Severe immediate allergic reactions to grapes: part of a lipid transfer protein-associated clinical syndrome.

BACKGROUND: Grape allergy is considered rare; grape lipid transfer protein (LTP; Vit v 1), an endochitinase and a thaumatin-like protein (TLP) have been reported as grape allergens. A considerable number of patients have referred to our department for severe reactions to grapes, and several IgE binding proteins were detected. OBJECTIVES: The aim of this study was to identify and characterise the allergens involved in severe allergic reactions to grapes and describe the population in which they occur. METHODS: Patients with reported severe allergic reactions to grapes (n = 37) are described. Grape allergens were purified/fractionated by a combination of chromatographic techniques, identified by proteomic analysis and biochemically characterised. Immunoreactivity was assessed by blot (inhibitions) and RAST (inhibitions), and skin prick tests were performed with the isolated allergens. RESULTS: All subjects were polyallergic, sensitised and reactive to several additional foods and pollen. All patients were sensitised to grape LTP. A 28-kDa expansin, a 37.5-kDa polygalacturonase-inhibiting protein, a 39-kDa beta-1,3-glucanase and a 60-kDa protein were identified as minor grape allergens. Endochitinase and TLP did not play a role. Inhibition experiments revealed the possible cross-reactive role of LTP for clinical sensitivities to other LTP-containing plant foods, but also the involvement of cross-reactive carbohydrate determinants of minor allergens in IgE cross-reactivity. CONCLUSIONS: LTP is the major grape allergen, while additional minor allergens may contribute to clinical reactivity. Severe grape allergy presents in atopic patients who frequently react to other LTP-containing, plant-derived foods. The 'LTP syndrome' is the appropriate term to describe this condition.

Effect of in vitro gastric and duodenal digestion on the allergenicity of grape lipid transfer protein.

BACKGROUND: Severe grape allergy has been linked to lipid transfer protein (LTP) sensitization. LTPs are known to be resistant to pepsin digestion, although the effect of gastroduodenal digestion on its allergenicity has not been reported. OBJECTIVE: We sought to investigate the effect of gastric and gastroduodenal digestion on the allergenic activity of grape LTP. METHODS: The proteolytic stability of grape LTP was investigated by using an in vitro model of gastrointestinal digestion. The allergenicity of LTP and its digesta was assessed in vitro by means of IgE immunoblotting, RASTs, and in vivo skin prick tests in the same patients with grape allergy. RESULTS: Grape LTP was resistant to gastric digestion, and yielded a 6000-d relative molecular mass C-terminally trimmed fragment after duodenal digestion. This fragment retained the in vitro IgE reactivity of the intact protein. Inclusion of phosphatidylcholine during gastric digestion protected the LTP to a limited extent against digestion. Digestion did not affect the in vivo (skin prick test) biologic activity of LTP. CONCLUSION: The allergenic activity of grape LTP was highly resistant to in vitro digestion. This property might facilitate sensitization through the gastrointestinal tract and might also potentiate the ability of LTPs to elicit severe allergic reactions in sensitized individuals. CLINICAL IMPLICATIONS: Purified natural allergens will facilitate the development of component-resolved diagnostic approaches, including allergen chips. This study contributes to our understanding of the role digestion plays in symptom elicitation in true food allergy.

Efficacy and safety of mometasone furoate vs nedocromil sodium as prophylactic treatment for moderate/severe seasonal allergic rhinitis.

BACKGROUND: The preventive use of medications has been proposed to be effective in the treatment of seasonal rhinitis. OBJECTIVE: To evaluate the efficacy and safety of mometasone furoate and nedocromil sodium nasal sprays as prophylactic treatment for moderate to severe seasonal allergic rhinitis (SAR). PATIENTS: Sixty-one patients were recruited from 3 referral allergy centers. Inclusion criteria were history of SAR for 2 years or longer, sensitization to relevant local pollen (grasses, Parietaria, and olive), and age older than 12 years. METHODS: An open-label, randomized, parallel-group, "real-life" study design was used. Patients received mometasone furoate nasal spray once daily or nedocromil sodium nasal spray 3 times daily starting 2 to 4 weeks before the pollen season and continuing for up to 4 months. Instructions regarding the use of additional medications were given. Diary cards recording symptoms, use of medication, and adverse events were kept by the patients. RESULTS: All 61 patients completed the study. The prophylactic use of mometasone furoate vs nedocromil sodium led to significantly more days without symptoms (75.1% vs 54.5%; P < .001). The mometasone furoate group also had lower nasal symptom scores (mean, 1.4 vs 2.9; median, 0 vs 2; P < .001) and was more satisfied (93.1% vs 43.5%; P < .001). No serious adverse event was recorded, and there was no difference between the treatments in any adverse event. CONCLUSIONS: Prophylactic administration of mometasone furoate before the pollen season is safe and may lead to improved control of SAR compared with the use of nedocromil sodium.

Disseminated nontuberculous mycobacterial infection in a child with interferon-gamma receptor 1 deficiency.

We describe the case of a 2-year-old boy with disseminated infection by a rapidly growing, poorly pathogenic mycobacterial species that belonged to the Mycobacterium fortuitum-Mycobacterium peregrinum complex. He had a severe course characterized by a poor response to treatment and recurrent lymph node abscess formation. Sequencing of the interferon-gamma receptor 1 gene (IFNgammaR1) revealed that he was homozygous for a novel null mutation, 453delT. Patients presenting with disseminated infections by rapidly growing environmental mycobacteria must be investigated for complete IFNgammaR1 deficiency. The spectrum of IFNgammaR1 genotypes associated with this immunological disorder is expanding.