Histamine Release Test Research Articles

Knockdown of miR-155 alleviates skin damage in rats with chronic spontaneous urticaria by modulating the JAK/STAT signaling pathway

ObjectiveThe aim of this study was to investigate the role and mechanisms of miR-155 in chronic spontaneous urticaria (CSU).MethodsThe expression level of miR-155 in the skin tissues of patients with CSU and experimental rats were detected by RT-qPCR, followed by the measurement of the histamine release rate in the serum through the histamine release test. Besides, hematoxylin & eosin staining was used to observe the pathological changes of the skin tissues; Corresponding detection kits and flow cytometry to measure the changes of immunoglobulins, inflammatory cytokines and T cell subsets in the serum of rats in each group; and western blot to check the expression level of proteins related to JAK/STAT signaling pathway in the skin tissues.ResultsKnockdown of miR-155 reduced the number and duration of pruritus, alleviated the skin damage, and decreased the number of eosinophils in CSU rats. Moreover, knockdown of miR-155 elevated the serum levels of IgG and IgM, decreased the levels of IgA and inflammatory cytokines, and reduced the proportion of CD4 + and CD4 + CD25 + T cells, as well as the CD4+/CD8 + ratio in CSU rats. However, Tyr705 intervention could reverse the effects of knockdown of miR-155 on CSU model rats. Furthermore, we found that knockdown of miR-155 significantly reduced the protein expression of IRF-9, as well as the P-JAK2/JAK2 and P-STAT3/STAT3 ratios in the skin tissues of CSU rats.ConclusionKnockdown of miR-155 can alleviate skin damage and inflammatory responses and relieve autoimmunity in CSU rats by inhibiting the JAK/STAT3 signaling pathway.

Improvement of digestive symptoms in fibromyalgia patients following a diet modification according to histamine release test - an observational study.

IntroductionThere is growing interest in the relationship between fibromyalgia and processes related to food, such as food intolerances. In fact, different associations have been described between the control of dietary habits and the improvement of the different symptoms of fibromyalgia.Material and methodsWe collected the results of applying a specific test of histamine release related to the diet of patients with fibromyalgia, and evaluated the changes in terms of the symptoms usually described by the patients. A total of 84 patients who met the established criteria were recruited; 40 of them underwent the exclusion diet for a period of 6 months, while the remaining ones continued with their usual dietary habits. All patients were instructed not to modify any other parameter during the study, such as medication, exercise, or other complementary treatments. The parameters studied were as follows: the Fibromyalgia Impact Questionnaire (FIQ), the Gastrointestinal Symptoms Rating Scale (GSRS), the pain Visual Analogue Scale (VAS), as well as the patients’ body weight was controlled.ResultsThere was a significant improvement (p < 0.05) in the group of patients who underwent the exclusion diet in assesment by GSRS and in total in total body weight. There were no differences compared to the rest of the patients in terms of VAS and FIQ.ConclusionsDiet modification in patients with fibromyalgia by specific histamine relase test improves certain clinical parameters related to the symptoms of the digestive sphere, compared to the control group. Our work opens a possible way of non-pharmacological treatment to improve some symptoms of this very prevalent disease.

Do basophil activation tests help elucidate allergic reactions to the ingredients in COVID-19 vaccines?

The worldwide use of COVID‐19 vaccines has shown that immediate allergic reactions to the ingredients are rare but should be clarified by means of an allergological work‐up. This review aims to highlight the current state of knowledge and possible pathogenesis based on the literature published to date. In addition to recording a detailed history and performing skin tests, cellular tests (basophil activation or basophil histamine release test) by using the vaccines or modified compounds containing polyethylene glycol (PEG), rather than unmodified PEGs, have proven to be particularly helpful. Negative results with vaccines seem to indicate tolerance. Details of the performance of these cellular tests with different vaccines, PEGs of different molecular weights, other ingredients of the vaccines, as well as other PEGylated drugs, and the results in the context of COVID‐19 vaccination of various working groups worldwide are summarized.

A novel detection method for cross-linking of IgE-receptors by autoantibodies in chronic spontaneous urticaria

BackgroundAutoantibodies (AAbs) against immunoglobulin E (IgE) antibodies (Abs) and their high-affinity receptor alpha subunits (FcεRIα) are key factors in the elicitation of type IIb autoimmune chronic spontaneous urticaria (type IIb aiCSU). In this study, we aimed to develop a new method to detect functional anti-FcεRIα and anti-IgE AAbs, which can crosslink the plural FcεRІα molecules and IgE Abs on the surface of mast cells and basophils, in sera from aiCSU patients using the amplified luminescence proximity homogeneous assay (Alpha). MethodsSera were obtained from 14 aiCSU patients, as diagnosed by recurrent chronic spontaneous urticaria episodes and positive results for the autologous serum skin test and/or histamine release test (HRT). The AAbs to FcεRIα and IgE Abs were determined in sera from aiCSU patients using enzyme-linked immunosorbent assay (ELISA) and Alpha by cross-linking (AlphaCL) of IgE Abs and/or FcεRІα. ResultsSerum anti-FcεRIα and anti-IgE AAb levels were not significantly different between aiCSU patients and healthy subjects in ELISA. Anti-FcεRIα AAbs were detected in 10 of 14 aiCSU patients who displayed positive (5/5) and negative (5/9) results in the HRT for anti-FcεRIα AAbs by AlphaCL, whereas no signals were observed in healthy subjects. Additionally, anti-IgE AAbs were detected in two of four aiCSU patients who displayed positive results in the HRT for anti-IgE AAbs. ConclusionsA new assay method using AlphaCL can detect anti-FcεRIα and anti-IgE AAbs with FcεRIα- and IgE-crosslinking abilities in sera from aiCSU patients. This simple and practical assay method may be available as a diagnostic tool for urticaria patients.

Patients with suspected allergic reactions to COVID-19 vaccines can be safely revaccinated after diagnostic work-up.

BackgroundWhen initiating the Danish vaccination program against COVID‐19, the incidence of anaphylaxis was estimated to be 10 times higher compared to other virus‐based vaccines. In this study, we present data on patients referred with suspected allergic reactions to COVID‐19 vaccines. The main purpose of the study is to investigate the incidence and severity of the allergic reactions, and to evaluate the safety of revaccination.MethodsAll patients in the region of Southern Denmark with case histories of allergic reactions to COVID‐19 vaccines in a defined period are included in this study. Diagnostic work up consisted of a detailed case history, evaluation of Brighton level of diagnostic certainty and World Allergy Organization grade of anaphylaxis and skin prick testing‐ and basophil histamine release testing with COVID‐19 vaccines and relevant drug excipients. Patients were revaccinated at the Allergy Center when possible.ResultsSixty‐one patients are included in this study. In 199,377 doses administered, nine patients fulfilled the criteria of anaphylaxis when using the Brighton Criteria (incidence being 45 per million). Of 55 patients with reactions to the first dose, 52 patients were revaccinated without adverse reactions. We found no proven cases of immediate anaphylaxis due to COVID‐19 vaccines. By skin prick test, we diagnosed three patients with drug excipient allergy and further a patient with mastocytosis was found.ConclusionsAnaphylactic reactions to COVID‐19 vaccines are rare and the incidence is similar to what is seen with other virus‐based vaccines. Revaccination is safe in the majority of patients; however, allergological evaluation is important since some prove to have drug excipient allergy.

Optimizing investigation of suspected allergy to polyethylene glycols

Polyethylene glycols (PEGs) are polymers of varying molecular weight (MW) used widely as excipients in drugs and other products, including the mRNA vaccines against coronavirus disease 2019. Allergy to PEGs is rare. Skin testing and graded challenge carries a high risk of inducing systemic reactions. We evaluated skin prick test (SPT) results and invitro reactivity over time to different MW PEGs and assessed cross-sensitization patterns in PEG allergy. Ten patients with previously diagnosed PEG allergy underwent SPT twice with PEGs 26 months apart. Lower MW (PEG 300, 3000, 6000) were tested, followed by PEG 20,000, in stepwise, increasing concentrations. Cross-sensitization to polysorbate 80 and poloxamer 407 was assessed. SPT was performed in 16 healthy controls. Invitro basophil histamine release (HR) test and passive sensitization HR test were performed in patients and controls. Patients previously testing positive on SPT to PEG 3000 and/or 6000 also tested positive to PEG 20,000. Patients with a longer interval since diagnosis tested negative to lower MW PEGs and positive mainly to higher concentrations of PEG 20,000. Three patients developed systemic urticaria during SPT. Eight patients showed cross-sensitization to poloxamer 407 and 3 to polysorbate 80. All controls tested negative. Invitro tests showed limited usefulness. Skin test reactivity to PEG can decrease over time, but titrated SPT with increasing concentrations of PEG 20,000 can be diagnostic when lower MW PEGs test negative. To avoid systemic reactions, stepwise SPT is mandatory.

Glycation of β-lactoglobulin combined by sonication pretreatment reduce its allergenic potential

β-lactoglobulin (β-Lg) was treated through different ultrasonic power and subsequently glycated with galactose to investigate its structural changes and immunological properties, and then evaluated by high-resolution mass spectrometry, enzyme-linked immunosorbent assay and basophil histamine release test. Ultrasonication combined with glycation (UCG) modification significantly reduced the IgE/IgG-binding capacity, and the release of β-hexosaminidase, histamine and interleukin-6, accompanied with changes in the secondary and tertiary structures. The decrease in the allergenicity of β-Lg depended not only on the glycation of K47, 60, 83, 91 and 135 within the linear epitopes, but also on the denaturation of conformational epitopes, which was supported by the glycation-induced alterations of the secondary and tertiary structures. This study confirmed that UCG modification is a promising method for decreasing the allergenic potential of allergic proteins, which is likely to develop a practical technology to produce hypo-allergenic milk.

Skin Test for Cutaneous Adverse Drug Reactions

Background: The incidence of drug eruptions is increasing during the last few years due to a large number of new medications. Early detection of the causative agent and the prevention from exposure are crucial managements in terms of drug eruption, mainly to prevent its recurrence. Objective: To understand skin test as a diagnostic modality in drug eruption, which includes skin patch test, skin prick test, and intradermal test. Literature review: Drug eruption is a form of skin eruption triggered by the use of medications, topical or systemic, in the right dose and indication. The manifestation can vary from maculopapular, urticaria, pustular, and bullous eruption; from the most nonsignificant to a life-threatening reaction. A diagnostic procedure is critical to discover the type of drugs that cause the eruption, i.e., skin test, specific IgE measurement, histamine-release test, and provocation test. Skin test is the first choice in the diagnostic process as it is simple, easy, practical and has high sensitivity and specificity. Conclusion: Skin test is one of the many available diagnostic tools. However, both false positive and false negative results might still arise. The experts are currently attempting to come up with more accurate and practical tests to aid the diagnostic of drug eruption, thus preventing its occurrence.

Role of IL-9 and IL-10 in the pathogenesis of chronic spontaneous urticaria through the JAK/STAT signalling pathway.

This study investigated the role of interleukin (IL)-9 and IL-10 in the pathogenesis of chronic spontaneous urticaria (CSU). Autologous serum skin test and histamine release test were performed in CSU patients and normal subjects. Kunming mice were used to develop a mouse model for CSU. We induced IL-9 overexpression, IL-10 overexpression, and JAK/STAT pathway inhibition as well as a combination of all three conditions in CSU and control mice. Eosinophils in the skin tissues, inflammatory cytokine expression, and distribution of T lymphocyte subsets in peripheral blood of mice were detected. Expression patterns of IL-9, IL-10, STAT3, JAK2, and INF-γ in clinical samples and mice were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The positive rate of autologous serum skin test and the histamine release rate of CSU patients, compared with normal subjects, were apparently elevated. Compared with controls, mice with CSU experienced longer duration and higher frequency of pruritus and demonstrated enhanced levels of CD8+ , the ratio of CD4+ /CD8+ , number of eosinophils, and inflammatory cytokine expression in serum as well as activated JAK/STAT signalling pathway; at the same time, levels of CD4+ and INF-γ were reduced. This trend was found in CSU mice overexpressing IL-9 and IL-10 when compared with the CSU mice without treatment. In contrast, JAK/STAT inhibition reversed the above trend. Overall, our study suggests that IL-9 and IL-10 contribute to CSU development via activation of the JAK/STAT signalling pathway.

Clinical utility of the basophil activation test in the diagnosis of sweat allergy

BackgroundMany patients with atopic dermatitis and cholinergic urticaria display an immediate-type allergy to autologous sweat. Although the histamine release test (HRT) using semi-purified sweat antigen (QR) was available for the detection of immediate sweat allergy, the existence of HRT low responders could not be disregarded. Furthermore, it has not been established whether the results of the HRT are consistent with the autologous sweat skin test (ASwST). We aimed to compare the HRT and basophil activation test (BAT) for the diagnosis of immediate sweat allergy. MethodsThe HRT and BAT were performed on 47 subjects (35 ASwST positive, 12 negative) whose symptoms had worsened on sweating. For the BAT, blood was incubated with QR or crude sweat and CD203c upregulation was assessed. A commercial HRT was performed and histamine release induced by QR was quantified. ResultsWhen excluding non-responders for anti-IgE antibody, the BAT using QR and the HRT had a sensitivity of 100% and 44% and specificity of 75% and 100%, respectively. The BAT and HRT had a positive predictive value of 91.3% and 100% and negative predictive value of 100% and 30%, respectively. The BAT detected 0% non-responders, whereas the HRT identified 22.5%. When using crude sweat for the BAT, the false-positives observed when using QR were not detected. ConclusionsThe BAT using QR displayed a higher sensitivity and negative predictive value and a lower number of non-responders compared with the HRT. Furthermore, the BAT using crude sweat can also be an alternative tool for the ASwST.

Development and validation of a highly sensitive LC–MS/MS method for in vitro measurement of histamine concentration

The basophil histamine release test (HRT) is an important in vitro diagnostic assay to evaluate immunoglobin E (IgE)-mediated allergic responses. In this study, a bioanalytical LC–MS/MS method was developed and validated to quantify histamine in the leukocyte suspension from human peripheral blood. The method used pre-column derivatization with phenylisothiocyanate (PITC) and the resulting phenylthiocarbamyl (PTC) histamine was analyzed by positive-ion electrospray ionization using the multiple reaction monitoring mode. Chromatographic separation was achieved using an Imtakt-HT C18 column (2.1 mm × 50 mm, 3.0 μm), with a flow rate of 0.35 mL/min, 2 μL injection, and gradient elution with a mixture of acetonitrile-2 mM ammonium acetate buffer (both containing 0.1% formic acid). The total runtime of the method was 3.0 min including equilibration time. The method had a lower limit of detection of 0.1 ng/mL, and the quantifiable range was 0.1–100 ng/mL in the leukocyte suspension. The intra-day and inter-day precision and accuracy results were within the acceptable limits. It was established that histamine quantification should be performed within 2 h of preparing the leukocyte suspension, and freezing and thawing should be avoided. This method was successfully applied to the diagnosis and evaluation of the pathophysiologic mechanism of respiratory or cutaneous allergic diseases.

No difference in human mast cells derived from peanut allergic versus non-allergic subjects.

IntroductionMast cells are the primary effector cells of allergy. This study aimed at characterizing human peripheral blood‐derived mast cells (PBdMC) from peanut allergic and non‐allergic subjects by investigating whether the molecular and stimulus‐response profile of PBdMC discriminate between peanut allergic and healthy individuals.MethodsPBdMC were generated from eight peanut allergic and 10 non‐allergic subjects. The molecular profile (cell surface receptor expression) was assessed using flow cytometry. The stimulus‐response profile (histamine release induced by secretagogues, secretion of cytokines/chemokines and changes in miRNA expression following anti‐IgE activation) was carried out with histamine release test, luminex multiplex assay and miRNA arrays.ResultsExpression of activating receptors (FcϵRI, CD48, CD88, CD117, and C3aR) on PBdMC was not different among peanut allergic and non‐allergic subjects. Likewise, inhibitory receptors (CD32, CD200R, CD300a, and siglec‐8) displayed comparable levels of expression. Both groups of PBdMC were unresponsive to substance P, compound 48/80 and C5a but released comparable levels of histamine when stimulated with anti‐IgE and C3a. Interestingly, among the secreted cytokines/chemokines (IL‐8, IL‐10, IL‐13, IL‐23, IL‐31, IL‐37, MCP‐1, VEGF, GM‐CSF) PBdMC from peanut allergic subjects showed a different secretion pattern of IL‐31 compared to non‐allergic subjects. Investigating miRNA expression from resting or activated PBdMC revealed no significantly difference between peanut allergic and non‐allergic subjects.ConclusionThe molecular and stimulus‐response profile revealed that PBdMC from peanut allergic subjects differently express IL‐31 compared to non‐allergic subjects. However, since only one altered parameter was found among 893 investigated, it is still questionable if the pathophysiological mechanisms of peanut allergy are revealed in PBdMC.

Acidic polypeptides A1a, A3 and A4 of Gly m 6 (glycinin) are allergenic for piglets

Gly m 6 (glycinin) is one of the major antigenic proteins in soybeans responsible for transient hypersensitivity to soybean meal in weaned piglets. The globulin is a hexamer consisting of subunits containing basic and acidic polypeptides. Multiple acidic polypeptides have long been demonstrated to be allergens for humans and play a key role in the overall allergenicity of Gly m 6. To date, knowledge on the allergenicity of the acidic polypeptides for piglets is very limited. The purpose of this study was to identify the acidic polypeptides that were allergenic for piglets and to characterize these acidic polypeptides by ELISA, western blot, skin prick and basophile histamine release test. The IgG and IgE antibody binding capacities of the acidic polypeptides of Gly m 6 were determined using ELISA and western blot analysis with sera from Gly m 6 sensitized piglets. Skin prick test and basophile histamine release test were conducted to measure the effector cell response to the polypeptides. Specific IgG and IgE antibodies against A1a, A3 and A4 of Gly m 6 were identified in the sera of Gly m 6 sensitized piglets. Meanwhile, positive skin prick test and specific histamine release responses were also induced by the acidic polypeptide A1a, A3 and A4 of Gly m 6 from the basophiles of Gly m 6 sensitized piglets. The results demonstrate that the acidic polypeptide A1a, A3 and A4 of Gly m 6 are allergenic for piglets.

Histamine-release test in angioedema patients without urticaria - a retrospective cohort study of 404 patients.

A subset of patients with angioedema (AE) and urticaria has histamine releasing autoantibodies. The histamine release test (HR-test) has been used as a tool in chronic urticaria to define the autoimmune subgroup and may possibly guide the clinician to a more personalized therapy, like omalizumab and cyclosporine. The prevalence and value of positive histamine releasing autoantibodies in monosymptomatic AE is sparsely described in the literature. The purpose of this study was to report the prevalence of positive histamine releasing autoantibodies in a cohort of patients with recurrent AE and evaluate the usefulness of this test in AE patients. We performed a retrospective cohort study of 612 patients referred due to AE between 1995 and 2013. HR-test results were available in 404 patients. In the sub-group of patients with AE and urticaria, 17.3% had a positive HR-test but only 4.3% of patients with mono-symptomatic AE had a positive HR-test. No statistically significant treatment benefits of antihistamines, corticosteroids or adrenaline were found comparing patients with angioedema +/- urticaria based on the result of the HR-test (negative / positive). Thus, the HR-test result cannot be used as predictor of the efficacy of anti-allergic treatment.

Patients with immediate hen’s egg allergy complicated by gastrointestinal symptoms show distinct features in responsiveness in histamine release test

Patients with immediate hen’s egg allergy complicated by gastrointestinal symptoms show distinct features in responsiveness in histamine release test

Basophil Histamine Release Induced by Amoxicilloyl-poly-L-lysine Compared With Amoxicillin in Patients With IgE-Mediated Allergic Reactions to Amoxicillin.

Amoxicillin (AX) is the ß-lactam most often involved in IgE-mediated reactions. Diagnosis is based mainly on skin testing, although sensitivity is not optimal. We produced a new AX derivative, amoxicilloyl-poly-L-lysine (APL), and analyzed its recognition of IgE using the passive histamine release test (pHRT). The study population comprised patients (n=19) with confirmed AX allergy and specific IgE to AX and controls (n=10) with good tolerance to AX. pHRT was performed using "IgE-stripped" blood from a single donor that was sensitized in vitro by patient sera and incubated with AX or APL. Histamine release was determined and expressed as nanograms of histamine released per milliliter of blood. The clinical symptoms were anaphylaxis (n=9), urticaria (n=7), erythema (n=2), and nondefined immediate reactions (n=1). The median (IQR) time interval between reaction and study was 90 (60-240) days and between drug intake and development of symptoms 24 (10-60) minutes. The median sIgE level was 3.37 (0.95-5.89) kUA/L. The sensitivity of pHRT to APL was 79% and the specificity 100%, which were higher than data obtained with pHRT to AX (63% sensitivity and 90% specificity). There was a positive correlation between maximal histamine release levels obtained with AX and APL (r=0.63). In patients with immediate hypersensitivity reactions to AX, APL showed higher sensitivity and specificity than the culprit drug, AX, when tested in vitro by pHRT. This indicates that APL can improve the in vitro diagnostic accuracy of allergic reactions to AX. Further assessment of skin testing is necessary.

Different hypersensitivities against homologous proteins of MGL_1304 in patients with atopic dermatitis

BackgroundAtopic dermatitis (AD) is exacerbated by sweating, and the skin of most patients with AD are resided by Malassezia (M.) fungi. Recently, MGL_1304 produced by Malassezia globosa was identified as the major histamine releasing antigen in human sweat. MethodsThe full length cDNA of the counterpart of MGL_1304 in Malassezia restricta (Mala r 8), was cloned by degenerate PCR and rapid identification of cDNA ends (RACE). Recombinant MGL_1304, and its counterparts, Mala s 8 (produced by Malassezia sympodialis) and Mala r 8 were prepared, and compared in their allergenicities by dot blot analysis and histamine release tests with sera and basophils of patients with AD. ResultsThe identities between MGL_1304 and Mala s 8, MGL_1304 and Mala r 8, and Mala s 8 and Mala r 8 were 68%, 78%, and 76%, respectively, in protein sequences. Dot blot analysis revealed that the level of IgE binding to Mala s 8 was higher than that of MGL_1304. However, histamine release tests revealed that MGL_1304 and Mala r 8 possessed higher activity than Mala s 8. In addition, the crude lysate of M. globosa showed higher histamine release ability than that of M. sympodialis. ConclusionsPatients with AD showed hypersensitivities against MGL_1304 and its homologs. However, the allergenicities of the homologs are variable and the histamine release activities may be different from the solid-phase binding activities for IgE. Sweat allergy should be carefully evaluated with biological activities of MGL_1304 and its homologs of other Malassezia fungi residing on the skin.

In vitro impact of anti-immunoglobulin E monoclonal antibodies, including omalizumab on whole blood basophil histamine release: Assessment of direct induction of basophil histamine release and evaluation of modulation of allergen-induced basophil histamine release.

The aim of this study was to evaluate the potential of anti-immunoglobulin E (IgE) and/or anti-IgE-IgE immune complexes to release histamine from peripheral blood basophils. In addition, a potential modulating effect of anti-IgE-IgE complexes on allergen-induced peripheral blood basophil histamine release was evaluated. Whole blood basophil histamine release (WBB-HR) tests done by using glass-fiber-based microtiter plates were performed in 62 patients with allergic rhinitis and/or asthma sensitized to perennial allergens. Evaluation of the direct effects of monoclonal anti-IgEs, including E25, E27, and QGE031, on WBB-HR, and the indirect effects of anti-IgE-serum IgE complexes on spontaneous and allergen-induced WBB-HR were conducted. The tests were performed with and without pretreatment of the basophils with interleukin 3, and the results were expressed as the fraction of total histamine content released. There was no difference between WBB-HR induced by any of the studied anti-IgE antibodies and that induced by isotype antibodies for all blood samples assessed, which, for each patient, was significantly less than that induced by positive anti-IgE control antibodies. Similarly, no effect of any of the studied anti-IgE-IgE complexes on spontaneous or allergen-induced WBB-HR could be demonstrated. There was no evidence that humanized, monoclonal anti-IgE antibodies E25 (omalizumab), E27, or QGE031 directly or indirectly induced histamine release from peripheral blood basophils.

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.