C. Incorvaia

The major allergen of peach (Prunus persica) is a lipid transfer protein

BACKGROUND Allergy to fresh fruits and vegetables is mostly observed in subjects with pollinosis, especially from birch, because of cross-reacting allergens in vegetable foods and pollens. However, allergic reactions to fruits, specifically Rosaceae fruits, have been reported in subjects without pollinosis. OBJECTIVE This study evaluated the pattern of IgE reactivity, identifying the allergen responsible in 2 groups of patients with oral allergy syndrome to peach with or without birch pollinosis. METHODS The allergenic components of peach were detected by SDS-PAGE and immunoblotting. The major peach allergen was purified by HPLC with a cation-exchange column followed by gel filtration chromatography. Its IgE-binding capacity and its homology with the protein of the crude extract were demonstrated by immunoblotting inhibition techniques. To better characterize this allergen, periodic acid-Schiff stain and isoelectrofocusing were used. The amino acid sequencing was done with a gas-phase sequencer. RESULTS SDS-PAGE and immunoblotting of the 15 patients allergic to peach, 8 without and 7 with birch pollinosis, showed that they all recognized a protein with a molecular weight of 9 kd. This was the only allergen recognized by patients not sensitized to pollen, whereas the birch pollen-sensitive patients had IgE binding to other allergenic proteins at higher molecular weights. The purified 9-kd protein retained its IgE-binding capacity, was negative to periodic acid-Schiff stain, and had an isoelectric point value of greater than 9. A search in the Swiss Prot Bank showed this was a lipid transfer protein, belonging to a group of molecules involved in the defensive system of plants. CONCLUSIONS The major allergen of peach is a 9-kd protein belonging to the group of lipid transfer proteins. This is the only allergen recognized by patients allergic to peach but not sensitized to birch pollen.

Identification of actinidin as the major allergen of kiwi fruit

BACKGROUND Allergic reactions to fruits and vegetables are among the most frequent food allergies in adults. Kiwi fruit (Actinidia chinensis) is commonly involved, causing local mucosal, systemic, or both types of symptoms by an IgE-mediated mechanism. In a previous study on 30 patients allergic to kiwi, we identified a major allergen of 30 kd against which all sera tested clearly reacted. Other allergens were detected at 12, 24, and 28 kd. OBJECTIVE The aim of this study was to fully characterize the major kiwi fruit allergen of 30 kd. METHODS Allergens were separated and purified by high-performance liquid chromatography with anion-exchange columns. The purity of the single proteins was checked by sodium dodecylsulfate-polyacrylamide gel electrophoresis, and their allergenicity was checked by immunoblotting with a pool of sera from patients allergic to kiwi. The allergens were characterized by isoelectrofocusing and amino acid sequencing, and periodic acid-Schiff stain was used to detect glycoproteins. RESULTS Proteins of 30, 28, 24, and 17 kd were purified by high-performance liquid chromatography. IgE binding indicated the 30 kd protein, which showed an isoelectric point of 3.5, as the major allergen of kiwi. Determination of its partial amino acid sequence and comparison with the Swiss Protein Bank showed that this was actinidin, the main protein component of kiwi. The 24 and 28 kd proteins had the same N-terminal sequence, which did not correspond to any known protein. The 17 kd protein had a blocked N-terminal sequence. CONCLUSIONS These results demonstrate that the major allergen of kiwi fruit, Act c 1, is actinidin, a proteolytic enzyme belonging to the class of thiol-proteases. Two other allergens of 24 and 28 kd appear identical on amino acid sequencing.

Role of the elimination diet in adults with food allergy

The aim of the study was to check whether, after a period of complete exclusion of the offending foods in adult subjects suffering from food allergy, these foods could subsequently be safely reintroduced into the diet. Patients with chronic urticaria and/or perennial rhinitis negative for secondary pathology or other allergies were subjected to a strict diagnostic protocol for food allergy. Briefly, out of a case list of 207 patients, we found 23 patients whose symptoms were clearly related, on open reintroduction, to at least one food. The really offending foods in these patients were subsequently identified by double-blind, placebo-controlled food challenges. Only 10 of the 23 patients had positive challenges for 13 foods. Double-blind challenges were repeated after 1 year or more of avoidance of the offending foods to evaluate the persistence or disappearance of sensitivity. We found that five (38%) of the 13 previously offending foods were well tolerated. Thus, in adults, as previously proved in children, dietary avoidance of the offending foods appears to be an effective measure for dealing with food allergy. The kind of foods involved and the completeness of their avoidance appeared to be important factors favoring the reestablishment of tolerance in adults.

Atopy and intolerance of antimicrobial drugs increase the risk of reactions to acetaminophen and nimesulide in patients allergic to nonsteroidal anti‐inflammatory drugs

This study evaluated the risk factors for developing allergic reactions to alternative drugs such as acetaminophen and nimesulide in 367 patients intolerant of nonsteroidal anti‐inflammatory drugs (NSAID) compared to 243 healthy controls. All subjects were given test doses (TD) of acetaminophen and nimesulide, and age, sex, atopy, and history of reactions also to unrelated drugs were compared in those who reacted and those who were tolerant of the challenge. TD was positive in 49 of 367 (t4%) NSAID‐allergic patients and in one (0.4%) ofthe controls (f <0.001). No difference was found in age and sex between the TD‐positive and TD‐negative subjects, although a significantly larger number of females were NSAID allergic (P<0.01). Of the 367 patients, 208 had a historj of reactions only to NSAID, and 148 to NSAID and antimicrobial drugs (AMD). TD with acetaminophen or nimesulide was positive in 6% of patients intolerant only of NSAID and i n 24% of those intolerant of both NSAID and AMD, with an odds ratio of 4.82. Atopy was more frequent among patients (36%) than controls (23%) (P=0.004). among TD‐positive (51%) than TD‐negative patients (33.5%) (P<0.02), and among patients intolerant of NSAID and AMD (48%) than those intolerant only of NSAID (F=0.006). The odds ratios were, respectively, 1.87, 2.57, and 3.16. This study provides evidence that atopy and history of allergic reactions to AMD increase the likelihood of intolerance of usually well‐tolerated alternative drugs such as acetaminophen and nimesulide in subjects allergic to NSAID.

Clinical and immunological effects of immunotherapy with alum‐absorbed grass allergoid in grass‐pollen‐induced hay fever

A double‐blind, placebo‐controlled study of immunotherapy was conducted in 19 patients with grass‐pollen hay fever to evaluate the efficacy and safety of a formalinized depot grass allergoid. The patients were assessed before and during IT by clinical (symptom‐medication scores during the grass‐ pollen season, specific nasal and skin reactivity) and immunological (specific IgE, IgG, IgG1 and IgG4 antibodies) parameters. High doses of grass allergoid, corresponding to a cumulative pre‐seasonal dosage of 46050 PNU, were administered, with only one systemic reaction. The actively treated patients had significantly lower symptom‐medication scores than placebo (p < 0.01) during the month of May and showed a significant decrease in specific skin (p < 0.01) and nasal (p < 0.05) reactivity, and a significant early increase in specific IgE (p < 0.01), IgG (p < 0.0005), IgG1 (p < 0.001) and IgG4 (p < 0.05), with a subsequent decrease of IgE and IgG1. No differences were detected in any of these parameters in the placebo group. A correlation was found between high IgG4/IgG1 ratio and the specific skin reactivity decrease (r = 0.691, p < 0.05), whereas a high IgG4/IgG1, ratio was associated with higher symptom‐medication scores (r = 0.654, p < 0.05). Possible explanations of these apparent discrepancies are proposed.

A double‐blind, placebo‐controlled study of immunotherapy with an alginate‐conjugated extract of Parietaria Judaica in patients with Parietaria hay fever

A double‐blind, placebo‐controlled study was conducted to evaluate the efficacy and safety of immunotherapy (IT) with a partially purified alginate‐conjugated extract of Parietaria judaica (Conjuvac®Parietaria, Dome/Hollister‐Stier) in patients suffering from rhinoconjunctivitis caused by Parietaria pollen. Eighteen patients (10 women, 8 men, mean age 35 years) received active treatment and 17 (10 women, 7 men, mean age 42.5 years) received placebo. Actively treated patients had significantly lower nasal symptom/medication scores (running nose P= 0.0087 and sneezing P= 0.048) during the Parietaria pollen season. Significant decreases in specific skin (P > 0.01), nasal (P > 0.05), and conjunctival (P > 0.01) reactivity to the Parietaria extract and significant increases of specific IgG (P > 0.001), IgGI (P > 0.001), and IgG4 (P > 0.001) in actively treated patients, but not in placebo, were found. IT was well tolerated, the active extract inducing five mild systemic reactions (four rhinitis and one urticaria) and placebo two (rhinitis). A significant correlation was found between low skin reactivity and high specific IgG (P= 0.0002) and IgG4 (P= 0.036). These findings indicate that IT with a partially purified P. judaica extract is an effective and safe treatment for Parietaria pollen allergy. The correlation between low immediate skin reactivity and high specific IgG and IgG4 suggests that, at least in the studied cutaneous model, these antibodies may exert a blocking effect.

New allergens in fruits and vegetables

regards the charac- terization of allergens, advances in allergology have served so far to introduce allergenic extracts capable of improving diagnostic and therapeutic performances rather than leading to a deep know- ledge of the etiopathogenesis of allergy. Currently, the concept that there are no peculiar properties making an antigen an efficient allergen is disputed, since recent data suggest that some allergens can directly induce an IgE response. This seems to be true of phospholipase

Hymenoptera stings in conscripts

T CLINICAL Weight of Hymenoptera venom allergy can be assessed by evaluating both its mortality rate and prevalence in the general population. Studies have suggested a mortality rate ranging from 0.09 to 0.45 cases per million of inhabitants per year (1). The prevalence of systemic reactions to Hymenoptera stings ranges between 0.3 and 3.3% (1-4). In Europe, a study in France (2) More than half of the reported prevalences Italian male population ^^ 0-9-3.3% m three difterent surveys; is slung before 20 years studies in Switzerland

Clinical evaluation of CAP System and RAST in the measurement of specific IgE

We investigated the diagnostic value of a new in vitro test, Pharmacia CAP System (Pharmacia Diagnostics AB, Uppsala, Sweden), for the quantitative measurement of allergen‐specific IgE antibodies by comparison with RAST in 2 groups of patients, 71 atopic and 48 non‐atopic. In the last 20 years RAST has supplied a good diagnostic tool, but this test presents some problems, the main one being sensitivity. The new test has a solid phase able to bind even very small amounts of specific IgE and an anti‐IgE tracer with very low cross‐reactivity with other immunoglobulins, thus presenting more favourable conditions. From the analysis of our results, Pharmaeia CAP System gave higher sensitivity (94% compared to 88% of RAST) with no loss of specificity (96% for both tests). The reliability of these results is ensured by the proper selection of patients who were all suffering from pollinosis and were clinically diagnosed as certainly hypersensitive to a single pollen. A positive trend was found between severity of asthma and levels of specific IgE for timothy. Pharmacia CAP System appears to identify a larger number of atopic patients than RAST.

Diagnostic problems due to cross‐reactions in food allergy

The immunochemical cross-reactivity of allergens is a common problem of diagnostic procedures, especially in food allergy (1). Cross-reactivity can elicit positive in vitro or in vivo allergy tests in subjects who do not display any clinical symptom, thus giving rise to the so-called asymptomatic sensitization. Cross-reactivity is an in vitro phenomenon caused by IgE antibodies directed against epitopes expressed in molecular structures from different allergenic sources, and does not always produce clinical symptoms. Cross-reactions in food allergy mainly affect specificity. Nonetheless, the positive tests in subjects who do not have symptoms cannot be simply classified as “false-positive results”, since they do not occur in nonatopic control subjects (2); therefore, their significance has yet to be fully understood. Cross-reactive allergens can be divided into three groups on the basis of the appearance/absence of resulting clinical symptoms. Group I comprises allergens which provoke clear clinical symptoms (Table l), most of which are taxonomically related, and clinical syndromes in which respiratory and food allergies are combined, such as the “birch-fruit’’ or “bird-egg’’ syndromes (3). Group I1 comprises cross-reactive allergens that do not always produce symptoms. Examples of these are profilins in the pollen-vegetable foods allergy association; cysteine proteases contained in kiwi fruit, papaya, pineapple, and mites; and the cross-reacting allergens in the “latex-fruit” syndrome. Group I11 comprises those cross-reactive allergens that do not produce symptoms, and thus seem to represent a mere in vitro phenomenon. Examples are legumes, cereals, and several differOr C. Ortolani Bizzozzero Division Niguarda Ca Granda Hospital Milan Italy