Human Allergic Skin Reactions Research Articles

Topical cromolyn can modify human allergic skin reactions

Topical cromolyn can modify human allergic skin reactions

Release of eosinophil granule proteins during IgE-mediated allergic skin reactions

To determine whether the eosinophil (EOS), a prominent component of human allergic skin reactions, releases its potentially pathogenic components in vivo, we appended collection chambers to the bases of unroofed skin blisters and challenged the sites for varying time periods with either pollen antigen (Ag) or buffer (B)-control solutions. In seven sensitive subjects, continuous challenge with pollen Ag consistently induced release of more major basic protein (MBP) and eosinophil-derived neutrophil (EDN) than did B solution. Low levels of both MBP and EDN were observed during the first hour with increased accumulation during the second to fifth hour. Comparison of Ag- versus B-challenged site responses in individual subjects demonstrated significantly higher levels of both MBP and EDN at Ag than at B sites during the second to fifth hour. Levels of both MBP and EDN in the second to fifth hour correlated significantly with histamine release in the same sites in the first hour ( r = 0.66 and 0.83, respectively). Imprints of the skin bases of the chambers after 5 hours demonstrated variable numbers of EOS at the Ag-challenged sites and only occasional EOS at the B-challenged sites; most cells on the skin bases were neutrophils. However, immunofluorescence localization of MBP in biopsy specimens of the blister bases revealed striking extra cellular MBP deposition. These findings indicate that EOS components accumulate in vivo in IgE-mediated human skin reactions, even when prominent EOS accumulation is not visualized, possibly because the EOS are degranulated in the allergic-reaction site. Release of EOS components in these reactions may be linked to earlier mast cell activation. Because cationic EOS granule proteins are toxic for tissues, they could play a pathogenic role in late-phase allergic reactions.

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)

Inhibition of human allergic skin reactions in vivo by pretreatment with cromolyn (disodium cromoglycate)

The effect of cromolyn on allergen-induced allergic skin reactions was studied. Two patients with allergic rhinitis, two patients with bronchial asthma and atopic dermatitis and two patients with allergic rhinitis and atopic dermatitis were included in this study. They were allergic to cedar pollen, house dust mite and house dust, respectively. Scratching with allergen induced wheal and erythema reactions in each patient. Simultaneous application of allergen and cromolyn solution did not modulate allergic reactions; however, pretreatment with cromolyn solution inhibited allergen-induced wheal and erythema reactions significantly.

Release of lactoferrin and elastase in human allergic skin reactions.

Our previous skin chamber studies have shown prominent accumulation of viable neutrophils in human allergic skin reaction sites. To determine whether such neutrophils release components that may be pathogenic in allergic reactions, we have compared the patterns of release of five components: 1) lactoferrin, present in specific granules; 2) and 3) elastase and myeloperoxidase, present mainly in azurophilic granules; 4) lactic dehydrogenase, a cytosolic component generally released during cell damage; 5) histamine, present in mast cells and basophils but not in neutrophils. In 13 pollen-sensitive subjects we found that continuous antigen challenge for 5 h lead to a peak of histamine release into overlying skin chambers during the 1st h, followed by a plateau of low level histamine release over the succeeding 4 h. In contrast, there was no significantly increased released of lactoferrin or elastase during the first h, but significantly increased accumulation of these components at Ag challenge sites over the next 4 h. There was no significant difference at Ag vs buffer control sites in the levels of either myeloperoxidase or lactic dehydrogenase. The increased levels of lactoferrin and elastase at antigen challenge sites in the 2nd to 5th h were not simply a reflection of the greater numbers of neutrophils present in such sites because the levels of these components did not correlate significantly with the number of neutrophils in chamber fluids obtained from individual sites. However, such lactoferrin levels did correlate significantly with the amount of histamine released earlier during the 1st h of Ag challenge at individual sites. These findings suggest a selective in vivo release of neutrophil components in IgE-mediated human allergic skin reactions, possibly related in degree to earlier mast cell activation. Inasmuch as lactoferrin likely plays a role in reactive oxidants effects and elastase is a potent nonspecific protease, release of these agents could play a pathogenic role in late phase allergic reactions.

Cellular inflammatory responces in human allergic skin reactions

To define better the role of inflammation in the response to pollen antigens, we have used our skin chamber model to study inflammatory cells recovered from the sites of ongoing allergic reactions. In 15 atopic subjects, paired skin blister sites were simultaneously challenged with ragweed- or grass-pollen antigen or buffer for 5 hours. There were 10 times as many cells recovered at antigen (20.7 × 10 5) than at buffer (20 × 10 5) sites, p < 0.005; > 97% of the cells recovered were neutrophils. The number of cells recovered at the antigen sites correlated with the total amount of histamine released (r = 0.57; p < 0.05) but not with the extinction dilution skin test reactivity nor with the intensity of the late cutaneous allergic response measured 6 hours after the injection of antigen. Phase-contrast microscopic examination of the cells recovered from the antigen sites demonstrated that 82% to 95% were polarized compared to 0% to 1.5% of autologous blood neutrophils obtained simultaneously from the peripheral blood. Antigen site cells were as capable of serum-dependent phagocytosis as peripheral blood neutrophils. There was no significant difference in the migratory response to buffer, the chemoattractant N-formyl-methionyl-leucyl-phenylalanine, or leukotrine B 4, but there was a significantly decreased response to platelet-activating factor when the cells recovered from antigen sites were compared to autologous blood neutrophils. We conclude that during ongoing allergic cutaneous reactions (1) that we can recover a significantly greater number of neutrophils at antigen than at buffer sites, (2) that these cells are capable of chemotaxis and phagocytosis, (3) that these neutrophils appear morphologically different from neutrophils in the peripheral blood, and (4) that the number of neutrophils recovered correlates with the intensity of the ongoing mast cell response as assessed by mediator release.

Accumulation of leukotriene C4 and histamine in human allergic skin reactions.

To determine whether lipoxygenase products of arachidonic acid metabolism are released in vivo during human allergic cutaneous reactions, we serially assayed chamber fluid placed over denuded skin sites for the presence of both C-6 peptide leukotrienes (e.g., LTC4, LTD4, and LTE4) and leukotriene B4 (LTB4), using radioimmune assay and HPLC separation, and compared it to histamine (assayed radioenzymatically) in 13 atopic and two nonatopic volunteers. Skin chamber sites challenged with ragweed or grass pollen antigen (250-750 protein nitrogen units/ml) for the first hour and phosphate-buffered saline (PBS) for the next 3 h were assayed hourly and compared to sites challenged with PBS alone. As assessed by HPLC, LTC4 composed greater than 85% of the C-6 peptide leukotriene released at any skin site, whereas little LTD4 or LTE4 was detected. LTC4 was present in significantly greater concentrations at antigen sites as compared to PBS-challenged sites throughout the 4-h period. Minimal concentrations of LTB4 were found throughout this time period and were not different at antigen or PBS sites. Histamine was present in significantly greater concentrations at antigen rather than PBS sites, but the pattern of release was different from that of LTC4. Peak histamine release invariably occurred during the first hour and decreased progressively thereafter, whereas the greatest amounts of LTC4 were detected during the 2nd to 4th hours. The amount of LTC4 accumulating at the site was dependent upon the dosage of antigen used in the epicutaneous challenge. We have demonstrated in this study that of the leukotrienes assessed LTC4 is released in the greatest quantity in situ during in vivo allergic cutaneous reactions and that it is present at such sites for at least 4 h after antigen challenge. Since intradermal injection of LTC4 in humans induces wheal and flare responses that persist for hours, our findings support the hypothesis that LTC4 is an important mediator of human allergic skin reactions.

315 Patterns of LTC4 release in human allergic skin reactions

315 Patterns of LTC4 release in human allergic skin reactions

Terbutaline modulation of human allergic skin reactions

Terbutaline, a preferential beta 2-adrenergic agonist, has been shown to inhibit allergen-induced histamine release in vitro. In contrast, orally administered therapeutic doses of terbutaline do not inhibit antigen-induced wheal and flare reactions. We studied the effects of local terbutaline on antigen-induced whealing response, histamine release, cellular inflammatory response, and ultramicroscopic mast cell changes in antigen-challenged skin sites in ragweed-sensitive subjects. Results showed that ragweed challenge significantly induced increased histamine release in all subjects. In contrast, no such histamine release was observed at sites challenged with antigen in the presence of terbutaline. Thus locally applied terbutaline in nontoxic doses modulates mediator release in certain allergic reactions.

Cromolyn does not modulate human allergic skin reactions in vivo

Cromolyn pretreatment frequently reduces antigen inhalation-induced bronchospasm possibly by inhibiting mast cell degranulation and mediator release. However, the local effects of cromolyn on type I hypersensitivity skin reactions are not well understood. We studied the effect of local cromolyn on antigen-induced skin reaction, histamine release, cellular inflammatory response, and ultramicroscopic changes of mast cells in 10 ragweed-sensitized subjects. Results showed that cromolyn 2% (nonirritant dose) does not modulate ragweed-induced skin whealing response, histamine release, and ultramicroscopic changes of must cells. Thus, unlike the situation in the tracheobronchial tree, allergic skin reactions and associated events are not inhibited by local cromolyn application.

Allergy and immunology: an annotated bibliography of recent literature. Allergy and Immunology Committee, American College of Physicians.

Allergy and immunology: an annotated bibliography of recent literature. Allergy and Immunology Committee, American College of Physicians.

Cromolyn does not modulate human allergic skin reactions in vivo

Cromolyn does not modulate human allergic skin reactions in vivo

In vivo release of eosinophil chemoattractant activity in human allergic skin reactions.

A search was made for in vivo release of factor(s) that may be responsible for prominent eosinophil accumulations in human allergic skin reactions. Using a specially designed skin chamber appended to the base of unroofed skin blisters, we have found at ragweed-challenged sites in sensitive subjects the release of significantly greater histamine (15 +/- 3 ng/ml) than at control sites (3 +/- 0.5 ng/ml). Eosinophil accumulation after 2 hr was also significantly greater on membrane filters appended to ragweed-challenged sites than control sites (55 +/- 15 vs 4 +/- 0.5). Intradermal injection of ultrafiltrates of the chamber fluids from antigen-challenged sites, but not of fluids from control sites, induced prominent eosinophil accumulation (mean = 25/mm2) when injected intradermally in autologous uninvolved skin. Neither ultrafiltered antigen solution nor histamine (employed in concentrations similar to those released in the chambers) evoked such in vivo responses when injected intradermally in the same subjects (mean = less than 1/mm2). The eosinophil responses to injected ultrafiltered chamber fluid from antigen-challenged sites peaked at 30 min, whereas even greater eosinophil responses to unaltered antigen started after 60 min. These findings suggest that in vivo release of a low m.w. factor or factors other than histamine is very likely responsible for at least part of the in vivo eosinophil accumulation in human allergic reaction sites. Additional findings suggest that a significant portion of the time lag between intradermal antigen and dermal eosinophil accumulation is encompassed by local mediator release.

Patterns of mast cell alterations and in vivo mediator release in human allergic skin reactions

Patterns of in vivo histamine release in skin sites challenged with ragweed antigen were compared in five human subjects sensitive to this antigen and four nonallergic individuals, using a newly developed skin-chamber technique. These findings were compared with inflammatory cell responses in the reaction sites and patterns of ultramicroscopic mast cell alterations in biopsy specimens of skin tests in the same subjects. Definite mast cell alterations occurred within 15 sec and appeared maximal within 5 to 10 min after antigen injection. Histamine levels in appended chambers increased after a lag of 10 to 30 min and were elevated for at least 60 min after antigen challenge. Eosinophils accumulated only in antigen-induced reaction sites. However, there was no precise quantitative correlation among the degree of change in these three measurements. These appear to be promising approaches to further in vivo studies of human allergic reactions.