline ranged from 52 to 309 and in ANC from 20 to 262 in the 2.5- and 5.0-micrograms/kg/day groups. The mean AEC change was 17-fold (range, 2- to 59-fold). Hemoglobin, hematocrit, platelets, and CD4 and CD8 counts were generally unaffected although individual patients demonstrated increases in hemoglobin and platelet levels. Toxicities were generally mild, but one patient developed a transient local erythematous rash at the sites of IL-3 injection which pathologically demonstrated hypersensitivity vasculitis. Of note, viral studies did not demonstrate any consistent changes in HIV-1 activity.

CONCLUSION

These data demonstrate limited hematological effects of IL-3 monotherapy in HIV-1-infected patients with cytopenia. However, should IL-3 be incorporated into combination cytokine therapies for HIV disease, these data suggest that IL-3 does not enhance in vivo HIV-1 activity.

Mucosal T cells recovered from mice after infection with respiratory syncytial virus display a memory/activation phenotype

Pgp-1 expression was studied as a marker of memory/activation on systemic and mucosal T cells of BALB/c and C57BL/6 mice after infection with respiratory syncytial virus (RSV), using two-color dual fluorescence flow cytometry employing anti-L3T4 (CD4), anti-Ly2 (CD8), and anti-Pgp-1 (CD44) monoclonal antibodies. Pgp-1 was expressed in relatively low densities on T cells of C57BL/6 mice, allowing differentiation of a dual population of Pgp-1(10) and Pgp-1hi T cells after antigenic stimulation in vivo. On the contrary, T cells of BALB/c mice were uniformly Pgp-1hi, making this mouse strain less suitable for studies with this marker. In blood and spleen consistently more CD8+ than CD4+ T cells were Pgp-1hi, while in BAL more CD4+ than CD8+ T cells were Pgp-1hi. After primary but not after secondary infection, CD4+ Pgp-1hi T cells increased significantly in the blood and spleen. After secondary infection both CD4+ Pgp-1hi and CD8+ Pgp-1hi T cells increased in the BAL. It is hypothesized that after primary infection systemic RSV-specific T cells acquire an activation/memory phenotype as characterized by an enhanced expression of Pgp-1, resulting in a faster and stronger influx of these cells in the lungs after secondary infection.

Effects of interleukin-3 following chemotherapy of non-Hodgkin's lymphoma. A prospective, controlled phase I/II study

The effect of rhIL-3 was investigated in 32 patients with newly diagnosed non-Hodgkin lymphoma in a phase I/II trial. All patients received 6 cycles of standard CHOP chemotherapy, and each patient was his own control where rhIL-3 was given as a daily s.c. injection for 14 days (day 2-15) in cycle 2 and 4, while cycle 1 and 3 were control cycles. Five dose levels were examined (0.5 - 1 - 5 - 7.5 - 10 micrograms/kg). Compared to the other more lineage-specific hemopoietic growth factors G- and GM-CSF, the effect of rhIL-3 on the hemopoiesis was less dramatic and more delayed, i.e. the most apparent effect was observed in the 2 weeks of treatment. Thus, the neutrophil counts from days 15 to 22 following CHOP were significantly raised and the duration of neutropenia was shorter (significantly only at 10 micrograms/kg), while the nadir values were unaffected. Platelet recovery from days 12-22 was significantly increased and nadir values occurred earlier compared to control cycles, but were only increased in some subsets. Other cell populations affected moderately in the recovery period were eosinophils and monocytes. Reticulocytes increased, but no effect on hemoglobin or RBC transfusion requirement was noted. Only moderate adverse reactions occurred such as fever, chills, flushing of the face and flu-like symptoms. There was no evidence of stimulation of tumor growth. Most significant, the rhIL-3 treatment at all but the lowest dose levels led to an improved tolerance to chemotherapy, as indicated by a decline in number of delayed cycles. A conclusion concerning the role of rhIL-3 as post-chemotherapy adjuvant should await studies using rhIL-3 in combination with more lineage-restricted hemopoietic growth factors.

The cellular basis for allergic rhinitis

In both seasonal and perennial rhinitis there is epithelial mast cell accumulation and tissue infiltration by eosinophils. Activation of these cells can be observed by electron microscopy and by elevated levels of tryptase and eosinophil cationic protein in nasal lavage fluid. Furthermore, seasonal increases in the antigen presenting cell (Langerhans' cell) are also evident. Investigations into the mechanisms involved in cell accumulation and activation reveals upregulation of leucocyte endothelial adhesion molecules and an increase in interleukin-4 (IL-4) in naturally occurring rhinitis, while mRNA for IL-4, IL-5 and granulocyte macrophage colony stimulating factor activity and lavage tumour necrosis factor-alpha (TNF alpha) levels are increased following local allergen challenge. These cytokines may be derived from a variety of sources, including mast cells, eosinophils and T-lymphocytes, and contribute to the underlying inflammatory process in rhinitis.

The effects of glucocorticoids on human eosinophils

It is readily apparent that eosinophils are important targets of steroid effects. Disruption of the cytokine network by glucocorticoids can indirectly diminish eosinophil generation, survival, and function. In addition, glucocorticoids appear to have direct effects on the survival, and perhaps on the function, of these cells. Rapid advances in our knowledge of the biochemistry of signal transduction, as well as the interaction between cell surface receptors and RNA transcription machinery, will allow detailed analysis of the mechanisms by which the function and life cycle of eosinophils are influenced by glucocorticoids.

Role of interleukin-5 in enhanced migration of eosinophils from airways of immunized guinea-pigs

1. Platelet activating factor (PAF), leukotriene B4 (LTB4) and interleukin-5 (IL-5) are potent chemoattractants for guinea-pig eosinophils, which may be involved in eosinophil recruitment and up-regulation in allergic diseases. Eosinophils from the bronchoalveolar lavage fluid (BALF) of ovalbumin-sensitized guinea-pigs were collected 24 h after antigen provocation and migration induced by PAF, LTB4 and rhIL-5 was studied. 2. Total BALF content and distribution of eosinophils were greater in immunized, ovalbumin-challenged guinea-pigs (5.0 +/- 0.8 x 10(6)/guinea-pig; 12 +/- 1%) than in immunized, saline-challenged animals (3.0 +/- 0.7 x 10(6)/guinea-pig; 7 +/- 1%). 3. The chemoattraction of eosinophils isolated on a metrizamide gradient was studied in micro-Boyden chambers, results being expressed as the number of migrating cells (mean +/- s.e. mean). PAF and LTB4-induced migration of eosinophils from immunized and OA-challenged guinea-pigs were significantly enhanced, as compared to immunized and saline-challenged animals (170 +/- 36 vs 35 +/- 9 migrating eosinophils for 10 nM PAF; 271 +/- 60 vs 110 +/- 19 for 1 nM LTB4). 4. The IL-5 antibody TRFK-5, in vivo, reduced eosinophil recruitment in BALF of antigen-challenged immunized animals as well as the enhanced responsiveness of eosinophils from the challenged animals, suggesting a role for IL-5 in the priming of eosinophils in vivo. 5. In contrast to TRFK-5, nedocromil sodium reduced to a similar extent eosinophil, macrophage and lymphocyte recruitment into the BALF of antigen-challenged, but failed to down-regulate the enhanced responsiveness of eosinophils from the challenged animals. 6. The increased eosinophil content in lungs from antigen-challenged guinea-pigs is thus selectively reduced by the anti-IL-5 antibody, which also attenuates the concomitant enhancement of the eosinophil responsiveness, supporting the concept that IL-5 is essential for recruitment and priming of eosinophils in vivo. In contrast, nedocromil sodium reduced non-selectively the total cell recruitment to the airways,but failed to attenuate the enhanced responsiveness of those eosinophils which migrated, indicating that its effects involve a different target.

Inflammation in nocturnal asthma?

At present there is some indirect evidence for increased nocturnal inflammation in patients suffering from nocturnal asthma: 1. Circulating eosinophil numbers and activation, as reflected by increased levels of ECP and EDN and low-density eosinophils, are increased at night. 2. Circulating histamine levels are increased at night. 3. Hyperresponsiveness to AMP at night is increased compared with hyperresponsiveness to methacholine. However, most results of various studies point to nocturnal asthma's being an expression of more severe asthma: 1. Both AMP and propranolol responsiveness, indirect measures of airway hyperresponsiveness, are lower both at 4:00 A.M. and 4:00 P.M. in asthmatics with nocturnal asthma than those without nocturnal asthma. 2. Patients with nocturnal asthma have higher circulating numbers of eosinophils at both 4:00 A.M. and 4:00 P.M. than those without nocturnal asthma, and eosinophil survival is not different at these times. 3. Patients with nocturnal asthma have higher PGD2 levels in BAL both at 4:00 A.M. and 4:00 P.M. than those without nocturnal asthma, but show no significant difference between levels at these two times. 4. Two studies have shown no difference in BAL eosinophil numbers and activation parameters at night in nocturnal asthma. 5. Histamine levels in BAL fluid are comparable day and night in patients with and without nocturnal asthma. 6. Inflammatory mediators in BAL are higher in asthmatic patients than in normal subjects, but are not different between patients with and without nocturnal asthma. Thus, patients with nocturnal asthmatic symptoms show an overall increased burden of mediators released from mast cells and other inflammatory cells. In conclusion, we feel that the term "nocturnal asthma" is misleading, in that it does not describe a unique entity in certain patients with asthma. We prefer, in view of the previous arguments, to consider nocturnal asthma a mere expression of more severe asthma. Thus we suggest the term "nocturnal asthma" be changed to "asthma with nocturnal symptoms."

Cellular and immunological markers of allergic and intrinsic bronchial asthma

Based on a growing body of evidence, allergic as well as intrinsic bronchial asthma have recently been defined as chronic persistent inflammatory disorders. Agreement has been reached that asthma can no longer be equated with bronchospasm only, and that the absence of reversibility of airflow obstruction does not exclude bronchial asthma. Bronchial hyperreactivity, on the other hand, although common to the vast majority of asthmatics, is not specific for bronchial asthma and provocation tests to measure bronchial hyperreactivity are not suited for routine monitoring of bronchial asthma. The clinical features of asthma are related to cellular as well as to soluble parameters of bronchial inflammation. Therefore, means of assessing and monitoring asthmatic inflammation have been investigated. Since eosinophils, T lymphocytes, mast cells, macrophages, neutrophils, epithelial cells, and structural cells, as well as various proinflammatory mediators and proteins, have been implicated in the pathogenesis of bronchial asthma, it has been anticipated that several of these cells or mediators might be either diagnostic of bronchial asthma or could serve as markers to monitor the underlying bronchial inflammation. Currently there is no diagnostic marker of bronchial asthma, which, on its own, either confirms or excludes bronchial asthma with appropriate sensitivity and specificity. Clinically the most reliable feature of bronchial asthma that seems to be related closely to the symptomatology still is the presence of eosinophils in peripheral blood, and especially in sputum. Eosinophil-derived products, particularly eosinophil granule proteins, have been investigated as markers of eosinophil participation in the pathogenesis of asthma and, comparable to eosinophil numbers themselves, are possible predictors of impending exacerbations of allergic, as well as intrinsic bronchial asthma. However, clinically their precise value in diagnosing and monitoring of bronchial asthma has not been documented convincingly and requires further investigation. Increasing data suggest that the regulation of eosinophilia is largely conveyed by interleukin-5 (IL-5) released from activated T-helper lymphocytes and possibly other cells. Therefore, T-lymphocyte activation, and especially assessment of systemic and local IL-5 levels, might be of diagnostic value and possibly useful in monitoring of inflammation in bronchial asthma in the future. A possible role and future applications for other markers of inflammation not related to eosinophils in monitoring or diagnosing bronchial asthma need to be established.

[Eosinophil and its pathology]

Hypercosinophilia was previously considered as a biological marker, particularly useful for diagnostic investigation. However, it can also appear as a marker of disease activity since fundamental studies have revealed the potent pathogenic role of human eosinophils. This new appreciation is related to a better definition of the molecular and cellular basis of eosinophil functions. Thus, eosinophils were identified as inflammatory and/or cytotoxic cells after the characterization of the role of surface molecules (adhesion molecules, Fc receptor of immunoglobulins) and mediators. The molecular components which endow the eosinophil with certain of its functional characteristics are primarily the cationic proteins of the specific granules and the phospholipid mediators that are newly formed during cellular activation. Some of these effector molecules are also directly involved in the induction of deleterious effects.

Priming of eosinophil and neutrophil migratory responses by interleukin 3 and interleukin 5

In the present study the influence of interleukin 3 and interleukin 5 on the migration of normal eosinophil and neutrophil granulocytes has been investigated. LTB4, PAF, f-MLP, C5a and ZAS were used as chemoattractants, and HSA and pooled normal human serum were used as chemokinetic agents. Recombinant human IL-5 (rh-IL5) at a concentration of 4 x 10(-12) mol/l was chemotactic for eosinophils, while recombinant mouse IL-5 (rm-IL5) attracted both eosinophils and neutrophils. IL-3 (rh-IL3) at a concentration around 10(-12) mol/l exerted a priming effect on eosinophil and neutrophil migration, i.e. chemotactic and chemokinetic responses to all agents tested. Human IL-5 at a concentration of 2 to 20 x 10(-12) mol/l primed the chemotactic and chemokinetic responses of eosinophils to all agents tested. The migration of neutrophils was also primed by rh-IL5, but at higher concentrations, i.e. around 10(-10) mol/l. IL-5 of mouse origin primed the migration of both eosinophils and neutrophils. In conclusion, IL-3 primed the migratory function of both eosinophils and neutrophils, while IL-5 was a more potent primer of eosinophil than of neutrophil migration.

Present and future clinical relevance of interleukin 3

Interleukin 3 (IL-3) is a hematopoietic growth factor with a pronounced thrombopoietic activity as well as a broad spectrum of activities on multipotent, committed and mature cells of different lineages. Available for clinical trials since 1989, IL-3 has been used in well over two thousand patients. In numerous phase I-II clinical trials, the tolerability profile and the various biologic activities have been defined, and ongoing phase III trials will finally establish its clinical relevance. Doses between 2.5 and 10 micrograms/kg/d given subcutaneously are well tolerated, cause low grade fever, occasional flu-like symptoms and headache. At these doses IL-3 enhances platelet and neutrophil recovery after cycles of myelotoxic chemotherapy, resulting in better adherence to the planned chemotherapy doses and schedules and a decrease in the need for platelet transfusions. Accelerated engraftment of platelets and neutrophils is seen with IL-3 also after bone marrow transplantation. The effect on neutrophil recovery can be enhanced by the use of a myeloid growth factor such as granulocyte-macrophage colony-stimulating factor (GM-CSF) or granulocyte (G)-CSF after five to 10 days of IL-3. Treatment enhancement is related to the effect of IL-3 on the proliferation of hematopoietic progenitors, which leads to an increase in target cells for GM- or G-CSF. Because of the increase in bone marrow proliferation, IL-3 is being used to increase the mobilization of progenitor cells to the blood and in bone marrow failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor beta abrogates the effects of hematopoietins on eosinophils and induces their apoptosis

Hematopoietins, interleukin (IL)-3, IL-5, and granulocyte/macrophage colony-stimulating factor (GM-CSF) have previously been shown to prolong eosinophil survival and abrogate apoptosis. The objective of this study was to investigate the effect of transforming growth factor beta (TGF-beta) on eosinophil survival and apoptosis. Eosinophils from peripheral blood of mildly eosinophilic donors were isolated to > 97% purity using discontinuous Percoll density gradient. Eosinophils were cultured with hematopoietins with or without TGF-beta for 4 d and their viability was assessed. We confirmed previous observations that hematopoietins prolonged eosinophil survival and inhibited apoptosis. TGF-beta at concentrations > or = 10(-12) M abrogated the survival-prolonging effects of hematopoietins in a dose-dependent manner and induced apoptosis as determined by DNA fragmentation in agarose gels. The effect of TGF-beta was blocked by an anti-TGF-beta antibody. The anti-TGF-beta antibody also prolonged eosinophil survival on its own. The culture of eosinophils with IL-3 and GM-CSF stimulated the synthesis of GM-CSF and IL-5, respectively, suggesting an autocrine mechanism of growth factor production. TGF-beta inhibited the synthesis of GM-CSF and IL-5 by eosinophils. TGF-beta did not have any effect on the expression of GM-CSF receptors on eosinophils. We also studied the effect of TGF-beta on eosinophil function and found that TGF-beta inhibited the release of eosinophil peroxidase. Thus, TGF-beta seems to inhibit eosinophil survival and function. The inhibition of endogenous synthesis of hematopoietins may be one mechanism by which TGF-beta blocks eosinophil survival and induces apoptosis.

Serum levels of major basic protein in patients with or without eosinophilia: measurement by enzyme-linked immunosorbent assay

A bone marrow proteoglycan (BMPG) has been purified which consists of the same amino acid sequence as that of pro-MBP, and produced two anti-BMPG mAbs. Serum levels of major basic protein (MBP), a cationic protein rich in the eosinophil granule, were measured in patients with eosinophilia or allergic diseases by an enzyme-linked immunosorbent assay (ELISA) using these mAbs. The serum levels of MBP in patients with eosinophilia (n = 64) and in those with allergic diseases without eosinophilia (n = 32) were elevated significantly (P < 0.001 and P = 0.038, respectively). There was a weak positive correlation between the serum levels of MBP and the eosinophil counts in the patients with eosinophilia (r = 0.38). Among these patients, extremely high serum levels of MBP were found in those with hypereosinophilic syndrome (HES) and Kimura's disease. Serum levels of MBP decreased more slowly than the eosinophil counts in patients with eosinophilia when treated by glucocorticoids. We conclude that measurement of serum levels of MBP is useful in evaluating the total-body proliferation and infiltration of eosinophils more accurately than following-up the eosinophil counts alone.