Transcript of "Lymphocyte Proliferation Response in Soy Allergy"
Response in Soy Allergy
J. Andrew Bird, M.D.
Fellow, Pediatric Allergy and Immunology
Texas Children’s Hospital
Baylor College of Medicine
Soy is listed as one of the 8 major food
Soy can be found in many foods
including mayonnaise, salad dressings,
commercially processed hamburger
patties, candies, and pasta.
1 Food and Agriculture Orgainzation of the United Nations (1995) Report of the FAO Technical consultation on Food Allergies 1995. Rome, Italy.
Prevalence of Soy Allergy in
High Risk Infants
Cantani meta-analysis, 19972
Looked at 17 different studies regarding soy
protein formula allergy in high risk infants.
High-risk infants – based on atopic history
status of parents and/or siblings
Soy allergy occurred in 3 – 4 % of subjects vs.
25% for cow’s milk
No occurrences of anaphylaxis reported.
Mostly GI related or AD symptoms.
2Cantani, A.and Lucenti, P. (1997). Natural history of soy allergy and/or intolerance in children, and clinical use of soy-
protein formulas. Pediatr. Allergy Immunol. 8:59-74.
Prevalence of soy in atopic
Patients with atopic symptoms
Magnolfi et al. – 704 atopic children – 21% soy
positive by SPT and 1.3% soy positive by DBPCFC3
Bruno et al. – 505 atopic children – 6% soy
positive by SPT and 1.8% soy positive by DBPCFC4
Burks et al. – 13% soy positive by SPT and 1.8%
soy positive by DBPCFC in 165 patients5
3Magnolfi, C et al. Soy allergy in atopic children. Ann. Allergy Asthma Immunol. 77:197-201.
4Bruno G, et al. Soy allergy is not common in atopic children: a multicenter study. Pedatr. Allergy Immunol. 8:190-193.
5Burks et al. Atopic dermatitis and food hypersensitivity reactions. J. Pediatr. 132:132-136.
Limitations for defining soy
Overall – high rate of false-positive results
when SPT and RAST are used to diagnose
symptomatic soy food allergy.
Need for DBCPFC to clearly define allergy
Advances in Food Allergy
Skin prick test – Hill (2004)6 - 100% PPV for
milk, egg, and peanut
No determination for soy.
RAST – Sampson (2001)7 - 90% and 95%
PPV for egg, peanut, cow’s milk, and fish.
RAST PPV for soy not defined to 90 or 95% PPV
DBPCFC still gold standard for diagnosis of
6Hill, D et al. The diagnostic value of skin prick testing in children with food allergy. Pediatric Allergy and Immunology 2004: 15; 435-441.
7 Sampson H. Utility fo food –specific IgE concentrations in predicting symptomatci food allergy. JACI, May 2001. Vol 107, No 5, pp 891 – 896.
T-cell sensitization has been demonstrated to
play a role in both IgE- and non-IgE-
mediated food allergy
Roehr et al. (2001) and Niggemann et al., (2000)
- Atopy patch tests used in conjunction with other
diagnostic modalities predictive of reaction.
LPR to cow’s milk – conflicting results with
studies – felt there is no significant LPR
(Hoffman, Ho, Sampson, 1997).
LPR to egg - specifically ovalbumin
more marked and prolonged in egg allergic
patients as compared to non-allergic
controls (Ng et al., 2002)
No studies published regarding LPR to
1. To evaluate whether soy extract can
cause in vitro T cell stimulation in non-
allergic and/or known soy allergic
2. To identify if an LPR threshold exists
between non-allergic and known soy
Selection of patients based on review of
patient database for those seen with
diagnoses of anaphylaxis or food allergy.
Chart review will further select those patients with
a history of soy allergy based on history of
repeated clinical reactivity and/or soy-specific IgE
Symptoms to include eczema, eye, nasal, respiratory or
GI IgE-mediated symptoms.
35 soy allergic volunteers
Age-matched ranges of 1 to 12 y/o and > 12 y/o.
Controls must tolerate soy orally by history and have
soy-specific IgE as measured by CAP RAST < 0.35
T-test to compare LPR tests between matched
Clinical reactivity upon soy ingestion with
detectable soy-specific IgE>0.35 kU/ml.
Includes eczema, eye, nasal, respiratory or GI IgE-
1 to 12 y/o vs. > 12 y/o
Excluded if they:
tolerate soy orally
are without clinical reactivity
and have no detectable soy-specific IgE.
Control subjects will be excluded if they:
have clinical reactivity upon soy ingestion
or soy-specific IgE>0.35 kU/ml.
Patients at TCH
Clinical Presentation of Soy Allergy Patients at TCH
Eczema Eye/Nasal Respiratory GI
Total: 41 patients with soy allergy
Fliers sent to local allergists
Over 120 mail-outs with recruitment
Announcements at local allergy society
Plan on follow-up phone calls.
All subjects will have blood drawn for LPR.
PBMCs will be isolated from whole blood via Ficoll
LPR performed with soy extract at 50,125,250, and 500
Concomitant studies will be performed using Candida
1:200 (positive control) and RPMI (negative control)
Each well will be pulsed with 3H-thymidine and
harvested 18 hours later.
CAP RAST to soy will be obtained if not obtained
in past year.
First visit, cont.
All patients without anaphylaxis will have skin
prick tests and atopy patch tests placed.
SPT performed using soybean reagent (Greer
laboratories, 1:20 concentration) and histamine and
APT performed using 50 microliters of soy milk on filter
paper and applying to unaffected skin on the patient’s
back by using 12-mm aluminum cups on adhesive tape
(Finn chambers on Scanpor).
Occlusion time will be 48 hours and results will be read 24
hours after removal for the final evaluation of the test.
Eczema assessment with SCORAD.
Preliminary Studies with
FCS vs HS
LPR to Media
14000 HS 10%
Determine feasibility of an
alternative/adjunctive diagnostic procedure
for soy allergy that could yield applicable
results within 2 to 3 years.
Potentially eliminate the need for DBPCFC
and better define the pathogenesis behind
manifestations of soy allergy.
Recently received IRB approval.
Fliers sent to allergy private practice
Calling within TCH Allergy/Immunology
Special thanks to Dr. Carla Davis,
Dr. Celine Hanson, Dr. Kim Shanks,
Dr. Duyen Nguyen, and Dr. Christy Nance
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