The osmolality of nasal secretions increases when inflammatory mediators are released in response to inhalation of cold, dry air

Inhaling cold, dry air nasally induces in some persons symptoms of rhinitis that are associated with an increase in the level of mast-cell-associated mediators in nasal lavages. The present study, directed at understanding the mechanism of this reaction, showed that 9 subjects who displayed symptoms and inflammatory mediator release had significant (p less than 0.01) increments in nasal fluid osmolality, whereas the osmolality of the fluids of 6 subjects unaffected by cold, dry air challenge did not differ from baseline. Significant correlations were found between the mediator concentration and the osmolality of recovered nasal lavages (rs = 0.617, p less than 0.02; rs = 0.679, p less than 0.01 for histamine and TAME-esterase(s), respectively). No changes in the osmolality of nasal secretions were found in atopic subjects undergoing nasal challenge with antigen, despite the generation of symptoms and significant elevations in the levels of inflammatory mediators in their nasal lavages. Because increasing the osmolality of the medium surrounding isolated mast cells in vitro triggers mediator secretion, these observations support the concept that the response to cold, dry air nasal inhalation is caused by the release of mediators secondary to an increase in the osmolality of the mucosal secretions.

Nasal provocation with bradykinin induces symptoms of rhinitis and a sore throat

Kinins are generated in nasal secretions during allergic reactions and during induced rhinovirus colds. To determine if kinins may contribute to the symptomatology of these inflammatory reactions, 8 subjects were challenged with increasing doses of bradykinin or with placebo. Levels of albumin, histamine, and N-alpha-tosyl-L-arginine methyl ester (TAME)-esterase were measured in nasal lavages, and symptom scores were noted. No symptoms or increases in mediators or protein were observed after placebo challenge. Symptom scores increased in a dose-dependent manner, however, in response to bradykinin challenge. Increased symptoms were associated with significant increases in albumin and TAME-esterase activity, but no increases in histamine were observed. Nasal conductance measurements confirmed that bradykinin induces dose-dependent unilateral obstruction in the challenged nostril. Other common symptoms were rhinorrhea and, of particular relevance to rhinovirus infections, a persistent sore throat. We conclude that bradykinin causes increased vascular permeability and rhinitis, which are independent of mast cell mediator release. Kinins may, therefore, contribute to the symptomatology of inflammatory reactions of the upper airways, including the common cold.

Is histamine responsible for the symptoms of rhinovirus colds? A look at the inflammatory mediators following infection

In an attempt to identify inflammatory mediators that may contribute to rhinorrhea, nasal congestion and other cold symptoms, we recruited 40 healthy young adults (median age, 20) for provocative rhinovirus challenge. Mediators measured included histamine, kinins and enzymes with arginine esterase activity. Volunteers were inoculated with rhinovirus or a sham inoculum. Nasal secretions for viral culture were obtained daily, and volunteers were deemed infected if they shed virus or had a 4-fold or greater increase in serum antibody titer. The virus-infected group was subdivided using the Jackson criteria into an ill or non-ill group; each group was compared to the control group. Of the 27 virus-inoculated subjects, 25 had positive cultures for the challenge virus, and 15 became ill. None of the controls had a positive culture. All variables measured--except histamine--grew stronger in direct relationship with the symptoms as the cold increased in severity. In the infected-ill group, the mean kinin level increased more than 10-fold over baseline. The kinin level remained relatively unchanged in the control and non-ill groups. Similar results were found for levels of albumin and enzymes with arginine esterase activity. Histamine levels remained constant in both the infected-ill and non-ill groups, which suggests that mast cells and basophils do not participate in the pathophysiology of rhinovirus infections and that antihistamines should be ineffective in treating rhinovirus colds. Since volunteers who developed cold symptoms exhibited a notable increase in kinin, a potent inflammatory mediator, we recommend further study of a kinin antagonist in reducing nasal symptoms.

In vivo release of inflammatory mediators by hyperosmolar solutions

Hyperosmolar environments induce histamine release from mast cells and basophils in vitro. To assess whether the same stimulus induces mediator release in vivo, 15 healthy human volunteers underwent nasal challenges with instilled solutions of differing osmolalities: lactated Ringer's solution (257 +/- 3 mOsm/kg), isosmolar mannitol (277 +/- 6 mOsm/kg), and hyperosmolar mannitol (869 +/- 8 mOsm/kg). The effect of these challenges on the volume, osmolality, and inflammatory mediator content of subsequent 5-ml isosmolar lavages was determined. The volumes of lavages returned after hyperosmolar challenges were significantly greater than those after isosmolar challenges (5.5 +/- 0.2 ml versus 4.2 +/- 0.1 ml; p less than 0.01) and these lavage solutions had higher osmolalities. Even when corrected for increased volumes, the lavages after hyperosmolar challenges contained significantly higher quantities of inflammatory mediators such as histamine (29.0 versus 10.1 ng; p less than 0.01), TAME-esterase activity (32.7 versus 11.1 cpm x 10(-3); p less than 0.01), and immunoreactive leukotrienes (9.9 versus 3.4 ng; p less than 0.01). The changes in mediators were dose dependent in that incremental increase in challenge osmolality were associated with incremental increases in histamine release. Therefore, when exposed to hyperosmolar stimuli in vivo, the nasal respiratory airway releases inflammatory mediators and fluid rapidly shifts into the airway lumen. It has been suggested that the mediator release observed on breathing cold and dry air is due to increased osmolality of airway secretions; the present data confirm that osmotic variations at the airway surface can provide an adequate stimulus for cell activation.

Profiling of bisenoic prostaglandins and thromboxane B2 in bronchoalveolar fluid from the lower respiratory tract of human subjects by combined capillary gas chromatography-mass spectrometry

Methods for the profiling of prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), 15(S),9 alpha,11 beta-trihydroxyprosta-5Z,13E-dien-1-oic acid (9 alpha,11 beta-PGF2), 6-keto-prostaglandin F1 alpha (6kPGF1 alpha), and thromboxane B2 (TxB2) in bronchoalveolar lavage (BAL) fluids from human subjects by combined capillary gas chromatography-mass spectrometry are described. Aliquots (5 ml) of BAL fluid obtained using a standardized lavage protocol were extracted on octadecylsilyl silica cartridges after addition of 0.8 to 2.0 nanograms of tetradeuterated analogs of PGE2, PGF2 alpha, and 6kPGF1 alpha as internal standards. Eluted analytes and internal standards were prepared for vapor phase analysis by sequential reactions resulting in the formation of methyloxime-pentafluorobenzyl ester-trimethylsilyl ether derivatives. The derivatized analytes were detected by simultaneous monitoring of ions at six different masses characteristic for each of the derivatized prostanoids. The samples were of adequate purity for identification and quantitation of each of the prostanoids with detection limits of 0.1 to 0.2 picograms of each analyte per milliliter of BAL fluid. The time required for analysis of each sample was approximately 30 minutes. Standard curves of unlabeled species of the six prostanoids extracted after addition to BAL fluid were linear over a range from subpicogram to nanogram quantities. The differences between the amounts of prostanoid added and the amounts of prostanoid measured were typically less than 19%, and the intra-assay coefficients of variation for repeated measurements of a single sample were less than 20%. PGE2, PGD2, PGF2 alpha, and TxB2 were detectable in BAL fluids from normal subjects with levels of each of these compounds being less than 2.6 picograms/ml. BAL fluids from patients with lung disease presented qualitative and quantitative profiles of prostanoids markedly different than those from normal subjects. These analytical methods provide a basis for in vivo comparisons of prostanoid profiles in the lower respiratory tract of man and should be readily adaptable for use in a variety of clinical studies.

Kinins are generated during experimental rhinovirus colds

We investigated the pathophysiology of rhinovirus colds by challenging volunteers with either of two strains of rhinovirus or with placebo. Nasal lavages were done before challenge and every 4 h for five days after challenge. We measured the levels of histamine, kinins, [3H]-N-alpha-p-tosyl-L-arginine methyl ester (TAME)-esterase activity, and albumin and counted the number of neutrophils in the recovered lavage fluid. Subjects who became both infected and symptomatic showed increases in levels of kinins (P less than .03), TAME-esterase activity (P less than .04), and albumin (P less than .05), as well as in the number of neutrophils (P less than .01). The total number of symptoms reported correlated significantly with the net increase in the concentration of kinins (r = .549; P less than .01), albumin (r = .674; P less than .001), TAME-esterase activity (r = .563; P less than .005), and neutrophils (r = .605; P less than .005). Levels of histamine did not change during the course of infection. During symptomatic rhinovirus infections (1) kinins are generated, (2) vascular permeability increases, (3) basophils and mast cells do not participate, and (4) neutrophils enter nasal secretions.

Detection and partial characterization of a human mast cell carboxypeptidase

Using a high performance liquid chromatography assay that detects the cleavage of the C-terminal leucine from angiotensin I, we have identified a carboxypeptidase activity in mast cells from human lung and in dispersed mast cell preparations from human skin. The enzyme activity was detected in a preparation of dispersed human mast cells from lung of greater than 99% purity and was released with histamine after stimulation with goat anti-human IgE. In nine preparations of dispersed human mast cells from lung of 10 to 99% purity, net percentage of release of carboxypeptidase correlated with the release of histamine, localizing carboxypeptidase to mast cell secretory granules. The enzyme activity was also detected in preparations of dispersed human mast cells from skin and in extracts of whole skin. The inhibitor profile and m.w. of carboxypeptidase activity from preparations of dispersed mast cells from skin was similar to that from dispersed mast cells from lung. Mast cell carboxypeptidase had a m.w. on gel filtration of 30,000 to 35,000. The enzyme in crude lysates of dispersed mast cell preparations had optimal activity between pH 8.5 and 9.5 and was inhibited by potato inhibitor, which distinguished it from carboxypeptidase in cultured human foreskin keratinocytes and adult fibroblasts, and from other proteolytic mast cell enzymes. The enzyme activity was also inhibited by EDTA, o-phenanthroline, and, to a small extent, by 8-OH quinoline, but not by Captopril, soybean trypsin inhibitor, or pepstatin. These findings demonstrate that human mast cell secretory granules contain carboxypeptidase in addition to tryptase and chymase. It appears that mast cells from skin may have a higher content of carboxypeptidase than do mast cells from lung.

Detection and partial characterization of a human mast cell carboxypeptidase

Using a high performance liquid chromatography assay that detects the cleavage of the C-terminal leucine from angiotensin I, we have identified a carboxypeptidase activity in mast cells from human lung and in dispersed mast cell preparations from human skin. The enzyme activity was detected in a preparation of dispersed human mast cells from lung of greater than 99% purity and was released with histamine after stimulation with goat anti-human IgE. In nine preparations of dispersed human mast cells from lung of 10 to 99% purity, net percentage of release of carboxypeptidase correlated with the release of histamine, localizing carboxypeptidase to mast cell secretory granules. The enzyme activity was also detected in preparations of dispersed human mast cells from skin and in extracts of whole skin. The inhibitor profile and m.w. of carboxypeptidase activity from preparations of dispersed mast cells from skin was similar to that from dispersed mast cells from lung. Mast cell carboxypeptidase had a m.w. on gel filtration of 30,000 to 35,000. The enzyme in crude lysates of dispersed mast cell preparations had optimal activity between pH 8.5 and 9.5 and was inhibited by potato inhibitor, which distinguished it from carboxypeptidase in cultured human foreskin keratinocytes and adult fibroblasts, and from other proteolytic mast cell enzymes. The enzyme activity was also inhibited by EDTA, o-phenanthroline, and, to a small extent, by 8-OH quinoline, but not by Captopril, soybean trypsin inhibitor, or pepstatin. These findings demonstrate that human mast cell secretory granules contain carboxypeptidase in addition to tryptase and chymase. It appears that mast cells from skin may have a higher content of carboxypeptidase than do mast cells from lung.

Effect of short-term systemic glucocorticoid treatment on human nasal mediator release after antigen challenge

The effect of systemic glucocorticoid treatment on early- and late-phase nasal allergic reactions after allergen challenge was determined in a double-blind, cross-over study in 13 allergic individuals. The subjects were pretreated for 2 d before challenge with 60 mg prednisone per day or a matching placebo. A previously described model using repeated nasal lavages for measuring mediator release in vivo was utilized. Symptom scores obtained repeatedly before, during, and after the challenge and the number and timing of sneezes were recorded. The mediators measured were histamine. N-alpha-p-tosyl-L-arginine methyl ester (TAME)-esterase activity, kinins, PGD2, and LTC4/D4. Albumin was also measured as a marker of plasma transudation. Blood samples were taken for determination of total number of white blood cells, differential count, and total blood histamine content. No effect of steroid therapy was found on the appearance of symptoms or any of the mediators, except a reduction in kinins, in the early phase of the allergic reaction. However, in the late phase, the prednisone reduced the number of sneezes (P less than 0.01), as well as the level of histamine (P less than 0.05), TAME-esterase activity (P less than 0.05), kinins (P less than 0.05), and albumin (P less than 0.05). Only low levels of leukotrienes were found in the late phase, but the quantities of these mediators seemed to be decreased by the glucocorticoid treatment (P = 0.06). PGD2 did not increase during the LPR and thus was not affected by glucocorticosteroids. The immediate response to a second challenge 11 h after the first was also evaluated. Whereas the appearance of mediators was enhanced over the initial response to the same challenge dose in placebo-treated subjects, this enhancement was abrogated after prednisone treatment. As this dose of drug is known to be clinically effective in treating hay fever, the present study confirms the earlier findings of others that short-term systemic glucocorticoid treatment inhibits the late phase but not the immediate phase of antigen challenge. Furthermore, secondary enhancement of immediate responses is inhibited. This study shows that glucocorticoids inhibit the generation or release of inflammatory mediators during the late reaction and the physiologic response.

The effect of a histamine synthesis inhibitor on the immediate nasal allergic reaction

We studied the effect of alpha-fluoromethyl histidine, an irreversible histamine synthesis inhibitor, on the immediate nasal reaction to antigen challenge in a double-blind, placebo controlled, randomized, parallel study using 13 subjects. The patients received either active drug 100 mg twice daily or placebo, for 3 weeks. A nasal allergen challenge was performed before and after at weekly intervals. Symptoms at challenge were assessed and the levels of histamine, TAME-esterase activity and kinins were measured in nasal lavages before and after antigen challenge. Skin tests were also performed at weekly intervals. In addition, the urinary excretion of the main histamine metabolite, telemethylimidazole acetic acid, was measured before and after 3 weeks of treatment. The active treatment induced 60% reduction in histamine levels in the lavage fluids before and after antigen challenge, as well as a reduction in the histamine levels in the lavage fluids before and after antigen challenge, as well as a reduction in the main urinary histamine metabolite. However, no reduction was found in nasal symptoms obtained after antigen challenge. The levels of kinins and TAME-esterase activity were not significantly reduced.

Studies of IgE-dependent histamine releasing factors: heterogeneity of IgE

Nasal lavage fluids from unstimulated individuals contain a histamine-releasing factor (HRF) similar to those which we have previously described from macrophages, platelets, and from blister fluids obtained during the late cutaneous reaction. The nasal HRF was partially purified by ion-exchange chromatography and gel filtration. Although some m.w. heterogeneity was observed, the majority of the HRF eluted at an apparent m.w. range of 15,000 to 30,000. This partially purified HRF induced histamine release from basophils of certain individuals. Histamine release occurred via a mechanism which is IgE-dependent in that: basophils desensitized by exposure to anti-IgE in the absence of calcium no longer respond to HRF, and desensitization with HRF reduces responsiveness to anti-IgE; and removal of IgE from the basophil surface by using lactic acid renders cells unresponsive to HRF. We have further defined this IgE dependence and have shown that the reason that only selected basophil donors respond to HRF is due to a previously unrecognized, functional heterogeneity of IgE. Thus, passive sensitization using sera from responders restored the responsiveness of acid-stripped basophils and conferred responsiveness to basophils of a nonresponder with naturally unoccupied IgE receptors. Sera from nonresponders failed to do this even though similar numbers of IgE molecules were put onto the basophil surface in each case. This property of responder sera was due to IgE because both heating sera at 56 degrees C for 2 hr and passage of sera over anti-IgE-Sepharose (which removes greater than 90% of the IgE) markedly reduced the ability of sera to induce responsiveness, and because an excess of either purified IgE myeloma or purified penicillin-specific IgE antibody from a nonresponder competitively inhibited the ability of IgE from responder sera to induce responsiveness to HRF. We conclude that nasal lavage fluids contain an HRF which induces basophil histamine release in a specific, IgE-dependent fashion but only from individuals with the appropriate type of IgE. Because we have shown that basophils are recruited into the nose during the late-phase reaction, we suggest that nasal HRF may induce these cells to release histamine and other mediators which could contribute to the symptomatology of the late-phase reaction.

Studies of IgE-dependent histamine releasing factors: heterogeneity of IgE

Nasal lavage fluids from unstimulated individuals contain a histamine-releasing factor (HRF) similar to those which we have previously described from macrophages, platelets, and from blister fluids obtained during the late cutaneous reaction. The nasal HRF was partially purified by ion-exchange chromatography and gel filtration. Although some m.w. heterogeneity was observed, the majority of the HRF eluted at an apparent m.w. range of 15,000 to 30,000. This partially purified HRF induced histamine release from basophils of certain individuals. Histamine release occurred via a mechanism which is IgE-dependent in that: basophils desensitized by exposure to anti-IgE in the absence of calcium no longer respond to HRF, and desensitization with HRF reduces responsiveness to anti-IgE; and removal of IgE from the basophil surface by using lactic acid renders cells unresponsive to HRF. We have further defined this IgE dependence and have shown that the reason that only selected basophil donors respond to HRF is due to a previously unrecognized, functional heterogeneity of IgE. Thus, passive sensitization using sera from responders restored the responsiveness of acid-stripped basophils and conferred responsiveness to basophils of a nonresponder with naturally unoccupied IgE receptors. Sera from nonresponders failed to do this even though similar numbers of IgE molecules were put onto the basophil surface in each case. This property of responder sera was due to IgE because both heating sera at 56 degrees C for 2 hr and passage of sera over anti-IgE-Sepharose (which removes greater than 90% of the IgE) markedly reduced the ability of sera to induce responsiveness, and because an excess of either purified IgE myeloma or purified penicillin-specific IgE antibody from a nonresponder competitively inhibited the ability of IgE from responder sera to induce responsiveness to HRF. We conclude that nasal lavage fluids contain an HRF which induces basophil histamine release in a specific, IgE-dependent fashion but only from individuals with the appropriate type of IgE. Because we have shown that basophils are recruited into the nose during the late-phase reaction, we suggest that nasal HRF may induce these cells to release histamine and other mediators which could contribute to the symptomatology of the late-phase reaction.

Inhibition of mediator release in allergic rhinitis by pretreatment with topical glucocorticosteroids

Patients with allergic rhinitis often have immediate symptoms after antigen challenge (the early-phase response), followed several hours later by a recurrence of symptoms (the late-phase response). Systemic glucocorticosteroids are known to inhibit the late-phase but not the early-phase response. We studied the effect of one week of pretreatment with topical (rather than systemic) glucocorticosteroids on the response to nasal challenge with antigen in a double-blind, randomized, placebo-controlled crossover study of 13 allergic patients who had previously had a dual response to nasal challenge. The patients were challenged with three 10-fold increments of allergen, producing an early response, and were then followed for 11 hours, encompassing the late response, before they were rechallenged with the lowest dose of allergen. We monitored their responses by means of symptom scores and measurements of the levels of histamine, tosyl-L-arginine methyl ester (TAME)-esterase activity, and kinins in nasal lavages. Topical glucocorticosteroids significantly reduced both the symptoms and the levels of histamine, TAME-esterase activity, and kinins in the early, late, and rechallenge allergic reactions. The fact that, in contrast to treatment with systemic glucocorticosteroids, prolonged pretreatment with topical glucocorticosteroids inhibited the early-phase response to antigen suggests that the route and duration of administration affect the mechanisms of action of the steroids. We conclude that inhibition of the early-phase as well as the late-phase response by topical glucocorticosteroids may provide an advantage over treatment with systemic glucocorticosteroids in patients with allergic rhinitis.

The effect of a topical tricyclic antihistamine on the response of the nasal mucosa to challenge with cold, dry air and histamine

We have previously demonstrated that azatadine, a tricyclic antihistamine, known also to inhibit mediator release from mast cells and basophils in vitro, inhibits the early release of histamine and other mediators after nasal challenge with antigen. In this article, we studied the effect of azatadine on preventing the release of histamine after nasal challenge with cold, dry air (CDA) and its effect on antagonizing nasal challenge with histamine. With histamine challenge, azatadine inhibited symptoms (sneezing, nasal congestion, and rhinorrhea) and the increase in the level of albumin in nasal secretions (p less than 0.01 all). With challenge with CDA, the drug had no effect on either symptoms or histamine and N-tosyl-L-arginine methyl ester-esterase release. Although the patterns of mediator release after CDA and after the early reaction to antigen are similar, the pharmacologic control differs, suggesting different mechanisms of induction of histamine release from mast cells.

Arachidonic acid metabolites during nasal challenge

In order to assess the role of arachidonic acid metabolites in the early reaction to antigen, we challenged six allergic individuals with and without premedication with aspirin and recorded their clinical response, as indicated by number of sneezes, and measured the levels of inflammatory mediators. The early reaction to antigen was associated with increases in the levels of histamine, N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity, prostaglandin (PG) D2, leukotriene C4, PGE, and thromboxane. Aspirin significantly inhibited the increases in the cyclooxygenase metabolites PGE, PGD2, PGF2 alpha, 6-keto-PGF1 alpha, and thromboxane but did not affect the amount of sneezing or the levels of histamine, TAME-esterase activity, or leukotrienes. The pattern of the metabolites and their response to pretreatment with aspirin parallel the response of purified human lung mast cells, supporting the notion that the early phase of allergic rhinitis is a mast cell-dominated event.

Kinin metabolism in human nasal secretions during experimentally induced allergic rhinitis

We have previously shown that both bradykinin and lysylbradykinin are generated in nasal secretions upon nasal challenge of allergic individuals with appropriate allergen and have suggested that these potent pro-inflammatory peptides may contribute to the pathogenesis of the allergic response. In this study we used a variety of synthetic substrates together with both thin layer and high performance liquid chromatography systems to examine the metabolism of these peptides in nasal secretions obtained by lavage. We now demonstrate that in addition to low levels of angiotensin-converting enzyme, nasal lavages contain an aminopeptidase activity that converts lysylbradykinin to bradykinin, and a carboxypeptidase that removes the C-terminal arginine from bradykinin and lysylbradykinin. The levels of all these activities are significantly increased after allergen challenge of allergic, but not nonallergic, individuals. The aminopeptidase and carboxypeptidase activities present in post-challenge lavages from allergic individuals convert lysylbradykinin to intermediate products (bradykinin and des (Arg10) lysylbradykinin) and eventually to des (Arg9) bradykinin. The nasal carboxypeptidase was activated 475% by 0.1 mM CoCl2 and was inhibited by the carboxypeptidase N inhibitor, MERGETPA (D-L-mercaptomethyl-3-guanidino-ethylthiopropanoic acid) (IC50 = 10 microM). The aminopeptidase activity was not affected by MERGETPA but was potently inhibited by amastatin and bestatin (IC50 = 0.05 microM and 3.0 microM, respectively). The activity of the aminopeptidase against its synthetic substrate was also inhibited by lysylbradykinin (IC50 = 50 microM). Both the carboxypeptidase and aminopeptidase activities had neutral pH optima and were inhibited by o-phenanthroline, but were unaffected by inhibitors of neutral endopeptidases (phosphoramidon) or angiotensin-converting enzyme (Captopril). The Km of bradykinin for the nasal carboxypeptidase was 139 +/- 14 microM (n = 3). We conclude that during the allergic response, nasal secretions contain aminopeptidase and carboxypeptidase activities that convert lysylbradykinin and bradykinin (B2 agonists) to des (Arg9) bradykinin (a B1 agonist). Because the nature of the kinin receptors in the nasal mucosa are currently unknown, it remains to be determined whether this metabolism results in the termination of biologic activity or the production of a biologically active moiety.

Kinin metabolism in human nasal secretions during experimentally induced allergic rhinitis

We have previously shown that both bradykinin and lysylbradykinin are generated in nasal secretions upon nasal challenge of allergic individuals with appropriate allergen and have suggested that these potent pro-inflammatory peptides may contribute to the pathogenesis of the allergic response. In this study we used a variety of synthetic substrates together with both thin layer and high performance liquid chromatography systems to examine the metabolism of these peptides in nasal secretions obtained by lavage. We now demonstrate that in addition to low levels of angiotensin-converting enzyme, nasal lavages contain an aminopeptidase activity that converts lysylbradykinin to bradykinin, and a carboxypeptidase that removes the C-terminal arginine from bradykinin and lysylbradykinin. The levels of all these activities are significantly increased after allergen challenge of allergic, but not nonallergic, individuals. The aminopeptidase and carboxypeptidase activities present in post-challenge lavages from allergic individuals convert lysylbradykinin to intermediate products (bradykinin and des (Arg10) lysylbradykinin) and eventually to des (Arg9) bradykinin. The nasal carboxypeptidase was activated 475% by 0.1 mM CoCl2 and was inhibited by the carboxypeptidase N inhibitor, MERGETPA (D-L-mercaptomethyl-3-guanidino-ethylthiopropanoic acid) (IC50 = 10 microM). The aminopeptidase activity was not affected by MERGETPA but was potently inhibited by amastatin and bestatin (IC50 = 0.05 microM and 3.0 microM, respectively). The activity of the aminopeptidase against its synthetic substrate was also inhibited by lysylbradykinin (IC50 = 50 microM). Both the carboxypeptidase and aminopeptidase activities had neutral pH optima and were inhibited by o-phenanthroline, but were unaffected by inhibitors of neutral endopeptidases (phosphoramidon) or angiotensin-converting enzyme (Captopril). The Km of bradykinin for the nasal carboxypeptidase was 139 +/- 14 microM (n = 3). We conclude that during the allergic response, nasal secretions contain aminopeptidase and carboxypeptidase activities that convert lysylbradykinin and bradykinin (B2 agonists) to des (Arg9) bradykinin (a B1 agonist). Because the nature of the kinin receptors in the nasal mucosa are currently unknown, it remains to be determined whether this metabolism results in the termination of biologic activity or the production of a biologically active moiety.

Detection of tissue kallikrein in the bronchoalveolar lavage fluid of asthmatic subjects

Kininogenase activity was detected by cleavage of radiolabeled substrate (125I-high molecular weight kininogen [HMWK]) in 22 of 24 bronchoalveolar lavage (BAL) fluid samples from 17 asthmatics who either responded to aerosolized allergen challenge or had symptoms of active asthma. In contrast, six of seven normal controls lacked enzymatic activity. Levels of free immunoreactive kinin found in BAL fluid correlated with the presence of kininogenase activity (P = 0.002). The cleavage pattern of 125I-HMWK by the BAL fluid kininogenase (a dominant 65,000-mol wt fragment), and synthetic inhibitor profile (phe-phe-arg-CH2Cl and phenylmethylsulfonyl fluoride) were compatible with a tissue kallikrein. Peak kininogenase activity eluted at an apparent molecular weight of 20,000-34,000 by HPLC gel filtration. Its antigenic identity was established by immunoblotting with anti-human urinary kallikrein antibody and its activity was inhibited by this antibody. Lysylbradykinin was generated during incubation of fractionated BAL fluid and purified HMWK, the characteristic cleavage product of the tissue kallikreins. We conclude that elevated amounts of tissue kallikrein and kinin are present in the bronchoalveolar spaces of asthmatic subjects. Kinin generation may contribute to the asthmatic response directly through edema formation and smooth muscle contraction and by augmenting release and/or production of preformed (histamine) and secondary mediators such as leukotrienes and platelet-activating factor.

Pharmacology of upper airways challenge

We have used a model of nasal provocation to study the effects of pharmacologic interventions upon various types of inflammatory reactions of the upper airways. Pretreatment of allergic individuals with aspirin reduces the levels of prostaglandins in nasal secretions during the immediate allergic response but has no effect on symptoms. Theophylline and azatadine both reduce symptoms and the levels of mast cell mediators during the allergic response. By contrast, azatadine has no effect on symptoms or mediator levels during the response to challenge with cold, dry air, suggesting different mechanisms of mast cell activation in response to allergen and cold, dry air. Both topical and systemic steroids are effective in reducing symptoms and mediators during the late allergic response, but topical steroids also significantly inhibit the immediate response. Nasal challenge provides a convenient, relatively noninvasive method to study inflammatory reactions of the upper airways.

Theophylline reduces histamine release during pollen-induced rhinitis

In an attempt to understand how theophylline achieves its in vivo therapeutic effect, a double-blind crossover study of the effect of theophylline on the immediate response of the upper airways to challenge with antigen was performed. Ten subjects with allergic rhinitis were challenged with increasing doses of antigen extract, and their responses were assessed by counting the number of sneezes and measuring the level of histamine, N-alpha-p-tosyl-L-arginine-methyl ester-esterase activity, and kinin in nasal secretions. One-week premedication with theophylline led to serum levels in the therapeutic range (8 to 21 micrograms/ml). There were significant reductions in both the physiologic response to antigen challenge and the appearance of mediators in secretions after drug administration as compared to placebo. These data suggest that theophylline, at therapeutic blood levels, achieves at least part of its in vivo efficacy by reducing the release of histamine and other mediators from mast cells/basophils.

Concentrations of glandular kallikrein in human nasal secretions increase during experimentally induced allergic rhinitis

We have previously demonstrated that a mixture of bradykinin and lysylbradykinin is generated in nasal secretions during the immediate allergic response to allergen. The present studies were performed to determine whether glandular kallikrein plays a role in kinin formation during the allergic reaction. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with appropriate allergen, and nasal lavages obtained before and after challenge were assayed for immunoreactive glandular kallikrein as well as for histamine, kinins, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity. The increase in postchallenge immunoreactive glandular kallikrein levels above baseline was significantly greater (p less than 0.01) for the allergic group (16.3 +/- 14 ng/ml; means +/- SD) than for the nonallergic controls (1.0 +/- 1.9 ng/ml). Increased levels of immunoreactive glandular kallikrein correlated with increases in kinins, histamine, and TAME-esterase activity and with the onset of clinical symptoms. Characterization of immunoreactive glandular kallikrein purified from postchallenge lavages by immunoaffinity chromatography confirmed the identity of this material as an authentic glandular kallikrein on the basis of its inhibition by protease inhibitors and by monospecific antibody to tissue kallikrein, its chromatographic behavior on gel filtration, and its ability to generate lysylbradykinin from highly purified human low m.w. kininogen. The specific activity of this purified material, in terms of kinin generation from kininogen, was very similar to that for authentic glandular kallikrein, suggesting that most if not all of the immunoreactive material purified from nasal lavages represented active enzyme. Inhibition studies by using pooled postchallenge lavages suggest that the majority of the kinin generating activity in these samples was due to glandular kallikrein. We conclude, therefore, that glandular kallikrein is secreted during the allergic response and can contribute to the formation of the lysylbradykinin produced during the allergic reaction.

Concentrations of glandular kallikrein in human nasal secretions increase during experimentally induced allergic rhinitis

We have previously demonstrated that a mixture of bradykinin and lysylbradykinin is generated in nasal secretions during the immediate allergic response to allergen. The present studies were performed to determine whether glandular kallikrein plays a role in kinin formation during the allergic reaction. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with appropriate allergen, and nasal lavages obtained before and after challenge were assayed for immunoreactive glandular kallikrein as well as for histamine, kinins, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity. The increase in postchallenge immunoreactive glandular kallikrein levels above baseline was significantly greater (p less than 0.01) for the allergic group (16.3 +/- 14 ng/ml; means +/- SD) than for the nonallergic controls (1.0 +/- 1.9 ng/ml). Increased levels of immunoreactive glandular kallikrein correlated with increases in kinins, histamine, and TAME-esterase activity and with the onset of clinical symptoms. Characterization of immunoreactive glandular kallikrein purified from postchallenge lavages by immunoaffinity chromatography confirmed the identity of this material as an authentic glandular kallikrein on the basis of its inhibition by protease inhibitors and by monospecific antibody to tissue kallikrein, its chromatographic behavior on gel filtration, and its ability to generate lysylbradykinin from highly purified human low m.w. kininogen. The specific activity of this purified material, in terms of kinin generation from kininogen, was very similar to that for authentic glandular kallikrein, suggesting that most if not all of the immunoreactive material purified from nasal lavages represented active enzyme. Inhibition studies by using pooled postchallenge lavages suggest that the majority of the kinin generating activity in these samples was due to glandular kallikrein. We conclude, therefore, that glandular kallikrein is secreted during the allergic response and can contribute to the formation of the lysylbradykinin produced during the allergic reaction.

Identification of a chymotrypsin-like proteinase in human mast cells

An antiserum was produced against a chymotryptic proteinase purified from human skin. The antiserum did not cross-react with human leukocyte cathepsin G and elastase, rat mast cell proteinase I, and human skin tryptase. Indirect immunofluorescent staining of frozen skin sections to localize the proteinase showed cytoplasmic staining of cells scattered about the papillary dermis and around blood vessels and appendages. Restaining these sections with toluidine blue revealed that the fluorescently stained cells contained metachromatically staining granules, the major distinguishing feature of mast cells. A similar correlation was found in lung tissue. Ultrastructural studies employing the ferritin bridge technique to immunologically identify the proteinase additionally localized the proteinase to mast cell granules. Biochemical and immunochemical characterization of chymotryptic activity solubilized from isolated human lung mast cells identified a chymotryptic proteinase that may be identical to the skin chymotryptic proteinase. These studies establish that human skin mast cells contain a chymotrypsin-like proteinase that is a granule constituent and provide evidence that indicates a comparable proteinase is also present in lung mast cells.

Plasma kallikrein during experimentally induced allergic rhinitis: role in kinin formation and contribution to TAME-esterase activity in nasal secretions

We have shown recently that kinins are generated during experimentally induced allergic rhinitis in man, and have demonstrated that substrates for kinin-forming enzymes are provided during the allergic response by a transudation of kininogens from plasma into nasal secretions. In light of this increased vascular permeability during the allergic reaction, we have extended our studies on the mechanisms of kinin formation to examine the potential involvement of plasma kallikrein. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with an allergen, and nasal lavages, obtained before and after challenge, were assayed for immunoreactive human plasma kallikrein/prekallikrein (iHPK). Post-challenge iHPK values were significantly elevated (p less than 0.01) in the allergic group (353 +/- 394 ng/ml; x +/- SD) as compared to the nonallergics (19 +/- 22 ng/ml), and correlated with increases in kinins, histamine, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity and with the onset of clinical symptoms. Gel filtration studies revealed that plasma prekallikrein is activated during the allergic response and contributes to kinin formation prior to interaction with plasma protease inhibitors. We also show that the majority of the TAME-esterase activity detected in nasal secretions during the allergic response is due to activities consistent with a plasma kallikrein/alpha 2-macroglobulin complex and with mast cell tryptase.

Plasma kallikrein during experimentally induced allergic rhinitis: role in kinin formation and contribution to TAME-esterase activity in nasal secretions

We have shown recently that kinins are generated during experimentally induced allergic rhinitis in man, and have demonstrated that substrates for kinin-forming enzymes are provided during the allergic response by a transudation of kininogens from plasma into nasal secretions. In light of this increased vascular permeability during the allergic reaction, we have extended our studies on the mechanisms of kinin formation to examine the potential involvement of plasma kallikrein. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with an allergen, and nasal lavages, obtained before and after challenge, were assayed for immunoreactive human plasma kallikrein/prekallikrein (iHPK). Post-challenge iHPK values were significantly elevated (p less than 0.01) in the allergic group (353 +/- 394 ng/ml; x +/- SD) as compared to the nonallergics (19 +/- 22 ng/ml), and correlated with increases in kinins, histamine, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity and with the onset of clinical symptoms. Gel filtration studies revealed that plasma prekallikrein is activated during the allergic response and contributes to kinin formation prior to interaction with plasma protease inhibitors. We also show that the majority of the TAME-esterase activity detected in nasal secretions during the allergic response is due to activities consistent with a plasma kallikrein/alpha 2-macroglobulin complex and with mast cell tryptase.

Identification of a chymotrypsin-like proteinase in human mast cells

An antiserum was produced against a chymotryptic proteinase purified from human skin. The antiserum did not cross-react with human leukocyte cathepsin G and elastase, rat mast cell proteinase I, and human skin tryptase. Indirect immunofluorescent staining of frozen skin sections to localize the proteinase showed cytoplasmic staining of cells scattered about the papillary dermis and around blood vessels and appendages. Restaining these sections with toluidine blue revealed that the fluorescently stained cells contained metachromatically staining granules, the major distinguishing feature of mast cells. A similar correlation was found in lung tissue. Ultrastructural studies employing the ferritin bridge technique to immunologically identify the proteinase additionally localized the proteinase to mast cell granules. Biochemical and immunochemical characterization of chymotryptic activity solubilized from isolated human lung mast cells identified a chymotryptic proteinase that may be identical to the skin chymotryptic proteinase. These studies establish that human skin mast cells contain a chymotrypsin-like proteinase that is a granule constituent and provide evidence that indicates a comparable proteinase is also present in lung mast cells.

Local generation of sulfidopeptide leukotrienes upon nasal provocation with cold, dry air

In order to assess whether sulfidopeptide leukotrienes are generated following nonimmunologic stimulation of inflammatory cells in vivo, 11 subjects complaining of symptoms of rhinitis when exposed to cold and dry environments were challenged by nasal breathing, first with warm, moist air and then with cold, dry air. Nasal lavages with normal saline were performed before and after each exposure. Immunoreactive leukotriene in the lavage fluids was significantly increased following cold, dry air exposure (2.6 ng/ml) compared with that after warm, moist air exposure (0.7 ng/ml) or at baseline (0.4 ng/ml) (p less than 0.01 in both instances). Six more subjects, denying cold-air sensitivity, were subjected to the same protocol and had no mediator and symptom score changes after cold, dry air challenge. Leukotriene changes after cold, dry air were highly concordant with increments in histamine, prostaglandin D2,N-alpha-tosyl-L-arginine methyl ester (TAME) esterase(s) activity and symptom scores (p less than 0.001). Separation of leukotrienes by high performance liquid chromatography in the nasal washes of 3 subjects showed variable amounts of LTC4, D4, and E4, suggesting metabolism of the former to the latter 2. To our knowledge, this is the first in vivo demonstration of leukotriene production in response to a physical stimulus, and it suggests a possible role of these and other inflammatory mediators in pathologic conditions, such as exercise-induced asthma, that involve physical causative factors.

The role of kinins in human allergic disease

We have provided clear evidence that kinins are generated during local allergic reactions in man and have begun studies on the mechanisms by which kinins are formed during these reactions. Clearly, the extent to which kinins may contribute to the symptomatology of allergic rhinitis remains to be determined, but the levels of kinins detected in the model systems described above are sufficient to cause relatively profound physiologic effects. In addition to its ability to produce vasodilatation and edema, bradykinin has been reported to stimulate fluid production from airway submucosal glands via a reflex action and could function to increase mucus production and cause rhinorrhea. Kinins have also been shown to increase chloride transport in the airway and to stimulate the production of prostaglandin E2 by epithelial cells. Thus we believe kinins must now be considered as potentially important mediators in the pathogenesis of human allergic diseases.

Human lung macrophage-derived histamine-releasing activity is due to IgE-dependent factors

Human lung macrophages obtained from surgical specimens spontaneously secreted a factor(s) (which we term macrophage factor) during 24-hr culture that induced calcium-dependent histamine release from human basophils and lung mast cells. Macrophage factor induced noncytotoxic histamine release from purified (85%) basophils. The kinetics of release were relatively slow and similar to that of anti-IgE. We performed a series of experiments to test the IgE dependence of macrophage factor-induced release. Preincubation of basophils with anti-IgE in calcium-free medium resulted in complete desensitization to macrophage factor-induced histamine release (i.e., when calcium and macrophage factor were added to the basophils, no histamine release occurred), and preincubation with macrophage factor in calcium-free medium resulted in partial desensitization to anti-IgE-induced histamine release. Pretreatment of basophils with pH 3.9 lactic acid buffer, which dissociates basophil IgE from its receptors, markedly reduced the capacity of basophils to release histamine in response to macrophage factor. Basophils that were incubated with IgE myeloma (but not with IgG) after lactic acid treatment partially or completely regained their capacity to release histamine in response to macrophage factor. Fluid-phase IgE myeloma (15 micrograms/ml) (but not IgG) inhibited basophil histamine release induced by two macrophage-derived supernatants, whereas IgE myeloma (200 micrograms/ml) did not inhibit release due to other supernatants. IgE-affinity columns removed the histamine-releasing activity of five macrophage-derived supernatants, and IgG-affinity columns had similar effects. However, neither affinity column removed the histamine-releasing activity of three other macrophage-derived supernatants. On Sephadex G-75 chromatography, nearly all of the histamine-releasing activity migrated as single peak with an apparent m.w. of 18,000. These results suggest that, although macrophage factor are heterogeneous, they are related, as they are a IgE-dependent factors that induce histamine release by interacting with cell surface IgE. These macrophage factors may be responsible for stimulation of basophil/mast cell mediator release in chronic allergic reactions.

Human lung macrophage-derived histamine-releasing activity is due to IgE-dependent factors

Human lung macrophages obtained from surgical specimens spontaneously secreted a factor(s) (which we term macrophage factor) during 24-hr culture that induced calcium-dependent histamine release from human basophils and lung mast cells. Macrophage factor induced noncytotoxic histamine release from purified (85%) basophils. The kinetics of release were relatively slow and similar to that of anti-IgE. We performed a series of experiments to test the IgE dependence of macrophage factor-induced release. Preincubation of basophils with anti-IgE in calcium-free medium resulted in complete desensitization to macrophage factor-induced histamine release (i.e., when calcium and macrophage factor were added to the basophils, no histamine release occurred), and preincubation with macrophage factor in calcium-free medium resulted in partial desensitization to anti-IgE-induced histamine release. Pretreatment of basophils with pH 3.9 lactic acid buffer, which dissociates basophil IgE from its receptors, markedly reduced the capacity of basophils to release histamine in response to macrophage factor. Basophils that were incubated with IgE myeloma (but not with IgG) after lactic acid treatment partially or completely regained their capacity to release histamine in response to macrophage factor. Fluid-phase IgE myeloma (15 micrograms/ml) (but not IgG) inhibited basophil histamine release induced by two macrophage-derived supernatants, whereas IgE myeloma (200 micrograms/ml) did not inhibit release due to other supernatants. IgE-affinity columns removed the histamine-releasing activity of five macrophage-derived supernatants, and IgG-affinity columns had similar effects. However, neither affinity column removed the histamine-releasing activity of three other macrophage-derived supernatants. On Sephadex G-75 chromatography, nearly all of the histamine-releasing activity migrated as single peak with an apparent m.w. of 18,000. These results suggest that, although macrophage factor are heterogeneous, they are related, as they are a IgE-dependent factors that induce histamine release by interacting with cell surface IgE. These macrophage factors may be responsible for stimulation of basophil/mast cell mediator release in chronic allergic reactions.

Basophil histamine release induced by a substance from stimulated human platelets

Platelet activation may occur during immunoglobulin E antibody (IgE)-mediated reactions. In these studies, we confirm that platelet-derived supernatants (PDS) induce histamine release from human mixed leukocytes containing basophils, one of the initial target cells in IgE-mediated reactions. In extending this observation, we have shown that this PDS-induced histamine release is both temperature- and calcium-dependent. Kinetic studies of release induced by PDS indicate that release is more rapid than that associated with IgE-dependent mechanisms. This platelet-derived, histamine-releasing activity is produced by platelet stimulation with collagen (5 micrograms/ml) and acetylglyceryl ether phosphorylcholine (10(-7)), as well as thrombin (1 U/ml). Initial characterization has shown that it is stable to acid and to freeze-thawing but not to boiling for 10 min. In addition, although this histamine-releasing activity is nondialyzable (i.e., greater than 3500 m.w.), it cannot be attributed to platelet factor 4. Thus, platelets, once activated, can produce a soluble substance or substances which can initiate basophil-mediated reactions, further suggesting that platelet activation can enhance allergic and inflammatory reactions.

Basophil histamine release induced by a substance from stimulated human platelets

Platelet activation may occur during immunoglobulin E antibody (IgE)-mediated reactions. In these studies, we confirm that platelet-derived supernatants (PDS) induce histamine release from human mixed leukocytes containing basophils, one of the initial target cells in IgE-mediated reactions. In extending this observation, we have shown that this PDS-induced histamine release is both temperature- and calcium-dependent. Kinetic studies of release induced by PDS indicate that release is more rapid than that associated with IgE-dependent mechanisms. This platelet-derived, histamine-releasing activity is produced by platelet stimulation with collagen (5 micrograms/ml) and acetylglyceryl ether phosphorylcholine (10(-7)), as well as thrombin (1 U/ml). Initial characterization has shown that it is stable to acid and to freeze-thawing but not to boiling for 10 min. In addition, although this histamine-releasing activity is nondialyzable (i.e., greater than 3500 m.w.), it cannot be attributed to platelet factor 4. Thus, platelets, once activated, can produce a soluble substance or substances which can initiate basophil-mediated reactions, further suggesting that platelet activation can enhance allergic and inflammatory reactions.

Differences between basophils and mast cells: failure to detect Charcot-Leyden crystal protein (lysophospholipase) and eosinophil granule major basic protein in human mast cells

Human eosinophils contain several distinctive proteins including eosinophil granule MBP and the membrane-associated CLC protein (lysophospholipase). Human basophils also contain these proteins, indicating biochemical similarities between eosinophils and basophils. To determine whether MBP or CLC protein is present in connective tissue mast cells, we studied human lung and cutaneous mast cells by immunofluorescence by utilizing specific antibodies to CLC and MBP. Cytocentrifuge slides of enriched lung mast cells and mast cells in sections of formalin-fixed, paraffin-embedded cutaneous tissue from urticaria pigmentosa lesions were stained for CLC and MBP. Neither pulmonary nor cutaneous mast cells stained for CLC protein or MBP. In contrast, lung and cutaneous eosinophils in the same preparations showed bright staining for both proteins. The failure to find CLC protein and MBP in mast cells provides additional evidence of dissimilarity between mast cells and basophils, and an immunochemical means to distinguish between them.

Differences between basophils and mast cells: failure to detect Charcot-Leyden crystal protein (lysophospholipase) and eosinophil granule major basic protein in human mast cells

Human eosinophils contain several distinctive proteins including eosinophil granule MBP and the membrane-associated CLC protein (lysophospholipase). Human basophils also contain these proteins, indicating biochemical similarities between eosinophils and basophils. To determine whether MBP or CLC protein is present in connective tissue mast cells, we studied human lung and cutaneous mast cells by immunofluorescence by utilizing specific antibodies to CLC and MBP. Cytocentrifuge slides of enriched lung mast cells and mast cells in sections of formalin-fixed, paraffin-embedded cutaneous tissue from urticaria pigmentosa lesions were stained for CLC and MBP. Neither pulmonary nor cutaneous mast cells stained for CLC protein or MBP. In contrast, lung and cutaneous eosinophils in the same preparations showed bright staining for both proteins. The failure to find CLC protein and MBP in mast cells provides additional evidence of dissimilarity between mast cells and basophils, and an immunochemical means to distinguish between them.

Demonstration of inhibition of mediator release from human mast cells by azatadine base. In vivo and in vitro evaluation

In vitro experimentation using dispersed human lung mast cells demonstrated that azatadine base, a compound with known H1-antihistamine properties, inhibited anti-IgE-induced release of histamine and leukotriene C4 by 45% and 85%, respectively. To assess the clinical relevance of these findings and to compare in vitro mast cell data with results obtained in vivo, nasally instilled azatadine was tested in a double-blind, placebo-controlled clinical trial in which nasal challenges with antigen were performed on eight allergic individuals. Pretreatment with azatadine significantly suppressed the number of sneezes following antigen challenge and inhibited the associated elevations in histamine, kinins, and enzyme(s) hydrolyzing the artificial substrate N-alpha-tosyl-L-arginine-methyl-ester in nasal secretions, whereas placebo was inactive. Hence, we showed agreement between our in vitro and in vivo experimental models of the allergic reaction. Topical application of azatadine base has the potential to become an effective antiallergic treatment.

Kininogens in nasal secretions after allergen challenge

Allergic individuals and nonallergic controls were subjected to nasal challenge with allergen; and nasal washes, obtained before and after challenge, were assayed for high molecular weight kininogen (HMWK), total kininogen (TK), albumin and kinins. Following challenge of allergic individuals, HMWK, TK, kinin and albumin all increased dramatically, correlating (p less than 0.001) with the onset of clinical symptoms and with increases in histamine and TAME-esterase activity. No such increases were seen upon challenge of nonallergics. The time course of appearance and disappearance of the kininogens, kinins and albumin were all highly correlated (p less than 0.001 in each case) by linear regression analysis, as were the increases in kinin and each of the proteins during antigen titrations. For each individual, the plasma ratio of HMWK/TK was similar to the ratio of these two proteins in post-challenge nasal washes from the same individual. These findings are consistent with the hypothesis that, during the allergic reaction, vascular permeability increases, allowing a transudation of kininogens from plasma into nasal secretions, where they can provide substrate for kinin-forming enzymes.

Dexamethasone inhibits plasminogen activator activity in experimental pemphigus in vivo but does not block acantholysis

In vitro studies have suggested that autoantibody-stimulated increases in epidermal plasminogen activator (PA) may be an important pathogenetic mechanism in pemphigus vulgaris (PV). We measured PA in murine epidermis after i.p. injection of normal human IgG (NH IgG) and PV IgG, with and without exposure to dexamethasone (DEX). BALB/c neonates received i.p. injections of saline control or DEX (20 mg/kg). Twenty-four hours later, they received a second injection of saline or DEX and a single dose of NH or PV IgG (20 mg/gm body weight). After 24 hr, epidermis was obtained and was sequentially extracted in 0.14 M NaCl, pH 6.8, and 0.5% Triton X-100 in 0.1 M Tris, pH 8.1. Epidermal PA was assayed in the Triton-Tris supernatant by a two-stage colorimetric reaction and was expressed as milliPloug units per milligram of protein (mPu/A280). PA in animals injected with NH IgG was 0.21 +/- 0.11 mPu/A280 (n = 8). Epidermal PA was increased in animals with cutaneous lesions of pemphigus to 0.42 +/- 0.29 (n = 15). Treatment with DEX decreased PA levels in both animals receiving NH IgG and PV IgG by 80%, to 0.04 +/- 0.05 (n = 15) and 0.09 +/- 0.07 (n = 7), respectively. Despite the decreased PA activity, all animals in the PV IgG and the PV IgG-plus-DEX group had identical and extensive cutaneous disease, and lesions developed at the same time points. This finding shows that PV autoantibodies can stimulate increases in epidermal PA, but reduction of PA by corticosteroids does not inhibit acantholysis in vivo. There is no clear correlation between PA and disease activity in the murine model of pemphigus.

A human lung mast cell chymotrypsin-like enzyme. Identification and partial characterization

We have used a high performance liquid chromatography assay, which detects chymotryptic cleavage of the phe8-his9 bond of angiotensin I to yield angiotensin II, in order to examine human lung mast cells for the presence of chymotryptic activity. Mast cells, purified from human lung by enzymatic dispersion, countercurrent elutriation, and Percoll gradient centrifugation, were lysed or challenged with goat anti-human IgE. In multiple experiments angiotensin II-converting activity was detected in lysates of 10-99% pure mast cell preparations. Regression analysis of net percent release values of histamine and the angiotensin I-converting activity from dose-response experiments demonstrated a correlation between the two parameters, indicating that the chymotrypsin-like enzyme is a constituent of the mast cell secretory granule. The chymotryptic activity was completely inhibited by 10(-3) M phenylmethylsulfonylfluoride but not by 10(-3) M Captopril, and the pH optimum of activity was 7.5-9.5. Gel filtration of released material separated the activity from tryptase and demonstrated an approximate molecular weight of 30-35,000. The mast cell enzyme, like a human skin chymotrypsin-like proteinase, can be distinguished from leukocyte cathepsin G by lack of susceptibility to inhibition by bovine pancreatic trypsin inhibitor. Thus, an enzyme with limited chymotryptic specificity is present in human lung mast cells. The Michaelis constant of the enzyme for angiotensin I of 6.0 X 10(-5) M is similar to that of endothelial cell angiotensin-converting enzyme and is consistent with a reaction of physiologic importance.

Kinins as mediators of human allergic reactions

We have demonstrated that kinins are generated following nasal challenge with allergen of allergic (5.6 +/- 0.17 ng/m-), but not nonallergic (0.04 +/- .02 ng/ml), individuals (n = 8 in each case). The presence of kinin was highly correlated with that of histamine and TAME-esterase activity and with clinical symptoms (p less than 0.001). In a double blind, placebo-controlled study, topical administration of the drug Azatadine, which inhibits mast cell mediator release in vitro, reduced the clinical response to allergen challenge and reduced the concentrations of kinins, histamine, and TAME-esterase activity observed following allergen challenge. In addition to the immediate response to allergen, some individuals experience a recurrence of symptoms some 3-12 hours after challenge; in seven such individuals (13.5 +/- 3.2 ng kinin/ml in the immediate reaction), there was a second increase in nasal kinins (2.95 +/- 1.4 ng/ml) during this late reaction, again correlating with increases in histamine and TAME-esterase activity. HPLC analysis revealed that a mixture of bradykinin and lysylbradykinin is produced during both responses. Finally, 12 subjects with a history of nasal symptoms upon exposure to cold, dry air (CDA) were compared to five asymptomatic individuals in a nasal challenge system involving nasal breathing of CDA and warm, moist air (WMA). For the symptomatic group the levels of kinin in nasal lavages were significantly increased after CDA (2.9 +/- 0.8 ng/ml) compared to baseline (0.06 +/- 0.01 ng/ml) or WMA (0.3 +/- 0.07 ng/ml). Kinin generation again correlated with increases in histamine, PGD2 and TAME-esterase activity and with onset of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Dexamethasone inhibits plasminogen activator activity in experimental pemphigus in vivo but does not block acantholysis

In vitro studies have suggested that autoantibody-stimulated increases in epidermal plasminogen activator (PA) may be an important pathogenetic mechanism in pemphigus vulgaris (PV). We measured PA in murine epidermis after i.p. injection of normal human IgG (NH IgG) and PV IgG, with and without exposure to dexamethasone (DEX). BALB/c neonates received i.p. injections of saline control or DEX (20 mg/kg). Twenty-four hours later, they received a second injection of saline or DEX and a single dose of NH or PV IgG (20 mg/gm body weight). After 24 hr, epidermis was obtained and was sequentially extracted in 0.14 M NaCl, pH 6.8, and 0.5% Triton X-100 in 0.1 M Tris, pH 8.1. Epidermal PA was assayed in the Triton-Tris supernatant by a two-stage colorimetric reaction and was expressed as milliPloug units per milligram of protein (mPu/A280). PA in animals injected with NH IgG was 0.21 +/- 0.11 mPu/A280 (n = 8). Epidermal PA was increased in animals with cutaneous lesions of pemphigus to 0.42 +/- 0.29 (n = 15). Treatment with DEX decreased PA levels in both animals receiving NH IgG and PV IgG by 80%, to 0.04 +/- 0.05 (n = 15) and 0.09 +/- 0.07 (n = 7), respectively. Despite the decreased PA activity, all animals in the PV IgG and the PV IgG-plus-DEX group had identical and extensive cutaneous disease, and lesions developed at the same time points. This finding shows that PV autoantibodies can stimulate increases in epidermal PA, but reduction of PA by corticosteroids does not inhibit acantholysis in vivo. There is no clear correlation between PA and disease activity in the murine model of pemphigus.

Mediator release during nasal provocation. A model to investigate the pathophysiology of rhinitis

The pathogenesis of rhinitis was investigated using a model of nasal provocation with different types of stimuli. Allergic subjects had an immediate response to antigenic challenge with symptoms of rhinitis highly correlated with increments in the concentrations of histamine, prostaglandin D2, kinins and kininogens, leukotrienes, and toluene sulfonyl arginine methyl ester esterase activity in their nasal secretions. This reaction was abated by a tricyclic antihistamine also capable of inhibiting mediator release from human mast cells in vitro and, in some subjects, by disodium cromoglycate. In a number of patients, symptoms reappeared three to 12 hours after nasal provocation. This late reaction also involves release of all of the aforementioned mediators except for prostaglandin D2, and preliminary data suggest that it can be inhibited by oral or topical steroids. Cold, dry air can induce rhinitis with mast cell mediator release from selected subjects. The pathogenesis of this reaction is unclear, but there are indications that osmolarity changes are responsible for mast cell activation. Thus, mast cells can be induced to release mediators and cause nasal symptoms by both immunologic and physical mechanisms, which may account for the pathophysiology of several types of rhinitis.

Nasal challenge with ragweed pollen in hay fever patients. Effect of immunotherapy

Challenge of the nasal mucosa of allergic subjects with specific allergen induces not only the expected sneezing and rhinorrhea, but also the appearance in nasal secretions of mediators commonly associated with activation of mast cells or basophils: histamine, leukotrienes, prostaglandin D2 (PGD2), kinins, and TAME ([3H]-N-alpha-tosyl-L-arginine methyl ester)-esterase. To determine whether specific immunotherapy alters mediator release in vivo, nasal pollen challenge was used to compare 27 untreated highly sensitive ragweed (RW)-allergic subjects with 12 similarly sensitive patients receiving long-term immunotherapy (3-5 yr) with RW extract (median dose, 6 micrograms RW antigen E). The two groups were equally sensitive based on skin tests and basophil histamine release. The immunized group had a diminished response as demonstrated by (a) the treated group required higher pollen doses to excite sneezing or mediator release; (b) significantly fewer subjects in the treated group released mediators at any dose (TAME-esterase [P = 0.005], PGD2 [P = 0.04]), and (c) the treated group released 3-5-fold less mediator (TAME-esterase [P = 0.01], and histamine [P = 0.02]).