Differential response of human basophils and mast cells to recombinant chemokines

Chemokines are proinflammatory peptides regulating the functions of various hematopoietic cells. We have analyzed the effects of seven recombinant human (rh) chemokines (MCAF, RANTES, MIP-1, MIP-1, IL-8, GRO, and IP-10) on the growth and function of human basophils and mast cells. We found that MCAF, but not RANTES, MlP-la, MIP-1, IL-8, GRO, or IP-10, causes direct and dose-dependent histamine release from basophils (MCAF, 5 g/ml: 26.9 ± 3.4%; other chemokines: < 5% of total histamine). An increased (2.1 to 3.5-fold) response to MCAF was obtained when basophils were preincubated with rh interleukin-3 (100 units/ml). Moreover, IL-3-primed basophils became responsive to physiologic concentrations (< 1 g/ml) of MCAF, IL-8, and RANTES. None of the chemokines tested was able to induce histamine secretion in mast cells obtained from lung (n=2), skin (n=1), uterus (n=3), or tonsils (n=3), even when cells had been preincubated with the mast cell agonist SCF. The chemokines also failed to modulate the expression of activation antigens (CD11b/C3biR, CD25/IL-2R, CD63, IL-3R, CD117/c-kit) on the mast cell line HMC-1 or the basophil cell line KU-812 and were unable to induce differentiation of basophils or mast cells in culture. Together, our results show that basophils respond to rhIL-8, rhMCAF, and rhRANTES and that, unlike human basophils, human mast cells are unresponsive to recombinant chemokines.This work was supported by FWF Austria, grant P-9359, and by Sandoz, Vienna     

Lethal or life-threatening allergic reactions to food.

Fatal or life-threatening anaphylactic reactions to food occur in infants, children and adults. Atopic individuals with bronchial asthma and prior allergic reactions to the same food are at a particularly high risk, whereby even the mere inhalation of the allergenic food can be fatal. Not only peanuts, seafood and milk can induce severe, potentially lethal anaphylaxis, but indeed a wide spectrum of foods, according to the different patterns of food sensitivity in different countries. Foods with "hidden" allergens and meals at restaurants are particularly dangerous for patients with food allergies. Similarly, schools, public places and restaurants are the major places of risk. However, the main factor contributing to a fatal outcome is the fact that the victims did not carry their emergency kit with adrenaline (epinephrine) with them. In cases of death where food anaphylaxis is suspected, it is important for forensic reasons to preserve uneaten portions of the food in order to identify (hidden) allergens. It is also important to determine postmortem specific serum IgE, tryptase and histamine levels to document the anaphylaxis. There is a need to raise awareness of the diagnosis and treatment of anaphylaxis among doctors, those called upon to administer emergency medical care, and the public, and also to provide increased support for those with potentially fatal food allergies through the help of patients' organizations, and national and international medical societies. The food industry should ensure a policy of comprehensive labelling of ingredients so that even the smallest amount of potentially lethal foodstuffs can be clearly identified. Finally, the pharmaceutical industry should be persuaded to reintroduce an adrenaline inhaler onto the market.     

Systemic allergic reactions to corticosteroids

Allergic anaphylactic (type I) reactions to corticosteroid medications are uncommon; however, a number of well-documented cases have been reported. We present a review of the literature, and report on two patients who suffered anaphylaxis after injections of corticosteroids. The first patient, a registered nurse, was finally found to be sensitive to all corticosteroid preparations containing carboxymethylcellulose, as well as the pure carboxymethylcellulose. The second patient had positive skin tests to hydrocortisone, hydrocortisone sodium succinate, methylprednisolone sodium succinate, and suxamethonium. Both patients were tested on two occasions; four normal subjects were tested in parallel, and did not elicit any positive skin reaction. In patients with systemic severe reactions to injectable corticosteroids, we recommend careful and comprehensive skin testing with most available corticosteroids, as well as the components of the injectables.     

Upregulated response to chemokines in oxidative metabolism of eosinophils in asthma and allergic rhinitis.

Reactive oxygen species (ROS) from eosinophils are known to cause tissue damage in allergic inflammation. CC chemokines, especially eotaxin and regulated on activation, normal T-cell expressed and secreted (RANTES), are involved not only in chemotaxis but also in eosinophil activation, such as ROS production. It has been shown that eosinophils from allergic patients are not functionally equivalent to those from normal subjects. In the present study, the characteristics of chemokine-primed ROS production in eosinophils from allergic patients and normal controls were compared. After pretreatment with chemokines, eosinophils were stimulated with calcium ionophore A23187. ROS production by eosinophils was measured using luminol-dependent chemiluminescence. Both RANTES and eotaxin exhibited a priming effect on calcium ionophore-induced ROS production from eosinophils. Despite there being no difference in expression of CC chemokine receptor 3, the priming effect of RANTES and eotaxin was significantly enhanced in eosinophils from the patients. Interleukin-5 further enhanced the priming effect of chemokines in eosinophils from normal subjects, but not those from allergic subjects. The present results suggest an upregulated response to chemokines in eosinophils from allergic patients, and that interleukin-5 can induce a similar phenotype to that found in vivo in allergic patients.     

Peripheral blood basophils, basophil progenitors, and nasal metachromatic cells in allergic rhinitis

Relationships among mature blood basophils, blood basophil colony-forming units in culture (CFU-c), and nasal metachromatic cells (NMC) were investigated using hemopoietic and histochemical techniques in 29 patients with allergic rhinitis and in 7 nonatopic control subjects. Total blood granulocyte and basophil CFU-c were significantly elevated in atopy; the highest levels of basophil CFU-c were found in patients with low total NMC counts in nasal scrapings (Group I), compared with those with intermediate (Group II) or high (Group III) counts: 10 +/- 3 basophil CFU-c per 10(6) cells in 10 Group I patients, 4 +/- 2 in 10 Group II patients, 3 +/- 1 in 9 Group III patients, and 0.1 +/- 0.1 in nonatopic control subjects (p less than 0.05). Mean histamine content and frequency of histamine-positive granulocyte colonies correlated with counts of basophils in colonies (r = 0.864, p less than 0.001). Peripheral blood basophils, which stained metachromatically with toluidine blue at pH 0.5 after Mota's lead acetate but not after formalin fixation, were highest in atopic Group III and lowest in Group I; a similar relationship was observed only for NMC, which also failed to stain after formalin fixation. Metachromatic cells in colonies were similar to formalin-sensitive NMC and to peripheral blood basophils in their sensitivity to different fixatives. Nasal symptoms correlated inversely with the number of basophil CFU and directly with the number of either formalin-sensitive NMC or peripheral blood basophils. These findings confirm and extend evidence for increased nasal metachromatic cells, basophilia, and alterations in basophilopoiesis in atopy.     

Deuterium-oxide-induced histamine release from basophils of allergic subjects. I. Responsiveness to deuterium oxide requires an activation step

Basophils from many atopic persons, and especially asthmatic patients, have been shown to release histamine in response to 44% deuterium oxide (D2O), whereas basophils from nonatopic persons do not release histamine. The present experiments analyzed the mechanisms by which D2O mediated release. It was found that although D2O induced release from washed leukocytes, it failed to induce release from whole blood or from leukocytes that had sedimented but had not been washed. The kinetics of release after washing were rapid and were equivalent regardless of the temperature at which cells were sedimented (O degrees or 37 degrees C). Washed cells became desensitized to the action of D2O within 30 to 60 min at 37 degrees C, whereas unwashed leukocytes did not become desensitized. Serum or plasma inhibited D2O-induced release, although high concentrations (1/5) were less inhibitory than lower ones (1/10 to 1/100). Basophils from D2O responders also released histamine in response to a "platelet enhancing factor" (PEF), whereas those from D2O nonresponders did not. As with D2O-mediated release, PEF-mediated release occurred only with washed leukocytes, desensitized within 30 to 60 min at 37 degrees C, and was inhibited by serum. These results suggest that D2O induces histamine release by augmenting the effects of an endogenous activation mechanism, and that PEF acts on the same (D2O-responsive) donors to augment this activation mechanism. Cell activation, as well as desensitization of this activation mechanism, occurs rapidly when basophils are washed free of plasma inhibitors and placed at 37 degrees C.     

Complementary DNA microarray analysis of chemokines and their receptors in allergic rhinitis.

OBJECTIVE: To analyze the roles of chemokines and their receptors in the pathogenesis of allergic rhinitis by observing the complementary DNA (cDNA) expression of the chemokines and their receptors in the nasal mucosa of patients with and without allergic rhinitis, using gene chips. METHODS: The total RNAs were isolated from the nasal mucosa of 20 allergic rhinitis patients and purified to messenger RNAs, and then reversely transcribed to cDNAs and incorporated with samples of fluorescence-labeled with Cy5-dUPT (rhinitis patient samples) or Cy3-dUTP (control samples of nonallergic nasal mucosa). Thirty-nine cDNAs of chemokines and their receptors were latticed into expression profile chips, which were hybridized with probes and then scanned with the computer to study gene expression according to the different fluorescence intensities. RESULTS: The cDNAs of the following chemokines were upregulated: CCL1, CCL2, CCL5, CCL7, CCL8, CCL11, CCL13, CCL14, CCL17, CCL18, CCL19, CCL24, and CX3CL1 in most of the allergic rhinitis sample chips. CCR2, CCR3, CCR4, CCR5, CCR8 and CX3CR1 were the highly expressed receptor genes. Low expression of CXCL4 was found in these tissues. CONCLUSION: The T helper cell (T(H)) immune system is not well regulated in allergic rhinitis. Most of the upregulated genes we identified are of chemokines and their receptors that play important roles in T(H)2 response, and some are involved in the induction of allergic reaction, accumulation of inflammatory cells, and degranulation of sensitized cells. These findings can point to new strategies for allergic rhinitis immunotherapy.     

Histamine antagonists in the treatment of acute allergic reactions.

STUDY OBJECTIVE: We compared the efficacies of cimetidine (an H2-receptor antagonist) and diphenhydramine (an H1-receptor antagonist) alone and in combination for alleviation of symptoms of acute allergic reactions. STUDY DESIGN AND INTERVENTIONS: In this prospective, randomized, double-blind study, patients and examiners assessed the severity of symptoms and signs of acute allergic reactions using a visual-analog scale before treatment and 30 minutes after treatment with 300 mg IV cimetidine and placebo, 50 mg IV diphenhydramine and placebo, or diphenhydramine plus cimetidine. SETTING AND PARTICIPANTS: Thirty-nine patients with acute allergic reactions presenting to two emergency departments of teaching hospitals. RESULTS: Of the 35 patients with pruritus, all 12 receiving diphenhydramine placebo had clinically significant relief compared with six of ten (60%) receiving cimetidine plus placebo (P = .03). Twelve of 13 (92%) receiving diphenhydramine plus cimetidine had relief, which was not a significant difference from the single drugs. Comparison of mean differences in pretreatment and post-treatment symptom scores (relief scores) among groups of patients with pruritus detected significantly more relief in the group receiving diphenhydramine plus placebo (80.3 +/- 7.4) than in those receiving cimetidine plus placebo (48.8 +/- 13.4) (P = .022). Of the 33 patients with urticaria, five of 11 (46%) receiving diphenhydramine plus placebo had clinically significant relief compared with eight of ten (80%) receiving cimetidine plus placebo (P = .18). Eleven of 12 patients (92%) receiving diphenhydramine plus cimetidine had relief, which is a significant difference from those receiving diphenhydramine plus placebo (P = .027). Comparison of mean relief scores in patients with urticaria detected significantly more relief in the group receiving diphenhydramine plus cimetidine (55.3 +/- 6.5) than in the group receiving diphenhydramine plus placebo (30.7 +/- 6.1) (P = .006). CONCLUSION: For treatment of pruritus from acute allergic reactions, diphenhydramine is more effective than cimetidine, and the combination offers no additional benefit. For treatment of acute urticaria, the combination of cimetidine and diphenhydramine is more effective than diphenhydramine alone.     

Involvement of hidden allergens in food allergic reactions.

BACKGROUND: Hidden allergens in foods can induce allergic reactions. Currently it is not possible to estimate the exact prevalence of these reactions but they are clearly a growing problem. OBJECTIVE: The purpose of this study was to provide an overview of the role of hidden allergens (their importance, the types of food involved, and the severity of reactions) in allergic reactions in our geographical area. METHODS: A retrospective study was carried out in an adult population. Over a five year period, a total of 530 food reactions were reviewed. RESULTS: One hundred nineteen reactions (22.4%) were considered to be due to hidden allergens. Thirty-two percent of these were anaphylactic reactions. The most common hidden allergen was the Anisakis simplex larvae present in fish and shellfish. Fish allergens hidden in other foods caused reactions in 35% of fish-allergic patients. Twenty-two per cent of allergic reactions caused by eggs were due to egg allergens hidden in foods. All but one of the reactions caused by hidden legume allergens occurred in soy-allergic patients. Reactions caused by hidden fruits and hidden nuts were very uncommon. CONCLUSION: Hidden allergens were the cause of a quarter of all food allergic reactions, mainly as a result of contamination and carelessness on the part of the patient. A simplex was the hidden allergen most frequently involved. Fruits and nuts were not frequent hidden allergens in our area. Reactions due to other uncommon foods such as soy, mustard, flavourings, and honey were multiple and usually went unnoticed. Only if the sources of hidden allergens are determined will it be possible to avoid such substances and thus guarantee the safety of the allergic patient.     

Cytokines, chemokines, RANTES, and eotaxin.

Over the past several years, a number of cytokines with chemoattractive properties (chemokines) have been identified. These low molecular weight molecules have been shown to be important leukocyte chemical attractants to sites of inflammation and infection. Chemokines act on leukocytes through selective receptors and are now known to function also in leukocyte maturation, trafficking, and homing of these cells. RANTES and eotaxin (among other chemokines) are important chemoattractants for eosinophils. Since eosinophils seem to play a critical role in the production of allergic inflammation, an understanding of the mechanism of action of these chemokines may lead to new therapies for asthma and other allergic processes.