Antigen-specific sulphidoleukotriene production and histamine release in pollinic patients

We studied sulphidoleukotriene (sLT) production, by means of CAST-ELISA (Bühlmann) in 92 atopic (54 pollinic and 38 non-pollinic) patients, and in 9 control subjects, after antigenic stimulation of peripheral blood leukocytes with 20 ng/ml and 2 ng/ml of Lolium perenne pollen extract, in the presence of IL-3. Antigen-specific stimulation of leukocytes from pollinic patients studied during the pollen season led to a sLT production significantly higher (p = 0.03 at 2 ng allergen/ml) than in those studied out of the pollen season. Histamine release was also significantly higher in pollen season than out of the season (p = 0.04 at 20 ng allergen/ml and p < 0.001 at 2 ng allergen/ml). There was a significant positive correlation between sLT production and histamine release (r = 0.67 at 2 ng allergen/ml and r = 0.57 at 20 ng/ml, both p < 0.001), and between sLT production and skin test results (r = 0.5 at 2 ng allergen/ml and r = 0.46 at 20 ng allergen/ml, both p < 0.001). We found that sLT production was lower, although not significantly, in patients older than 40 years, and histamine release was significantly (p = 0.02) higher in women than in men at 2 ng allergen/ml. We conclude that sLT production in pollinic patients is higher when antigenic pressure is increased in the environment, and that sLT quantification by CAST-ELISA might be useful for evaluation of this sensitization, with analogous results to the histamine release test.

Serum ECP levels in asthmatic patients: comparison with other follow-up parameters

In recent years, eosinophil cationic protein (ECP) has been considered as a useful eosinophilic activation marker in asthmatic patients. In this study, serum ECP levels in different stages of bronchial asthma were evaluated. We studied 123 patients suffering from asthma, which was classified as mild (n = 49), moderate (n = 49), severe asthma (n = 25), and also 31 healthy controls. Serum ECP levels were 13.22 +/- 1.11 ng/mL (mean +/- s.e.m.) in controls, and 30.15 +/- 2.38 ng/mL in asthmatic patients. By subgroups, ECP levels were 24.23 +/- 3.37 ng/mL, 31.69 +/- 4.21 ng/mL and 37.61 +/- 4.52 ng/mL, in mild, moderate and severe asthmatic patients, respectively, being the differences among the three groups statistically significant (P < 0.01-P < 0.001). Peripheral blood eosinophil numbers were 157 +/- 20 eos/mm3 in controls, and 334 +/- 35 eos/mm3, 510 +/- 87 eos/mm3, and 658 +/- 72 eos/mm3, in mild, moderate, and severe asthmatic patients, respectively, with significant differences among all groups (P < 0.05-P < 0.001). The serum ECP levels as well as the eosinophil numbers were higher in symptomatic patients than in the asymptomatic ones (P < 0.01). Moderate negative correlations, although highly significant (P < or = 0.001), were found between serum ECP levels and forced vital capacity (FVC) (rs = -0.27), FEV1, MEF25-75 (rs = -031), and MEF50 (rs = -0.32). There was also a good positive correlation between ECP levels and peripheral blood eosinophil numbers (rs = 0.67, P < 0.001).

Diagnostic reliability considerations of specific IgE determination

Total IgE determination constitutes a good method for the screening of atopic diseases, though its actual value is controversial because normal values of total IgE do not exclude the existence of atopic disease, and high values of total IgE are not pathognomonic of atopy by themselves. The first step in identifying an atopic individual as such, after doing his anamnesis, can be carried out by means of total IgE determination. Most atopic individuals have high IgE values, but a normal result must be carefully interpreted: age and season-related variations must be considered. In general, atopic patients with IgE values greater than 1000 Ul/ml, always have positive specific IgE against some allergen. Antigen-specific IgE will be the next step in the in vitro identification of the responsible allergen. Nowadays, there are more than 400 characterized allergens available for in vitro diagnostic tests and several useful methodologies for specific IgE determination. Specific IgE results obtained with the different methods vary significantly, with absolute agreement in 55-65% of the cases, differences in one IgE class in 20-30% of the cases and differences in more than two classes in 5-10%. The specificity of the anti-IgE antibody used in the assay is of critical importance because any contaminant antibody can render unspecific results. On the other hand, it must be pointed out that there is a compromise between specificity and sensitivity, such that an increase in the sensitivity of a technique leads to a decrease in its specificity. It cannot be said that there is one method which is better than the others; it is better to examine them individually, allergen by allergen. Thus, specific IgE determination varies depending on the type of allergen. In general terms, for inhalant allergens, specificity and sensitivity of the methods are within the range of 85-95%, but these values (especially the specificity) decrease in the case of food allergens, and they are still lower when the allergen is a beta-lactamic drug. There is a good correlation between clinical history and specific IgE against inhalant allergens, and a lower correlation in the case of food allergens. Due to the fact that most food allergens are not standardized, the definitive diagnosis of food hypersensitivity is achieved by means of provocation tests. Nevertheless, negative specific IgE (7-18% of the cases) does not rule out a sensitization against the tested allergen, and a positive specific IgE without symptoms must be carefully interpreted because it can be due to a low degree of sensitization, unable to express clinical symptoms at this moment, but useful in the future as a guide on the disease course. In the evolutive period of the disease, specific IgE levels can be modified in a natural way (in beta-lactam allergy, 50% of the cases with specific IgE become negative after a year), or as an effect of the treatment (e.g., after immunotherapy in the case of Hymenoptera venom allergy), or it can remain positive for a long time, as in the case of pollinosis. On the other hand, the cutoff of the method, and subsequently the range of values to be considered as positive, will depend on the allergen studied. While inhalant allergens (with the exception of some molds) offer relatively high mean values of specific IgE, food and drug allergens yield less significant values. In general, a class greater than 2 is interpreted as clinically significant, class 1 as dubious or negative (depending on the allergen) and class 0 as negative. In the interpretation of the results, the possible presence of IgG and anti-IgE antibodies, capable of modifying the results, will be taken into account. When comparing the diagnostic reliability of specific IgE with respect to other allergologic diagnostic methods, we find a significant and positive correlation of this technique with skin tests (but never greater than 90-95%) and with the histamine release test.

Specific IgE determination in the diagnosis of beta-lactam allergy

Allergic reactions to beta-lactams are the most frequent adverse reactions to drugs, but conventional methods of detection of beta-lactam specific IgE detect only a low number of positivities. In this study we evaluated the diagnostic reliability of one of these methods (CAP FEIA, Pharmacia) which has been proven very useful in inhalant and food specific IgE determinations. We studied specific IgE to penicillin G, penicillin V, amoxicillin and ampicillin in 1078 patients who had been diagnosed with an adverse reaction to beta-lactams, and out of this group, in a selected subgroup of 149 patients with a very suggestive clinical history of beta-lactam anaphylactic reaction. Also, positivity of specific IgE was studied in a group of 58 patients with a clinical history of immediate hypersensitivity to beta-lactams and with positive skin tests, and positivity of skin tests was studied in a subgroup of 13 patients with positive specific IgE. To increase the sensitivity of IgE determinations, we concentrated 5-fold the sera from six selected patients. In the first group we found that penicillin G specific IgE was positive in 28% of the cases when considering a cutoff > or = class 1, and 6% when considering a cutoff > or = class 2. For penicillin V, positivities were 9% (> or = class 1) and 4% (> or = class 2). In the second group, we found 31.81% sensitivity and 88.57% relative specificity of CAP FEIA with respect to the skin test. In the group of 58 patients with a clinical history of immediate hypersensitivity to beta-lactams, we found a disagreement between skin testing and specific IgE determination in 28.2%, and a positive agreement in 9.4% of the cases. After sera concentration, there was a significant increase (p < 0.001), from 0.58 to 1.61 kU/l, in beta-lactam specific IgE. Our results suggest that skin testing offers greater reliability and sensitivity than beta-lactam specific IgE determination by CAP FEIA.

Reliability of histamine release test in dust mite allergy: influence of the degree of sensitization

The histamine release test has been proven to be a very useful method for in vitro diagnosis of IgE-mediated allergy to inhalant and food allergens, as well as for the immunotherapy follow-up of the allergic patient. The aim of the present study was to assess the influence of the degree of sensitization in allergic patients sensitive to Dermatophagoides pteronyssinus on their dose-response curves in histamine release tests. To achieve this aim, we studied 109 D. pteronyssinus allergic patients and 25 healthy control subjects. Intracutaneous skin test, D. pteronyssinus-specific and total IgE quantitations, and histamine release tests were carried out in all the patients. In the case of the histamine release test, five D. pteronyssinus extract concentrations were used (2822.5, 282.25, 28.22, 2.82 and 0.28 UBE/ml), and two patterns of histamine release in sensitive patients were found: one with maximal histamine release at the highest antigen concentration (group I) and the other with maximal release attained at lower concentrations (group II). A sensitization score was designed, after the results from specific IgE and intracutaneous skin tests. There were significant differences (p < 0.05) in antigen-specific and total IgE levels, and in papule diameters and sensitization scores, between the control group and groups I and II. Both groups showed significantly higher (p < 0.05) histamine releases than the control group in response to anti-IgE antibodies. When stimulating the cells with anti-IgE antibodies, histamine release in group II was higher than in group I, although this difference was not significant. Finally, the best correlation between sensitization score and antigen-specific histamine release was found at the 2.82 UBE/ml concentration (r = 0.84, p < 0.001).

Fruit sensitization in patients with allergy to latex

In the last years, latex has frequently been found to be involved in immediate hypersensitivity reactions. The first case mentioned with recurrent urticaria and laryngoedema was reported by Stern (1) in 1927. Since then, latex has also been implicated in generalized urticaria, rhinoconjunctivitis, asthma and anaphylaxis. Associated sensitization to several fruits is frequently seen in latex-allergic patients with the symptoms described above. This study was performed in seven patients (six females and one male) with hypersensitivity to latex and concomitant fruit sensitization. Six of them were healthcare personnel. The age of the patients ranged from 25-39 years, with a mean of 30 years. Prick tests and intracutaneous tests with latex (10% w/v in PBS), banana, chestnut, avocado, kiwi and melon were carried out. A specific histamine release test (HRT) was performed according to the fluorometric assay. Antigen-specific IgE was also performed. Latex CAP inhibition with banana and SDS-PAGE immunoblotting were carried out in one patient. Although in latex-allergic patients multiple sensitization to fruits may be observed, banana and avocado are those most frequently involved, followed by chestnut and melon. This is likely to be due to the presence of common antigens in these fruits and latex, as demonstrated in our study only for banana and avocado. We consider that further investigation is needed on the possible sensitization to latex in sanitary personnel reporting symptoms after fruit ingestion.

Dander is the best epithelial source for dog allergenic extract preparations

Four different commercially available raw materials of dog epithelia (dander, hair and skin scraping, skin scraping, and whole skin) were compared by means of biochemical methods such as SDS-PAGE and chromatography with the SMART System, immunochemical methods such as RAST and SDS-PAGE immunoblotting, and cutaneous tests. Dander extract clearly exhibited the highest IgE binding and in vivo allergenic activity. The dog major allergens Can fI and the 19-kDa protein were adequately detected only in dander extract. Thus, it is concluded that dander is the most suitable epithelial source for preparing dog allergenic extracts.

Modulation of beta 2-adrenoceptors in human lymphocytes by in vitro stimulation with mediators

Since Szentivanyi established the beta-adrenergic theory, many attempts have been made to explain the dynamics of bronchial hyperreactivity and cytotropic allergic reaction by this mechanism. In previous work, we found that beta-adrenoceptor numbers were decreased in symptomatic patients and after specific antigenic exposure. As a result, we postulated that this might be due to mediator activity. Blood was extracted from 46 healthy donors for this study. Radioligand [125I]-iodocyanopindolol was used for beta-adrenoceptor determination in peripheral blood lymphocytes following Brodde's method. Student's t test was used for statistical analysis. beta-Adrenoceptor number was determined before and after exposure to mediators (histamine, PAF, LTD4), and after melittin (phospholipase A2, PLA2, activator) exposure. A significant decrease was obtained after histamine (p < 0.05), LTD4 (p < 0.05) and melittin (p < 0.001) exposure; PAF did not modify the number of beta-adrenoceptors. In conclusion, our results confirm that down-regulation of beta-adrenoceptors can be induced by mediator release.

Effect of aspirin on beta-receptors in lymphocytes from patients with aspirin-induced asthma

We studied the effect of aspirin on beta-adrenergic receptors in lymphocytes from three groups of subjects: 5 asthmatic patients presenting sensitivity to aspirin, 10 asthmatic patients with tolerance to aspirin and a control group. Lymphocytes were incubated with aspirin-lysine (36 micrograms/ml). The number of beta-receptors/cell and the dissociation constants (Kd) were assessed by means of [125I]-cyanopindolol (ICYP). There was a decrease in the number of beta-receptors after incubation with aspirin in all asthmatic patients with sensitivity. The differences between mean basal (660 +/- 171 receptors/cell) and postincubation (398 +/- 110 receptors/cell) values were significant (p < 0.05). There were also significant differences (p < 0.01) between basal (23.4 +/- 6 pM) and postincubation (15 +/- 5.1 pM) Kd values, which indicates that the affinity of ICYP increased. In the subjects in the other two groups, aspirin both increased and decreased the number of beta-receptors, but the effects were not significant. It is suggested that in patients with sensitivity, aspirin could induce changes in the plasmatic membrane, thus altering beta-receptors or inducing the release of inflammatory mediators that exert their effect upon these receptors.

Spontaneous in vitro IgE synthesis: modifications induced by immunotherapy

In this study, we used an in vitro experimental model with peripheral mononuclear cells (PBMCs) capable of synthesizing IgE to study the possible parallelism between in vitro IgE synthesis and the findings obtained in vivo showing changes in serum IgE values during immunotherapy (IT). Blood samples were extracted from 10 healthy subjects and 39 allergic patients for lymphocyte culture. Allergic patients were classified into five groups according to the time of IT. After incubation for 7 days at 37 degrees C, IgE values were assessed by means of a radioimmunoassay technique modified for low values. Likewise, total serum IgE was assessed. Spontaneous in vitro production of IgE in control individuals (G0) was significantly lower (p < 0.001) than the mean production in allergic patients (GA). When patients were grouped according to the time of IT, we observed that IgE values decreased during the course of IT. The significant differences found between allergic patients and control individuals eventually disappeared from the third year of treatment. We found a statistically significant positive correlation (r = 0.575, p < 0.001) between total serum IgE values and in vitro IgE production in all subjects. We conclude that IT induces a series of variations in lymphocyte IgE production in vitro, which consists of a significant decrease in IgE production from the second year of IT compared with that of patients without IT. IgE production eventually reaches levels similar to those in healthy subjects. The symptomatic recovery shown by all patients was associated with evident immunological changes, which confirms the clinical utility of this treatment in allergic diseases and the importance of its long-term effects.

Modulation of beta 2-adrenoceptors in lymphocytes of allergic patients after in vitro antigenic stimulation

In this study, we assessed the effect of antigen-specific stimulation on beta-adrenoceptors of human lymphocytes in order to study the beta-receptor atopy theory of Szentivanyi. Determination of these receptors was basically carried out as described by Brodde et al., utilizing [125I]-cyanopindolol as ligand in control and allergic patients before and after stimulation with specific antigen. We found that in vitro the specific antigen-antibody reaction induces a decrease in beta-adrenoceptors. This alteration takes place in patients with rhinitis and asthma with sensitization to Dermatophagoides and grass pollen, regardless of their baseline clinical status. Therefore, in view of the results, we question the validity of Szentivanyi's atopy theory. We hypothesize that the modification in the beta-adrenoceptor system is a consequence rather than the cause of the activity of atopic diseases.

Influence of immunotherapy on histamine release and other immunological parameters of immediate hypersensitivity in pollinosis

Specific immunotherapy in pollen-allergic patients leads to a significant time-dependent decrease in the seasonal differences in IgE values, that is, the shorter the duration of immunotherapy, the smaller the difference. Immunotherapy leads to a maximum specific histamine release during the first year, with higher values during the pollen season. Later, the amount of histamine released from basophils decreases gradually in relation to the duration of immunotherapy and the clinical recovery, indicating that this would be a useful parameter in the follow-up of the efficacy of this type of treatment. Inversely, total histamine, which may be considered a parameter indicating the histamine stored in basophil granules, decreases significantly, reaching its lowest values at the end of the first year, with eventual recovery to initial values. From these results we may conclude that hyposensitizing treatment should not be interrupted before 3 years, since the immunological variations of the immediate hypersensitivity parameters take place during the first 2 years, and then stabilize. On the other hand, the correlation between the degree of recovery after hyposensitizing treatment and the duration of the treatment leads us to recommend immunotherapy for periods longer than 2 years.

IgE synthesis suppressor factor: modifications in the course of long-term immunotherapy

Many authors have described an increase in total serum IgE values during the first few months of immunotherapy (IT), followed by a subsequent decrease. In previous studies in patients undergoing medium-term IT, we detected an IgE synthesis suppressor factor (SF), which was modified during the course of IT. In this study, we investigated the influence of long-term IT on the production of SF and the lymphocyte response to its stimulus. Mixed bidirectional cultures of lymphocytes isolated from healthy individuals (n = 62) and allergic patients (n = 98) were carried out after different periods of IT. The resulting supernatants were subjected to affinity chromatography, from which two fractions were obtained: the first one, likely to contain SF, was added to lymphocyte cultures from 13 allergic patients undergoing no IT (LyG1) and 6 allergic patients with > 3 years of IT (LyG5), in order to assess its inhibitory effect on IgE synthesis. We found that patients undergoing IT for > 3 years presented a significant increase in SF production and an important lymphocyte response to exogenous SF from most of the groups studied, but little response to their own SF. These results could be ascribed to an alteration in the quantity and/or structure of the lymphocyte receptors likely to be sensitive to these factors induced by IT.

Modifications in IgG subclasses in the course of immunotherapy with grass pollen

In this study, we evaluated the evolution of IgG subclasses in the course of immunotherapy, and related this to the clinical evolution. We selected 226 adult patients with sensitivity to grass pollen alone, undergoing immunotherapy for 0-26 months. The following results may be highlighted: 1) IgG1 increased with immunotherapy and reached its peak at 6 months; 2) IgG2 increased significantly, reaching its peak after 24 months of treatment; 3) IgG3, however, did not present significant modifications in the course of immunotherapy; and 4) IgG4 was high in all patients undergoing immunotherapy compared to patients without hyposensitizing treatment, the peak being reached in the group of patients with the longest course of immunotherapy. Only IgG4 showed a positive and significant (p < 0.05) correlation with the degree of clinical recovery reached with immunotherapy.

IgG4 blocking effect on the release of antigen-specific histamine

We evaluated the biological effect of IgG4 antibodies in pollinosis. We studied the ability of IgG4 to mediate histamine release by measuring anti-IgG4 in pollinic patients without previous immunotherapy. We also evaluated the modifications that sera rich in specific IgG4 and IgG itself exert upon antigen-specific histamine release. According to our results, stimulation with anti-IgG4 did not induce histamine release, as opposed to stimulation with anti-IgE, which induced histamine release in all the cases studied. On the other hand, hyperimmune sera from pollinic subjects under immunotherapy and with high levels of specific IgG4 significantly inhibited the release of antigen-specific histamine from basophils of untreated patients. After isolating IgG4 by means of affinity chromatography, preincubation of this fraction with the allergen gave rise to a significant reduction in histamine release compared to preincubation of the antigen with normal sera.

IgE synthesis-enhancing factor: modification of its production in the course of long-term immunotherapy

The isotype-specific mechanisms involved in IgE synthesis are a sophisticated system about which very little is known. Several research groups have demonstrated that there is an enhancing factor (EF) in lymphocyte supernatants which is related to the regulation of the synthesis of IgE, and the influence medium-long-term immunotherapy (IT) exerts on it. Following this line of research, we studied the influence of long-term IT (> 3 years) and the presence of interleukin-4 (IL-4), not only in the different fractions where EF is contained, but also in lymphocyte supernatants after stimulation. Bidirectional mixed lymphocyte cultures were performed between lymphocytes from healthy controls (n = 62) and allergic patients (n = 98) after different periods of IT. The supernatants obtained were submitted to affinity chromatography and the second fractions, containing EF, were added to healthy control lymphocytes (n = 11) in order to test their enhancing effect on IgE synthesis. Modifications in EF production were observed, depending on the duration of IT. There were no detectable levels of IL-4 either in EF fractions or supernatants from stimulated lymphocytes.

Binding of a 15 kDa glycoprotein from spermatozoa of boars to surface of zona pellucida and cumulus oophorus cells

A highly purified 15 kDa glycoprotein isolated from ejaculated spermatozoa was used to raise antisera in female rabbits. An indirect immunofluorescence technique was used to detect the antigen in the seminal vesicle tissue and on the acrosomes of ejaculated, native and capacitated, boar spermatozoa. No immunoreactivity was detected on cells of the seminiferous tubules (spermatogonia, spermatocytes, and spermatids), on spermatozoa in the ductus epididymis and in cells of the epididymal and testicular tissues. These observations support the view that the 15 kDa protein is produced in the seminal vesicle secretory epithelium, and is attached to the sperm plasma membrane during the exposure of spermatozoa to seminal vesicle compounds. The observations that the antigen remained on the acrosome of ejaculated spermatozoa after capacitation and blocked sperm-oocyte binding in vitro suggest that the antigen plays a role in sperm-egg interactions. The strong immunoreactivity exhibited by cumulus cells after incubation of antisera with the porcine egg surrounded by cumulus cells shows the possible importance of the 15 kDa glycoprotein for contact of spermatozoa with cells of the cumulus oophorus surrounding the egg.

Specific IgG subclasses in pollinosis

We studied IgG subclasses in pollinosis in order to determine the possible immunopathological role of these antibodies, especially antigen-specific IgG4. The selection of pollinosic patients allowed us to observe the influence natural antigenic exposure exerts upon antibodies. On the other hand, we intended to study the possible modifications immunotherapy produces on IgG subclasses. For this purpose, we selected 266 patients who were classified into the following groups: Group I, 65 patients without immunotherapy, 35 of whom were studied during the pollen season and 30 outside the pollen season; Group II, 40 nonpollinosic patients with hypersensitization to Dermatophagoides pteronyssinus were taken as atopic controls; Group III, 161 pollinosic patients with from 3 to 42 months of immunotherapy. For every patient, IgG1, IgG2 and IgG3 against Phleum pratense were determined by means of ELAST (Leti), and IgG4 against the same allergen by means of the ELISA technique developed by us. Our results confirm, first, that untreated pollinosic patients present higher concentrations of IgG4 against Phleum than nonpollinosic patients, and second, that immunotherapy produces significant modifications in the production of antigen-specific IgG.

A randomized trial of late reperfusion therapy for acute myocardial infarction. Thrombolysis and Angioplasty in Myocardial Infarction-6 Study Group

BACKGROUND

Experimental and observational clinical studies of acute coronary occlusion have suggested that late reperfusion prevents infarct expansion and facilitates myocardial healing. The purpose of this trial was to assess whether infarct vessel patency could be achieved in late-entry patients and what benefit, if any, can be demonstrated.

METHODS AND RESULTS

In a double-blind fashion, 197 patients with 6 to 24 hours of symptoms and ECG ST elevation were randomly assigned to tissue-type plasminogen activator (100 mg over 2 hours) or placebo. Coronary angiography within 24 hours was used to determine infarct vessel patency status. Patients with infarct-related occluded arteries were then eligible for a second randomization to either angioplasty (34 patients) or no angioplasty (37 patients). Ventricular function and cavity size were reassessed at 1 month by gated blood pool scintigraphy and at 6 months by repeat cardiac catheterization. The primary end point, infarct vessel patency, was 65% for plasminogen activator patients compared with 27% in the placebo group (p less than 0.0001). There were no differences between these groups in ejection fraction or infarct zone regional wall motion at 1 or 6 months. At 6 months, infarct vessel patency was 59% in both groups. In the placebo group, there was a significant increase in end-diastolic volume from acute phase of 127 ml to 159 ml at 6-month follow-up (p = 0.006) but no increase in cavity size for the plasminogen activator group patients. Coronary angioplasty was associated with an initial 81% recanalization success and improved ventricular function at 1 month, but by late follow-up no advantage could be demonstrated for this procedure, and there was a 38% spontaneous recanalization rate in the patients assigned to no angioplasty.

CONCLUSIONS

The study demonstrates that it is possible to achieve infarct vessel recanalization in the majority of late-entry patients with either thrombolytic therapy or angioplasty. Thrombolytic intervention had a favorable effect on prevention of cavity dilatation and left ventricular remodeling, but there are no late benefits on systolic function after thrombolysis or coronary angioplasty. The conclusions concerning overall potential benefit of applying late reperfusion therapy will require data from large-scale trials designed to assess mortality reduction.

Food allergy as a cause of rhinitis and/or asthma

We studied the histories of patients who had visited our Department during the last 5 years, presenting food allergy with exclusively respiratory symptoms (18.5%). We studied the correlation between IgE levels and the histamine release test and the type of food implicated. Seventy-seven percent of patients presented sensitization to one food, and 23% presented polysensitization. We found that foods such as snails and eggs have a strong predilection for the bronchial tree as the shock organ. High total IgE was found in 85.2% of patients. The histamine release test was positive in 66% of cases. We conclude that this is a highly sensitive method for the in vitro diagnosis of food allergy.

Study of IgE-dependent basophil releasability in allergic patients

For this study, venous blood from 160 patients with a diagnosis of asthma and/or rhinitis was used. Histamine release test (H.R.T.) with anti-IgE at 1/5 and 1/25 dilutions and with causal antigen in the case of atopic patients (144) was carried out on all patients. Basophils from atopic patients released more histamine than those from nonatopic patients (p < 0.001). Basophils of atopic patients released more histamine with 1/5 anti-IgE dilution (p < 0.01), while non-atopic patients did so with the 1/25 dilution (p < 0.05). On grouping atopic patients according to positive or negative results in Ag-specific histamine release, 14% of patients presented negative Ag-specific H.R.T. and 85.7% of the cases did not respond to anti-IgE stimulus; this was 12% of the total number of atopics. On the other hand, 17% of the patients studied did not show positive histamine release against anti-IgE and 70.6% of them had negative Ag-specific release. As for the effect of age on IgE-dependent histamine release, the group of patients who presented greater releasability corresponded to those older than 6 years of age. The discrepancies observed between the clinical history, skin tests, serum IgE and antigen-dependent histamine release in some patients could be related to the individual basophil ability to release histamine. Therefore, this basophil releasability evaluation has an important practical application in discerning false negatives in antigen-specific H.R.T.

Beta-receptor decrease in bronchial asthma

Sinesterases that intervene in cAMP and oGMP equilibrium in the cytoplasm of mast cells are activated by the adrenergic system through beta-receptors. A study was made on 96 atopic patients with mono sensitization to Dermatophagoides pteronissinus, in 3 groups. Radioligands were used to quantitate the number of beta receptors. In the control group mean no/cell was 541, bronchial symptomatic patients had 327 and nasal symptomatics 348. Asymptomatic patients were similar to controls. The results were similar with pollen-sensitive patients. Beta receptor decrease is a consequence of clinical allergy in atopic patients and is secondary to the immunological events that follow antigen-antibody reactions and cell membrane changes.

Different influence of endothelium in the mechanical responses of human and cat isolated cerebral arteries to several agents

The present work was undertaken to elucidate the role of the vascular endothelium in the changes of isometric tension elicited by different compounds in isolated cylinders of human and cat cerebral arteries and cat pulmonary arteries. Endothelium removal by rubbing significantly reduced the relaxing response to acetylcholine (ACh) of isolated segments of all the arteries. The same treatment did not modify the contraction elicited by 5-hydroxytryptamine (5-HT) in the human and cat cerebral segments but increased the contractile effect of the amine in cat pulmonary arteries. The mechanical responses to vasopressin, ATP and adenosine in isolated segments of cat cerebral arteries were unaffected after removing the endothelial layer. L-Arginine, but not D-arginine (10(-5) M), enhanced significantly the relaxation induced by increasing doses of ACh in unrubbed cat cerebral arteries whereas it did not modify the response to ACh in rubbed ones. However, L-arginine had no effect on the dose-response curve to 5-HT in both kinds of preparation and did not change the tone in precontracted unrubbed cat cerebral segments. These results suggest that the endothelium of the cerebrovascular bed plays a minor role in regulating the mechanical response induced by several vasoactive agents, although it retains its ability to produce an endothelium-derived relaxing factor.