New insights into the sensitization to nonspecific lipid transfer proteins from pollen and food: New role of allergen Ole e 7

Abstract

Background Ole e 7 is a nonspecific lipid transfer protein (nsLTP) from olive pollen, one of the main allergenic pollens worldwide. This allergenic nsLTP is responsible for severe symptoms in regions with high olive pollen exposure, where many Ole e 7‐sensitized patients exhibit a co‐sensitization to the peach nsLTP, Pru p 3. However, there is no evidence of cross‐reactivity, which explains this observed co‐sensitization. Therefore, the purpose of this study was to explore the relationship between Ole e 7 and Pru p 3. Methods A total of 48 patients sensitized to Ole e 7 and/or Pru p 3 were included in the study. Specific IgE serum levels were measured by ImmunoCAP 250 and ELISA. Inhibition assays were performed to determine the existence of cross‐reactivity between both nsLTPs. Allergic response was analyzed ex vivo (basophil activation test) and in vitro (RBL‐2H3 mast cell model). Results Common IgG and IgE epitopes were identified between both allergens. IgE‐binding inhibition was detected in Ole e 7–monosensitized patients using rPru p 3 as inhibitor, reaching inhibition values of 25 and 100%. Ex vivo and in vitro assays revealed a response against rPru p 3 in four (31%) Ole e 7–monosensitized patients. Conclusions Our results suggest that Ole e 7 could play a new role as primary sensitizer in regions with high olive pollen exposure, leading to the peach nsLTP sensitization. This co‐sensitization process would occur because of the cross‐reactivity between Ole e 7 and Pru p 3 observed in some allergic patients.

Non‐specific lipid‐transfer proteins: Allergen structure and function, cross‐reactivity, sensitization, and epidemiology

“…95 A recent study reported that common IgG and IgE epitopes were identified in Ole e 7 and Pru p 3, with inhibition studies suggesting that primary sensitization to Ole e 7 could lead to sensitization to Pru p 3. 96 There has been some suggestion that the greater the atmospheric burden of birch pollen, the lower the incidence of nsLTP sensitization, leading to a hypothesis that high levels of birch pollen protect against nsLTP allergy. 97 It is suggested one potential explanation could be lower reactivity of effector cells exposed to the nsLTPs, as described by Christensen et al, on the basis of interference by other IgE molecules bound to the high-affinity IgE receptors on effector cells.…”

“…Although it has less than 20% amino acid sequence identity with Pru p 3, recognition of Ole e 7 is associated with reactions to plant‐derived food (mainly peach, walnut and peanut), and 80% of Ole e 7 reactors are sensitized to food nsLTPs versus only 30% of Ole e 1 reactors 95 . A recent study reported that common IgG and IgE epitopes were identified in Ole e 7 and Pru p 3, with inhibition studies suggesting that primary sensitization to Ole e 7 could lead to sensitization to Pru p 3 96 …”

Why lipid transfer protein allergy is not a pollen-food syndrome: novel data and literature review

“…Although the association between severe food allergy and sensitization to Ole e 7 has been described (24), two Spanish studies were unable to detect any correlation between peach and olive tree pollen in LTP hypersensitive subjects (25) and between food allergy and Ole e 7 (18), respectively. Nonetheless, recently the possibility of olive tree pollen being the primary sensitizer to LTP in regions with high exposure was put forward once more from Spanish authors based on in-vitro inhibition assays (26). Although about 80% of Ole e 7 reactors score positive to at least one plant food LTP ( 27), the fact remains that most Pru p 3 hypersensitive patients do not show any IgE reactivity to olive tree pollen on in-vivo testing (11).…”

Molecular approach to a patient’s tailored diagnosis of the oral allergy syndrome

“…IgE specific to Pla a 3 could identify the subgroup of plane tree pollen allergic patients predisposed to allergy to food LTP [110 ]. Recently, new insights into the possibility that the olive LTP, Ole e 7, could play a role as a primary sensitizer in regions with a high olive pollen exposure has been confirmed [111 ].…”