Dimerisation increases the immunogenicity of recombinant Parj1/Parj2 allergens

Purified recombinant Parj1 and Parj2 allergens bind an IgE repertoire common to the Parietaria species, allowing their use as marker molecules for diagnosis and therapy of allergic disease induced by the Urticaceae family. Preclinical studies on the in vivo immunogenicity of recombinant Parj1, Parj2 and their isoforms indicated differential capacity to induce IgG1 antibody responses, as indication of potential clinical use. A recombinant hetero-dimeric hybrid derivative (PjED), encompassing the shorter Parj1 isoform (Parj1.0201) and Parj2 allergen, was characterised. In vivo immunisation with PjED induces IgG1 antibodies capable of binding all the isoforms of Parietaria major allergens, overcoming the poor immunogenicity of single monomeric allergens. This feature makes PjED a promising candidate molecule to be further characterised for clinical applications in the treatment of Parietaria allergy.

The major allergen of the Parietaria pollen contains an LPS-binding region with immuno-modulatory activity

BACKGROUND

The major allergens in Parietaria pollen, Par j 1 and Par j 2, have been identified as lipid transfer proteins. The family of the Par j 1 allergens is composed of two isoforms, which differ by the presence of a 37 amino acid peptide (Par37) exclusive to the Par j 1.0101 isoform. The goal of this study was to elucidate the biological properties of the Par37 peptide.

METHODS

In silico analysis, spectrofluorimetric experiments and in vitro cell culture assays were used to identify the biological properties of Par37. In addition, a mouse model of sensitization was used to study the influence of Par37 in the murine immune response.

RESULTS

In silico analysis predicted that Par37 displays characteristics of a host defence peptide. Spectrofluorimetric analysis, real-time PCR and ELISA assays demonstrated that Par37 possesses an LPS-binding activity influencing cell signalling in vitro. In RAW264.7 cells, LPS-induced IL-6 and TNF-α transcription and translation were inhibited after preincubation with Par37. Consistent with these data, inhibition of IFN-γ secretion was observed in murine spleen cells and in human PBMC. Finally, mice immunized with the two Par j 1 isoforms differing in the presence or absence of the Par37 peptide showed different immunological behaviours in vivo.

CONCLUSIONS

This study demonstrates that the Par j 1.0101 allergen displays LPS-binding activity due to the presence of a 37 amino acid COOH-terminal region and that this region is capable of influencing cytokine and antibody responses in vitro and in vivo.

Characterization of a Par j 1/Par j 2 mutant hybrid with reduced allergenicity for immunotherapy of Parietaria allergy

BACKGROUND

Parietaria pollen is one of the major cause of pollinosis in the southern Europe. Specific immunotherapy is the only treatment able to modify the natural outcome of the disease restoring a normal immunity against allergens.

METHODS

We designed a recombinant molecule (PjEDloop1) comprised of genetic-engineered variants of the major allergens of the Parietaria pollen (Par j 2/Par j 1). Purity and chemical-physical properties of the derivative were analysed by RP-HPLC chromatography and Photon Correlation Spectroscopy. Immunological activity was evaluated by means of Western blotting, ELISA inhibition and PBMC proliferation assay in 10 Parietaria allergic patients. Basophil activation was studied in six subjects. The immunogenicity of the hybrid was studied looking at the immune responses induced in a mouse model of sensitization.

RESULTS

The PjEDloop1 hybrid was produced as a purified recombinant protein with high stability in solution. Western blot, ELISA inhibition and basophil activation test showed that the PjEDloop1 displays a remarkable reduced IgE binding and anaphylactic activity. CD3 reactivity was conserved in all patients. Mice immunization with the rPjEDloop1 induced antibodies and T cell responses comparable to that obtained by the wild type allergens. Such antibodies shared the specificities to rPar j 1 and rPar j 2 with human IgE antibodies.

CONCLUSION

Our results demonstrated that a mutant hybrid expressing genetically engineered forms of the major P. judaica allergens displayed reduced allergenicity and retained T cell reactivity for the induction of protective antibodies in vaccination approaches for the treatment of Parietaria pollinosis.

Oral therapeutic administration of a probiotic mixture suppresses established Th2 responses and systemic anaphylaxis in a murine model of food allergy

BACKGROUND

No effective treatment is available for food allergy and its primary management still consists of avoiding relevant allergens. Probiotics are claimed to beneficially affect the immune system. We sought to investigate the therapeutic potential of VSL#3 probiotic mixture on specific immune responses and anaphylactic reaction induced in mice by the major food allergen shrimp tropomyosin (ST).

METHODS

The cytokine production by spleen cell from ST-sensitized mice upon allergen re-stimulation in the presence of VSL#3 was analysed. Next, the effects of oral administration of VSL#3 on allergen-induced anaphylaxis and Th2 response in the murine model of food allergy to ST was investigated by evaluating symptom score and histamine content in the faeces after allergen challenge, antibody response in serum and faeces, and cytokine and transcription factor expression in the jejunum.

RESULTS

The in vitro studies on mouse spleen cells indicates that the VSL#3 preparation has the capacity to shift a polarized Th2 response to a Th1/T regulatory-type profile. Oral therapeutic administration of VSL#3 to ST-sensitized mice significantly reduces symptom score and histamine release in the faeces following allergen challenge, as well as specific IgE response. In the jejunum, IL-4, IL-5 and IL-13 tissue content was significantly reduced, whereas FOXP3 and IL-27 mRNA expression, IL-10, TGF-β and IFN-γ tissue content were up-regulated.

CONCLUSIONS

Oral therapeutic treatment with the probiotic mixture VSL#3 is effective in redirecting allergen-specific Th2-polarized immune responses towards Th1-T regulatory responses and in the protection against anaphylactic reactions induced by the allergen in a murine model of food allergy.

Isolation, expression and immunological characterization of a calcium-binding protein from Parietaria pollen

The diagnosis and therapy of allergic disorders are usually performed with crude extracts which are a heterogeneous mixture of proteins with different allergenic potency. The knowledge of the allergenic composition is a key step for diagnostic and therapeutic options. Parietaria judaica pollen represents one of the main sources of allergens in the Mediterranean area and its major allergens have already been identified (Par j 1 and Par j 2). In addition, inhibition studies performed using a calcium-binding protein (CBP) from grass pollen (Phl p 7) showed the presence of a homologue of this cross-reactive allergen in the Parietaria extract. Screening of a cDNA library allowed us to isolate a 480bp cDNA containing the information for an 87 AA long protein with high level of homology to calcium-binding proteins from other allergenic sources. It was expressed as a recombinant allergen in Escherichia coli and purified by affinity chromatography. Its expression allowed us to study the prevalence of this allergen in a population of allergic patients in southern Europe. Immunoblotting and inhibition studies showed that this allergen shares a pattern of IgE epitopes in common with other 2-EF-hand calcium-binding proteins from botanically non-related species. The immunological properties of the Pj CBP were investigated by CD63 activation assay and CFDA-SE staining. In conclusion, DNA recombinant technology allowed the isolation, expression and immunological characterization of a cross-reactive calcium-binding protein allergen from Parietaria judaica pollen.

The CREATE project: development of certified reference materials for allergenic products and validation of methods for their quantification

Allergen extracts have been used for diagnosis and treatment of allergy for around 100 years. During the second half of 20th century, the notion increasingly gained foothold that accurate standardization of such extracts is of great importance for improvement of their quality. As a consequence, manufacturers have implemented extensive protocols for standardization and quality control. These protocols have overall IgE-binding potencies as their focus. Unfortunately, each company is using their own in-house reference materials and their own unique units to express potencies. This does not facilitate comparison of different products. During the last decades, most major allergens of relevant allergen sources have been identified and it has been established that effective immunotherapy requires certain minimum quantities of these allergens to be present in the administered maintenance dose. Therefore, the idea developed to introduce major allergens measurements into standardization protocols. Such protocols based on mass units of major allergen, quantify the active ingredients of the treatment and will at the same time allow comparison of competitor products. In 2001, an EU funded project, the CREATE project, was started to support introduction of major allergen based standardization. The aim of the project was to evaluate the use of recombinant allergens as reference materials and of ELISA assays for major allergen measurements. This paper gives an overview of the achievements of the CREATE project.

A hybrid expressing genetically engineered major allergens of the Parietaria pollen as a tool for specific allergy vaccination

BACKGROUND

Allergy is an immunological disorder affecting about 25% of the population living in the industrialized countries. Specific immunotherapy is the only treatment with a long-lasting relief of allergic symptoms and able to reduce the risk of developing new allergic sensitizations and inhibiting the development of clinical asthma in children treated for allergic rhinitis.

METHODS

By means of DNA recombinant technology, we were able to design a head to tail dimer expressing disulphide bond variants of the major allergen of the Parietaria pollen. IgE binding activity was studied by Western blot, ELISA inhibition assays and the skin prick test. T cell recognition was studied by peripheral blood mononuclear cell proliferation. The immunogenicity of the hybrid was studied in a mouse model of sensitization.

RESULTS

In vitro and in vivo analysis showed that the disruption of specific cysteine residues in both allergens caused a strong reduction in IgE binding activity of the PjEDcys hybrid. In addition,we were able to show that a reduction in the IgE epitope content profoundly reduced the anaphylactic activity of the hybrid (from 100 to 1,000 times less than wild-type allergens) without interfering with the T cell recognition. Sera from BALB/c mice immunized with the hybrid were able to bind the natural Parietaria allergens and to inhibit the binding of human IgE to wild-type Par j 1 and Par j 2 allergens up to 90%.

CONCLUSION

Our results demonstrate that hybrid-expressing disulphide bond variants of the major allergens of the Parietaria pollen displayed reduced allergenicity and maintained T cell reactivity for induction of protective antibodies.

Evaluation of allergenicity of genetically modified soybean protein extract in a murine model of oral allergen-specific sensitization

BACKGROUND

With the development of genetically modified crop plants there has been a growing interest in the approaches available to assess the potential allergenicity of novel gene products. For additional assessment of the potential allergenicity of expressed proteins, informative data can be generated using animal models. Soybean is one of the major source of protein in human and animal nutrition, and has also been well characterized as a major allergenic source. Advances in biotechnology have resulted in an increasing number of genetically engineered foods, and among these soybean is one of the most widespread.

OBJECTIVE

To develop and characterize a murine model of IgE-mediated soybean sensitization induced by intragastric immunization, in the presence of Cholera Toxin, with wild-type soybean extract (wt-SE) or with genetically modified soybean extract (gm-SE).

METHODS

Balb/c mice born in our animal facilities, from females fed on soy-free food, were fed with the same soy-free food and used in all the experiments. Mice were sensitized by gavages with soybean extracts, and allergen-specific IgE and IgG responses were studied by direct ELISA and ELISA inhibition. Antigen-specific cell proliferation and cytokine production were evaluated in spleen cell cultures. Results Sensitization with both soybean extracts induced high levels of antigen-specific IgE and IgG1 and low levels of specific IgG2a. Both wt-SE and gm-SE were able to inhibit the binding of specific IgE from mice immunized with gm-SE to the same antigen used for the ELISA coating. A comparable proliferative response was obtained with the homologous as well as with the heterologous extracts.

CONCLUSION

In sensitized mice, we observed a predominantly T-helper type 2 (Th2)-type immune response, with increased soybean-specific IgE and IgG1 antibodies and a concomitant increase of IL-4 and IL-5 production.

RESULTS

obtained by specific IgE ELISA inhibition and by antigen-specific T cell proliferation demonstrated that wt-SE and gm-SE shared B and T epitopes. The present murine model of soybean sensitization established by the oral route should provide valuable information about risk assessment for food allergy from new proteins of genetically modified foods.

Immunological characterization of a recombinant tropomyosin from a new indoor source, Lepisma saccharina

BACKGROUND

The presence of specific IgE antibodies to invertebrates is common among patients with rhinitis and asthma. Tropomyosin has been described as an invertebrate cross-reactive allergen. We have recently characterized an allergenic extract from silverfish (Lepisma saccharina). Since this insect could be a new source of tropomyosin in the indoor environment, we have thought important to clone and characterize the tropomyosin from it.

METHODS

Recombinant tropomyosin was cloned and characterized by means of immunoblotting with tropomyosin-specific monoclonal antibodies, rabbit polyclonal antibodies and IgE from allergic patients. Its allergenic activity was investigated in histamine release assays. Immunoblotting and ELISA inhibition were carried out to identify the natural tropomyosin in the silverfish extract and to study the cross-reactivity among other arthropod tropomyosins.

RESULTS

Tropomyosin-specific antibodies recognized in immunoblotting the natural tropomyosin in the insoluble fraction of silverfish extract. The silverfish tropomyosin (Lep s 1) was cloned and fully expressed. It shared high homology with other arthropod tropomyosins. rLep s 1 was recognized by tropomyosin-specific monoclonal and polyclonal antibodies and by IgE of allergic patients. It was able to inhibit the IgE binding to the insoluble fraction of silverfish extract, and to induce histamine release by an arthropod-allergic serum. Inhibition experiments revealed IgE cross-reactivity between rLep s 1 and other arthropod tropomyosins.

CONCLUSION

rLep s 1 is the first allergen cloned and characterized from silverfish extract. It enabled us to identify the natural counterpart in the insoluble fraction of silverfish extract, suggesting that the tropomyosin is not readily extractable with a classic aqueous extraction procedure. rLep s 1 displayed biological activity, suggesting that it could be regarded as a useful tool to study the role of silverfish tropomyosin in the sensitization to invertebrate allergic sources.

Allergen skin weal/radioallergosorbent test relationship in childhood populations that differ in histamine skin reactivity: a multi-national survey

BACKGROUND

Histamine skin reactivity (HSR, the dimension of the skin weal elicited by histamine 10 mg/mL) is a variable that differs in children from different European countries and increases over time in the same place (Italy).

OBJECTIVE

In this epidemiologic study, we investigated to what extent differences in HSR influence the relationship between positive allergen skin prick tests (ASPTs) and serum-specific IgE concentrations.

METHODS

Between October 2001 and February 2002, 591 unselected 9-10-year-old schoolchildren drawn from five small towns in central Poland (Starachowice), central Italy (Ronciglione, Guardea) and Libya (Al-Azyzia, near the Mediterranean sea and Samno, 900 km south of the coast) were analysed for histamine, common ASPT and for serum total and specific IgE.

RESULTS

HSR differed markedly in children from the three countries (Libya>Italy>Poland) whereas serum total IgE concentrations remained the same. The prevalence of children with measurable serum specific IgE (> or = 0.35 kU) or with a positive ASPT for five common allergens was high in Italy, lower in Poland and far lower in Libya. A 3-mm ASPT weal corresponded to a serum-specific IgE concentration that was two to threefold higher in children with low HSR compared with children with high HSR (P = 0.008).

CONCLUSION

These findings suggest that HSR--a variable that differs in schoolchildren populations from the three countries studied--independently influences the results of ASPT and its influence should be considered when ASPT are assessed in international studies. The HSR differences found in the populations reported here probably reflect a complex, dynamic, environmental interaction that should be monitored in the different parts of the world.

The recombinant major allergen of Parietaria judaica and its hypoallergenic variant: in vivo evaluation in a murine model of allergic sensitization

BACKGROUND

Par j 1 represents the major allergenic component of Parietaria judaica pollen. Its three-dimensional structure is stabilized by four disulphide bridges. A family of three-dimensional mutants of the recombinant Par j 1 (rPar j 1) allergen, showing reduced allergenicity and retained T cell recognition has been recently developed by site-directed mutagenesis.

OBJECTIVE

To develop and characterize a murine model of IgE sensitization to rPar j 1. To evaluate similarities between the murine model and the human IgE response. To investigate in this model the recognition of a hypoallergenic mutant of Par j 1, and to study the immune responses elicited in mice by the mutant itself.

METHODS

BALB/c mice were sensitized by two intraperitoneal immunizations with rPar j 1 in alum on days 0 and 21. Allergen-specific serum IgE and IgG responses were studied by direct ELISA and immunoblotting, ELISA inhibition and competitive ELISA. Cell proliferation was evaluated in splenocyte cultures.

RESULTS

Sensitization with rPar j 1 induced high levels of IgE and IgG1 vs. low levels of IgG2a. Mouse antibodies specific to rPar j 1 were able to compete with human IgE for recognition of rPar j 1. IgE from mice immunized with rPar j 1 showed a significantly reduced binding activity towards the hypoallergenic variant rPjC, which lacks three disulphide bridges. On the contrary, rPjC was recognized by IgG1 and IgG2a antibodies as well as rPar j 1. The proliferative response to rPjC by splenocytes from mice immunized with rPar j 1 was comparable to that stimulated by rPar j 1. Immunization with rPjC induced low levels of IgE antibodies to the rPjC itself, while IgG and proliferative responses were similar to those induced by rPar j 1.

CONCLUSION

Conformational variants of allergens, displaying reduced allergenicity accompanied by retained IgG and T cell recognition, offer a safe, specific and flexible approach to immunotherapy of type I allergy. Our mouse model of IgE sensitization to a recombinant allergen, mimicking the human response to its native counterpart, could provide valuable information for pre-clinical testing of such hypoallergenic molecules.

Comparison between the native glycosylated and the recombinant Cup a1 allergen: role of carbohydrates in the histamine release from basophils

BACKGROUND

Cypress pollinosis is an important cause of respiratory allergies. Recently, the Cupressus arizonica major allergen, Cup a1, has been cloned and expressed. The native counterpart of this allergen has been purified and characterized by our group. It has been suggested that sugar moieties play a role in the in vitro IgE binding on Cupressus arizonica pollen extract.

OBJECTIVE

To characterize the immunoreactivity of the recombinant major allergen in comparison with its native counterpart. To evaluate the role of carbohydrate moieties in the IgE-mediated in vitro histamine release from basophils by using the native glycosylated Cup a1 as compared with the recombinant one.

METHODS

Recombinant Cup a1 was expressed in E. coli. IgE reactivity of Cupressaceae-allergic patients on the native as well as the recombinant molecule was investigated by immunoblotting, ELISA experiments and histamine release test from passively sensitized basophils.

RESULTS

Fourteen out of 17 Cup a1-positive sera had IgE antibodies reactive with the native molecule only and lost their reactivity-after periodate deglycosylation of the allergen. Moreover, only native molecule was capable of inducing histamine release by this group of sera. Both the recombinant and the native molecules were recognized by three out of the 17 sera and were equally capable of triggering degranulation.

CONCLUSION

A large number of sera reactive with the major allergen recognize carbohydrate epitopes only. IgE from these sera are able to induce histamine release from basophils and they might play a functional role in the clinical symptoms of allergy.

Preparation and characterization of silverfish (Lepisma saccharina) extract and identification of allergenic components

BACKGROUND

Airborne insect antigens represent important aeroallergens which have been widely investigated. Although it has been demonstrated that house dust contains significant silverfish (Lepisma saccharina) levels, none of the extracts obtained so far has been extensively characterized. Thus, we have prepared and characterized a silverfish extract and investigated its IgE-reactive components by testing the reactivity of sera from patients allergic to inhalant insect allergens.

METHODS

The extract from silverfish insect bodies was prepared by homogenizing frozen silverfish in Tris-HCl buffer. The soluble material (Sup) was filtered and the insoluble material (Ppt) was resuspended in 100 mM Tris pH 10.6. The two fractions were characterized by biochemical and immunochemical methods. IgE reactivity was investigated on both fractions before and after periodate treatment.

RESULTS

Protein content and total carbohydrates was 2 and 3% w/w for Sup and 1 and 0.3% w/w for Ppt. The SDS-PAGE profile of the two fractions showed a different pattern in the MW range of 5-175 kD. Sup and Ppt, probed with allergic sera, showed a complex pattern of IgE reactivity. When periodate-treated fractions were tested, IgE reactivity was either completely abrogated, reduced or not affected, depending on the allergic serum employed.

CONCLUSIONS

The results obtained indicate that the classic aqueous-extraction procedures that have been used up to now for other insects might not be completely satisfactory, since several allergenic components are not soluble at the normally used pH. We developed a dedicated extraction procedure allowing the detection of a certain degree of reactivity in sera negative to allergens extracted following classic procedures.

Rapid isolation, characterization, and glycan analysis of Cup a 1, the major allergen of Arizona cypress (Cupressus arizonica) pollen

BACKGROUND

A rapid method for the purification of the major 43-kDa allergen of Cupressus arizonica pollen, Cup a 1, was developed.

METHODS

The salient feature was a wash of the pollen in acidic buffer, followed by an extraction of the proteins and their purification by chromatography. Immunoblotting, ELISA, and lectin binding were tested on both the crude extract and the purified Cup a 1. Biochemical analyses were performed to assess the Cup a 1 isoelectric point, its partial amino-acid sequence, and its glycan composition.

RESULTS

Immunochemical analysis of Cup a 1 confirmed that the allergenic reactivity is maintained after the purification process. Partial amino-acid sequencing indicated a high degree of homology between Cup a 1 and allergenic proteins from the Cupressaceae and Taxodiaceae families displaying a similar molecular mass. The purified protein shows one band with an isoelectric point of 5.2. Nineteen out of 33 sera (57%) from patients allergic to cypress demonstrated significant reactivity to purified Cup a 1. MALDI-TOF mass spectrometry indicated the presence of three N-linked oligosaccharide structures: GnGnXF(3) (i.e., a horseradish peroxidase-type oligosaccharide substituted with two nonreducing N-acetylglucosamine residues), GGnXF(3)/GnGXF(3) (i.e., GnGnXF with one nonreducing galactose residue), and (GF)GnXF(3)/Gn(GF)XF(3) (with a Lewisa epitope on one arm) in the molar ratio 67:8:23.

CONCLUSION

The rapid purification process of Cup a 1 allowed some fine studies on its properties and structure, as well as the evaluation of its IgE reactivity in native conditions. The similarities of amino-acid sequences and some complex glycan stuctures could explain the high degree of cross-reactivity among the Cupressaceae and Taxodiaceae families.

Hypoallergenic variants of the Parietaria judaica major allergen Par j 1: a member of the non-specific lipid transfer protein plant family

BACKGROUND

Par j 1 represents a major allergenic component of Parietaria judaica (Pj) pollen, since it is able to induce an immunoglobulin E (IgE) response in 95% of Pj-allergic patients. It belongs to the non-specific lipid transfer protein family, sharing with them a common three-dimensional structure.

METHODS

Disulphide bond variants of the recombinant Par j 1 (rPar j 1) allergen were generated by site-directed mutagenesis, and the immunological activity of rPar j 1 and its conformational mutants was compared with the use of the skin prick test (SPT). The ability to bind IgE antibodies was evaluated by Western blot, ELISA and ELISA inhibition. T cell reactivity was measured by peripheral blood mononuclear cell proliferation assay.

RESULTS

The disruption of Cys14-Cys29 and Cys30-Cys75 bridging (PjA mutant) caused the loss of the majority of specific IgE-binding activity. Additional disruption of the Cys4-Cys52 bridge (PjC mutant) and the latter Cys50-Cys91 bridge (PjD mutant) led to the abolition of IgE-binding activity. On the SPT, PjB (lacking the Cys4-Cys52 and Cys50-Cys91 bridges) was still capable of triggering a type I hypersensitive reaction in 9 out of 10 patients, and PjA in 3 out of 10 patients, while PjC and PjD did not show any SPT reactivity. All the mutants preserved their T cell reactivity.

CONCLUSION

Recombinant hypoallergenic variants of the rPar j 1 allergen described herein may represent a useful tool for improved immunotherapy.

Cupressaceae pollinosis: identification, purification and cloning of relevant allergens

Allergy to Cupressaceae pollen is a worldwide pollinosis caused by several species. Pollen extracts prepared from allergenic species belonging to this family are characterised by low protein and high carbohydrate content. The allergenic components represented in the pollen extracts from different species of the Cupressaceae family show high levels of cross-reactivity when probed with human IgE from allergic subjects and share a number of common epitopes also identified by polyclonal rabbit antisera and monoclonal antibodies. A close relationship has also been described with the Taxodiaceae and Podocarpaceae families. Although both proteic and carbohydrate epitopes appear to be involved in IgE recognition and allergenic cross-reactivity, a large portion of the IgE reactivity of Cupressaceae-allergic patients seems to be associated with sugar moieties present on the relevant allergenic molecules. From this point of view, Cupressaceae/Taxodiaceae allergens constitute a particularly useful model to study IgE cross-reactivity, as they have been shown to display different levels of homology. Moreover, the availability of the purified allergens, together with their recombinant counterparts, may shed light on the actual role played by carbohydrate in allergic sensitisation, IgE recognition and allergenic cross-reactivity.

Effect of lifestyle, smoking, and diet on development of intestinal metaplasia in H. pylori-positive subjects

OBJECTIVES

This study aimed to evaluate the influence of environmental and sociodemographic factors and the effect of smoking, alcohol, and dietary habits on the risk of gastric intestinal metaplasia (IM) in Helicobacter pylori-infected subjects.

METHODS

The investigation was based on 2598 consecutive volunteer blood donors tested for the presence of antibodies against H. pylori from March 1995 to March 1997. Endoscopy with multiple biopsies was offered to all H. pylori-positive, symptomatic subjects. The presence or absence of IM was diagnosed by gastric biopsies. A serologically H. pylori-positive subject with gastric IM was defined as a case, whereas serologically H. pylori-positive subjects without IM were used as controls. All patients answered a detailed questionnaire collecting sociodemographic characteristics and smoking, alcohol drinking, and dietary habits. Odds ratios (ORs) and their 95% CIs were estimated by unconditional logistic regression, including terms for age and sex, to assess the association between the data collected and IM.

RESULTS

Three hundred forty-four subjects with serological H. pylori infection and upper-GI symptoms underwent GI endoscopy, during which biopsies were taken for histological diagnosis. Histology revealed metaplasia in 74 subjects (21.5%). Incomplete IM was found in 37.8% of these cases. No significant associations were found between IM and anthropometric or sociodemographic factors. There was a significant association between age and IM (chi2 for trend, 6.67; p value, 0.009). Current smokers of over 20 cigarettes per day had a 4-fold risk of IM (OR, 4.75, 95% CI, 1.33-16.99). A 2-fold increased risk was found for high butter consumers (OR, 2.17; 95% CI, 1.14-4.11). No significant specific associations were found between the variables studied and complete or incomplete IM.

CONCLUSIONS

This study found that smoking and high butter consumption may increase the risk of having gastric IM in H. pylori-positive subjects.

A monoclonal antibody specific for a carbohydrate epitope recognizes an IgE-binding determinant shared by taxonomically unrelated allergenic pollens

Carbohydrate epitopes are capable of binding human IgE from allergic subjects and these epitopes play a role in the cross-reactivity between allergens from unrelated sources. A monoclonal antibody (5E6), specific for a carbohydrate epitope detectable on components of Cupressus arizonica pollen extract, has been produced and characterized. To study the relationship between the epitopes recognized by the monoclonal antibody and by IgE from allergic subjects. To investigate the presence of such carbohydrate IgE determinant in extracts from 21 pollen species belonging to 16 taxonomically related and unrelated families, by means of the monoclonal antibody. IgG-depleted fraction from protein G-purified human allergic serum was obtained. The monoclonal antibody and the IgE from the purified fraction were tested on two glycoproteins, polyamine oxidase and ascorbate oxidase, adsorbed on the ELISA plates. The relationship between the monoclonal- and the IgE-recognized epitopes was investigated by ELISA-competition experiments. Analysis of the distribution of this carbohydrate epitope was performed by direct binding of the monoclonal antibody onto the various extracts. The monoclonal antibody and the IgE were able to bind carbohydrate epitopes on the two plant glycoproteins, ascorbate oxidase and polyamine oxidase. Polyamine oxidase shows only one N-glycosilation site whose carbohydrate moiety seems to be composed of a branched chain of seven ordered sugars, i.e. two N-acetyl-D-glucosamine-, three mannose-, one fucose- and one xylose-residues. This structure bears the epitope recognized by mAb 5E6. Human IgE from the IgG-depleted fraction were found capable of inhibiting the monoclonal antibody binding. The allergenic epitope identified was shared by a large number of extracts with different levels of reactivity (OD490 ranging from 0.110 to 2.060). Our data support the finding that a monoclonal antibody specific for a carbohydrate epitope of Cupressus arizonica pollen extract detects an epitope which is also recognized by IgE from allergic subjects. This characterized reagent could be a useful tool for studying distribution of cross-reactive carbohydrate determinants in allergenic pollen extracts and their components.

Five-year survival results of subcutaneous low-dose immunotherapy with interleukin-2 alone in metastatic renal cell cancer patients

After the discovery of its essential role in anticancer immunity, IL-2 cancer immunotherapy has shown that comparable results may be obtained with different schedules, including intravenous high-dose IL-2 as a bolus or as a 24-hour intravenous infusion or prolonged subcutaneous injection of low-dose IL-2 with or without IFN-alpha. This study shows the long-term results obtained in 92 metastatic renal cell cancer (RCC) patients with low-dose subcutaneous IL-2, which was given at 3 million IU twice/day for 5 days/week for 6 consecutive weeks. In nonprogressing patients, a second cycle was planned after a 21-day rest period, followed by maintenance therapy consisting of 5 days of treatment every month until disease progression. Complete response (CR) was achieved in only 2/92 (2%) patients, and partial response (PR) was observed in 19 patients (21%). Therefore, the response rate (CR + PR) was 21/92 (23%), with a median duration of response of 25 months. Stable disease (SD) occurred in 37 patients (40%), whereas the other 34 (37%) had a progressive disease (PD). The response rate was significantly higher in patients with a disease-free interval of >1 year than in those with a lower interval, in patients with a high performance status (PS) than in those with a low PS, and in patients with sites of disease other than the liver. A 5-year survival was obtained in 9/92 (9%) patients, and the percent of survival was significantly higher in patients with a response or SD than in those with PD. The treatment was well tolerated in all patients. This study confirms that low-dose subcutaneous IL-2 alone in an effective and well tolerated therapy of metastatic RCC, with results comparable to those described with more aggressive and toxic IL-2 schedules.

Allergenicity of mare's milk in children with cow's milk allergy

BACKGROUND

Cow's milk allergy is a common disease of infancy and early childhood. If the baby is not breast-fed, a substitute for cow's milk formula is necessary.

OBJECTIVE

The aim of this study was to investigate, in vitro and in vivo, the allergenicity of mare's milk in a population of selected children with severe IgE-mediated cow's milk allergy.

METHODS

Twenty-five children (17 male and 8 female) aged 19 to 72 months (median age 34 months) with IgE-mediated cow's milk allergy were selected for this study. All the children underwent skin prick tests with cow's milk and mare's milk and double-blind placebo-controlled oral food challenge (DBPCOFC) with fresh cow's milk, fresh mare's milk, and, as placebo, a soy formula (Isomil, Abbott, Campoverde, Italy). We performed immunoblotting of cow's and mare's milk developed with IgE from allergic children.

RESULTS

All the children showed strong positive skin test responses to cow's milk (4+); 2 children had positive skin test responses to mare's milk (2+). All children had positive DBPCOFCs to cow's milk; one child had a positive DBPCOFC to mare's milk. No children reacted to the placebo (Isomil). In the cow's milk, some proteins are able to strongly react with human IgE; when the sera are tested with mare's milk, the bands corresponding to the same proteins are recognized by a lower percentage of sera.

CONCLUSION

These data suggest that mare's milk can be regarded as a good substitute of cow's milk in most children with severe IgE-mediated cow's milk allergy. It would be prudent, however, to confirm its tolerability by a supervised titrated oral challenge test.

[Functional status of intestinal t lymphocytes, regulatory mechanisms, and their variations in the course of Crohn disease and ulcerative colitis]

We analyzed the phenotype, proliferative responsiveness, cytokine production and apoptosis susceptibility of lamina propria lymphocytes to different activation pathways. Lamina propria lymphocytes is a population enriched of activated lymphocytes showing a "memory" phenotype. As opposite to peripheral blood lymphocytes, lamina propria lymphocytes show proliferative hyporesponsiveness when stimulated via TCR/CD3 pathway while proliferative response to the CD2 activation pathway is relatively preserved. Under the latter activation pathway, cytokine production, especially IL-4 and IFN-gamma, is higher than that observed in peripheral lymphocytes. When compared to controls, lamina propria lymphocytes isolated from inflammatory bowel disease (Crohn's disease and ulcerative colitis) show distinctive variation in the cytokine production. In particular, Crohn's disease is characterized by an increased production of IFN-gamma, while in ulcerative colitis an increased production of IL-5 is observable. Among the different regulatory mechanisms contributing to maintain immunological homeostasis we analyzed the susceptibility to apoptosis of lamina propria lymphocytes. We found that CD2-activation pathway is regulated by Fas-mediated apoptosis, which regulates proliferation and cytokine production. In inflammatory bowel disease this apoptosis is defective thus contributing to the chronic inflammation and cytokine dysregulation.

Determinants of Helicobacter pylori seroprevalence among Italian blood donors

BACKGROUND/AIM

Helicobacter pylori is a worldwide infection. It is estimated that approximately 50% of the general population is affected, but this percentage varies considerably between countries. To investigate the prevalence of H. pylori infection, a cross-sectional epidemiological study, based on the serological determination of the IgG antibodies against H. pylori, was carried out in healthy Italian blood donors by using a commercially available kit.

METHODS

From March 1995 to March 1997, a total of 2598 consecutive volunteer blood donors were tested for the presence of antibodies against H. pylori. All patients answered a detailed questionnaire which collected sociodemographic characteristics, and smoking, alcohol drinking and dietary habits. Test-positive subjects with gastrointestinal symptoms underwent endoscopy, with biopsies taken for histological diagnosis.

RESULTS

The global prevalence of H. pylori infection in our study was 1161/2598 (45%). It was directly correlated with age (67% in subjects aged > or = 50 years). The prevalence of H. pylori infection was higher in men (46.4%) than women (38.4%), and more frequent in patients with a low educational level, in the lower quintile of height and in the upper quintile of body mass index (BMI). No significant association with smoking and alcohol drinking was found. Inverse associations were found with elevated consumption of milk (chi-square for trend 5.49, P < 0.05), but not other examined food groups. Multivariate analysis selected sex, age, BMI and educational level as the variables independently related to H. pylori infection.

CONCLUSION

This study confirms relatively high prevalence of H. pylori seropositivity among Italian healthy adults and points to sex, age, BMI and sociocultural class as persisting determinant features of H. pylori infection.

Role of carbohydrate moieties in IgE binding to allergenic components of Cupressus arizonica pollen extract

BACKGROUND

A reduction of IgE immunoreactivity after periodate-treatment has been previously reported for various glycoprotein allergens.

OBJECTIVE

The aim of this study was to investigate the role of glycan moiety of a C. arizonica extract in the binding of patients' IgE and to identify the carbohydrates possibly involved.

METHODS

The reactivity of IgE with C. arizonica extract, before and after periodate-treatment, was evaluated by immunoblotting and ELISA inhibition. The specificity of carbohydrate-reactive IgE was evaluated by ELISA using unrelated glycoproteins with known sugar composition and structure, such as pineapple bromelain, honeybee venom phospholipase A2, and ovalbumin, before and after periodate treatment.

RESULTS

When periodate-treated C. arizonica extract was probed after SDS-PAGE and immunoblotting with patients' IgE, no reactivity could be detected. Furthermore, a very poor inhibitory activity of the periodate-treated C. arizonica extract as compared with the untreated sample could be observed in the ELISA inhibition experiments performed using C. arizonica extract as antigen. When phospholipase A2 and bromelain were used as antigens in ELISA, they were recognized by patients' IgE, whereas ovalbumin was negative. Treatment of phospholipase A2 and bromelain with periodate completely abolishes the IgE reactivity.

CONCLUSION

A large portion of the IgE reactivity of Cupressaceae-allergic subjects appears to be associated with sugar moieties of C. arizonica extract which appear to be shared by bromelain and phospholipase A2, thus suggesting that the IgE of patients reacting with such epitopes probably react with beta 1 --> 2 xylose, alpha 1 --> 3 fucose and/or alpha 1 --> 6 fucose.

Specific IgE to cross-reactive carbohydrate determinants strongly affect the in vitro diagnosis of allergic diseases

BACKGROUND

Cross-reacting carbohydrate determinants (CCDs) are antigenic structures shared by allergenic components from taxonomically distant sources. The case history of a patient with a great discrepancy between skin test and specific IgE results led us to investigate the role of these determinants in his specific case and in an allergic population.

OBJECTIVE

We sought to determine the role of CCDs in causing false-positive and clinically irrelevant results in in vitro tests.

METHODS

The involvement of CCDs was studied by specific IgE inhibition by using glycoproteins with a known carbohydrate structure. Direct and inhibition assays were performed by commercially available systems, in-house ELISA, and the immunoblotting technique. The binding to the periodate-oxidated carbohydrate structure of glycoproteins and allergenic extracts was also evaluated. A comparative study between skin test and specific IgE responses to the antigens studied was carried out in 428 consecutive allergic subjects.

RESULTS

All the tests performed suggested that cross-reacting carbohydrate epitopes were the cause of false-positive specific IgE results in one of the commercial systems and the high reactivity in all the solid-phase in vitro tests. None of the cross-reacting carbohydrate allergens yielded a positive skin test response. Periodate treatment caused variable degrees of reduction of IgE binding to the different antigens studied, indicating that CCDs played a different role in each of them. About 41% of patients allergic to pollen had specific IgE for a glycoprotein, without a positive skin test response to the same molecule.

CONCLUSIONS

CCDs must be taken into account when evaluating the clinical relevance of positive results in in vitro specific IgE assays, at least in the diagnosis of patients with pollen allergy. Commercial systems should be carefully assessed for the ability to detect specific IgE for carbohydrate determinants to avoid false-positive or clinically irrelevant results.

Results of EUS in detecting perirectal lymph node metastases of rectal cancer: the pathologist makes the difference

BACKGROUND

Accurate preoperative staging of primary rectal cancer is mandatory because the result may affect therapeutic decisions. Endoscopic ultrasonography (EUS) is considered the most accurate method for locoregional staging, but the issue of possible variations in the assessment of its accuracy related to technical aspects of pathologic staging has never been raised. The aim of this study was to assess EUS results as determined by two different methods of dissection of surgical specimens.

METHODS

Among all cases with primary rectal cancer staged with EUS from April 1991 to April 1997, 131 patients underwent surgery without preoperative radiotherapy; EUS results for nodal staging were compared with those obtained by pathology. Resected specimens were examined using two different techniques (conventional vs. special dissection).

RESULTS

There was a significant decrease in diagnostic accuracy of EUS according to pathologic technique. Overall accuracy, sensitivity, specificity, positive and negative predictive values for conventional versus special dissection were as follows: 74.6% vs. 43. 3% (p = 0.0001), 67.8% vs. 21.8% (p = 0.0002), 79.1% vs. 67.8% (p = 0.14), 67.8% vs. 43.7% ( p = 0.02), and 79.1% vs. 43.2% (p = 0.0003), respectively. EUS sensitivity according to size of metastatic lymph nodes was significantly lower for nodes smaller than 5 mm in diameter (p = 0.025) when special dissection was performed because of a larger number of lymph nodes harvested.

CONCLUSIONS

Our findings raise concern about the results of EUS staging of lymph node metastases in rectal cancer. Further prospective studies on a node-by-node basis could clarify the real diagnostic yield of EUS.

Pretreatment serum markers and lymphocyte response to interleukin-2 therapy

Lymphocytosis is a marker of subcutaneous interleukin (IL)-2 therapy efficacy, whereas baseline elevated inflammatory indices were noticed in IL-2-resistant disease. The aim of this study was to analyse the relationship between pretreatment circulating values of IL-6, neopterin, sIL-2R, ESR and the changes in lymphocyte number in response to IL-2 administration. Twenty metastatic renal cell cancer patients were treated with subcutaneous IL-2 immunotherapy (6 000 000 IU day(-1) for 6 days per week for 4 weeks); tumour response consisted of partial response (PR) in four patients, stable disease (SD) in eight patients and progressive disease (PD) in eight patients. Abnormally high pretreatment values of each marker were found as follows: IL-6 in seven patients, neopterin in nine patients, sIL-2R in 13 patients. In response to IL-2 immunotherapy, a significantly higher mean increase in lymphocyte number and a higher percentage of patients with tumour response or stable disease were observed when pretreatment values of IL-6, neopterin and sIL-2R were within the normal range, in comparison to patients with high values for these markers. The pretreatment excess of these serum inflammatory markers seems to negatively influence both the host and tumour response to IL-2 administration, by preventing the IL-2-induced lymphocytosis and resulting in tumour progression. Further studies are requested to verify if overall survival and quality of life may depend on pretreatment host immune status and/or lymphocyte response after IL-2 administration.

Lamina propria T cells in Crohn's disease and other gastrointestinal inflammation show defective CD2 pathway-induced apoptosis

BACKGROUND & AIMS

Normal human lamina propria lymphocytes manifest increased unstimulated apoptosis compared with peripheral lymphocytes, which are enhanced after stimulation via the CD2 activation pathway. This activation-induced apoptosis down-regulates cell expansion and cytokine production. In previous studies, it was shown that lamina propria T cells from patients with Crohn's disease and ulcerative colitis manifest abnormal proliferation and cytokine production. It was therefore of interest to determine if such cells also showed abnormal patterns of apoptosis.

METHODS

Apoptosis was evaluated by propidium iodide staining of cells followed by flow cytometric analysis. Fas expression and Bcl-2 levels in cells were evaluated by immunofluorescence.

RESULTS

Lamina propria lymphocytes from patients with Crohn's disease and ulcerative colitis as well as from 2 patients with diverticulitis showed defective CD2 pathway-induced apoptosis. Studies of the mechanisms of this defect focusing on cells from patients with Crohn's disease showed that Crohn's disease lamina propria lymphocytes from inflamed tissues express the same amount of cell surface Fas but are less sensitive to Fas-mediated apoptosis than control cells. In addition, lamina propria lymphocytes from inflamed Crohn's disease tissues manifest increased expression of Bcl-2 after CD2 pathway stimulation and elevated Bcl-2 levels in cultures of unstimulated T cells.

CONCLUSIONS

T cells isolated from areas of inflammation in Crohn's disease, ulcerative colitis, and other inflammatory states manifest decreased CD2 pathway-induced apoptosis. Studies of cells from inflamed Crohn's disease tissue indicate that this defect is accompanied by elevated Bcl-2 levels. These changes are probably caused by the chronic inflammation and may aggravate the underlying disease processes that are present.

Use of antagonist peptides to inhibit in vitro T cell responses to Par j1, the major allergen of Parietaria judaica pollen

Antigenic peptides with substituted side chains inhibit immune responses to a number of recall Ags from infectious agents in vitro. Here we show that the same strategy can be applied to peptides derived from a pollen protein, the major allergen of Parietaria judaica(Par j1), a plant responsible for most allergenic sensitization in the southern Mediterranean area. Three T cell lines responding to Par j1 protein were used to identify a stimulatory peptide. Two different monosubstituted altered peptide ligands (APL) were identified that bound to the HLA-DR of the responders, did not stimulate the T cell lines on their own, and decreased the response to subsaturating amounts of the unmodified stimulatory peptide. Most important, these APL were able to inhibit the response of these cell lines to intact Par j1 protein. A third monosubstituted peptide bound to the HLA-DR but did not show inhibitory activity. The two APL had a lower affinity than the unsubstituted peptide for the HLA-DR. The last two observations make MHC blockade an unlikely explanation for the observed effect. These results indicate the action of a specific peptide-mediated antagonism that may be useful in controlling the T cell component of an allergic response.

In vivo stimulation of IL-12 secretion by subcutaneous low-dose IL-2 in metastatic cancer patients

Despite the well-demonstrated involvement of both interleukin 2 (IL-2) and interleukin 12 (IL-12) in the activation of host anti-cancer response, the knowledge of IL-2-IL-12 interactions has still to be better investigated. This study was performed to evaluate the effects of subcutaneous (s.c.) low-dose IL-2 on IL-12 secretion in metastatic cancer patients. The study included 19 evaluable metastatic renal cell cancer patients, who received s.c. low-dose IL-2 (6 MIU day(-1) for 6 days per week for 4 weeks) as a first-line immunotherapy of their metastatic disease. Serum levels of IL-12 were measured using an enzyme immunoassay on venous blood samples collected before the immunotherapy and at 1-week intervals. The clinical response consisted of partial response (PR) in four and stable disease (SD) in eight patients, whereas the other seven patients progressed. Mean serum levels of IL-12 observed in the overall patients significantly increased in response to IL-2 injection. Moreover, by evaluating IL-12 variations in relation to the clinical response, a marked significant increase in IL-12 mean values occurred in patients with response or SD, whereas the progressing patients showed a significant decline in IL-12 levels during IL-2 administration. Finally, IL-12 mean pretreatment values observed in patients who progressed were significantly higher than those seen in non-progressing patients. This study shows that low-dose IL-2 immunotherapy of cancer may stimulate the in vivo release of IL-12, and it would suggest that IL-2-induced IL-12 enhancement is associated with a favourable prognosis.

Juniperus oxycedrus: a new allergenic pollen from the Cupressaceae family

BACKGROUND

Cupressaceae allergy is a worldwide pollinosis caused by several species. Some species in limited geographic areas pollinate in fall and winter. Juniperus oxycedrus matches these features.

OBJECTIVE

We sought to define the immunochemical, allergologic, and environmental aspects of J. oxycedrus pollen.

METHODS

Pollen extract from J. oxycedrus was prepared and characterized by biochemical analysis and human specific IgE binding by means of ELISA and immunoblotting. A 3-year phenological study was conducted to define the pollinating period of J. oxycedrus. Forty consecutive patients allergic to cypress were recruited in two areas and divided into two groups according to their exposure to J. oxycedrus pollen. Clinical evaluation, skin prick tests, and specific IgE determination with J. oxycedrus, J. ashei, and Cupressus arizonica extracts were carried out on both groups.

RESULTS

J. oxycedrus pollen extract was obtained, and it showed specific IgE binding and wide cross-reactivity with other Cupressaceae species. The extract caused a positive skin test response in all the patients tested, with about 80% of them having detectable specific IgE. Symptoms related to J. oxycedrus pollen exposure were recorded in 72% of the directly exposed patients and occasionally in 9% of the nonexposed patients. In the Mediterranean coastal area considered, J. oxycedrus was the first Cupressaceae species that started to pollinate at the beginning of November and ended in the first part of December.

CONCLUSIONS

J. oxycedrus represents a newly characterized pollen species of the Cupressaceae family that cross-reacts with other members of the same family. Subjects with cypress allergy have in vivo and in vitro positive test responses for J. oxycedrus and can show symptoms when exposed to its pollen. Finally, the most important feature of J. oxycedrus is its early pollinating period in southern Europe (Italy), causing a further extension of the cypress pollen season in areas where other Cupressaceae species are present.

Molecular characterization of a cross-reactive Juniperus oxycedrus pollen allergen, Jun o 2: a novel calcium-binding allergen

BACKGROUND

Species belonging to the Cupressaceae family are a relevant source of allergens that are present in a wide number of countries.

OBJECTIVE

We sought to identify, purify, and characterize recombinant allergens from Juniperus oxycedrus, a species belonging to the Cupressaceae family.

METHODS

Double-stranded cDNA was synthesized from mRNA and cloned into the lambda-ZAP expression vector. IgE screening of the library was performed with a pool of sera from subjects allergic to Cupressaceae. A recombinant 6xHis-tagged Juniperus oxycedrus allergen, Jun o 2, was expressed in Escherichia coli and purified by Ni2+ affinity chromatography. It was studied further by immunoblotting inhibition with pollen extracts from other Cupressaceae, Oleaceae, Urticaceae, and Graminaceae. The role of protein-bound calcium on the allergen's IgE-binding capacity was tested in a plaque assay in the presence or absence of EGTA.

RESULTS

A cDNA coding for a newly identified Juniperus oxycedrus pollen allergen, rJun o 2, was isolated. The deduced amino acid sequence contained four typical Ca2+ binding sites and showed a significant sequence similarity to calmodulins. Depletion of Ca2+ in the plaque assay led to a loss of IgE-binding capacity of rJun o 2. Immunoblotting inhibition revealed that J. oxycedrus, J. ashei, Cupressus arizonica, C. sempervirens, Parietaria judaica, Olea europaea, and Lolium perenne pollen extracts were able to inhibit IgE binding to blotted rJun o 2 at different concentrations.

CONCLUSION

rJun o 2 contains IgE-binding epitopes shared by taxonomically unrelated species, and therefore it can be regarded as a new panallergen. These findings could contribute to an explanation for the phenomenon of multiple positive test results in polysensitized patients and the potential symptom-eliciting role of allergenic sources previously not encountered.

Arizona cypress (Cupressus arizonica) pollen allergens. Identification of cross-reactive periodate-resistant and -sensitive epitopes with monoclonal antibodies

Species of the Cupressaceae family are a worldwide cause of respiratory allergies. We used monoclonal antibodies (mAbs) to investigate the presence and the nature of cross-reacting epitopes shared by various components within Cupressus arizonica pollen extract (CaE) or by CaE and pollen extract from C. sempervirens (CsE). mAbs were produced in mice immunized with whole CaE (4A6 and 5E6) or with the major allergen components (2D5). Their reactivity was investigated by ELISA and immunoblotting before and after CaE periodate treatment. Cross-reactivity was evaluated by ELISA inhibition and immunoblotting. mAbs 2D5 and 4A6 recognized periodate-resistant epitopes, whereas the mAb 5E6 reacted with a periodate-sensitive determinant. The former mAbs recognized epitopes present on CaE major allergen and also shared by other components. mAb 5E6 showed a spread reactivity on CaE, with exclusion of the major allergen. When the three mAbs were tested with CsE, a restricted pattern of reactivity to mAbs 2D5 and 4A6 was obtained, whereas mAb 5E6 maintained a spread reactivity. The CaE major allergen is represented by two components recognized by human IgE and sharing common epitopes, as proven by mAbs reactivity. The use of these mAbs demonstrates that cross-reactivity within CaE components and between CaE and CsE is due to the presence of periodate-sensitive as well as -resistant epitopes.

Initial chemotherapy for primary resectable large-cell lymphoma of the stomach

BACKGROUND

We aimed to evaluate the safety and effectiveness of a conservative approach with short-term chemotherapy with or without consolidation radiotherapy in primary resectable large-cell gastric lymphoma in patients not requiring emergency surgery at presentation.

PATIENTS AND METHODS

Seventeen consecutive patients presenting with resectable primary large-cell lymphoma of the stomach not requiring immediate surgery were initially treated with chemotherapy with or without consolidation radiotherapy. Subtotal or total resection of the stomach was planned only as salvage treatment for those patients who failed locally, or as emergency surgery in instances of acute iatrogenic complications of treatment. Chemotherapy included four to six cycles of an anthracycline-containing regimen, and consolidation radiotherapy was planned on the entire stomach and surrounding lymph node areas for complete responders readily capable of compliance with a daily treatment schedule at our Institution.

RESULTS

None of the patients in the present series experienced acute iatrogenic morbidity or mortality from local complications. After a median follow-up of almost six years, two patients failing first-line chemotherapy have died of progressive lymphoma, while 15 patients are well and currently disease-free.

CONCLUSIONS

Up-front chemotherapy as initial treatment for primary gastric large-cell lymphoma appears to be a safe and effective treatment by which most patients can probably be spared surgical gastrectomy. Consolidation radiation therapy on the stomach can probably improve on the effectiveness of chemotherapy alone. More experience is needed to elucidate the prognostic factors, treatment-related long-term toxic effects and the feasibility of such a treatment administered outside of highly specialized institutions.

Reactivation of a normal endogenous secretion of interleukin-2 in metastatic cancer patients by a chronic subcutaneous injection of interleukin-2

It is known that advanced cancer patients may show abnormally low levels of IL-2. The immunotherapy with IL-2 can induce objective tumor regressions, but at present there are no data about the influence of a chronic exogenous IL-2 administration on endogenous secretion of IL-2. This preliminary study was performed to evaluate whether a prolonged IL-2 injection may be able to correct an eventual IL-2 endogenous deficiency in cancer patients. The study included 10 metastatic renal cancer patients, who underwent an immunotherapeutic cycle consisting of IL-2 at 6 million IU/day subcutaneously for 6 days/week for 4 weeks. Serum levels of IL-2 evaluated on venous blood samples collected before and 21 days after the end of IL-2 injection. Before the onset of treatment, abonormally low levels of IL-2 were seen in 6/10 patients. In patients with response or stable disease, mean levels of IL-2 observed 21 days after IL-2 cycle were significantly higher than those seen before therapy, whereas no difference occurred in those who progressed. This preliminary study would suggest that a prolonged subcutaneous injection of low-dose IL-2 may correct an eventual IL-2 endogenous deficiency in advanced cancer patients.

Cross-reactivity between Cupressus arizonica and Cupressus sempervirens pollen extracts

BACKGROUND

Cupressus arizonica and C. sempervirens, two species belonging to the Cupressaceae family, are recognized as an important cause of respiratory allergies in countries with a Mediterranean climate.

OBJECTIVE

The relationship between pollen extracts from these two species was studied by evaluating the reactivity with polyclonal rabbit antisera and human IgE.

METHODS

The two extracts were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Cross-reactivity was evaluated by ELISA and immunoblotting inhibition experiments.

RESULTS

The electrophoretic patterns of the two extracts are quite different, although some components display identical molecular weights. The immunoblotting developed with human IgE from subjects allergic to members of the Cupressaceae family indicated that two major IgE-reactive components, displaying molecular weights of about 43,000 and 36,000 d, were similarly detected in both extracts. Inhibition experiments showed a high degree of crossreactivity between the two extracts when tested with rabbit polyclonal antibodies against C. arizonica and C. sempervirens. When tested with human IgE inhibition methods, both extracts were able to reciprocally inhibit all of the IgE-reactive bands, although C. arizonica extract was always a better inhibitor.

CONCLUSIONS

C. arizonica and C. sempervirens extracts are highly cross-reactive at the IgE level and share a number of common epitopes also identified by polyclonal rabbit antisera.

Assessment of skin prick test and serum specific IgE detection in the diagnosis of Cupressaceae pollinosis

BACKGROUND

There is increasing evidence for the relevance of Cupressaceae pollinosis among persons living in geographic areas where these species are native or imported.

OBJECTIVE

Previously reported problems in obtaining valid allergenic extracts to be used in the diagnosis of this winter pollinosis prompted us to assess the value of available Cupressaceae pollen extracts for in vivo and in vitro diagnosis.

METHODS

Commercial and in-house allergenic extracts from Cupressaceae and Taxodiaceae families were used for skin prick testing and specific IgE detection in six groups of subjects exposed to a high concentration of Cupressaceae pollen.

RESULTS

Four commercial and two in-house Cupressus sempervirens pollen extracts showed low cutaneous reactivity. Positive test results were recorded in 26% of the 713 subjects tested. C. arizonica in-house pollen extracts gave rise to larger cutaneous reactions. Furthermore, the skin prick test response was positive in a greater number of subjects (38%) of the same group. Six commercial immunoassays were able to detect specific IgE to C. sempervirens in rates ranging from 8.1% to 81.1%. Specific IgE to C. arizonica was detected by means of an in-house immunoenzymatic method in 70.3% of 54 patients with suspected "cypress" allergy, and specific IgE to C. sempervirens was detected in 75.9% of these patients by using a commercial system. High rates of cross-reactivity within the Cupressaceae family and with species of the Taxodiaceae family were recorded with both in vivo and in vitro tests.

CONCLUSIONS

The use fo C. sempervirens in vivo diagnostics should be carefully evaluated until better characterized extracts are developed. In-house-characterized extracts of C. arizonica seem to be more reliable in the diagnosis of Cupressaceae allergy by means of skin prick testing. the sensitivity of commercially available in vitro methods to detect specific IgE to C. sempervirens should be carefully evaluated; nevertheless, valid results can be obtained with some already available immunoassays.

Parietaria judaica-specific T-cell clones from atopic patients: heterogeneity in restriction, V beta usage, and cytokine profile

The pollen of Parietaria spp. is one of the most clinically relevant sources of allergens in the Mediterranean area. CD4+ T-lymphocyte clones specific for Parietaria allergens were isolated from peripheral blood of atopic donors, and their phenotype, HLA restriction, V beta usage, and cytokine profile were determined. All the T-cell clones expressed the alpha/beta T-cell receptor and were induced to express CD40 ligand after activation with phorbol-myristate-acetate plus ionomycin. When the proliferative response to three chromatographic fractions of the extract was analyzed, distinct reactivity patterns were found. Interestingly, most of the clones responded to the fraction that was the most enriched for the major allergen Par j 1. The clones were either HLA-DR- or HLA-DQ-restricted and did not show any preferential usage of T-cell receptor V beta segments. Five of the 17 clones tested produced only IL-4 and no interferon-gamma, thus displaying a TH2 phenotype. The other clones displayed a TH0 phenotype in that they produced both IL-4 and interferon-gamma. These results show that in atopic patients T-cell response against Parietaria judaica allergen involves different T-cell subsets in terms of restriction, V beta usage, and cytokine profile.

Use of monoclonal antibodies in the standardization of Parietaria judaica allergenic extracts

Two monoclonal antibodies (MoAb) specific for Parietaria judaica allergenic components were selected on the basis of their capability to recognize either the Parietaria judaica major allergen (MoAb 1A6/1D1) or several other allergenic components (MoAb 1A4/2F8) except the major allergen. These two antibodies, either individually or combined, were used to develop an ELISA-inhibition system using a reference Parietaria judaica extract (in-house Reference preparation, IHR). The assays performed with these reagents were firstly standardized by testing the IHR several times. A good reproducibility, evaluated both at the level of 50% inhibition values, and in terms of analysis of the variance of the slopes of the regression curves, was obtained. Subsequently, the potency of several Parietaria judaica extracts, either obtained by manufacturing companies or produced in other laboratories, was evaluated by these tests. Data obtained by interpolation with the IHR values and expressed in terms of arbitrary units (AU) were compared with those obtained by classical human IgE inhibition, performed with sera from allergic patients. Results indicate that the monoclonal antibodies produced in our laboratory can be successfully employed, either individually or combined, in the standardization of allergenic preparations in addition to, and possibly replacing, the classical IgE-based standardization procedures which require human specimens often available in limited amounts only.

In vitro production of cytokines by peripheral blood mononuclear cells from hydatid patients

The role of cytokines in human hydatidosis (Echinococcus granulosus infection) was evaluated in immunoassays determining production of IL-4, IL-10 and interferon-gamma (IFN-gamma) in peripheral blood mononuclear cell (PBMC) cultures from 30 hydatid patients and 14 uninfected controls. In cell cultures from hydatid patients parasite and non-parasite antigen stimulation significantly increased IL-4 production (P < or 0.005). Spontaneous and mitogen-driven IL-4 production was similar in patients and controls. IL-10 and IFN-gamma production did not differ statistically in the two groups, even though some hydatid patients produced these cytokines in large amounts. Notably, antigen-driven IFN-gamma concentrations were invariably higher in patients than in uninfected controls. Data analysis showed a relationship between IgE and IgG4 responses and parasite-driven cytokine production. High IgE and IgG4 responders produced high IL-4 and IL-10 concentrations. High IgE responders showed decreased IFN-gamma production, but high IgG4 responders had IFN-gamma levels slightly higher than those of low responders. Cytokine response patterns did not relate to the clinical stage of disease. The significantly increased IL-4 and the high IL-10 concentrations found in PBMC from many hydatid patients in this study are consistent with Th2 cell activation in human hydatidosis. The presence of antigen-driven IFN-gamma production in patients with E. granulosus infection implies concurrent intervention of the Th1 or Th0 cell subset.

Allergens of Arizona cypress (Cupressus arizonica) pollen: characterization of the pollen extract and identification of the allergenic components

Species of the Cupressaceae family are an important cause of respiratory allergies in countries with a Mediterranean climate. An allergenic extract from Cupressus arizonica pollen was prepared with two extraction steps followed by ammonium sulfate precipitation, giving a protein yield of about 3%. Cupressus arizonica pollen extract was also characterized by means of sodium dodecylsulfate-polyacrylamide gel electrophoresis, followed by IgE and IgG immunoblotting and lectin blotting. IgE reactivity was restricted to six components, whereas IgG binding showed a more complex pattern. A 43 kd component, predominant both in its intensity and frequency of recognition by human IgE antibodies, was identified as the major allergen of C. arizonica. Four of the six IgE-binding components, including the major allergen, seem to be glycoproteins, as confirmed by the lectin blotting analysis. The extract produced inhouse was used to set up an immunoenzymatic test to evaluate the specific IgE binding in a panel of sera from 33 immunotherapy-free subjects who were monosensitized to cypress pollen. The percent of positivity obtained was much higher than that reported in the literature for commercial immunoassays.

IgG subclass antibodies against Parietaria judaica in normal and allergic subjects

IgG antibody response to the inhalant allergen Parietaria judaica (Pj) and IgG subclass distribution were studied in 82 normal subjects, divided into three groups according to age (0-1, 1-20, and 20-60 years) and in 32 allergic subjects aged 20-60 years. Both normal and allergic subjects showed an IgG response, and all had IgG1 antibodies specific for PjE. Serum IgG2, IgG3, and IgG4 against PjE were detectable in 36%, 46%, and 22% of normal subjects, and in 58%, 31%, and 65% of allergic subjects, respectively. A significant difference in class distribution between allergic and age-matched normal subjects was found only for IgG4 antibodies against PjE (65% and 17%; P < 0.01). The ELISA results were also analyzed quantitatively, taking into account the relative proportion of specific antibodies. Thus, in normal subjects IgG1 antibodies showed a decreasing trend as the age rose, while no differences according to the age of the subject were found for IgG2 and IgG4. When data from allergic subjects (20-60 years) and the age-matched normal group were compared, they were different for the relative percentage of IgG2 only, showing for this a significantly lower value (P < 0.001). The present data indicate that normal and allergic subjects show differences in the IgG isotype distribution depending on their sensitivity and duration of allergen exposure.