Why lipid transfer protein allergy is not a pollen-food syndrome: novel data and literature review

Summary

Background.Based on the cross-reactivity between pollen lipid transfer proteins (LTPs) and the peach LTP, Pru p 3, it has been suggested that the pollen might initiate the LTP sensitization process. Objective. To establish whether LTP allergy can be considered as a pollen-food syndrome. Methods. The literature was reviewed and new data of component-resolved diagnosis from Italy obtained by both ISAC immunoassay and ImmunoCAP on large populations of LTP hypersensitive patients were provided and analyzed. Results. Among Pru p 3 reactors, patients positive for Art v 3 and Pla a 3 largely exceeded those sensitized to the respective major pollen allergens, Art v 1 and Pla a 1/Pla a 2. Pru p 3 reactivity remained stable around 80-90% at all ages, whereas Art v 3 and Ole e 7 recognition was missing in younger patients. Pru p 3 IgE exceeded IgE specific for pollen LTP at all ages. Inhibition studies carried out on LTP reactors showed that commercial extracts of mugwort and plane pollen were unable to inhibit significantly Pru p 3 IgE reactivity. In follow-up studies, baseline Pru p 3 IgE levels exceeded Art v 3 IgE levels in 84% of those sensitized to both allergens, and all patients positive to only one LTP allergen at baseline were sensitized to Pru p 3. Further, most of the patients who did not show any LTP reactivity at baseline became exclusive Pru p 3 reactors. On ImmunoCAP singleplex Pru p 3 IgE levels exceeded Art v 3 IgE levels in 89% of cases (p less than 0.0001). Most literature data were in keeping with these new observations. Conclusions. The evidence for LTP syndrome being a pollen-food syndrome is presently very thin. Our data do not rule out the possible sensitization to the protein, via the airways or the skin.

Comparison of the performance of Skin Prick and ISAC Tests in the diagnosis of allergy

Summary

The recent European Union and Italian regulations in the matter of in vivo test could strongly impact on current diagnostic approach, increasing the usage of in vitro tests in daily clinical practice. We evaluated 506 patients with both skin prick test and a microarray system (ImmunoCAP ISAC 112). The overall evaluation between ImmunoCAP^® ISAC vs SPT showed a moderate agreement (k=0.509, 95% C.I. 0.480-0.540, SE: 0.016) considering both aeroallergens and food allergens. When we considered the concordant results (double-positive plus double-negatives), the agreement ranged from 69% to 80% for pollen allergens, between 74% and 76% for dust mites, and between 74% and 93% for animal epithelia. In the case of food allergens, the accordance was pretty lower, accounting values ranging from 67% to 86%. ISAC testing identified from 22% to 26% more cases than SPTs in peach and nuts hyper-sensitivity. In 2.8% of the control group, the ISAC-test failed to detect an allergy sensitization caused by dust mite, shrimp, Anisakis, or seed storage proteins. Multiplex testing is more than a promising tool for more precise and comprehensive profiling of allergic patients and can be considered as a second-line approach, after the anamnesis, in the diagnosis of allergic diseases.

House dust mite allergy and shrimp allergy: a complex interaction

Summary

Background and Objective. Sensitization and allergy to shrimp among Italian house dust mite allergic patients are not well defined and were investigated in a large multicenter study. Methods. Shrimp sensitization and allergy were assessed in 526 house dust mite (HDM)-allergic patients submitted to the detection of IgE to Der p 10 and 100 atopic control not sensitized to HDM. Results. Shrimp allergy occurred in 9% of patients (vs 0% of 100 atopic controls not sensitized to HDM; p minor 0.001). Shrimp-allergic patients were less frequently hypersensitive to airborne allergens other than HDM than crustacean-tolerant subjects (35% vs 58.8%; p minor 0.005). Only 51% of tropomyosin-sensitized patients had shrimp allergy, and these showed significantly higher Der p 10 IgE levels than shrimp-tolerant ones (mean 22.2 KU/l vs 6.2 KU/l; p minor 0.05). Altogether 53% of shrimp-allergic patients did not react against tropomyosin. Conclusions. Shrimp allergy seems to occur uniquely in association with hypersensitivity to HDM allergens and tropomyosin is the main shrimp allergen but not a major one, at least in Italy. Along with tropomyosin-specific IgE levels, monosensitization to HDM seems to represent a risk factor for the development of shrimp allergy among HDM allergic patients.

Evaluation of two commercial peach extracts for skin prick testing in the diagnosis of hypersensitivity to lipid transfer protein. A multicenter study

Summary

The clinical usefulness of two commercial peach extracts for SPT (by Lofarma SpA and ALK-Abellò, respectively) was compared in a multicenter study carried out in Italy. Peach allergic patients were tested with the two extracts in parallel and underwent the detection of IgE specific for all three peach allergens currently available (Pru p1, Pru p3, and Pru p4, respectively). The two extracts were almost identical in terms of sensitivity and specificity, being able to detect virtually all patients sensitized to stable peach allergens (lipid transfer protein (LTP) and, presumably, peamaclein) but scoring negative in patients exclusively sensitive to labile allergens (either PR-10 and/or profilin). Thus, the two extracts represent an excellent tool to carry out a preliminary component-resolved diagnosis of peach allergy at the first patient visit.

Recommendations for the Use of Tryptase in the Diagnosis of Anaphylaxis and Clonal Mastcell Disorders

Summary

Tryptase is a serin-protease produced and released by mast cells after IgE-mediated or non-IgE mediated stimuli. We here review the various aspects related to the molecular characteristics of the enzyme and its biological effects, the genetic basis of its production and the release kinetics. Recommendations for the clinical use of tryptase measurement developed by a task force of Società Italiana di Patologia Clinica e Medicina di Laboratorio and Associazione Allergologi Immunologi Italiani Territoriali e Ospedalieri are given on the best procedure for a correct definition of the reference values in relation to the inter-individual variability and to the correct determination of tryptase in blood and other biological liquids, in the diagnosis of anaphylaxis (from drugs, food, insect sting, or idiophatic), death from anaphylaxis (post mortem assessment) and cutaneous or clonal mastcell disorders.

Use of a comprehensive diagnostic algorithm for Anisakis allergy in a high seroprevalence Mediterranean setting

Summary

Background.Diagnosis of anisakis allergy (AA) is based on the skin prick test (SPT) and specific IgE (sIgE) determination. Anyway, false positivity cases are due to cross reactivity with numerous allergens. The aim of the study was to evaluate the reliability of a comprehensive diagnostic algorithm for the AA. Methods.An observational study was conducted on a sample of consecutive subjects accessing the allergology outpatient ambulatories of two hospitals located in Western Sicily. All the recruited outpatients were tested by Skin Prick Test performed using anisakis extracts by ALK-Abellò (Madrid, Spain). Specific IgE dosage for anisakis extracts was then performed by using ImmunoCAP250 (Immunodiagnostics Uppsala, Sweden). Consequently, outpatients who tested positive to first line tests underwent sIgE testing for ascaris and tropomyosin. Lastly, outpatients positive to the first line were invited to be further tested by basophil activation test (BAT) by using Flow CAST kit and anisakis commercial extract (Bühlmann Laboratories AG, Schönenbuch, Switzerland), as confirmatory analysis. Results.One hundred and eleven outpatients with an anamnesis suggestive of sensitization to anisakis (AS) and 466 subjects with chronic urticaria (CU) were recruited in the study. Of these, 22 with AS and 41 with CU showed a sensitization to anisakis allergens. The diagnostic algorithm revealed that 8.8% of outpatients who tested positive to sIgE determination were affected by CU, while 82.5% of all the sIgE positivity was related to cross-reactivity. Overall, a genuine anisakis seroprevalence of 2.3% was documented. Within a sub-sample of 15 subjects with clinical symptoms related to AA, n. 8 showed a real positivity after BAT. A greater response to A. pegreffii allergens as compared to A. simplex was reported. Conclusions.Our preliminary findings support the high clinical specificity of BAT for AA diagnosis, suggesting implementing this method in a comprehensive diagnostic algorithm.

An unusual case of positive sIgE to Galactose-alpha-1,3-galactose from South Italy

Summary

We report the case of a 38-year-old man who was bitten several times during his life by a tick. He didn't report any previous history of anaphylaxis after the ingestion of red meat. The serum specific IgE showed positivity to α-Gal. The proximity of the bits didn't increase the titer of IgE antibodies to alpha-gal. We could hypothesize that the frequency of the exposure to the tick Corresponding author bites and the amount of tick bites during his lifetime induced a sort of tolerance in this patient.

Diagnostic accuracy of IgA anti-tissue transglutaminase antibody assays in celiac disease patients with selective IgA deficiency

Clinical studies have estimated a 10- to 20-fold increased risk for celiac disease (CD) in patients with selective IgA deficiency (SIgAD). For this reason, screening for CD is mandatory in SIgAD patients, but it represents a special challenge since the specific IgA class antibodies against gliadin (AGA), endomysium (EMA), and tissue-transglutaminase (tTG) are not produced in patients with CD. IgG class counterparts of these antibodies may be informative; in particular IgG EMA has been demonstrated to be a valid marker for diagnosing CD in SIgAD cases, but it is not used much in clinical laboratories, because it is cumbersome and involves some technical difficulties. Even if it was widely used in clinical laboratories, the measuring of IgG AGA has shown a less-than-optimum diagnostic accuracy, so that now it tends to be substituted by tests for anti-tTG IgG, for which the few available studies have shown diagnostic performances superior to AGA. Since it is not known whether various available methods for measuring IgG anti-tTG antibodies offer similar diagnostic performances, we have compared the results obtained from nine second-generation commercial methods (D-tek, Phadia, Immco, Orgentec, Radim, Euroimmun, Inova, Aesku, Generic Assays), measuring IgG anti-tTG antibodies in 20 patients with CD and SIgAD and in 113 controls (9 patients with SIgAD without CD, 54 patients with chronic liver disease, and 50 healthy individuals). Diagnostic sensitivity, calculated by means of ROC plot analysis, ranged between 75% and 95%, and specificity ranged from 94% to 100%. In the same population, the diagnostic sensitivity and specificity of AGA IgG were 40% and 87%, respectively. Even though they perform differently, all IgG anti-tTG methods evaluated are reliable serological assays for the diagnosis of CD in SIgAD patients, with diagnostic accuracy superior to the AGA IgG method. The methods that use a mix of tTG and gliadin peptides as the antigenic preparation have a specificity slightly lower than that of the methods that use only tTG.

IgA anti-actin antibodies ELISA in coeliac disease: a multicentre study

BACKGROUND

Previous studies have demonstrated that serum anti-actin antibodies are a reliable marker of intestinal damage severity in coeliac disease.

AIMS

To validate in a multicentre study the clinical usefulness of serum IgA anti-actin antibody ELISA and its possible use in monitoring intestinal mucosa lesions during gluten-free diet.

PATIENTS AND METHODS

Four centres recruited 205 newly diagnosed coeliac disease patients with villous atrophy, 80 healthy controls and 81 "disease" controls. Twelve coeliac disease patients on gluten-free diet but with persistent symptoms underwent serum IgA anti-actin antibody assay and intestinal histology evaluation. IgA anti-actin antibody ELISA was performed with a commercial kit. All coeliac disease patients underwent intestinal histology study.

RESULTS

IgA anti-actin antibodies showed a sensitivity of 80% and a specificity of 85% in the diagnosis of coeliac disease patients with villous atrophy. The area under the receiving operator curve for anti-actin antibodies was 0.873 [95% C.I. 0.805-0.899]. Serum anti-actin antibodies values were significantly higher in coeliac disease patients than in healthy or "disease" controls (P<0.0001). Serum anti-actin antibodies were positive in 41 of the 60 coeliac disease patients with mild intestinal histology lesions (69%) and in 123 of the 145 with severe lesions (85.3%) (P<0.05). There was a significant inverse correlation between anti-actin antibody values and the villi/crypts ratio (r=-0.423; P<0.0001). In the 12 coeliac disease patients on gluten-free diet who underwent re-evaluation as they were persistently symptomatic, intestinal histology showed three cases with persistent villous atrophy: all of these were positive for serum anti-actin antibodies ELISA, whereas both serum anti-tTG and EmAs were negative. The other nine patients showed normal intestinal villi and were negative for serum anti-actin antibodies.

CONCLUSIONS

Anti-actin antibodies are a reliable marker of severe intestinal mucosa damage in coeliac disease patients and a simple ELISA technique offers an accurate method for their determination. These antibodies seem to be a very reliable marker of persistent intestinal damage in coeliac disease patients.

Usefulness of N-terminal pro-B-type natriuretic peptide levels in predicting residual myocardial ischemia in patients with ST elevation acute myocardial infarction

AIM

N-terminal pro-b-type natriuretic peptide (NT pro-BNP) is a neurohormone synthesized predominantly in ventricular myocardium. In patients with symptoms of heart failure, elevation in NT pro-BNP accurately identifies ventricular dysfunction. However, NT pro-BNP levels are not specific for ventricular dysfunction in patients who do not have overt symptoms of heart failure, suggesting that other cardiac processes such as myocardial ischemia may also cause elevation in NT pro-BNP. The study was aimed to determine whether NT pro-BNP elevations are associated with myocardial ischemia.

METHODS

One hundred and thirty patients (104 males, 26 females, mean age 61+12 years), with ST elevation acute myocardial infarction (STEMI) and preserved left ventricular ejection fraction (>45%) at echocardiography performed at entry, from February 2003 and February 2004 were enrolled. In all patients NT pro-BNP plasma levels were checked at entry and 4-5 days after symptoms onset. In addition, maximal or symptom-limited exercise treadmill test (Bruce protocol), and myocardial perfusion scintigraphy using [(99m)Tc]Tetrofosmin single photon emission computed tomography (SPECT) imaging were performed within 30 days of STEMI. Ischemia was defined as reversible perfusion abnormalities.

RESULTS

Of the 130 participants, 66 (51%) had inducible ischemia. Compared with patients in the lowest tertile, those in the highest tertile of NT pro-BNP had a greater significant risk of residual ischemia (odds ratio: 8.66; 95% CI, 3.90 to 19.24). Nevertheless patients in the highest tertile were older (64.19+/-10.80 years versus 55.90+/-9.67 years, P = 0.0001), had a lower left ventricular ejection fraction (49.70+13.46% versus 59.49+/-6.58%, P = 0.0001) and had a great rate of acute myocardial infarction (anterior acute myocardial infarction = 40.63% versus 25%).

CONCLUSIONS

Elevated levels of NT pro-BNP are associated with residual myocardial ischemia among patients with STEMI and preserved left ventricular ejection fraction, as demonstrated by perfusion defect on SPECT imaging, suggesting that these patients may need further evaluation for stratification of the future risk of fatal events. The observed association between NT pro-BNP levels and ischemia may explain because tests for NT pro-BNP are not specific for ventricular dysfunction among patients with coronary artery disease.

Evaluation of antibodies to thymine ROS-modified DNA poly(dT), in patients with immunologic disorders: relationships to anti n-DNA and anti ENA autoantibodies

BACKGROUND

Hydroxyl radical, one of the most potent of all reactive oxygen species, is known to modify adenine and thymine in cellular DNA, producing some modified DNA fragments (ROS-DNA) with different antigenic properties. Despite several in vitro studies about ROS-DNA, data regarding their clinical significance are scanty. The aim of our study was to seek out the presence and clinical significance of the anti poly(dT) auto-antibodies in a group of patients suspected of autoimmune disease.

METHODS

We initially evaluated more than 900 consecutive sera of hospitalized patients (range age from 6 to 70 yrs) referred to our laboratory during 18 months. Anti n-DNA, anti-ENA and poly(dT) autoantibodies were performed on 158 ANA positive sera and 28 ANA negative sera from patients strongly suspected of rheumatic diseases or affected by HCV infection.

RESULTS

Anti poly (dT) were found in 22 out of 186 sera. As regards the clinical evaluation, 8 patients were affected by SLE, 5 by Scleroderma, 3 by HCV-related chronic hepatitis, 4 by recurrent abortions (without presence of the anti-cardiolipin antibodies and other clinical symptoms). In two patients the ACR criteria and the clinical aspects did not allow a definite diagnosis. Anti-Histones were detected in 18 out of 22 poly (dT) positive patients.

CONCLUSIONS

Our data suggest that anti poly(dT) autoantibodies are sensitive markers of various autoimmune diseases, but with a minor specificity as compared to anti n-DNA for the diagnosis of SLE.

Effects of dextran sulphate on lymphoblast extravasation into inflammatory skin sites

The effects of high molecular weight dextran sulphate (DXS) on the migration of 125I-labelled deoxyuridine-labelled peripheral lymphoblasts (stimulated by oxazolone) were studied in vivo by injecting the drug (50 mg/kg) subcutaneously in recipients, and by following the fate of oxazolone-stimulated peripheral lymphocytes treated in vitro with DXS in non-treated syngeneic recipients. Both types of experiments demonstrate that DXS considerably reduces lymphoblast extravasation in skin sites inflamed either by non-immune causes or by DTH. Our results also demonstrate that oxazolone-stimulated peripheral lymphocytes, after in vitro treatment with DXS, are unable to transfer antigen-specific contact hypersensitivity to unsensitized recipients. The results obtained suggest that the drug acts on both T effector cells and lymphoblasts.