Adrenaline-stimulated,aspirin-sensitive synthesis of histamine in the rat

The intravenous injection of 40 g/kg of adrenaline raised total rat lung histamine from 5.3±0.7 g, to 8.4±0.7 g and rat skin histamine from 624±51 g to 835±85 within 5 min. These changes were no longer apparent after 10 min. Stomach histamine was unaffected. Blood drawn 2 min after the injection of adrenaline failed to show an increased content of histamine. Rats given 1 mg/kg of compound 48/80, had greatly elevated levels of histamine in blood, but exhibited no increase in lung histamine. This result, as well as the extent of the increase of histamine observed in skin, which cannot be accounted for in any other way, point towards stepped-up local synthesis as the origin of the effect of adrenaline. Aspirin (20 mg/kg, intravenously 10 min prior to adrenaline), prevented increases of skin histamine. Evidence suggesting mast cells as the site of action of adrenaline, is discussed.     

Skin histamine in chronic urticaria

To further study the role of histamine in the pathogenesis of chronic urticaria, the concentration of histamine in tissue extracts from skin biopsy samples and in plasma from patients with chronic urticaria was measured by a sensitive radioenzymatic assay. Tissue histamine levels from urticarial lesions and uninvolved skin were compared with extracts of biopsy samples taken from normal controls. The average tissue histamine content in 15 biopsy samples from the chronic urticaria patients was significantly higher than in those of 15 normal controls. Forty percent of the patients had levels 2 SD greater than the mean of the control group. Elevated histamine levels were also found in biopsy samples of uninvolved skin from some urticaria patients. Circulating histamine levels from chronic urticaria patients were rarely elevated and did not correlate with skin concentration. No correlation was noted between tissue histamine concentration and estimated mast cell concentration on Giemsa-stained sections of five biopsy samples. These results indicate that tissue histamine levels are increased in some patients with chronic urticaria. This suggests that local histamine elevations may be important in the pathogenesis of many patients with this disease. In addition, increased tissue histamine in these patients is not reflected by elevated circulating levels.     

Abnormalities in histamine pharmacodynamics in chronic urticaria

Histamine plays a key role in the pathogenesis of chronic urticaria (CU). The authors of this paper have studied the effects of ingested histamine in 25 patients with CU. A 120 mg dose of histamine, well-tolerated in the healthy subject, was instillated into the duodenum. Concomitantly, plasma histamine (H) levels and plasma and urinary methylhistamine (MH) levels were measured. Intraduodenal administration of histamine was responsible for the development of an attack of urticaria in 64% of patients, while control subjects were asymptomatic. Plasma histamine levels were significantly higher after digestive histamine challenge (DHC) in patients with CU compared with controls. An abnormal increase in plasma histamine was observed in 72% of them. Plasma MH exhibited the same kinetic behaviour with a usually delayed time-pattern. Urinary MH concentration was higher in patients presenting with early-onset urticaria during the first hour than in those with the late-onset type between 1 and 12 hr after DHC. The coefficient of methylation (plasma MH/MH+H) was not significantly different in patients presenting with an attack of urticaria following DHC and in other subjects. Urinary excretion of MH and urinary flow increased significantly in patients presenting with an attack of urticaria following DHC which corresponds to increased absorption of histamine during the 5-hr period following DHC and its role on excretion by the kidney via vasodilation which it induces. This study demonstrates the abnormal frequency of disturbances in the metabolism of exogenous histamine in patients with CU. Increased plasma H accounts for the abnormal passage of H across the intestinal barrier which can result either from intestinal hyperpermeability and/or a deficit in the enzymatic catabolism of histamine. The systems of methylation and urinary clearance of MH appear to be effective. It is thus postulated that there is a deficit in diamine oxidase (DAO) in the enterocyte. The lack of correlation between the kinetic behaviour of plasma H and the onset of urticaria draws attention to the extent of individual variability in skin reactivity to histamine.     

Cutaneous histamine metabolism in chronic urticaria.

Impaired metabolism of histamine in the skin of patients with chronic idiopathic urticaria (CIU) might explain the observed enhanced and prolonged skin responses to intradermal histamine. Histamine metabolism was measured in homogenates from unaffected forearm skin in nine patients with CIU and in skin of age- and sex-matched control subjects with a radiochromatographic assay, and the results are expressed as nanograms of histamine metabolized per milligram of protein per hour. Endogenous histamine content was determined by RIA. There was a highly significant increase in endogenous histamine content in the skin of patients with urticaria (407.8 +/- 188.3 ng/mg of protein) compared with that in skin of control subjects (240.0 +/- 73.0 ng/mg of protein) (mean +/- 1 SD; p less than 0.02), which suggests either an increase in mast cell number or histamine concentration per cell. No significant difference was observed in the metabolism of histamine between patient and control group; therefore, an alternative mechanism may underlie differences in skin reactivity to histamine.     

Complement dependence of histamine release in chronic urticaria.

BACKGROUND: IgG autoantibodies directed to the alpha-subunit of the IgE receptor have been identified in 30% to 45% of patients with chronic urticaria. However, the exact mechanism by which histamine secretion is initiated is uncertain. OBJECTIVE: Histamine release from cutaneous mast cells may occur by cross-linking the IgE receptor or by activation of complement. Our goal is to distinguish these 2 possibilities. METHODS: We incubated human cutaneous mast cells with patient sera, decomplemented sera, or purified patient IgG. The IgG was also added to pooled normal serum or to sera deficient in either C2 or C5, and its ability to activate mast cells was assessed. Mast cells were incubated with human IgE myeloma to saturate alpha-subunits to determine the effect on histamine release. RESULTS: Patient sera released histamine (18.26% +/- 4.39%), but purified IgG from patients (5.5% +/- 4.3%) did not. Addition of the patient IgG to normal sera rendered the sera positive for histamine-releasing activity (18.4% +/- 4.3%), whereas control IgG or patient IgG added to C2- or C5-deficient sera did not release histamine. Histamine release with decomplemented patient sera was also diminished (8.34% +/- 4.3%). Preincubation of mast cells with a C5-blocking peptide decreased histamine release but was not statistically significant; there was a significant decrease after preincubating mast cells with IgE myeloma. CONCLUSION: The degranulation of mast cells by IgG autoantibodies in patients with chronic urticaria requires binding to the IgE receptor and activation of the classical complement cascade. Saturation of the IgE receptor with IgE inhibits such degranulation, presumably by preventing binding of the requisite IgG.     

Secretion of cytokines,histamine and leukotrienes in chronic urticaria

BACKGROUND: Approximately 35-40% of patients with chronic urticaria have an IgG autoantibody to the IgE receptor which can activate basophils and mast cells so that they release histamine. In this study we assessed the cytokine profile present in chronic urticaria sera, and then measured cytokine and leukotriene release from basophils and mast cells upon incubation with chronic urticaria sera. Finally we assessed cytokine expression at the single-cell level and characterized the T cell subpopulations involved in their production. We chose IL-4 as representative of Th2 lymphocytes and IFN-gamma for Th1 lymphocytes. METHODS: We analyzed IL-4, IL-5 and IFN-gamma in 60 chronic urticaria sera versus 51 controls. Sera were incubated with purified human basophils and cutaneous mast cells and the release of histamine, IL-4 and leukotrienes (C(4), D(4), E(4)) was quantitated. Immunoblotting was performed to identify IgG antibody to FcepsilonRIalpha, alpha subunit. We measured intracellular cytokine production in peripheral blood mononuclear cells of 17 chronic urticaria patients compared to 50 healthy controls. RESULTS: We found higher IL-4 levels (p = 0.028) in the sera of chronic urticaria patients (1.03 pg/ml) versus healthy donors (0.20 pg/ml) but no difference between urticaria sera and atopic control sera (0.52 pg/ml). We did not detect IFN-gamma or IL-5 in any serum. However, sera that activated basophils so that they released histamine also produced leukotriene and IL-4, and leukotriene production by cutaneous mast cells and basophils was closely correlated. However, there was no correlation between immunoblotting and the functional ability to induce either histamine or IL-4. After stimulating with PMA-ionomycin we found significant differences in CD4+ lymphocyte production of IL-4 and IFN-gamma with no differences in CD8+ lymphocyte production of either cytokine. CONCLUSION: Our data support the presence of basophil and mast cell activators in the sera of patients with chronic urticaria which can lead to the production of leukotrienes and IL-4 in addition to the histamine. IL-4 levels are similar to those seen in atopic subjects. We found that CD4+ T cells from patients with chronic urticaria are activated and tend to produce higher cytokine levels than CD4+ T cells from healthy controls. There were no differences when cytokine production by CD8+ lymphocytes was similarly assessed. These results are consistent with the histology found in biopsies of chronic urticaria lesions, where a CD4+-predominant infiltrate is found with cytokine production suggesting either a Th0 response or a mixture of Th1 and Th2 lymphocytes.     

Assessment of tissue fluid histamine levels in patients with urticaria

Tissue fluid histamine in lesions and normal skin sites of patients with various forms of physically induced urticaria and chronic idiopathic urticaria was assessed utilizing suction-induced blisters. Histamine levels were elevated over challenged sites in cold urticaria, solar urticaria, and delayed pressure urticaria. Histamine levels were elevated in both challenged and “control” sites in patients with immediate-pressure urticaria and local heat urticaria in whom the apparatus provoked lesions. In 5 of 13 patients with chronic idiopathic urticaria, the blister fluid histamine levels were elevated in lesions but not in normal-appearing skin, while in 7 patients the blister fluid histamine levels were elevated in lesions as well as in normal-appearing skin. Although the pathogenesis of chronic idiopathic urticaria is unknown, a clear abnormality related to skin histamine has been identified.     

Plasma neuropeptide pattern in acute idiopathic urticaria

Immediate hypersensitivity responses, as acute urticaria, produce a release of neuropeptides by nerve endings, which present specificity of recognition by mast cells, basophils and other target cells. We have measured vasoactive intestinal peptide (VIP), somatostatin, bombesin, neurotensin and beta-endorphin by radioimmunoassay in plasma extracts of 20 patients with acute idiopathic urticaria and of 20 healthy subjects. VIP- and beta-endorphin-like immunoreactivities were found to be significantly decreased with respect to controls (p less than 0.001 and p less than 0.01, respectively). On the contrary, somatostatin- and bombesin-like immunoreactivities were significantly increased (p less than 0.001 and p less than 0.05, respectively). These findings could be a reflection in blood of a raised release of somatostatin and bombesin by nerve endings in the urticaria process. Moreover, the decreased plasma levels of VIP- and beta-endorphin-like immunoreactivities could be explained by a raised specific metabolism of these peptides in the urticaria process.     

Plasma acetylsalicylic acid and salicylic acid levels during aspirin provocation in aspirin-sensitive subjects

The ability of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit the cyclo-oxygenase which catalyzes formation of prostaglandins appears to be central to the mechanisms involved in aspirin sensitivity. We have investigated whether the plasma levels of acetylsalicylic acid (ASA) and its main metabolite salicylic acid (SA) at the time of intolerance reactions correspond with the concentrations required for enzyme inhibition in vitro. Twelve aspirin-sensitive and 15 aspirin-tolerant subjects were followed during provocation with aspirin. ASA and SA concentrations in plasma were determined by HPLC. After oral provocation (up to 460 mg cumulative dose), the levels of ASA and SA in plasma were equivalent in aspirin-sensitive and aspirin-tolerant subjects. For the aspirin-sensitive subjects, at the time of adverse reaction, the concentration range was 2.9–33.3 μM for ASA and 18.1–245 μM for SA. Oral provocation with sodium salicylate yielding 10-fold higher SA levels did not elicit intolerance reactions. Statistically significantly lower levels of ASA and SA (P>0.01) evoked airway obstruction, as compared with merely extrapulmonary symptoms. Bronchial absorption of aspirin was found after inhalation of lysine-aspirin and was comparable in asthmatic and nonasthmatic subjects. In three aspirin-sensitive subjects who developed airway obstruction, the plasma levels for ASA and SA were 0.9–2.6 μM and 0.0–6.7 μM, respectively. In conclusion, the plasma levels of ASA reached at the time of a positive reaction are of the magnitude known to inhibit cyclo-oxygenases. Neither differences in bioavailability of ASA nor the formation of SA seems to contribute to the aspirin-elicited reactions.     

Plasma histamine levels in polytraumatized patients

In a prospective clinical trial, plasma histamine levels were measured in 28 polytrauma patients on day 1, 5 and 14 after trauma. Only those subjects who died were drop-outs. All patients had severe polytrauma with at least 3 body regions involved. The median plasma histamine levels at all three time points were significantly higher than in patients with single trauma of the extremities or before selective orthopaedic surgery but still in the normal range (<1 ng/ml). However, all patients with plasma levels above 1 ng/ml on days 1 and 5 died, as did all patients with levels above 0.5 ng/ml on day 1. Thus the elevation of plasma histamine levels, for whatever reason, appears to be a prognostic factor for bad outcome in polytrauma patients.     

Plasma histamine concentrations in atopic eczema

Plasma histamine concentrations were determined using a radio-enzymatic assay in fifty-four patients suffering from atopic eczema and in thirty-nine controls (contact dermatitis, psoriasis and normal non-alopic healthy volunteers). While in none of the controls histamine levels in plasma exceeded 1 ng/ ml, seventeen out of fifty-four patients with atopic eczema showed increased plasma histamine concentrations ranging between 1-2 and 5′2 ng/ml. Elevated plasma histamine levels were found mostly in patients with severe eczema and high serum IgE. levels. Longitudinal studies in seven patients revealed normal plasma histamine values during clinical remission.     

Release of gastric histamine in patients with urticaria and food allergy

In a clinical study the participation of histamine in the allergenic response of patients with food allergy was investigated.The resting levels of gastric tissue and plasma histamines of 10 patients were slightly higher than the respective values of normal volunteers. 5 minutes after local intragastral allergenic provocation a decline of the mucosal histamine content of the allergen-treated area was noticed. Parallel investigations on the mast cell content of the stomach mucosa revealed a parallel decrease of theo-phthaldialdehyde stained cells, whereas the number of toluidine blue stained cells remained unchanged. These data are in accordance with an antigen-induced IgE-dependent liberation of the mast cell histamine stores.     

Basophil histamine release and lymphocyte proliferation tests in latex contact urticaria

Basophil histamine release and lymphocyte proliferation tests were examined with latex allergen prepared from surgical gloves in 15 patients with latex contact urticaria. The basophil histamine release test (BHRT) yielded positive results in 13/14 (93%) patients, whereas commercial latex RAST was positive in only 9/15 (60%) patients. Lymphocyte proliferation test (LPT) was positive in 3/15 (20%) patients, suggesting that cell-mediated immune reactions may also occur in latex allergy. However, patch tests to latex were negative and neither were epidermal Langerhans cells able to present latex antigen to T lymphocytes in vitro.     

Blood histamine levels and eosinophil, basophil counts in urticaria.

The blood histamine levels, basophil and eosinophil counts and the percentage of vacuolated eosinophils were observed in 30 controls and 15 patients of urticaria. There was a definite rise in eosinophil and basophil count during the acute stage of the disease which decreased in the quiescent or the symptom-free stage. The behavior of blood histamine level was similar. The mechanisms involved are discussed.     

Plasma histamine profiles in paediatric cardiopulmonary bypass

We have previously reported our findings of very high plasma histamine levels in the extracorporeal blood primes of infants undergoing cardiopulmonary bypass (CPB) for correction of congenital cardiac defects and have now extended this enquiry to examine the whole peri-operative period. In this preliminary study, samples of blood for plasma histamine were drawn from a mixed group of congenital cardiac patients featuring varying degrees of cyanosis, differing hypothermic operative conditions and utilising two oxygenator systems. Despite the diversity of this group a common pattern of histamine release emerged with a clear origin at the commencement of bypass, and continuing during the operative period. Our results suggest that priming procedures using stored donor blood provide a major contributing source of histamine release with inevitable deleterious consequences to the post-operative outcome.     

Plasma histamine levels and symptoms in double blind placebo controlled histamine provocation

Inflammation Research -     

Basophil histamine release activity and disease severity in chronic idiopathic urticaria.

BACKGROUND: Altered basophil degranulation phenotypes are found in patients with chronic idiopathic urticaria (CIU). OBJECTIVE: To evaluate CIU disease severity in relation to basophil histamine release (HR) characteristics. METHODS: Patients with CIU were recruited from allergy and dermatology clinics. Patients with recent use of systemic corticosteroids or immunosuppressants were excluded. Patients completed disease severity surveys and had blood basophils isolated and stimulated for HR using polyclonal goat anti-human IgE and N-formyl-met-leu-phe. The HR was measured using automated fluorometry. Multivariate linear regression analyses were used to investigate relationships between HR data and CIU disease measures. RESULTS: Fifty patients completed surveys, of which 34 were further categorized into 2 subgroups based on basophil HR response to anti-IgE stimulation: responders (> or = 10% HR) and nonresponders (< 10% HR). Responders and nonresponders reported similar use of oral corticosteroids, work absences, and quality-of-life impairment but differed in their patterns of medications used for CIU. Basophil responders had a trend of higher use of the emergency department for CIU management. Multivariate regression revealed that patients with the basophil responder phenotype experienced significantly higher current itch scores (P = .02) compared with nonresponders. CONCLUSIONS: Quality-of-life impairment is similar in CIU basophil subsets. Patients with CIU with a basophil responder phenotype report longer disease duration, a higher frequency of emergency department use, and significantly higher itch severity.