Oral allergy syndrome to sapodilla (Achras zapota)

is considered a specific form of chronic fibrosing interstitial pneumonia of unknown cause with a histologic pattern of UIP on open lung biopsy. Major and minor criteria are given to aid in the differentiation from other interstitial lung diseases of known cause that might closely mimic IPF. Chronic insidious hypersensitivity pneumonia (HP) is one such disorder that can be difficult to differentiate by clinical presentation,1,2 high-resolution computed tomography scans,3 and open lung biopsy.2,4,5 Despite the remarkable similarities of these 2 disorders, there is a striking difference in morbidity and mortality when HP is appropriately diagnosed and the causative antigen(s) avoided. There is, however, a paucity of data in the current literature concerning environmental investigation or the assessment of antibodies directed toward environmental antigens in patients diagnosed with IPF that could prove vital in changing the diagnosis to IPF secondary to HP. The condition of the patient described has progressed to the point at which long-term survival is unlikely despite her having moved from her contaminated home. Although the presence of specific antibodies is not diagnostic of HP and simply reflects significant exposure, other factors that might have altered the prognosis include the following: (1) open lung biopsy earlier in the course of the disease to clearly identify the histopathologic pattern of hypersensitivity pneumonia, (2) an indepth environmental history of both the home and the workplace since onset of symptoms, (3) an environmental investigation to identify the source and specific microbes involved, and (4) remediation of or moving away from the contamination. All patients with idiopathic interstitial lung disease must be suspected of having a hypersensitivity pneumonia to a home or workplace contaminant until aggressive evaluation proves otherwise.6 Robert L. Jacobs, MD Biogenics Research Institute 8229 Fredericksburg Rd San Antonio, TX 78229 I thank Jacqueline Coalson, PhD, for her expertise in the review and interpretation of the histopathology of the open lung biopsy.

REFERENCES 1. American Thoracic Society. Idiopathic pulmonary fibrosis: diagnosis and treatment. International consensus statement. Am J Respir Crit Care Med 2000;161:646-64. 2. Perez-Padilla R, Salas J, Chapela R, Sanchez M, Carrillo G, Perez R, et al. Mortality in Mexican patients with chronic pigeon breeder’s lung compared to those with usual interstitial pneumonia. Am Rev Respir Dis 1993;146:49-53. 3. Lynch DA, Newell JD, Logan PM, King TE, Mueller NL. Can CT distinguish hypersensitivity pneumonitis from idiopathic pulmonary fibrosis. Am J Roentgenol 1995,165;807-11. 4. Hammer S. Hypersensitivity pneumonitis. Pathol Annu 1988;23:195-215. 5. Greenberger PA, Pien LC, Patterson R, Robinson P, Roberts M. Endstage lung and ultimately fatal disease in a bird fancier. Am J Med 1989;86:119-22. 6. Jacobs RL, Andrews CP, Coalson J. Organic antigen-induced interstitial lung disease: diagnosis and management. Ann Allergy Asthma Immunol 2002;88:30-41.

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Oral allergy syndrome to sapodilla (Achras zapota) To the Editor: The constellation of immediate symptoms appearing less than 1 hour after ingestion of certain vegetables and fruits eaten in raw form is usually confined to the oropharyngeal area and has been

Letters to the Editor 533

FIG 1. Analysis of sapodilla extract (50% w/v) by electrophoresis and immunoblotting. a, 12% SDS-PAGE (silver staining): lane 1, molecular weight markers; lane 2, sapodilla extract (approximately 10 µg protein). b, IgE-immunoblot: lane N, control serum (pooled sera of normal subjects); lanes 1, 2, and 3, serum from cases 1, 2, and 3, respectively.

termed oral allergy syndrome (OAS).1-3 Typical symptoms of OAS involve tingling in the lips, itching, and swelling of the tongue and/or swelling in the throat. During the course of a random survey of 600 adults in Mysore, India, for detection of food allergy to fruits and vegetables, we came across 3 cases of allergy to sapodilla. Sapodilla (Achras zapota L syn Manilkara zapota van Royen, a member of the Sapotaceae family), also known as the sapota or sapodilla plum, is popular for its delicious fruit.4 (The sapodilla plum, an exotic fruit, is not related to the familiar plum that belongs to the Rosaceae family.) Here we present these 3 cases of allergy to sapodilla and describe the detection of the causative allergen by immunoblot analysis. Case 1. A 20-year-old atopic female had experienced allergy to sapodilla for the first time at the age of 12 years after eating one quarter to one half of a sapodilla plum. Within 15 minutes, she had experienced swelling of the lips (lip edema), accompanied by itching in the lips, tongue, and throat (oropharyngeal pruritus), as well as a feeling of dryness and hardness in the throat (glottic edema). There was a similar incident when she was 15 years old. The family history of allergy is positive; the subject’s mother and brother are allergic to certain foods (mango, Indian dill, and egg), and her brother had childhood asthma. Case 2. A 23-year-old atopic female first experienced allergy to sapodilla at the age of 22 years. She had severe itching of the mouth (perioral pruritus) and swelling of the lips and tongue (lip and tongue edema), which began approximately 10 to 20 minutes after she ate a sapodilla plum. On several other occasions, she had experienced mild oral reactions to sapodilla. In childhood she had had allergy to egg, which she has outgrown. Case 3. A 23-year-old atopic male experienced very mild itching or unpleasantness while eating sapodilla. As a result of this adverse reaction, he does not relish sapodilla and avoids eating it. Allergic (urticaria) to several analgesics, particularly ibuprofen, this subject had a family history of allergy (his father being allergic to certain drugs).

Letters to the Editor

J ALLERGY CLIN IMMUNOL VOLUME 110, NUMBER 3

534 Letters to the Editor

J ALLERGY CLIN IMMUNOL SEPTEMBER 2002

Central Food Technological Research Institute (CFTRI) Mysore - 570013 India

TABLE I. Skin prick test, prick-by-prick test, and allergenspecific IgE to sapodilla Wheal/flare diameter (mm)

Negative control (glycerinated PBS) Positive control (histamine, 1mg/mL)† Case 1 Case 2 Case 3

ELISA units (A492)*

SPT

PPT

0-1/0

NA

—

6-8/20->30 9.5/>30 4.0/20 5.0/20

NA 6.5/25 4.0/20 4.0/16

— 0.333 0.276 0.287

SPT, Skin prick test; PPT, prick-by-prick test; PBS, phosphate-buffered saline solution; NA, not applicable. *Mean of triplicate determinations. Values for 2 normal sera: 0.190 and 0.199. †Histamine dihydrochloride, 1.66 mg/mL (equivalent to 1 mg/mL histamine base).

Letters to the Editor

This study was undertaken after clearance by our Institutional Ethics Committee; informed consent was obtained from all allergic and normal subjects in the age range 15 to 60 years. Skin prick testing (SPT)5 was performed with fresh sapodilla juice (protein content, 0.45 mg/mL), obtained by blending the pulp for approximately 5 minutes and filtering. For prick-by-prick testing (PPT), the pulp portion of a freshly opened, ripe sapodilla was pricked with a sterile lancet; the subject’s skin was then pricked with the same lancet. Both SPT results and PPT results were positive in all 3 allergic subjects (Table I); case 1 showed maximum skin reactivity. Results of SPT with common inhalant weed pollen and grass pollen-mixes were negative in all 3 allergic subjects (data not shown). Results of SPT and PPT with sapodilla were negative (01/0 mm) in 15 normal subjects. Sapodilla pulp was blended in phosphate-buffered saline solution (PBS) and filtered through Whatman 1 filter paper to obtain 50% w/v extract. Allergen-specific IgE was detected by means of ELISA.5 Briefly, Maxisorp microtiter wells (Nunc, Roskilde, Denmark) were coated with sapodilla extract (pH 9.6; 50 µg protein/well); this was followed by incubation with allergic or normal serum at a dilution of 1:3. Peroxidase-conjugated goat antihuman IgE (Sigma-Aldrich, St Louis, Mo) was used as secondary antibody (1:1000 dilution). Serum allergen-specific IgE for sapodilla was positive in all 3 allergic subjects (Table I). Sapodilla extract was subjected to SDS-PAGE and immunoblot analysis.6 Silver staining revealed several protein bands in the range 15 to 90 kd; the 3 major bands corresponded to relative molecular weights (Mr) of 37, 28, and 20 kd (Fig 1, A). In the immunoblot (Fig 1, B), all 3 allergic subjects’ sera (1:3 dilution) detected the 20-kd protein band, whereas the control serum did not detect any protein band. Allergies to fruits and vegetables are usually associated with sensitization to pollen1-3 or latex (latex-fruit syndrome),7 and a few cross-reactive allergens have been identified. However, localized oral symptoms to fresh fruits without associated pollenosis are also referred to as OAS and categorized as non–pollen-associated OAS.3,8 In the present study, the allergic subjects were not allergic to any other fruits or vegetables or to latex/natural rubber products, nor did they have any pollen-related or respiratory allergic symptoms. Hence, we feel that the 20-kd sapodilla allergen responsible for OAS is not a cross-reactive allergen. To our knowledge, this is the first report of allergy to ingestion of sapodilla. Venkatesh L. Hegde, MSc Yeldur P. Venkatesh, PhD Department of Biochemistry and Nutrition

The assistance rendered by the staff of the Health Centre, CFTRI, Mysore, is gratefully acknowledged. We thank the Council of Scientific & Industrial Research (CSIR), New Delhi, for financial support (Y.P.V., institutional project MLP-1407 [“Allergens from fruits”]; V.L.H., senior research fellowship).

REFERENCES 1. Amlot PL, Kemeny DM, Zachary C, Parkes P, Lessof MH. Oral allergy syndrome (OAS): symptoms of IgE-mediated hypersensitivity to foods. Clin Allergy 1987;17:33-42. 2. Ortolani C, Ispano M, Pastorello EA, Bigi A, Ansaloni R. The oral allergy syndrome. Ann Allergy 1988;61:47-52. 3. Hill DJ, Hosking CS. The management and prevention of food allergy. In: Frieri M, Kettelhut B, editors. Food hypersensitivity and adverse reactions: a practical guide for diagnosis and management. New York: Marcel Dekker; 1999. p. 423-47. 4. Kute LS, Shete MB. Sapota (Sapodilla). In: Salunkhe DK, Kadam SS, editors. Handbook of fruit science and technology: production, composition, storage, and processing. New York: Marcel Dekker; 1995. p. 47584. 5. Bernstein IL, Storms WW. Practice parameters for allergy diagnostic testing. Ann Allergy Asthma Immunol 1995;75:553-625. 6. Towbin H, Staehelin T, Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets. Procedure and some applications. Proc Natl Acad Sci 1979;76:4350-4. 7. Brehler R, Theissen U, Mohr C, Luger T. “Latex-fruit syndrome”: frequency of cross-reacting IgE antibodies. Allergy 1997;52:404-10. 8. Fernandez-Rivas M, Van Ree R, Cuevas M. Allergy to Rosaceae fruits without related pollinosis. J Allergy Clin Immunol 1997;100:728-33.

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Anaphylaxis to latex after ingestion of a cream-filled doughnut contaminated with latex To the Editor: Latex products can be responsible for IgE-mediated type I allergic reactions.1 The use of latex gloves by food handlers is a potential route of inadvertent exposure to latex allergens.2,3 We describe the case of a child with allergy to latex who experienced anaphylaxis after ingestion of a cream-filled doughnut that had been prepared through use of latex gloves and contaminated with latex proteins. A 10-year-old boy was referred to our center for evaluation of a recent anaphylactic reaction (angioedema, urticaria, lip and tongue edema, cough, dyspnea, thoracic pain, and low blood pressure) that had occurred 10 minutes after he ate a cream-filled doughnut that had been purchased at a doughnut shop (shop A). Before this event, the child had often eaten cream-filled doughnuts without having any symptoms; however, the doughnuts had always been purchased at another shop (shop B). The patient did not belong to a latex allergy risk group1,4 and had no history of rhinitis, asthma, or food allergy. He did, however, have a history of 2 episodes of allergic reactions (urticaria, conjunctivitis, lip edema, tongue edema, orbit edema, cough, and difficulty swallowing); these had been caused by (1) latex gloves used by a dentist and (2) a latex balloon that the child had inflated by mouth. IgE to latex was demonstrated with a positive skin prick test (SPT) result for latex (wheal size, 10 mm); the testing was conducted through use of 2 commercial latex extracts (Laboratorio Lofarma, Milan, Italy, and Stallergenes, Saronno, Varese, Italy) and in the presence of specific serum IgE to latex (9.11 kUA/L, Uni-