• cross-reactivity;
  • mold hypersensitivity;
  • mushroom;
  • spinach

A 31-year-old woman was referred for two systemic reactions after spinach intake; the second was anaphylactic shock with respiratory failure. She also had had four episodes of Oral Allergy Syndrome a few minutes after mushroom intake. For the previous eight years she had suffered from persistent allergic asthma.

Skin prick tests (SPT) were positive to mites and airborne molds, and were negative to pollens, latex and commercial spinach extract. Prick-by-prick tests with raw and boiled spinach, raw beet and chard were positive. Specific bronchial challenge with Alternaria alternata was positive.

Total serum IgE was 786 kU/l and specific IgE was detected to Aspergillus fumigatus, Cladosporium herbarum, Aalternata, Acarus siro, Glycyphagus domesticus, and cat dander.

Extracts of spinach (raw and boiled leaves, and boiling water), mushroom, chard and beet were obtained by grinding 10 g of each in 100 ml PBS. After centrifugation, supernatants were precipitated in 90% ethanol for 30 min and centrifuged for 15 min at 4500 g. Precipitates were re-dissolved in 1 ml PBS and re-centrifuged under the same conditions.

SDS-PAGE and immunoblotting of the different extracts showed the strongest recognition of spinach allergens in the 10 × concentrated boiling water. Therefore, the entire in vitro study was performed using this spinach extract.

The spinach extract showed two main bands of 20 and 25 kDa, and several minor bands (14–18 kDa). Several bands between 14 and 35 kDa were detected in mushroom and chard extracts

Immunoblotting (1) of the spinach extract showed four bands from about 18–35 kDa. In the mushroom extract, the patient's serum recognized a 22 kDa band, a broad zone without defined bands of lower molecular weight (16–18 kDa), and a faint band of about 15 kDa. In the chard extract we detected four very faint bands from about 23–30 kDa.

Spinach immunoblotting inhibition is shown in Fig. 1A. Mushroom and chard extracts were able to inhibit recognition of spinach allergens, with complete inhibition of three allergens between 23 and 35 kDa. Regarding mushroom immunoblotting inhibition (Fig. 1B), C. herbarum, spinach and chard extracts were able to cause complete inhibition of the faint 15 kDa band, which was also partially inhibited using A. alternata as inhibitor. The 16–18 kDa zone was partially inhibited by C. herbarum and spinach, and totally inhibited by chard. The upper 22 kDa band was inhibited in part by spinach and chard.


Figure 1.  A: Immunoblot inhibition to spinach proteins with beet (lane 1), latex (lane 2), Cladosporium herbarum (lane 3), Alternaria alternata (lane 4), Aspergillus fumigatus (lane 5), chard (lane 6), mushroom (lane 7) and spinach (positive control, lane 8). B: Immunoblot inhibition to mushroom proteins with dog dander (negative control, lane 1), Aspergillus fumigatus (lane 2), Alternaria alternata (lane 3), Cladosporium herbarum (lane 4), spinach (lane 5), chard (lane 6), and mushroom (positive control, lane 7).

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IgE-mediated allergy to vegetables has been associated with sensitization to pollens and latex by the existence of common allergens, the pathogenesis-related proteins (2). Allergic reactions after eating spinach relatively unknown, with only four cases described so far (3–6); in three of these studies, the allergy was related to latex sensitization. In our case, both in vivo and in vitro aspects of the study discarded association with sensitization to latex or pollens, including Chenopodium album. Furthermore, we have not found previous reports of food allergy to mushroom Agaricus bisporus or of cross-reactivity between edible mushrooms and airborne molds belonging to the fungi Imperfecti.

In conclusion, spinach and mushroom, two foods with no taxonomical relationship, must have some common epitopes responsible for this newly found cross-reactivity. Although this is a single case report, due to the fact that mold sensitization is relatively common, more in-depth study of the possible cross-reactivity between edible mushrooms and airborne molds should be performed in order to estimate clinical relevance.


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  2. References
  • 1
    Moneo I, Caballero ML, Gomez F, Ortega E, Alonso MJ. Isolation and characterization of a major allergen from the fish parasite Anisakis simplex. J Allergy Clin Immunol 2000;106:177182.
  • 2
    Breitender H, Ebner C. Molecular and biochemical classification of plant-derived food allergens. J Allergy Clin Immunol 2000;106:2736.
  • 3
    Maillard H, Lemerle E, Garot D, Leclech C, Machet L. Crossed spinach-latex allergy revealed by exercise-induced anaphylaxis. Allerg Immunol (Paris) 1999;31:156157.
  • 4
    Drouet M, Le Sellin J, Gay G, El Founini M, Sabbah A. Allergy to Chenopodiaceae (beets, spinach) associated with latex allergy. Allerg Immunol (Paris) 1994;26:113114.
  • 5
    Maillar H, Machet L, Meurisse Y, Garot D, Toledano C, Jan V, et al. Cross allergy to latex and spinach. Acta Derm Venereol 2000;80:51.
  • 6
    Sanchez A, Rodriguez F, GarcÍa-Abujeta JL, Fernández L, Quiñones D, Martín-Gil D. Oral allergy syndrome induced by spinach. Allergy 1997;52:12451246.

Accepted for publication 7 December 2001