Mary Valenzano

Characteristics of histamine-releasing activity in the sera of patients with chronic idiopathic urticaria

BACKGROUND The serum histamine-releasing activity (HRA) found in a sizable percentage of patients with chronic idiopathic urticaria (CIU) has been partially characterized. However, the variable effect of individual HRA+ sera in basophils of different donors and the relationship of HRA to the clinical course require further investigation. OBJECTIVE The study was performed to characterize the HRA found in sera of some members of a sizable group of carefully evaluated patients with CIU. METHODS Sera of 70 patients with CIU, evaluated with a standard protocol, were screened for increased HRA. HRA+ sera were fractionated, heated, and tested on unaltered and altered basophils obtained from a panel of normal donors. HRA levels were compared with concomitant clinical manifestations. RESULTS HRA+ sera were found in 30% of our patients with CIU, HRA was predominantly in the IgG fraction, sensitive to 56 degrees C heating for 4 hours, and generally reacted more with IgE-stripped basophils. Considerable variation in the degree of response to HRA+ sera in the basophils of different normal subjects did not correlate with the degree of response of these cells to heterologous anti-IgE antiserum. Serum HRA levels were generally much lower when symptoms decreased in these patients with CIU. CONCLUSION Serum HRA from patients with CIU appears to bind most commonly to the IgE receptor and may be a marker of clinical disease activity. HRA appears in an IgG-containing fraction of the serum and may contain IgE in some cases.

In vivo antigen-induced cutaneous mediator release: simultaneous comparisons of histamine, tryptase, and prostaglandin D2 release and the effect of oral corticosteroid administration.

To determine if basophils were responsible for the persistent release of histamine during continuous antigen (Ag) administration in the skin, we compared the release of histamine, tryptase, and prostaglandin D2 (PGD2) at sites of continuous (5 hours) and intermittent Ag and codeine skin-chamber challenge in the skin of 16 atopic and four nonatopic subjects. In addition, we compared the release of these three mediators at sites of continuous Ag challenge in five subjects during oral administration of 1 mg/kg of methylprednisolone. Continuous Ag challenge induced an initial (first hour) peak of histamine release followed by a lower level plateau of histamine release during the next 4 hours. The level of histamine release during the second to fifth hours was significantly higher at these sites of continuous Ag challenge than at the codeine- or intermittent Ag-challenge sites. Levels of both tryptase and PGD2 were increased after the first hour of Ag or codeine challenge, and tryptase decreased progressively thereafter at all sites. In corticosteroid-treated subjects, the persistent histamine release during the second to fifth hours of Ag challenge was significantly reduced. In contrast, corticosteroid therapy did not affect histamine release during the first hour of Ag challenge nor the release of PGD2 or tryptase at any time period. These findings suggest that basophils are the source of the persistent histamine release at sites of continuous in vivo Ag challenge, since such release (1) was unaccompanied by release of tryptase or PGD2 (released from mast cells but not basophils), (2) did not occur after codeine challenge that activates mast cells but not basophils, and (3) was inhibited by steroids that inhibit the accumulation and release of histamine from basophils but not mast cells.

Correlations of in vivo mediator release with late cutaneous allergic responses in humans: I. Kinetics of histamine release

To evaluate the contribution of mast cell-derived mediators in the late cutaneous allergic response, the duration and quantity of antigen-induced histamine release was compared to the intensity of the antigen-induced skin reactions in atopic volunteers. Chambers containing either pollen extract or buffer were appended to denuded bases for 1 hr and were replaced hourly with buffer for 3 additional hr. These were compared to the extinction dilution skin test titer and to the mean diameters of the 20-minute wheal and induration at 6 and 8 hr after intradermal injection of antigen. Chamber-fluid histamine levels were significantly higher at antigen than at buffer sites throughout the 4 hr. The hourly histamine levels correlated with the size of the induration at 6 and 8 hr but not with the wheal size or skin test titer. We conclude that (1) histamine is released for at least 4 hr at skin sites of antigen challenge as a consequence of prolonged release either from individual or sequentially activated mast cells, and (2) the quantity of histamine released correlates with the intensity of the late-phase skin response. We hypothesize that histamine might be a marker for prolonged release from the mast cell of other mediators that are responsible for the late-phase response.

Plasma concentrations of histamine measured by radioenzymatic assay: effects of histaminase incubations

To help resolve the current uncertainty as to whether assays for plasma histamine are measuring non-histamine compounds as well, we compared the effects of prior incubation with histaminase and buffer on measurements in (1) normal plasma, (2) buffer and normal plasma to which several amounts of exogenous histamine had been added, and (3) plasma obtained after inhalation-induced asthma or form the site of a local heat urticaria challenge. As measured by the radioenzymatic technique, low (1 to 4 ng/ml) levels of histamine-like material were present in normal plasma after incubation with either histaminase or buffer. In contrast, histaminase (but not buffer) incubation markedly reduced measured histamine in all other specimens. Exogenous histamine in buffer was reduced almost 100% by histaminase, whereas the degree of reduction in plasma specimens varied directly with the starting histamine level. Therefore it appears that low levels of histaminase-resistant material reacting in histamine assays is present in normal plasma. The use of histaminase incubation appears to be helpful in differentiating this from true histamine release in allergic reactions.

Determinants of in vivo histamine release in cutaneous allergic reactions in humans

To determine host factors influencing the magnitude of mediator release during ongoing cutaneous allergic reactions in humans, we compared, in 22 subjects, the first-hour, second- to fifth-hour, and total (0 to 5 hours) skin chamber histamine release to (1) the in vitro reactivity and sensitivity of basophils to antigen for histamine release and (2) skin test sensitivity and reactivity to antigen, histamine, and codeine. There was no significant correlation between the first-hour and second- to fifth-hour histamine release. With a combination of basophil, antigen, histamine, and codeine skin sensitivity and reactivity, 64% to 75% of the magnitude of the first-hour, second- to fifth-hour, and total (0 to 5 hours) skin chamber histamine release could be accounted for. We conclude that antigen-induced in vivo allergic responses are a complex phenomenon dependent, in part, on antigen sensitivity, basophil and mast cell reactivity, and end organ responsiveness to mediators.

Identification of leukotriene B4 as the neutrophil chemotactic factor released by antigen challenge from passively sensitized guinea pig lungs

Neutrophils are prominent in some IgE-mediated allergic reactions and may contribute to the pathophysiology of immediate hypersensitivity. Antigen challenge of fragments of guinea pig lung tissue that were passively sensitized with IgE or IgG antibody evoked the release of neutrophil chemotactic activity (NCA) in parallel with histamine. The NCA released from lung tissue by both IgG- and IgE-dependent stimulation coeluted from a column of Sephacryl S-300 with synthetic leukotriene B4 (LTB4). The NCA in eluates from the Sephacryl S-300 column contained LTB4, as determined by high-performance liquid chromatography and specific radioimmunoassay, in quantities that accounted for the observed chemoattractant activity in the eluates. Furthermore, the NCA of supernatants from antigen-challenged lung fragments was reduced by a mean of 80% after absorption with a monoclonal antibody to LTB4. LTB4 thus constitutes the major functional constituent of NCA released after anaphylactic challenge of IgE- and IgG-sensitized guinea pig lung tissue.

The effects of gender on allergen-induced histamine release in ongoing allergic cutaneous reactions

BACKGROUND Marked variability in the amount of histamine released in the first hour of ongoing cutaneous reactions has been noted. This variability occurs even among subjects with similar degrees of skin test reactivity to antigen. METHODS To determine gender effects on mediator release, we retrospectively compared: (1) skin chamber histamine release after a 0 to 1-hour and 1 to 5-hour exposure to antigen; (2) neutrophil accumulation after 5 hours of antigen exposure and skin test reactivity to antigen, histamine, and codeine in 91 male and 60 female subjects. RESULTS There was no difference in skin test reactivity to antigen, histamine, or codeine between male and female subjects. However, in the group as a whole, male subjects released higher amounts of histamine in the first hour (74 +/- 4 ng/ml) than female subjects (55 +/- 4 ng/ml), (p < 0.01). When subjects were matched for equivalent skin reactivity to antigen, male subjects who were sensitive to 10 PNU/ml and 1 PNU/ml released more histamine (67 +/- 9 ng/ml and 82 +/- 9 ng/ml) than female subjects (51 +/- 7 ng/ml and 55 +/- 7 ng/ml) (p < 0.05 and < 0.01). In the most sensitive subjects, those with skin sensitivity to 0.01 PNU/ml of antigen, there was not a significant difference between the histamine release in the first hour in male (79 +/- 12 ng/ml) or female (69 +/- 9 ng/ml) subjects. No difference was observed between male and female subjects in either neutrophil or histamine accumulation in the 1- to 5-hour period. CONCLUSIONS Since the first hour release of histamine is secondary to mast cell activation and the 1- to 5-hour histamine release is secondary to basophil activation, we conclude that the gender of the subject influences the degree of in vivo antigen-induced histamine release from mast cells.

Fibrin formation during ongoing cutaneous allergic reactions : comparison of responses to antigen and codeine

BACKGROUND Fibrin formation, assessed by fibrinopeptide A levels, was evaluated over a 5-hour period at skin chamber sites challenged continuously with pollen antigen or codeine in 10 reactive individuals. METHODS The levels of fibrinopeptide A at antigen sites were compared with those at sites challenged with buffer diluent alone or with codeine for the first 3 hours, followed by antigen challenge during the subsequent 2 hours. RESULTS Findings showed: (1) fibrinopeptide A levels were higher at antigen challenge sites than at codeine challenge sites by the third hour, with these levels at both sites greater than those at buffer sites; (2) antigen challenge of the previous codeine sites during the third to fifth hours led to a further increase in fibrinopeptide A levels; (3) fibrinopeptide A levels correlated with chamber fluid immunoglobulin G levels but not with chamber fluid histamine levels. CONCLUSIONS Because antigen and codeine both activate mast cells prominently, these findings suggest that other factors play a role in the persistent fibrin formation at allergic skin reaction sites. Because antigen activates both basophils and mast cells and codeine only activates mast cells, we conclude that both basophils and mast cells contribute to the persistent fibrin formation at sites of 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 X 10(5)) than at buffer (2.0 X 10(5)) sites, p less than 0.005; greater than 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 less than 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 leukotriene B4, but there was a significantly decreased response to platelet-activating factor when the cells recovered from antigen sites were compared to autologous blood neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of serum histamine releasing activity in chronic idiopathic urticaria

BACKGROUND Sera of about 30% of patients with chronic idiopathic urticaria (CIU) have increased histamine releasing activity (HRA+) on normal basophils. It is not known whether other CIU sera would be HRA+ if a more sensitive histamine release assay was used. Although most HRA+ CIU sera appear to have anti Fc(epsilon)R1 activity, it is not known whether post-binding basophil intracellular events are similar to those after anti-IgE stimulation. RESULTS In the presence of D2O, the HR stimulated by 28 previously documented HRA- sera increased from 4+/-0.4 to 21+/-4% with 13 of the 28 sera now considered HRA+. No previous HRA sera was HRA+ with IL-3 treated cells. Histamine release induced by both HRA+ sera and anti-IgE were inhibited by genistein, and Ca2+/Mg2+ depletion but not by bisindoylmaleimide. HRA+ sera induced prominent HR from normal basophils with little surface IgE, but induced no increased HR from basophils unresponsive to anti-IgE. CONCLUSIONS Up to 61% of CIU sera will induce increased HR from normal basophils in a sufficiently sensitive assay system. HR induced by most HRA+ sera is more prominent in basophils with very little surface IgE. However, there may be similar post-binding intracellular activation pathways following stimulation by HRA+ sera and anti-IgE.