 |
Thank you for your recent inquiry.
The type of question you are asking is something that we all encounter daily in practice. We are, as you well know, often faced with advising patients who react to a food as to whether or not they can eat foods that are closely related (e.g., shrimp and other shellfish). There is no definitive answer to this question in any such instance. The only completely accurate way to determine if cross-reactivity does exist is an oral challenge.
However, there is a very helpful article written by Dr. Scott Sicherer that deals with this issue in depth. It is entitled "Clinical Implications of Cross Reactive Food Allergens" and is in The Journal of Allergy and Clinical Immunology, Volume 108, Issue 6, Pages 881-890 (December 2001). There is a very helpful colored photo in that article which gives a rough estimate of relative risks for cross-reactivity in various food groups. To put it briefly, he assesses the risk for cross-reactivity between peanuts and other legumes as being very low (approximately 5%). Of course, we cannot interpret that to refer to the cross-reactivity between other legumes, but there is encouraging evidence that this cross-reactivity, as Dr. Sicherer notes, is indeed low.
There is an abstract co-authored by Dr. Hugh Sampson, which I have copied for you below, which looked at this issue. As you can see, he also found that there is a low cross-reactivity between legumes regarding anaphylactic sensitivity.
Unfortunately, as is clearly stated in Dr. Sicherer's article, there is a relatively high rate of "false-positive" skin tests between botanically related foods. Thus neither in vitro or in vivo tests can be used to predict clinical cross-reactivity with great reliability. This is seen by the article in Allergology and Immunopathology which is also copied below.
From the above articles, it appears that cross-reactivity between legumes is reasonably rare. However, slightly on the distaff side of this issue, is a more recent article, also from Spain, appearing in the International Archives of Allergy and Immunology. As you can from the abstract copied below, in vitro cross-reactivity in different lentils was reasonably high. In addition, food challenges confirmed that cross-reactivity in this particular cohort of Spanish children occurred more frequently than previously observed.
However, it is important to note that these beans were not Pinto beans, but lentils, chickpeas, and peas. Reactions to Pinto beans are reasonably rare, and I could find no detailed study analyzing cross-reactivity in regards to this specific bean.
Also of note is the fact that these studies of cross-reactivity are done in the Mediterranean where allergy to lentils and other beans is more common than in the United States (as you can see from the more recent article abstracted from the Annals of Allergy below).
In summary, based on a general assessment of this body of literature, we can probably make the following conclusions relevant to your patient:
Allergy to Pinto beans itself is relatively rare (in fact, with typing in "Pinto bean anaphylaxis" into PubMed, I received no references; however, there are isolated case reports of Pinto bean allergy. Nonetheless, more than likely because such allergy is rare, I could find no large studies dealing with cross-reactivity between Pinto beans and other legumes.
Based on what we do know through the work of Sampson, Sicherer, and others, it appears that cross-reactivity between beans, at least in the North American population, is reasonably rare, at least compared to that between other food groups.
The exception to this is the Mediterranean area where allergy to other legumes such as lentils appears to be more common, and unfortunately, cross-reactivity appears to a greater extent.
Finally, the only true way to determine cross-reactivity is through food challenge; unfortunately, a somewhat impractical approach in this case.
Thank you again for your inquiry and we hope this response is helpful to you.
Abstract 1:
Cross-allergenicity in the legume botanical family in children with food hypersensitivity.
Bernhisel-Broadbent J, Sampson HA
J Allergy Clin Immunol 1989; 83:435-40.
Sixty-nine patients with one or more positive prick skin tests to legumes (peanut, soybean, green bean, pea, and lima bean) were evaluated for food hypersensitivity with in-hospital oral food challenges. Of the 280 prick skin tests to legumes performed, 130 were positive. Forty-three positive food challenges occurred in 41 patients. The prevalence of legume allergy was not statistically different in those patients (N = 36) with two or more positive legume prick skin test (64% positive) compared to those patients (N = 33) with only one positive legume prick skin test (55% positive; p greater than 0.10). Even in this selected patient population, only two patients had symptomatic hypersensitivity to two legumes. Among patients with a positive prick skin test to peanut (N = 60), the mean wheal size was larger in patients with a positive versus a negative oral food challenge to peanut (p less than 0.001). Results of oral food challenges demonstrate that clinically important cross-reactivity to legumes in children is very rare. Clinical hypersensitivity to one legume does not warrant dietary elimination of all legumes. Results of prick skin tests should not be used to determine prolonged food restriction diets.
Abstract 2:
Background: Serologic cross-reactivity among legumes has been described; however, it is rarely clinically significant. In this study 3 patients with a history of anaphylaxis to pea are described who subsequently had symptoms after ingestion of peanut. Objective: We investigated whether the peanut-related symptoms were due to cross-reactivity between pea and peanut proteins. Methods: Peanut-related symptoms were documented according to case history or double-blind, placebo-controlled food challenge results. Skin prick tests were performed, and specific IgE levels were determined for pea and peanut with the CAP system FEIA. IgE-binding proteins in pea and peanut were identified by using immunoblot analysis. Cross-reactivity was studied by means of immunoblot and ELISA inhibition studies with whole extracts and purified allergens. Results: Peanut-related symptoms consisted of oral symptoms in all patients, with additional urticaria and dyspnea or angioedema in 2 patients. All patients had a positive skin prick test response and an increased IgE level to pea and peanut. Immunoblotting revealed strong IgE binding to mainly vicilin in pea extract and exclusively to Ara h 1 in crude peanut extract. Immunoblot and ELISA inhibition studies with crude extracts, as well as purified proteins, showed that IgE binding to peanut could be inhibited by pea but not or only partially the other way around. Conclusion: Clinically relevant cross-reactivity between pea and peanut does occur. Vicilin homologues in pea and peanut (Ara h 1) are the molecular basis for this cross-reactivity. (J Allergy Clin Immunol 2003;111:420-4.)
Abstract 3:
Allergol Immunopathol (Madr). 2003 May-Jun;31(3):151-61.
[Legume cross-reactivity]
[Article in Spanish]
Ibáñez MD, Martínez M, Sánchez JJ, Fernández-Caldas E.
Servicio de Alergia del Hospital Niño Jesús, Madrid. Spain.
Legumes are dicotyledonous plants belonging to the Fabales order. The main distinctive characteristic of which is their fruit (legumen, seeds contained in pods). This botanical order is formed by three families: Mimosaceae, Caesalpiniaceae and Papilionaceae or Fabacea. The Papilionaceae family includes the most important allergenic species: Lens culinaris (lentil), Cicer arietinum (chick-pea), Pisum sátivum (pea), Arachis hipogea (peanut), Phaseolus vulgaris (bean) y Glycine max (soy).Legumes are an important ingredient in the Mediterranean diet. Among Spanish children, sensitivity to legumes is the fifth most prevalent food allergy. Lentil and chick-pea are the most frequent cause of allergic reactions to legumes in Spanish children. Legumes could be involved in severe allergic symptoms.The different legumes have structurally homologous proteins, but they are not all equally allergenic, thus making it difficult to distinguish in vitro and in vivo cross-reactivity. We have demonstrated by skin tests and CAP that most of the patients are sensitised to more than one species. We have demonstrated a great degree of cross-reactivity among lentil, chick-pea, pea and peanut by ELISA inhibition (> 50 % max. inhibition). Unlike the Anglo-Saxons population, this phenomenon implies clinical sensitisation for many Spanish children. The majority of our patients have had symptoms with more than one legume (median 3 legumes). Thirty-nine patients were challenged (open or simple blind) with two or more legumes and 32 (82 %) reacted to two or more legumes: 43,5 % to 3, 25,6 % to 2, 13 % to 4 legumes. Seventy three per cent of the patients challenged with lentil and pea had positive challenge to both, 69,4 % to lentil and chick-pea, 60 % to chick-pea and 64,3 % to lentil, chick-pea and pea simultaneously. Peanut allergy peanut can be associated to allergy to lentil, chick-pea and pea but less frequently. Contrarily, white bean and overall green bean and soy are well tolerated by children allergic to other legumes.In our study, 82 % of the children allergic to legumes had a sensitisation to pollen. Pea and bean are the legumes with more in vitro cross-reactivity with Lolium perenne, Olea europea and Betula alba. This cross-reactivity could be because of common antigenic determinants or due to the coexistence of pollen and legume allergy. Panallergens implication seems to be less probable.It is important to emphasize that in spite of an evident clinical and immunological cross-reactivity, the diagnosis of legume allergy should not be based only on specific IgE tests. The decision to eliminate one legume from the diet should be based on a positive oral food challenge.
Abstract 4:
Int Arch Allergy Immunol. 2008;147(3):222-30. Epub 2008 Jul 2.
In vitro and in vivo cross-reactivity studies of legume allergy in a Mediterranean population.
Martínez San Ireneo M, Ibáñez MD, Fernández-Caldas E, Carnés J.
Servicio de Alergia, Hospital Ntra. Sra. del Prado, Talavera de la Reina, Spain.
BACKGROUND: Legume allergy, mainly to lentils and chickpeas, is the fifth most common cause of food allergy in Spanish children. Serological cross-reactivity among legumes is frequent, but its clinical relevance is controversial. The aim of this study was to investigate the cross-reactivity among lentils, chickpeas, peas, white beans and peanuts and its clinical relevance in pediatric patients. METHODS: Fifty-four children with clinical allergy to legumes were included. Cross-reactivity was evaluated by ELISA inhibition experiments and oral food challenges to legumes. SDS-PAGE immunoblots were conducted with raw and boiled legume extracts. RESULTS: ELISA inhibition experiments demonstrated more than 80% inhibition with lentil, chickpea and pea extracts. Immunoblots performed with raw legume extracts (lentil, chickpea and pea) and individual sera revealed that more than 50% of the sera identified an allergen with approximately 50 kDa in all three legume extracts. In all three boiled extracts an intense band at approximately 50 kDa was visualized using a serum pool. The oral legume challenges demonstrated that 37 children (69%) were allergic to 2 or more legumes (median 3 legumes). The most frequent associations were allergy to lentils and chickpeas (57%), allergy to lentils and peas (54%) and allergy to lentils, chickpeas and peas (43%). CONCLUSIONS: In vitro inhibition experiments demonstrated a high degree of cross-reactivity among lentils, chickpeas and peas. Food challenges confirmed that clinical allergy to all three legumes is frequent in our cohort of Spanish children.
Abstract 5:
Ann Allergy Asthma Immunol. 2008 Aug;101(2):179-84.
Clinical features of legume allergy in children from a Mediterranean area.
Martínez San Ireneo M, Ibáñez MD, Sánchez JJ, Carnés J, Fernández-Caldas E.
Servicio de Alergia, Hospital Nuestra Señora del Prado, Talavera de la Reina, Toledo, Spain mmsan@sescam.jccm.es
BACKGROUND: Lentils, chickpeas, beans, and peas are the most common consumed legumes in the Mediterranean area. However, there is little information about allergy to these legumes. OBJECTIVES: To describe the clinical features of a Spanish pediatric population allergic to legumes (lentils, chickpeas, peas, white beans, and peanuts), to evaluate the clinical allergy to several legumes, and to determine which legume extract is most appropriate to use in the diagnosis of legume allergy by skin tests. METHODS: Fifty-four children with allergic reactions after exposure to legumes were studied. The diagnosis of legume allergy was confirmed by positive skin prick test results with legume extracts and food challenges or a recent convincing history of severe reactions. RESULTS: The onset of allergic reactions was at approximately the age of 2 years (median, 22 months). Skin prick test results were positive for at least 3 legumes in 38 children (70%). Positive results were more frequent to boiled extracts than to raw extracts in children with a positive oral challenge. Allergy to lentil was the most frequently diagnosed legume allergy (43 children [80%]), followed by allergy to chickpea (32 children [59%]). Oral challenges with more than 1 legume (median, 3 legumes) were positive in 37 children (69%). The most frequent induced symptoms on challenge were respiratory (rhinitis and/or asthma) and cutaneous. CONCLUSION: In this population, lentils and chickpeas are the legumes that cause most allergic reactions, clinical allergy to more than 1 legume is common, and boiled legume extracts are most appropriate to discriminate between allergic and tolerant sensitized children.
Sincerely,
Phil Lieberman, M.D.
7205 Wolf River Boulevard, Suite 200
Germantown, TN 38138
Telephone: 901-757-6100
Fax: 901-757-6109
PL:kl
|
About AAAAI
