Thank you for your recent inquiry.
Unfortunately I could find nothing in the literature that specifically dealt with the cross reactivity of pistachio, cashew and pollens. But there were references that discussed antigens in these nuts that are common to both foods and pollen.
I have copied below two quotes; one regarding pistachio and the other regarding cashew, taken from the ImmunoCap website which is the most detailed source I could find for you that discusses potential cross-reactivity between pistachio, cashew, and other foods and the alergens in these nuts that might be common to foods and pollen. In addition, I have copied below an abstract and study which looked into this issue as well.
Finally, a good general source of the clinical significance of food cross-reactivity is the reference by Dr. Scott Sicherer, which is cited below.
I could find no other information dealing with the potential cross-reactivity between cashew, pistachio, and pollen allergens.
Thank you again for your inquiry and we hope this response is helpful to you.
1. Quote Re: Potential Cross Reactivities of pistachios and other foods; Source Immunocap web site:
"The close relationships among the Anacardiaceae suggest cross-reactivity, and this is supported by studies demonstrating cross-reactivity between Cashew and Pistachio (8). In a study of 42 children with Cashew allergy, 7 had an associated food allergy to Pistachio (9).
By means of serum from 2 children with Pistachio nut allergy, both were shown to be reacting to several Pistachio and Cashew allergens with common antigenic determinants. Cross-reactivity was also found between Pistachio nut and Mango seed, but not Mango pulp (5).
In a study of 3 individuals who experienced anaphylaxis to Cashew nut, all demonstrated IgE antibodies to Cashew and Pistachio. Evaluation of the allergen found that the strongest IgE-binding bands had similar molecular weights and that a 15 kDa protein band may have been a 2S albumin panallergen (4). Whether further cross-reactivity occurs as a result of other foods containing the 2S albumin has not been evaluated, but cross-reactivity has been demonstrated between Pistachio, Peanut, Walnut and Sunflower seed (3), all known to contain the albumin; and similarly, cross-reactivity has been reported to occur among allergens in Sesame seed and allergens in other foods, including Hazel nut, Rye, Kiwi, Poppy seed, Black walnut, Cashew, Macadamia, Pistachio, and Peanuts (10).
Cross-reactivity among Pistachio, Mango (14) and Artemisia (11) has been suggested. Sensitisation to Pistachio is common in Parietaria allergy (12). Cross-reactivity may also occur between Pellitory and Pistachio (13). Cross-reactivity with other lipid transfer protein-containing foods is possible (6).
As Pistachio contains an 11S globulin (Pis v 2) and a vicilin-like protein (Pis v 3), cross-reactivity with other foods containing these allergens is possible, but it has not been elucidated as yet.
Cashew nut, and possibly Pistachio nut, allergy may be associated with pectin allergy, and the possibility of pectin allergy should be considered in Cashew- or Pistachio-allergic patients who have unexplained allergic reactions. A study describes a 3 1/2-year-old boy who developed anaphylaxis after eating Cashew nut and later after eating a pectin-containing fruit "smoothie". The child had skin reactivity to pectin and a high IgE antibody level to Cashew nut and Pistachio nut, as well as a low levels to Grapefruit, to which he had previously also reacted. The pectin in the smoothie was confirmed to be of citrus origin (14)."
2. Quote re: Potential Cross reactivity between cashew and other food: Source Immunocap web site:
" Significant cross-reactivity has been reported between Pistachio nut and Cashew nut (13,16-17). Cross-reactivity between Cashew nut and Walnut is possible, as a result of Ana o 2, the legumin protein which is a major allergen in Cashew nut and present in Walnut (13); and the cross-reactivity is also suggested by in vitro studies. A recent study described significant sequence homology between the recombinant Jug r 4 from Walnut, and Hazel nut and Cashew legumin allergens (18).
An early study reported little cross-reactivity between Cashew and Peanut or Brazil nut. (19) Although Cashew nut and Peanut vicilins share 27% identity, they were reported to not share linear epitopes, and hence did not appear to be cross-reactive (8,12,20). However, a recent study argued that the vicilin allergens of Peanut (Ara h 1), Walnut (Jug r 2), Hazel nut (Cor a 11) and Cashew nut (Ana o 1) share structurally related IgE-binding epitopes; that this epitopic community creates a risk of cross-sensitisation; and that a restriction or avoidance of tree nuts should be recommended to Peanut-sensitised individuals (10).
A 19 kDa protein from Buckwheat was reported to have weak homology to the vicilin-like allergens of Cashew, Walnut (Jug r 2), and 7S globulin from Sesamum indicum (21).
Conformational analysis of the legumin allergens of Peanut (Ara h 3), Walnut (Jug r 4), and Hazel nut (Cor a 9), along with Ana o 2 of Cashew nut, showed that consensual surface-exposed IgE-binding epitopes exhibited some structural homology. The authors suggested that individuals allergic to Peanut should avoid the other 3 nuts to prevent possible allergic reactions (14).
Pectin has been shown to contain all of the allergen epitopes of Cashew nut, whereas Cashew nut does not exhibit all of the epitopes of pectin. The clinical significance of this fact has not yet been established, and further studies are required to characterise these cross-reacting allergens (22). However, a recent study reported that Cashew nut allergy, and possibly Pistachio nut allergy, may be associated with pectin allergy, and the possibility of pectin allergy should be considered in Cashew- or Pistachio-allergic patients who have unexplained allergic reactions. The study described a 3 1/2-year-old boy who developed anaphylaxis after eating Cashew nut and later after eating a pectin-containing fruit "smoothie". The child had skin reactivity to pectin and a high level of IgE antibodies to Cashew nut and Pistachio nut, as well as a low level of IgE to Grapefruit, to which he had previously also reacted. The pectin in the smoothie was confirmed to be of citrus origin (23).
Cardol, found in the Cashew nut shell, is not usually present in the nut unless contamination occurs. An early study reported cross-reactivity of poison ivy and Cashew nut as a result of the nut being contaminated with cardol (24)."
Clin Exp Allergy. 1993 Dec;23(12):996-1001.
Pistachio nut hypersensitivity: identification of pistachio nut allergens.
Parra FM, Cuevas M, Lezaun A, Alonso MD, Beristain AM, Losada E.
Servicios de Alergia, Hospital Ramon y Cajal, Madrid, Spain.
Type I hypersensitivity to pistachio nut antigens was demonstrated in three patients by means of immediate skin-test reactivity, specific IgE determination by a fluoroimmunoassay (CAP), CAP-inhibition and leucocyte histamine release. Sensitization to other dried fruits and pollens was observed in the patients. The CAP-inhibition studies revealed significant crossreactivity between pistachio and cashew nut belonging to the Anacardiaceae family, and between pistachio nut and other dried fruits belonging to taxonomically unrelated botanical families. No relevant crossallergenicity was observed between pistachio nut and Lolium and Olea pollens. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a pistachio nut extract followed by immunoblotting analysis identified four IgE-binding bands with molecular weights.
4. Reference: Clinical implications of cross-reactive food allergens by Scott H. Sicherer; The Journal of Allergy and Clinical Immunology, December 2001 (Vol. 108, Issue 6, Pages 881-890)
Phil Lieberman, M.D.