Late cutaneous allergic responses in isolated IgE-dependent reactions

Endogenous cortisol regulates immunoglobulin E-dependent late phase reactions

To investigate the impact that physiological variation in serum cortisol has on IgE-mediated events, 10 atopic subjects underwent cutaneous antigen challenge with measurement of the early phase wheal (EPW) at 20 min and the late phase reaction (LPR) at 6 h. All subjects were challenged during control conditions between 8:00 and 9:00 a.m. Repeat challenges were performed in five subjects at 6:00 p.m. and in eight subjects after ingestion of metyrapone, a specific inhibitor of cortisol synthesis. Compared with control values, mean serum cortisol was suppressed in the evening and after metyrapone (P less than 0.05 all time points). No effect was seen on the EPW, but mean LPR diameters at three antigen dilutions were significantly increased by cortisol suppression (P less than 0.05). Replacement doses of hydrocortisone given in the evening and with metyrapone abrogated these increases. Blinded analysis of LPR biopsies from cortisol-suppressed subjects revealed increases in leukocytoclasis (P less than or equal to 0.0001), interstitial leukocytes (P less than or equal to 0.01), and eosinophils (P less than or equal to 0.04). These results indicate that physiological levels of serum cortisol can regulate IgE-dependent cutaneous inflammation by affecting the expression of cellular events at late phase sites.

Immunohistology of the nasal mucosa following allergen-induced rhinitis. Identification of activated T lymphocytes, eosinophils, and neutrophils

We have studied the immunohistology of the nasal mucosa in allergen-induced rhinitis. Sixteen grass pollen-sensitive patients were challenged twice by randomly allocated allergen or control solutions applied on filter paper disks to the inferior turbinate. All had immediate nasal responses, but late-phase responses were equivocal and only evident as nostril blockage. When cell counts in the nasal submucosa were compared with control values 24 h after allergen, there were no changes in CD45+ (total leukocytes), CD3+, or CD8+ cells. Significant increases were found in the numbers of CD4+ T-helper cells (p less than 0.05) and CD25+ [interleukin-2 receptor (IL-2R+)] cells (p less than 0.02). Increases in eosinophils (anti-major basic protein, p less than 0.01) and neutrophils (antineutrophil elastase, p less than 0.01) were also observed. There were increases in tissue macrophages and HLA-DR-positive immunostaining and a reduction in mast cells (tryptase positive), but none of these changes was statistically significant. No significant changes in epithelial thickness, cross-sectional area, or integrity were observed. There was a significant correlation between CD4+ and CD25+ cells (r = 0.61, p less than 0.01) but not between macrophages and CD25+ cells (r = 0.18). The changes in the nasal submucosa were not merely a reflection of alterations in circulating cell populations since it was shown that a significant increase in the lymphocyte CD4/CD8 ratio (p less than 0.05) was observed in nasal biopsies but not in peripheral blood after allergen challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemopoietic growth factors induce human basophil migration in vitro

Accumulation of basophils in inflammatory sites is an important aspect of the late-phase allergic reaction involving skin and upper and lower airways, suggesting the existence of mechanisms for basophil migration. Because haemopoietic growth factors have been shown to stimulate various functions of human basophils, we tested the ability of haemopoietic growth factors to migrate basophils in vitro. Both IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induced migration of purified normal basophils (purity c. 80%) in a dose-dependent fashion at picomolar concentrations, while granulocyte (G)-CSF, macrophage (M)-CSF, and IL-4 had no effect at all. Chequerboard analyses indicate that migratory activity of both factors are chemokinetic. These results suggest that local production of both factors during allergic reactions might potentially play an initial role in the recruitment of basophils from the circulation to sites of inflammatory reactions.

Inhibitory effects of formoterol and terbutaline on the development of late phase skin reactions

The capacity of the beta 2-agonist terbutaline and the longer-acting beta 2-agonist formoterol to suppress the development of late phase skin reactions to anti-human IgE was evaluated in 17 healthy volunteers. Anti-IgE injected intradermally per se induced an early weal and flare reaction, followed by a progressively increasing induration, the LCR, with a duration of greater than or equal to 24 hr. The LCR was inhibited by 40% when the weal was infiltrated with formoterol 250 ng 30 min after challenge (n = 9, P less than 0.01). The same anti-LCR effect was achieved by compensating for the shorter duration of action of terbutaline with repeated drug infiltration in 12.5 micrograms doses of the weal produced by anti-IgE up to 3 1/2 hr after challenge (n = 8). The data support the hypothesis that beta 2-agonists, both short- and long-acting, inhibit IgE-dependent LCRs by preferentially interacting with inflammatory events after the initial mast cell degranulation.

Activation of the coagulation pathway during ongoing allergic cutaneous reactions in humans

The levels of histamine, fibrinopeptide A (FPA), and IgG were determined in chamber fluids overlying sites of antigen versus buffer incubation for up to 7 hours in seven atopic and four antigen-nonreactive subjects. Significant increases in histamine were observed at antigen versus buffer sites in the atopic subjects throughout the 7-hour period. FPA and IgG levels were higher in antigen than in buffer sites from 0 to 5 hours in the atopic subjects. Furthermore, FPA levels correlated with the magnitude of induration at 6 hours after antigen injection in atopic subjects. There were no differences in the levels of histamine, FPA, or IgG at antigen versus buffer sites in the skin test-negative subjects. We suggest that the combination of vascular leakage of proteins, induced by vasoactive mediator release, and activation of these proteins during ongoing cutaneous reactions is responsible for fibrin formation that contributes to the pathophysiology of late-phase allergic responses in the skin.

Allergic asthma to Bacillus subtilis enzyme: a model for the effects of inhalable proteins

The passage of 24 years since the diagnosis of allergic asthma in heavily exposed workers and in a few consumers due to dusty enzyme preparations of Bacillus subtilis compounded with laundry powder makes it possible to review objectively the many problems it raised. It emphasizes the lessons to be learned, relevant to inhalable enzyme products and to other inhalable proteins in general. Occupational allergic respiratory diseases were little studied at the time and the enzyme problems stimulated interest in what has now become a well-established and important field of medicine involving not only protein allergens but low molecular weight chemicals as well.

Profile of prostanoid release following antigen challenge in vivo in the skin of man

We have previously characterized the kinetics of prostaglandin D2 (PGD2) production at cutaneous sites of allergic inflammation employing a blister-chamber model. In this study, a more complete profile of prostaglandins released in vivo was obtained. PGD2 release, as measured by radioimmunoassay and by combined gas chromatography-mass spectrometry, was evident within 1 h after antigen challenge with maximal levels occurring 3-4 h post-challenge. The 11-ketoreductase metabolite of PGD2, 9 alpha, 11 beta-prostaglandin F2 was present in blister fluid from three of six patients at the time of maximal levels of PGD2. The stable non-enzymatic hydrolysis product of prostacyclin, 6-keto-prostaglandin F1 alpha, was significantly elevated in blister fluid from five of six patients following antigen challenge. In these subjects, the levels of 6 kappa-PGF1 alpha were highest in samples obtained 1 and 2 h after antigen challenge and remained significantly elevated until 5 h post-challenge. Levels of prostaglandin E2, prostaglandin F2 alpha and thromboxane B2 did not vary significantly. These studies suggest that following antigen challenge two fatty-acid cyclo-oxygenase products of arachidonic acid are released, PGD2 and prostacyclin. The 11-ketoreductase metabolism of PGD2 to 9 alpha, 11 beta-PGF2 could represent a mechanism by which the biological effects of PGD2 are prolonged in cutaneous tissue. The presence of 6 kappa-PGF1 alpha in the blister fluid suggests that significant prostacyclin release occurs as the result of antigen challenge and could represent a mechanism by which the prolonged microvascular response in cutaneous tissue may occur.

Failure to detect deposition of complement and immunoglobulin in allergen-induced late-phase skin reaction in atopic subjects

There still remains some controversy regarding the possible role of immune complexes in the pathogenesis of the late-phase skin reaction (LPSR). To assess this, skin biopsies were obtained from LPSR induced in atopic human subjects 6, 24 and 48 h after allergen challenge. Cryostat sections were stained by direct immunofluorescence for the presence of fibrinogen, immunoglobulin classes IgM and IgG and for the complement components C1q and C3c. Complement components were observed in only two of the 29 biopsies studied. In both instances, only C3c was detected. One of these subjects also had unequivocal IgG staining at 6 h. IgM staining was detected in two out of 10 subjects at 6 h but no significant deposition of immunoglobulins could be found at 24 or 48 h. Fibrinogen deposition was observed in about half of the biopsies at each time-point. This study suggests that substantial complement and immunoglobulin deposition are not overt features of the allergen-induced LPSR, although the presence of small amounts of immune complexes, below the sensitivity of the method employed cannot be excluded. Fibrin deposition occurs in the LPSR but does not appear to be a prerequisite for LPSR development.

Effect of H1-receptor blockade on late cutaneous reactions to antigen: a double-blind, controlled study

This study is of the effect of the blockade of histamine H1 receptors by a long-acting antihistamine on the immediate and late clinical response to antigen (Ag) and on the recruitment of eosinophils in the late-phase cutaneous reaction. Ten adult volunteers with late-phase reactions to the intradermal injection of either Dermatophagoides pteronyssinus or Phleum pratense (timothy) pollen performed a double-blind, crossover study. Each volunteer took astemizole, 10 mg, or identical placebo, daily for 2 weeks. Ag in the concentration that induced a late reaction in the screening visit was injected intradermally at the end of each drug period. The early reaction was measured serially for 30 minutes and the late reaction at 4 and 6 hours. Biopsies of the Ag and control sites were also performed at 6 hours. After a 6-week washout period, subjects then took the opposite medication for 2 weeks and returned for skin testing and biopsy. Skin testing demonstrated that astemizole inhibited the immediate response to both histamine and allergen but had no effect on the late response at 4 hours and at 6 hours. Biopsy specimens revealed no significant effect on eosinophil recruitment at 6 hours. We conclude that histamine H1-receptor blockade has no effect on the late cutaneous reaction to Ag.

Expression of endothelial-leukocyte adhesion molecule-1 in elicited late phase allergic reactions

To better understand the events involved in the local migration of inflammatory cells into sites of allergic reactions, we studied expression of the cytokine inducible endothelial cell (EC) neutrophil adhesion molecule, endothelial-leukocyte adhesion molecule (ELAM-1), in sequential skin biopsies from patients with respiratory allergy during the late phase reaction (LPR) between 20 min and until 24 h after intradermal allergen (ragweed or dust mites) injection. In 7 of 7 atopic patients but in only 1 of 4 apparently normal controls, allergen induced appearance of ELAM-1 on EC. ELAM-1 expression occurred concurrently with the development of inflammatory cell infiltrates by 3-4 h after intradermal injection. Saline injected sites in all subjects were negative. Skin organ cultures demonstrated that allergen could produce the same EC changes in vitro whether allergen was injected in vivo 20 min before culture or added during skin culture. These EC changes in organ culture were inhibited by the presence of combined anti-sera to both TNF-alpha and IL-1, but not by antisera to either cytokine alone. We conclude that EC activation occurs in elicited LPR and suggest that cytokine-induced EC activation may play a role in the migration of inflammatory cells into allergic skin reactions. Furthermore, resident cells in the skin rather than infiltrating leukocytes appear to be the source of the cytokines that mediate endothelial activation.

Recruitment of neutrophils during IgE-dependent cutaneous late phase reactions in the mouse is mast cell-dependent. Partial inhibition of the reaction with antiserum against tumor necrosis factor-alpha

Much of the clinically important pathology associated with IgE-dependent disorders is thought to reflect the actions of the blood-borne leukocytes recruited during these responses. To evaluate the extent to which mast cells are responsible for the leukocyte infiltration associated with IgE-dependent cutaneous reactions, we attempted to elicit these responses in normal mice, genetically mast cell-deficient W/Wv mice, and in W/Wv mice selectively repaired of their mast cell deficiency by the intradermal injection of cultured mast cells derived from the congenic normal (+/+) mice. We found that the tissue swelling associated with IgE-dependent passive cutaneous anaphylaxis reactions developed rapidly and diminished markedly from 2 to 4 h after antigen challenge, but remained detectable for at least 24 h after elicitation of the responses. Infiltration of leukocytes (predominantly neutrophils) also occurred at these sites, but reached maximal levels 6-12 h after antigen challenge, persisted at high levels for 24 h, and largely waned by 48 h. Virtually all of the tissue swelling and leukocyte infiltration associated with IgE-dependent cutaneous reactions was mast cell dependent. Intradermal injection of 40 U of recombinant murine TNF-alpha (rmTNF-alpha) elicited neutrophil infiltration similar in magnitude and kinetics to that observed after IgE-dependent mast cell degranulation. A rabbit anti-rmTNF-alpha (R anti-rmTNF-alpha) antiserum, which was able to inhibit 84% of the neutrophil infiltration observed after i.d. injection of rmTNF-alpha, inhibited IgE-, and mast cell-dependent leukocyte infiltration by 47 +/- 7% in three separate experiments. These findings indicate that TNF-alpha contributes to mast cell-dependent recruitment of leukocytes during IgE-dependent cutaneous late phase reactions, but suggest that other mast cell-associated mediators probably also contribute to this response.

Histamine-releasing factors and heterogeneity of IgE

The duration and severity of the allergic response are variable. Even though antigens are rapidly cleared from the individual, an acute allergic response is frequently followed by a recrudescence of symptoms hours or even days after the initial exposure. Experimentally, the cellular infiltrates and mediators released during this late response resemble those associated with chronic inflammatory disease. Although basophils are present in this late reaction, the stimuli for their activation remain unknown. A heterogeneous group of unique cytokines called histamine-releasing factors (HRF), discovered over a decade ago, may well play a role in stimulating basophils during this late-phase reaction. These factors have been reported from a variety of cell sources including alveolar macrophages, platelets, vascular endothelial cells, B and T lymphocytes, mononuclear cell cultures, the U937 monocyte/macrophage-like cell line and the RPMI 8866 B cell line. These ubiquitous factors cause non-cytotoxic, calcium-dependent mediator release from human basophils in vitro and are also present and active in vivo. Purification attempts have revealed that HRF exists in at least three forms, based on molecular weight. In our hands, the mechanism of mediator release by one of the forms of HRF is IgE dependent. Since only about 50% of allergic donors' basophils respond to HRF, a heretofore unappreciated heterogeneity of IgE was revealed. The presence of HRF has been shown to correlate with severity of allergic disease in children with food allergies, with symptoms in the late-phase response in adults and with severity of the allergic response to an inhaled antigen. Thus, the study of HRF has evolved over the last decade and may lead to better understanding of the complex allergic response.

Interleukin-1 is released at sites of human cutaneous allergic reactions

Interleukin-1 (IL-1) promotes cell recruitment and influences allergic mediator release. We analyzed histamine, prostaglandin D2, IL-1, and leukocytes accumulating hourly for 12 hours at skin-chamber sites after local ragweed challenge in eight allergic subjects with cutaneous late-phase reactions. Ragweed induced a peak of histamine at 1 hour (p less than 0.02), which diminished, and then steadily increased (p less than 0.02). Prostaglandin D2 levels peaked by the second hour (p less than 0.02) and then decreased, approaching prechallenge levels by 12 hours. Leukocyte infiltration (predominantly neutrophils) was detectable 3 to 4 hours after challenge, although selective enrichment of mononuclear cells, eosinophils, and basophils ws observed at later hours (p less than 0.02). IL-1 bioactivity was detected in fluids 10 to 12 hours after challenge but not at control sites (p less than 0.05). Analysis of IL-1 beta levels by RIA revealed an initial peak at 1 hour of 0.90 ng/ml (p less than 0.02) and a second elevation of up to 0.75 ng/ml during the later hours (p less than 0.04). Ragweed challenge of three nonatopic subjects did not change levels of the above-mentioned mediators or cells. Bioactivity in chamber fluids from antigen-challenged sites of atopic subjects was significantly neutralized by an anti-IL-1 beta antiserum, although treatment with anti-IL-1 alpha and anti-IL-1 beta was needed for complete neutralization, IL-1 released locally during cutaneous allergic reactions may contribute to IgE-dependent cutaneous inflammation.

Allergen dose response and late symptoms in a human model of ocular allergy

Eleven ryegrass-sensitive patients were challenged weekly for 4 weeks with incremental doses of ryegrass allergen applied topically to one eye; a buffer was applied to the other eye. A clinical examination and tear-fluid cytology were performed before challenge and at 20 minutes, 1 hour, and 6 hours after challenge. A significant clinical reaction and neutrophil accumulation in the tear film occurred at 20 minutes. At 1 hour, a clinical response and tear cytologic reaction were present only at higher antigen concentrations. Six hours after antigen challenge, only the highest allergen concentration (320,000 BU/ml) produced a clinical late-phase reaction (LPR) (p less than 0.01) and tear cytologic change (presence of eosinophils and lymphocytes). Five nonryegrass-sensitive control subjects were unresponsive to a similar challenge. These results indicate that a conjunctival response to allergen challenge is dose dependent, that is, the higher the dose, the more likely an LPR will occur and that an LPR correlates with significant numbers of inflammatory cells in the tear film.

A guinea pig model for study of bladder mast cell function: histamine release and smooth muscle contraction

To study the function of mast cells in bladder tissue, guinea pigs were sensitized with ovalbumin by intraperitoneal injections, bladder tissue strips were superfused, and tissue contractile force and histamine release were studied. Upon challenge with ovalbumin, bladder tissue contracted 64 +/- 4% (mean +/- S.E.M.) of the maximum carbachol contraction and released 14.1 +/- 1.6% of the total tissue histamine content. Incubation of sensitized bladder tissue with indomethacin led to an increased force and duration of the contraction while incubation with nordihydroguaiaretic acid combined with pyrilamine reduced histamine release and abolished the contraction. Tissue histamine content was significantly higher in the bladder neck than in the dome, and significantly elevated following sensitization. Histochemical studies of bladder tissue demonstrated mast cell degranulation in antigen challenge experiments. In addition, a group of guinea pigs were sensitized to ovalbumin through bladder instillations. With this model, study of the functional characteristics of bladder mast cells and the acute actions of mast cell products on the bladder microenvironment, should now be feasible.

Inhibition of anti-IgE induced skin response in normals by formoterol, a new beta 2-adrenoceptor agonist, and terbutaline. 2. Effect on the late phase reaction

Formoterol, a new beta 2-selective long-acting bronchodilator, was compared with terbutaline in terms of ability to inhibit dual phase skin reactions to anti-human IgE in volunteers. Anti-IgE induced an early wheal and flare reaction (WFR) followed by a progressively increasing induration, the late phase reaction (LCR), lasting greater than or equal to 24 h. Intradermal injection of formoterol 20 ng or terbutaline 500 ng 5 min before challenge gave equal inhibition of the WFR. The subsequent LCR was suppressed by formoterol (30%) for the whole 24 h period, while terbutaline only attenuated the first 4 h period. Increasing the dose range of both drugs 25-fold, caused a further analogous reduction of the WFR to anti-IgE. In this higher dose range formoterol (0.5 micrograms) antagonized the following 1-24 h LCR by 50%, while terbutaline (25 micrograms) only attenuated the LCR by an average of 20%, with higher effect in the first 6 h period. The anti-LCR capacity of formoterol was highly superior to that of terbutaline (P less than 0.001). The histamine-elicited wheal response was attenuated by both drugs, but they had no effect on the flare response, favouring an anti-permeability action of both compounds. The data support the concept that terbutaline, given locally in a single dose shortly before challenge, inhibits the mast cell mediator release reaction with limited consequences for the following LCR. In contrast to terbutaline, formoterol exerted a substantial anti-LCR action, probably by interfering with inflammatory mechanisms after the initial mast cell mediator release.

Release of histamine and tryptase during continuous and interrupted cutaneous challenge with allergen in humans

To help in understanding the patterns of in vivo mediator release in human allergic skin reactions, we have used a skin chamber model to challenge the denuded bases of skin blisters of 11 sensitive subjects with pollen antigens (Ags) and codeine (C), a mast cell degranulator. Challenges were performed either (1) continuously for 6 hours or (2) in an intermittent fashion that is, Ag or C for the first hour, buffer for the next 4 hours, and then Ag or C during the sixth hour. Fluids in the overlying chamber were assayed for levels of the mast cell components, histamine and tryptase. There was peak release of both histamine and tryptase during the first hour of Ag incubation (89 +/- 11 ng/ml and 1428 +/- 260 ng/ml, respectively). At continuous Ag-challenge sites, there was a plateau of histamine levels (8.0 to 9.5 ng/ml) during the next 4 hours, whereas tryptase levels decreased progressively to baseline levels. Challenge of continuous Ag-incubation sites with C, a mast cell activator, led to another peak release of both histamine and tryptase. At interrupted Ag-challenge sites, histamine levels decreased abruptly, and tryptase levels decreased progressively after the first hour. Rechallenge of such sites with Ag during the sixth hour induced a peak release of histamine but no increase in tryptase levels. Continuous challenge with C for up to 5 hours in other sites induced an initial peak histamine release without a subsequent plateau. However, such a plateau of histamine (but not tryptase) release occurred after an initial C challenge if Ag was subsequently incubated in a continuous fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions between histamine and prostanoids in IgE-dependent, late cutaneous reactions in man

The contribution of histamine and cyclooxygenase metabolites of arachidonic acid to the wheal-and-flare reaction (WFR) (0 to 30 minutes) and the late cutaneous reaction (LCR) (1 to 24 hours) evoked by intradermal injection of antihuman IgE was appreciated in a comprehensive study of human volunteers treated with H1 and H2 antihistamines, cyclooxygenase inhibitors, as well as the combination of both types of drugs. The findings reinforce the concept that histamine is the major, but not exclusive, mediator of the WFR. In contrast, histamine accounted for but a limited portion of the LCR, but 48 hours of pretreatment with three different cyclooxygenase inhibitors, acetylsalicylic acid, indomethacin, or diclofenac sodium, had but a minor influence on the WFR, whereas all drugs produced a distinct overall inhibition of the LCR. However, for indomethacin, the inhibition was preceded by a potentiation (at 1 to 2 hours), which was abolished by antihistamines, suggesting increased histamine release from skin mast cells after cyclooxygenase inhibition. Furthermore, there was synergism between indomethacin and antihistamines during the LCR, and the combination of diclofenac sodium with antihistamines produced additive inhibition. It is proposed that cyclooxygenase products, such as prostaglandins and thromboxanes, contribute to IgE-dependent skin reactions, both as modulators of mediator release and as vasoactive mediators.

Does reversed-type anaphylaxis in healthy subjects mimic a real allergic reaction?

Immediate and late cutaneous reactions were induced in healthy and atopic subjects by anti-IgE challenge and a skin-window technique was used in order to verify if the pattern of cells observed at 24 hr was similar in both groups. The study was first performed under basal conditions, and in a second double-blind cross-over step, it was performed again during treatment with cetirizine 10 mg b.i.d. and terfenadine 60 mg b.i.d. Anti-IgE challenge was followed by a significant eosinophil accumulation in atopic subjects only. Cetirizine significantly inhibited this phenomenon while terfenadine showed a mild non-significant inhibitory effect.

Evidence that neutrophils do not participate in the late-phase airway response provoked by ovalbumin inhalation in conscious, sensitized guinea pigs

Inhalation of ovalbumin by conscious, sensitized guinea pigs induced two phases of airway obstruction measured at 2 h (EAR) and at 17 h (LAR), respectively. In addition to causing airway obstruction, allergen challenge induced an accumulation in the bronchial lumen of eosinophil and neutrophil polymorphonuclear leukocytes at 17 h. Intraperitoneal injection of guinea pigs with a specific rabbit anti-guinea pig neutrophil serum 24 h before challenge reduced the number of circulating neutrophils by 94% and the airway neutrophilia after challenge by 90%, but it had no effect on the magnitude of either the EAR or the LAR. The observation that the LAR was not effected by neutropenia supports previous conclusions derived from experiments using the anti-allergic drugs, cromolyn sodium and nedocromil sodium, and the beta 2-adrenoceptor stimulant, albuterol, that, although there is a temporal relationship between neutrophil accumulation in the airways and the peak of the LAR, this polymorphonuclear leukocyte does not play a central role in the pathophysiologic processes that give rise to the late-phase response to guinea pig airways.

The neutrophil and chronic allergic inflammation. Immunochemical localization of neutrophil elastase

To test whether neutrophils infiltrate and degranulate in areas of chronic respiratory allergic inflammation, we developed an indirect immunofluorescence technique to localize neutrophil elastase in formalin-fixed, paraffin-embedded tissues. The affinity-purified antielastase stained only neutrophils on peripheral blood buffy coat smears, and in lung tissue from patients with pneumonia. We examined tissue specimens from four patients with fatal asthma, 10 patients with chronic sinusitis, and 10 patients with nasal polyposis for the presence of elastase, as well as eosinophil granule major basic protein (MBP). Neutrophil infiltration and extracellular elastase deposition in association with damage to respiratory epithelium were generally sparse in most specimens; the exceptions were one patient with asthma, one patient with chronic sinusitis, and two patients with nasal polyposis. In contrast, eosinophil infiltration and extracellular MBP deposition were generally marked in most specimens; the exceptions were one patient with asthma and one patient with nasal polyps where extracellular MBP deposition did not coincide with damage to respiratory epithelium. The results suggest that the neutrophil does not usually infiltrate tissues showing allergic inflammation; however, on occasion, it may participate in these inflammatory reactions.

New concepts in the pathogenesis of asthma

Heightened airways reactivity is a major characteristic of asthma. Several stimuli capable of producing an inflammatory reaction within the respiratory tract can increase airways reactivity in both normal and asthmatic subjects. The association between lower airways inflammation and alterations in airways function has been studied most extensively after antigen exposure leading to an immediate and/or late asthmatic response in atopic subjects. The late asthmatic response (LAR) is of special interest because it lasts for hours, is prevented by corticosteroids and not adrenergic agents, and is associated with more severe asthma as well as increases in airways responsiveness. While late phase reactions in the lung and skin were initially thought to be Arthus reactions, more recent observations in man and animal models suggest they may be initiated when antigen-specific IgE is present, and may be blunted by antigen-specific IgG. In terms of pathology, immediate reactions are characterized primarily by edema while late phase reactions are associated with infiltration of the involved tissues with inflammatory cells. The potential importance of granulocytes to the reactions in the skin of rats and the lungs of rabbits was suggested when cytotoxic drugs that produced granulocytopenia prevented late phase responses. Several other factors also appear to be important in determining if an LAR will occur. These include the antigen load, level of airways reactivity, histamine releasing factors, lymphocyte populations within the lung, and endogenous corticosteroid levels. While various mediators of inflammation and hypersensitivity such as platelet activating factor and cyclooxygenase and lipoxygenase products of arachidonic acid metabolism produce some of the clinical features seen in asthma, one mediator is unlikely to be responsible for all the manifestations of this disorder. Rather, a series of cell-to-cell interactions mediated through the products they release are likely to produce the pathologic and physiologic features of the disease.

Nasal mucosal response to repeated challenges with pollen allergen

In order to explore the dynamics of the cellular response of the airway mucosa to allergen exposure, controlled daily allergen challenges were performed for 7 days during the pollen-free winter months in nine patients with strictly seasonal allergic rhinitis caused by birch pollen allergen. Symptoms obtained after the challenge were related to morphologic changes within and on the surface of the nasal mucosa. Cell samples were obtained daily prior to challenge from the nasal mucosa using mucosal imprints on plastic strips, brush samplings from the nasal mucosa, and nasal lavage. For light microscopy, the cellular material obtained by brushing and nasal lavage were cytocentrifuged onto object slides. Histamine was measured in the cell pellets that were obtained using the lavage and brush procedures as well as in the lavage supernatant fluid. Four symptoms (sneezes, itching, secretion, and blockage) were recorded and expressed individually as well as in the form of a composite symptom score. Nasal blockage was measured using a nasal peak flow meter. The patients displayed an increase in nasal symptoms after the allergen challenge, which was further increased between Days 2 to 7 (p less than 0.05). The light microscopic evaluation of the lavage revealed an immediate increase in eosinophils from 2.3 to 13.1% and was maintained on the same level throughout the period of challenges. A similar increase was noted in the brush specimens, and a strong correlation was obtained between these two methods of sampling.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of the cutaneous response to antigen by a thromboxane-synthetase inhibitor (OKY-046) in allergic dogs

We studied the effect of a selective thromboxane-synthetase inhibitor, sodium (E)-3-[4-(1-imidazolymethyl)-phenyl]-2-propanoate) (OKY-046) on the late-phase response to antigen in ragweed-sensitized dogs. Skin biopsies were performed before and 1, 6, and 24 hours after ragweed injection. OKY-046 was infused (100 micrograms.kg-1.min) from 1 hour before until 6 hours after intracutaneous ragweed in five dogs. The early clinical response to ragweed (wheal at 20 minutes) was not changed by OKY-046. A late-phase response (induration at 6 hours) was not observed in any of the OKY-046-treated dogs but was present at 6 hours in 4/5 dogs without OKY-046. Typical mast cells responded similarly in both groups with progressive degranulation during 24 hours. Maximal degranulation of atypical mast cells was delayed to 6 hours with OKY-046, whereas these cells responded completely at 1 hour without OKY-046. The inflammatory response to ragweed followed the same pattern in both groups, but the numbers of each cell type were decreased with OKY-046. With OKY-046, the cutaneous response to histamine was not changed significantly from baseline at 6 hours but was increased (p less than 0.05) at 24 hours, whereas without OKY-046, histamine response was significantly increased at 6 hours (p less than 0.001) and 24 hours (p less than 0.01). We conclude that OKY-046 alters the antigen-induced response of atypical mast cells, the subsequent cellular and clinical late-phase response, and prevents the increase in histamine response.

The human skin mast cell

The abundance of mast cells in human dermis, together with their ability to release a variety of vasoactive and pro-inflammatory mediators following cross-linkage of their cell-surface receptors for IgE, enables these cells to provide an effective defence mechanism within this organ. A similar defensive function is attributed to mast cells of other human organs such as intestine and lung which are in contact with the external environment and therefore susceptible to infiltration by foreign allergens and micro-organisms. However, mast cells of the skin apparently differ from those present in lung and intestine in being activated for histamine release by a variety of endogenous neuropeptides which stimulate the rapid release of histamine in the virtual absence of eicosanoids. This would provide a mechanism of neurogenic control of a variety of homeostatic functions such as blood flow, angiogenesis and fibroblast proliferation. Such processes would aid in the remodelling of tissue during wound healing, and increased numbers of mast cells have been noted around healing wounds of rat skin and areas of developing fibrosis. Neuropeptides modulate the activity of a variety of immuno-competent leucocytes including macrophages, monocytes and lymphocytes. The findings that skin mast cells are activated by neuropeptides suggest that these cells may also be included amongst those involved in neuro-immune interactions. Activation of skin mast cells by non-immunological stimuli may contribute to the aetiology of some forms of skin disease. Patients with chronic idiopathic urticaria appear to have enhanced vascular responsiveness to intradermal injections of the histamine liberator codeine suggesting that this disease may involve hyper-responsiveness of their mast cells to endogenous non-immunological stimuli. The findings of large increases in histamine accompanied by small increases in PGD2 in venous effluent of thermally challenged limbs of patients with cold- or heat-induced urticaria may suggest that their mast cells had been activated by a non-immunological stimulus. However, the interpretation of results gained using such relatively complex in-vivo systems are difficult, as the cellular origin of the detected mediators is by no means clear. However, it is hoped that in the future the alliance of newly developed in-vitro techniques to investigate mast cell function together with in-vivo methods to investigate their interaction with elements in their tissue environment will greatly increase our understanding of the role of the human skin mast cell in health and disease.

The late phase of hematoporphyrin derivative-induced phototoxicity in mice: release of histamine and histologic changes

This study was designed to directly examine the role of mast cells and the histologic changes in the late phase (4-48 h) of hematoporphyrin derivative-induced phototoxicity. BALB/c mice were rendered phototoxic by intraperitoneal injection of HpD, followed by exposure to 1.59 kJ/m2 of 396-406 nm radiation. Immediately before radiation, and at 4, 8, 12, 18, 24 and 48 h after radiation, the ear thickness, serum histamine levels and histologic changes of ears were examined. A maximal net increase in ear thickness of 33.5 +/- 0.3 X 10(-2) mm (mean +/- SE) was noted at 12 h, associated with a maximal net increase of serum histamine (43.3 +/- 11.6 ng/ml, mean +/- SE), and a maximal mast cell degranulation. Other histologic changes consisted of mild epidermal spongiosis at 18-24 h, and a predominant neutrophilic infiltrate, which peaked at 24 h (211.6 +/- 0.4 cells/mm2). No significant alteration was observed in control mice. These data indicated that mast cells participate in the late phase of HpD-induced phototoxicity in mice.

Rabbit F(ab')2 antihuman IgE is a universal skin test reagent in the evaluation of skin mast cell degranulation in vivo

Antihuman IgE is often used to study basophil- and mast cell-mediator release in vitro but is infrequently used in vivo. To evaluate in vivo skin reactivity to anti-IgE, an affinity-purified rabbit F(ab')2 fragment of antihuman IgE was injected intradermally in 22 nonallergic and 27 allergic subjects. All 49 subjects (including a subject with less than 1 ng/ml of total serum IgE) had positive immediate cutaneous reactions to anti-IgE. Although total serum IgE level was weakly correlated (r = -0.51; p less than 0.005) with in vivo skin reactivity to anti-IgE for the entire population, allergic subjects did not have significantly increased skin reactivity compared to nonallergic subjects (p = 0.18), despite having higher total serum IgE levels (p less than 0.002). A late-phase cutaneous response (LPR) to anti-IgE occurred in 60% of the allergic and in 50% of the nonallergic subjects. Subjects with an LPR required approximately tenfold higher concentrations of anti-IgE to produce an immediate wheal of 10 mm compared to subjects who did not develop an LPR (p = 0.02), suggesting that the concentration of the stimulus injected is more important for the development of a LPR than the size of the immediate cutaneous response. Skin reactivity to codeine phosphate (a non-IgE-dependent secretagogue) was correlated with skin reactivity to anti-IgE (r = 0.47; p less than 0.05), suggesting that in vivo skin mast cell degranulation is partially a function of mast cell releasability.(ABSTRACT TRUNCATED AT 250 WORDS)

Cutaneous late-phase response to allergen. Mediator release and inflammatory cell infiltration

To better define the inflammatory infiltrates and kinetics of mediator release during the cutaneous late-phase reaction (LPR), we examined skin biopsies at 8 h, and skin chamber cell counts and mediator release for 12 h after antigen challenge. Compared with the control sites, the antigen-stimulated biopsy sites contained 14 times as many basophils (P less than 0.01) and six times as many eosinophils (P less than 0.001) with one to two fold more mononuclear cells (P less than 0.03) and neutrophils (P less than or equal to 0.01). Similar changes were found in the skin chambers. Although there were neutrophils in the control chamber, they were only twice as numerous in the antigen challenged site (P less than 0.01). Eosinophils were 35-fold (P less than or equal to 0.03) more prevalent in the antigen chamber than the control chamber for hours 8-12 and basophils were noted starting in the eighth hour and were 20-fold (P less than or equal to 0.03) more concentrated in the antigen chamber during the next 4 h. The mononuclear cells were not significantly different between antigen and control blisters. With respect to inflammatory mediators, there was an initial peak of histamine (13.2 +/- 2.9 ng/ml) in the blister fluid at 1 h. The level then fell to approximately 2 ng/ml, followed by a secondary rise starting at the eighth hour and increasing to 9.8 +/- 2.8 ng/ml by the twelfth hour. This secondary increase in histamine correlated significantly (r = 0.81, P less than 0.05) with the observed influx of basophils. PGD2 in the blister fluid rose to 371+/-25 pg/ml during the first 4 h and then slowly decreased to half this level during the last 4 h. Thus, the cutaneous LPR has been shown to manifest a secondary increase in histamine levels and a markedly specific increase in eosinophils and basophils with mediator release apparently being derived from the latter cells.

Dissociation of cutaneous vascular permeability and the development of cutaneous late-phase allergic reactions

Cutaneous late-phase allergic reactions (LPR) are characterized by an early, immediate hypersensitivity whealing reaction followed by persistent, localized induration that peaks 6 to 8 hours later. In this study we used rodents to examine the relationship between vascular permeability (VP) and induration during LPR. Efflux of macromolecular tracers from the vasculature into skin was measured with the use of radiolabeled albumin and neutral dextran tracers having large molecular radii. To induce LPR immunologically, we used either intradermal injections of antirat IgE or passive cutaneous sensitization with IgE antidinitrophenyl followed 24 hours later by intravenous injection of albumin-dinitrophenyl. [125I]albumin and [3H]dextran tracers were injected intravenously before and at various intervals after the induction of LPR. Although a marked increase in VP occurred within the first 30 minutes after induction of mast cell degranulation, analysis of radiolabeled tracer accumulation at 2, 4, 8, and 24 hours failed to demonstrate any further increase in VP. These findings indicate that the induration observed in rodent LPR is not associated with increased VP beyond the immediate hypersensitivity stage and suggest that impairment of lymphatic drainage, cellular infiltration, and/or fibrin deposition are contributing factors.

The effect of an increase in inhaled allergen dose after terfenadine on the occurrence and magnitude of the late asthmatic response

We have attempted to use a potent and selective histamine H1-receptor antagonist terfenadine to allow a larger dose of allergen to be administered to previous single early responders to investigate if an increased dose of allergen could induce a late asthmatic response. Pre-treatment with 180 mg of terfenadine enabled a geometric mean increase in allergen dose of 4.12-fold to be inhaled by eight atopic subjects with mild asthma, who initially were classified as single early responders, with maximal fall in FEV1 3-8 hr after allergen challenge (Lmax) of less than 15% from baseline value. The magnitude of early asthmatic response was similar to that obtained on the control day when allergen challenge was performed in the absence of terfenadine. Two subjects were converted to dual responders with Lmax of 23.1 and 24.3%, which occurred with a 32- and 65-fold increase in allergen dose respectively, and a 6- and 4.9-fold decrease in non-specific airways responsiveness measured as the cumulative provocative concentration of methacholine that caused a 20% fall in FEV1 from baseline. The remaining six subjects failed to achieve an Lmax of greater than 10% even with a 1.29-2.66-fold increase in allergen dose. For the group as a whole an increase in allergen dose was associated with an increase in overall bronchoconstrictor response 3-8 hr after challenge. These results indicate that it is possible to induce a late asthmatic response in a subject who previously demonstrated only an early response by increasing the dose of allergen inhaled.

The cellular response of the human allergic mucosa to natural allergen exposure

It has been suggested that the IgE-dependent late-phase reaction to allergen exposure, with the features of an inflammatory cellular infiltration and airway hyperreactivity, is a link between anaphylaxis and continuous allergic airway disease. Our main knowledge of the cellular response to allergen in sensitized individuals has been derived from allergen-challenge models. To explore the dynamics of the cellular response during the actual disease, patients with a strictly seasonal allergic rhinitis were studied during natural allergen exposure. Ten patients suffering from an isolated birch-pollen allergy were followed from a symptom-free state before, during, and to the height of the birch-pollen season. Repeated parallel cell samplings from the nasal mucosa were performed with cytologic imprints on plastic strips, nasal lavages with the recovery of the cells in the lavage fluid with cytocentrifugation on object slides for cytologic study, and scrapings from the nasal surface with a curette for histologic and ultrastructural evaluation. The histamine content was determined in lavage fluid and cell pellets. The tosyl-alpha-tosyl-L-arginine methyl esterase activity of the nasal lavage fluid was also determined as a biochemical marker of the allergic inflammatory reaction. The birch-pollen season was moderate in terms of pollen counts, and this resulted in mild to moderate nasal symptoms that ran parallel to the birch-pollen counts. The total number of cells recovered in the lavage fluid was 1.2 +/- 0.4 (SEM) x 10(6) before and 3.2 +/- 2.0 per 10(6) cells (not significant) during pollen exposure. Most cells were neutrophils and mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis of allergy in different age groups of children: use of mixed allergen RAST discs, Phadiatop and Paediatric Mix

Childhood asthma often begins in children under 3 years of age. Allergy contributes to the severity and persistence of childhood asthma so we examined the application of mixed allergen RAST discs (Paediatric Mix, a mixture of food antigens and Phadiatop, a mixture of inhalants) to the diagnosis of allergy. One hundred and nine children with a median age of 3 years, 71.6% of whom had asthma, were first assessed by one allergist who recorded their atopic status as positive, negative or questionable, on clinical grounds. Serum from each of these patients was used to determine a total IgE and 13 RAST assays. A laboratory definition of atopy was defined as a serum IgE greater than 1 standard deviation from normal, plus one or more positive RAST assays. The laboratory results influenced the assessment of atopy in 41% of cases. The use of just two mixed allergen discs (Paediatric Mix and Phadiatop) correctly assigned the presence or absence of atopy with a sensitivity of 98% and specificity of 98%, compared with the full laboratory evaluation. Very young infants were often just positive to food allergens but the Phadiatop disc could be used to suggest the onset of immunological sensitivity to inhalant antigens. Thus the application of mixed allergen RAST discs facilitated the diagnosis of atopy in young children.

Isolated late cutaneous skin test response to ampicillin: a distinct entity

A case presentation describes a young woman with a history of two reactions to ampicillin therapy and a reproducible skin test reaction of intermediate timing that disappeared within 48 hours. The skin test response was to ampicillin only and not to other penicillin-related skin test reagents. Tests for serum IgE and IgG antibody to ampicillin were negative. The histology was that of a mononuclear and neutrophilic cellular infiltrate with neutrophil margination in the vessels. There was no immunoglobulin, complement, or fibrin deposition. The skin test reaction began and ended earlier than would be expected for a classic delayed hypersensitivity reaction. It is considered to be an isolated late cutaneous response but cannot yet be designated a late cutaneous allergic response. Reactants characteristic of an Arthus reaction were not present, and no alternative immunologic basis was confirmed.