Clóvis Eduardo Santos Galvão

Measurement of IgE antibodies to shrimp tropomyosin is superior to skin prick testing with commercial extract and measurement of IgE to shrimp for predicting clinically relevant allergic reactions after shrimp ingestion

BACKGROUND Shrimp is a frequent cause of food allergy. Tropomyosin is the major allergen in shrimp, and it shares homology to tropomyosins from other crustaceans, dust mites, cockroach, and parasites. OBJECTIVE The aim of this study was to determine the value of detection of IgE to shrimp tropomyosin in the diagnosis of shrimp allergy. METHODS We have studied 35 patients with asthma, rhinitis, or both who were sensitized to Dermatophagoides pteronyssinus. All subjects underwent skin prick testing in addition to double-blind, placebo-controlled food challenges (DBPCFC); oral open challenges; or both with shrimp. Measurements of IgE to shrimp and shrimp tropomyosin were carried out by means of CAP and chimeric ELISA, respectively. RESULTS Oral challenges confirmed the diagnosis of shrimp allergy in 7 patients. IgE measurement to shrimp tropomyosin was positive in 71.4% of the patients with shrimp allergy. Of the 28 patients without shrimp allergy, only 7.1% (2/28) had IgE to shrimp tropomyosin compared with 25% (7/28) who had IgE to shrimp and 35.7% (10/28) who had positive skin prick test responses to shrimp. Sensitivity was similar for all 3 methods (71.4%); in contrast, specificity of IgE to shrimp tropomyosin (92.8%) was greater than that of IgE to shrimp (75%) and skin prick testing (64.2%). With regard to diagnostic efficiency, measurement of IgE to shrimp tropomyosin was superior to measurement of IgE to shrimp and skin prick testing (88.5%, 74.2%, and 65.7%, respectively). CONCLUSION Use of measurements of IgE to shrimp tropomyosin provided added value to the diagnosis of shrimp allergy.

Specific immunotherapy using Hymenoptera venom: systematic review

CONTEXT AND OBJECTIVE The only effective treatment for patients who have severe reactions after Hymenoptera stings is venom immunotherapy. The aim of this study was to review the literature to assess the effects of venom immunotherapy among patients presenting severe reactions after Hymenoptera stings. DESIGN AND SETTING Randomized controlled trials in the worldwide literature were reviewed. The manuscript was produced in the Discipline of Allergy and Clinical Immunology, Universidade de São Paulo (USP). METHODS Randomized controlled trials involving venom immunotherapy versus placebo or only patient follow-up were evaluated. The risk of systemic reactions after specific immunotherapy was evaluated by calculating odds ratios (OR) and their 95% confidence intervals. RESULTS 2,273 abstracts were identified by the keywords search. Only four studies were included in this review. The chi-square test for heterogeneity showed that two studies were homogeneous and could be included in a meta-analysis. By combining the two studies, the odds ratio became significant: 0.29 (0.10-0.87). However, analysis on the severity of the reactions after immunotherapy showed that the benefits may not be so significant because the reactions were mostly similar to or milder than the original reaction. CONCLUSIONS Specific immunotherapy should be recommended for adults and children with moderate to severe reactions, but there is no need to prescribe it for children with skin reactions alone, especially if the exposure is very sporadic. On the other hand, the risk-benefit relation should always be assessed in each case.

Novel allergens from ancient foods: Man e 5 from manioc (Manihot esculenta Crantz) cross reacts with Hev b 5 from latex

SCOPE Manioc (Manihot esculenta) is a tuber mainly consumed in the Southern Hemisphere and used worldwide by food and chemistry industry. We aimed to recombinantly produce and characterize the first manioc allergen and evaluate its IgE reactivity in sera of Brazilian and Italian patients. METHODS AND RESULTS The molecule, termed Man e5, was expressed in E. coli, characterized by amino acid analysis, mass spectrometry, circular dichroism, HPLC, and dynamic light scattering. A tertiary structural model of the protein was produced using bioinformatics and susceptibility to pepsin digestion was analyzed in vitro. Based on its high content of charged residues, heat stability, flexibility and lack of secondary structure elements, the allergen was determined a member of the intrinsically disordered protein family. Brazilian patients were selected based on manioc allergy and Italians based on latex allergy and sensitization to Hev b 5.71% of Brazilians and 40% of Italians were in vitro IgE positive to Man e5. Cross-inhibition assays suggest a possible involvement of this allergen in the latex-fruit syndrome. CONCLUSION Man e5, the first purified allergen from manioc demonstrates IgE cross-reactivity with Hev b 5. Data suggest Hev b 5 might act as primary sensitizer and could therefore lead to allergic manifestations upon manioc consumption without prior exposition.

Inflammatory mediators in nasal lavage among school-age children from urban and rural areas in São Paulo, Brazil

CONTEXT Some studies have shown that inflammatory processes in the nasal air passages may reflect or affect those in the lower airways. We decided to indirectly assess the inflammatory status of the nasal airways in two groups of children with different sensitization rates to aeroallergens. OBJECTIVE To compare the inflammatory activity in the nasal airways, through the determination of mediators in nasal lavage fluid in two distinct populations. TYPE OF STUDY Cross-sectional study. SETTING Two public elementary schools, one in an urban setting and the other in a rural setting of the State of São Paulo, Brazil. METHODS Two groups of 40 elementary school children with different sensitization rates to aeroallergens were formed. Samples of nasal lavage fluid were assessed for eosinophil cationic protein (ECP) and tryptase. Non-parametric tests were used for statistical analysis. RESULTS Significantly higher levels of ECP were observed among students living in the urban area than those in the rural area (p < 0.05). No significant difference in the tryptase levels was observed. Also, the urban children who were sensitized to aeroallergens presented higher levels of ECP in nasal mucosa than the non-sensitized children, while this difference was not observed among the rural children. DISCUSSION The lack of mast cell activity and increased eosinophil degranulation revealed a chronic inflammatory state in the nasal air passages. The higher eosinophil activity in the urban area, coinciding with higher sensitization to aeroallergens, suggests that there must be some factors in the urban area that can modulate airway inflammation by influencing the activation of inflammatory cells. CONCLUSION Our findings showed that there was no difference in the concentrations of tryptase in nasal lavage fluids between the two studied groups. However, the children from the urban area presented with higher concentrations of eosinophil cationic protein than did those from the rural area. Also, the urban children who were sensitized to aeroallergens presented with greater concentrations of eosinophil cationic protein in nasal mucosa than the non-sensitized children, while this difference was not observed among the rural children.

Diagnostic assessment of occupational asthma due to persulfate salts in a professional hairdresser: a case report

Many different causative agents have been ascribed to occupational asthma (OA). Persulfate salts are low molecular weight chemical compounds widely used in different manufacturing processes, particularly in the cosmetics industry. Persulfate-induced asthma may represent 4% of all OA cases,1 and although the first cases due to persulfate salts were described approximately 30 years ago,2 the prevalence of the disease, its mechanisms, the risk factors for its development, the value of diagnostic tests, and the progression of these patients remain unknown. We report the case of a hairdresser with respiratory symptoms associated with exposure to persulfate salts. The diagnosis of occupational asthma due to this compound was confirmed only by specific bronchial challenge test.

Functional changes of dendritic cells in hypersensivity reactions to amoxicillin

A better understanding of dendritic cell (DC) involvement in responses to haptenic drugs is needed, because it represents a possible approach to the development of an in vitro test, which could identify patients prone to drug allergies. There are two main DC subsets: plasmacytoid DC (pDC) and myeloid DC (mDC). β-lactams form hapten-carrier conjugates and may provide a suitable model to study DC behavior in drug allergy reactions. It has been demonstrated that drugs interact differently with DC in drug allergic and non-allergic patients, but there are no studies regarding these subsets. Our aim was to assess the functional changes of mDC and pDC harvested from an amoxicillin-hypersensitive 32-year-old woman who experienced a severe maculopapular exanthema as reflected in interleukin-6 (IL-6) production after stimulation with this drug and penicillin. We also aim to demonstrate, for the first time, the feasibility of this method for dendritic cell isolation followed by in vitro stimulation for studies of drug allergy physiopathology. DC were harvested using a double Percoll density gradient, which generates a basophil-depleted cell (BDC) suspension. Further, pDC were isolated by blood DC antigen 4-positive magnetic selection and gravity filtration through magnetized columns. After stimulation with amoxicillin, penicillin and positive and negative controls, IL-6 production was measured by ELISA. A positive dose-response curve for IL-6 after stimulation with amoxicillin and penicillin was observed for pDC, but not for mDC or BDC suspension. These preliminary results demonstrate the feasibility of this methodology to expand the knowledge of the effect of dendritic cell activation by drug allergens.

Prevalence of sensitivity signals to latex in meningomyelocele patients undergoing multiple surgical procedures

BACKGROUND AND OBJECTIVES The number of patients allergic to latex has increased significantly. It is crucial to recognize the cases in order to prevent and apply adequate treatment. The objective of this study was to evaluate the prevalence of allergy to latex in meningomyelocele patients. MATERIALS AND METHODS A retrospective evaluation of medical records of patients with meningomyelocele diagnosis from January 2002 to December 2007 was conducted. Patients were grouped into allergics and non-allergics. The comparison of groups for gender was made by the Chi-Squared test, the Students t test was used to compare age, and Mann-Whitney test was used to compare groups for clinical manifestations of allergy, number of procedures under anesthesia, hospital admissions and vesical catheterizations. RESULTS The mean number of procedures under anesthesia was 7 in the group with allergy and 4 in the group without allergy; this difference was statistically significant (p=0.028). The mean number of hospital admissions was 4.5 in the group with allergy and 3.4 in group without allergy and mean vesical catheterization was 24.5 in allergic patients and 21.7 in non allergic ones. CONCLUSIONS Meningomyelocele patients undergoing multiple procedures under anesthesia have high risk of developing clinical signals of allergy to latex. It is necessary that patients with meningomyelocele diagnosis should undergo exclusively latex-free procedures, avoiding high risk of sensitization and its complications. Specific tests to evaluate sensitization, genetic markers and latex-fruit relationship may contribute to a better understanding of risk factors related to allergy to latex and ways to prevent it.

Sensitization to cat allergen and its association with respiratory allergies: cross-sectional study

Cats are a significant source of allergens that contribute towards worsening of allergic diseases. The aim of this study was to investigate the association between sensitization to cat allergens and allergic respiratory diseases.This was an observational retrospective study based on the skin pricktests results of patients at a tertiary-level hospital in São Paulo. A total of 1,985 test results were assessed. The prevalence of sensitization to cat allergen was 20% (399 patients). Our data indicated that in this population of atopic patients, a positive skin prick test result for cat allergen was not associated significantly with a diagnosis of respiratory allergy.

Identification of new Brazilian allergens from manioc (Manihot esculenta)

Brazil is a very rich country in terms of biodiversity offering broad spectra of possibilities to study new allergens, particularly from foods. In poor and developing countries manioc is a major source of carbohydrates in the diet of millions of people. In Brazil is the ninth cultivated food and the country takes the second place in the world as manioc cultivator. Allergic reactions to manioc were previously reported, but the allergen molecules involved and the cross-reactivity with other plant food sources or latex remain unknown. The aim of present work is to identify new manioc allergens, clone and express them. Based on clinical history, nine patients allergic to manioc were submitted to prick-to-prick test and basophil activation tests and sera were used for immunoblot analysis and ISAC. All patients demonstrated positive IgE reactivity to manioc proteins of approximately 30 and 40 kDa in 1D gel electrophoresis. Using 2D analysis, 6 immunoreactive spots were identified as allergenic-related protein Pt2L4, GADPH and fructose-bisphosphate-aldolase. Three out of five tested sera showed IgE reactivity to Hev b 5 in ISAC. The rich glutamic acid protein, Pt2L4 shows around 40% sequence identity with Hev b5 and 2 of 5 linear IgE epitopes identified for Hev b 5 are partially conserved in Pt2L4. Therefore, the mature sequence was amplified from manioc cDNA using specific primers and cloned into a pET-based expression vector. Clones from two different cultivars were checked and they are all the same sequence but deviate 3 amino acids from the three previously published sequences. Recombinant allergenic-related protein was expressed in E. coli BL21 Star and purified by ion exchange and size exclusion chromatography. Protein will be characterized regarding its physicochemical properties using aminoacid analysis, mass spectrometry, circular dichroism and simulated duodenal digestion. The IgE-binding activity of the recombinant molecule is assessed by IgE immunoblot and ELISA. In addition, IgE cross-reactivity with purified natural Hev b 5 is evaluated using sera of manioc and latex allergic patients.

Anaphylaxis triggered by prick test with latex extract: a case report

CONTEXT Adverse reactions associated with prick tests are rare but may be present as serious systemic reactions. CASE REPORT A 38-year-old female nursing technician complained of three episodes of anaphylaxis in one year, all in the workplace. To investigate latex allergy, the patient underwent the prick test with latex, and immediately developed a rash, itchy skin, hoarseness, dyspnea and dry cough. Her condition improved promptly after appropriate measures were established for controlling her anaphylaxis. CONCLUSION The skin test must be performed under medical supervision, since complications that can lead to life-threatening reactions, if support measures are not readily implemented, have been attributed to this test.