Advanced Technology in Food Production

ATFP: Human Consumption of Plant Foods Produced Using Genetic Engineering (GE) Technologies (2015)

Lee SK, Ye YM, Yoon SH, Lee BO, Kim SH, Park HS. Evaluation of the sensitization rates and identification of IgE-binding components in wild and genetically modified potatoes in patients with allergic disorders. Clin Mol Allergy. 2006; 4: 10.

  PubMed ID: 16817976
Study Design:
Non-Randomized Crossover Trial
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
The purpose of this study was to compare the allergenicity of genetically modified (GM) potatoes with that of wild-type potatoes using in vivo and in vitro methods in adult allergy patients sensitized to potatoes.
Inclusion Criteria:
  • Aged between 15 years and 65 years
  • Patients were admitted to a hospital for the treatment of various allergic diseases including asthma, allergic rhinitis and food and drug allergy. They were skin prick tested with common inhalant allergens and with extracts from GM and wild-type potatoes. 
  • Provided written informed consent.
Exclusion Criteria:
Not described.
Description of Study Protocol:
  • Recruitment: Patients were recruited from the Department of Allergy and Rheumatology at Ajou University School of Medicine in Suwon, Korea
  • Design: Non-randomized crossover controlled trial
  • Blinding used: Implied with measurements
  • Intervention: Allergenicity of genetically modified (GM) potatoes and wild-type potatoes was compared
  • Statistical analysis: Not described.
Data Collection Summary:

Timing of Measurements

Measurements completed once.

Dependent Variables

  • Skin-prick testing and IgE-ELISA were carried out with extracts prepared from wild-type and GM potatoes
  • An ELISA inhibition test was used to confirm the binding specificity
  • IgE-binding components in extracts from the two types of potato were identified by SDS-PAGE and IgE immunoblotting
  • The effects of digestive enzymes and heat on the allergenicity of the extracts was evaluated by pre-incubating the potatoes with or without simulated gastric and intestinal fluids in the absence of heat.
Independent Variables

Genetically modified (GM) potatoes and wild-type potatoes.

Description of Actual Data Sample:
  • Initial N: 1,886 patients with various allergic diseases and 38 healthy controls
  • Attrition (final N): As above
  • Age: Ranging from 15 years to 65 years
  • Ethnicity: Not described
  • Other relevant demographics: Not described
  • Anthropometrics: Not described
  • Location: Korea.
Summary of Results:

Key Findings

  • Positive responses [ratio of the wheal size induced by the allergen to that induced by histamine (A/H)] greater than or equal to wild-type or GM potato extracts, as demonstrated by the skin-prick test, were observed in 108 patients (5.7%)
  • Serum-specific IgE was detected in 0% to 88% of subjects who tested positively 
  • ELISA inhibition tests indicated significant inhibition when extract from each type of potato was added
  • IgE-immunoblot analysis demonstrated the presence of 14 IgE binding components within the wild-type potato and nine within the GM potato
  • Furthermore, a common 45-kDA binding component that yielded similar IgE binding patterns was noted in more than 80% of the reactions using sera from patients sensitized to wild-type or GM potato
  • Exposure to stimulated gastric fluid and heat treatment similarly inhibited IgE binding by extracts from wild-type and GM potatoes, whereas minimal changes were obtained following exposure of the extracts to simulated intestinal fluid.
Author Conclusion:
  • The results of this study strongly suggest that genetic manipulation of potatoes using antibiotic resistance and herbicide tolerance genes does not increase their allergenic risk
  • The sensitization rate of adult allergy patients to both types of extract was 5.7% and a common major allergen (45 kDa) was identified.
Funding Source:
Other: Not reported
Reviewer Comments:
Large numbers of allergic subjects and controls, but subjects were not well described.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes