Faculty Bibliography

BACKGROUND: There is no consensus on the diagnosis and therapy of oral allergy syndrome (OAS; also known as pollen-food allergy syndrome), a disorder caused by IgE antibody-mediated reactions to homologous proteins in pollens and fruits and vegetables. OBJECTIVE: We sought to determine how practicing allergists define and treat OAS. METHODS: A questionnaire was mailed to 226 randomly selected US allergists from the American Academy of Allergy, Asthma and Immunology directory. RESULTS: One hundred twenty-two (54%) returned surveys were analyzed. Median estimates of the prevalence of OAS among the patients with pollen allergy were 5% among children and 8% among adults. Twenty percent of allergists reported that some patients progressed to systemic symptoms. Fifty-three percent of allergists recommended complete avoidance of causal foods to all patients, whereas 9% did not advocate any restrictions. Thirty percent never prescribed epinephrine for OAS, 3% always did, and the remainder did so on the basis of symptoms. When presented with clinical cases, 20% diagnosed systemic reactions to peach as OAS, 13% believed peanut could cause OAS, and 25% did not prescribe epinephrine for peanut allergy manifested by oral symptoms. CONCLUSION: Allergists' estimates of the prevalence of OAS in patients with pollen allergy (5%-8%) are lower than the prevalence reported (approximately 50%) in the published studies of these patients, perhaps reflecting a low index of suspicion, underdiagnosis, or both. The wide range of responses regarding diagnosis and management indicates the need for a better definition for the disorder and standard therapeutic guidelines. Discrepancies might be related to the term OAS, and therefore use of the more specific term "pollen-food allergy syndrome" is suggested.

BACKGROUND: Casual skin contact or inhalation of peanut butter fumes is reported and feared to cause allergic reactions in highly sensitive children with peanut allergy but has not been systematically studied. OBJECTIVE: We sought to determine the clinical relevance of exposure to peanut butter by means of inhalation and skin contact in children with peanut allergy. METHODS: Children with significant peanut allergy (recent peanut-specific IgE antibody concentration >50 kIU/L or evidence of peanut-specific IgE antibody and one of the following: clinical anaphylaxis, a reported inhalation-contact reaction, or positive double-blind, placebo-controlled oral challenge result to peanut) underwent double-blind, placebo-controlled, randomized exposures to peanut butter by means of contact with intact skin (0.2 mL pressed flat for 1 minute) and inhalation (surface area of 6.3 square inches 12 inches from the face for 10 minutes). Placebo challenges were performed by using soy butter mixed with histamine (contact), and scent was masked with soy butter, tuna, and mint (inhalation). RESULTS: Thirty children underwent the challenges (median age, 7.7 years; median peanut IgE level, >100 kIU/L; 13 with prior history of contact and 11 with inhalation reactions). None experienced a systemic or respiratory reaction. Erythema (3 subjects), pruritus without erythema (5 subjects), and wheal-and-flare reactions (2 subjects) developed only at the site of skin contact with peanut butter. From this number of participants, it can be stated with 96% confidence that at least 90% of highly sensitive children with peanut allergy would not experience a systemic-respiratory reaction from casual exposure to peanut butter. CONCLUSIONS: Casual exposure to peanut butter is unlikely to elicit significant allergic reactions. The results cannot be generalized to larger exposures or to contact with peanut in other forms (flour and roasted peanuts)

Leukocyte adhesion deficiency type 2 (LADII) is characterized by defective selectin ligand formation, recurrent infection, and mental retardation. This rare syndrome has only been described in 2 kindreds of Middle Eastern descent who have differentially responded to exogenous fucose treatment. The molecular defect was recently ascribed to single and distinct missense mutations in a putative Golgi guanosine diphosphate (GDP)-fucose transporter. Here, we describe a patient of Brazilian origin with features of LADII. Sequencing of the GDP-fucose transporter revealed a novel single nucleotide deletion producing a shift in the open-reading frame and severe truncation of the polypeptide. Overexpression of the mutant protein in the patient's fibroblasts did not rescue fucosylation, suggesting that the deletion ablated the activity of the transporter. Administration of oral L-fucose to the patient produced molecular and clinical responses, as measured by the appearance of selectin ligands, normalization of neutrophil counts, and prevention of infectious recurrence. The lower neutrophil counts paralleled improved neutrophil interactions with activated endothelium in cremasteric venules of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. However, fucose supplementation induced autoimmune neutropenia and the appearance of H antigen on erythrocytes, albeit without evidence of intravascular hemolysis. The robust response to fucose despite a severely truncated transporter suggests alternative means to transport GDP-fucose into the Golgi complex.