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

Citation:

Singh AK, Mehta AK, Sridhara S, Gaur SN, Singh BP, Sarma PU, Arora N. Allergenicity assessment of transgenic mustard (Brassica juncea) expressing bacterial codA gene. Allergy, 2006; 61 (4): 491-497.

PubMed ID: 16512812
 
Study Design:
Non-Randomized Crossover Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
This study aimed to assess the allergenicity of Brassica juncea (mustard), expressing choline oxidase (codA) gene from Arthrobacter globiformis, that provides resistance against abiotic stresses. 
Inclusion Criteria:
  • Diagnosis of asthma defined by the American Thoracic Society
  • Provided written informed consent.
Exclusion Criteria:
Not mentioned.
Description of Study Protocol:

Recruitment

  • Subjects were allergy patients aged 15 years to 45 years at the outpatient department (OPD), V.P. Chest Institute, Delhi, a referral chest hospital which receives patients from different parts of the country for diagnosis and treatment of allergy and asthma
  • For the present study, the diagnosis of asthma was ascertained in cases following the guideline of the American Thoracic Society
  • Patients having any two of the symptoms: Sneezing, rhinorrhea, nasal blockage, postnasal drip, etc. were diagnosed as having rhinitis.

Design

Non-randomized crossover trial.

Blinding Used

Implied with measurements.

Intervention

Sera were collected from SPT-positive patients and normal healthy volunteers for immunoassays with GM and native mustard.

Statistical Analysis

  • Specific IgE levels against GM and native mustard in mice and food-hypersensitive patients' sera were compared by using the paired T-test
  • Skin prick test results were compared by Wilcoxon test. P<0.05 was considered statistically significant.
Data Collection Summary:

Timing of Measurements

Measurements made in all subjects.

Dependent Variables

  • Sequence homology study was done using Structural Database of Allergenic Proteins (SDAP) and Food Allergy Resources and Research Program (FARRP) to identify any allergen presenting a 35% amino acid identity through a window of 80 amino acids with choline oxidase
  • The digestibility of the purified choline oxidase protein produced from A. globiformis was examined
  • Leaves of B. juncea expressing codA gene isolated from A. globiformis and native species were used for the present study
  • Genetically modified and native mustard proteins were resolved onto 12% SDS PAGE
  • Skin prick tests were performed with GM and native mustard 
  • Specific IgE levels against GM and native mustard was estimated by using enzyme-linked immunosorbent assay (ELISA)
  • Serum antibodies specific for OVA, native or GM protein were measured by using ELISA.
Independent Variables
  • GM vs. native mustard
  • Allergic patients versus healthy controls.
Description of Actual Data Sample:
  • Initial N: 96 (61 male, 35 female) patients and 10 healthy controls
  • Attrition (final N): As above
  • Age: Range 15 years to 45 years
  • Ethnicity: Not reported
  • Other relevant demographics: Not reported 
  • Anthropometrics: Not reported
  • Location: Delhi, India.
Summary of Results:

Key Findings

  • Choline oxidase showed no significant homology with allergenic proteins in SDAP and FARRP databases
  • Cross-reactive epitope search showed a stretch similar to Hev b 6 having some antigenic properties
  • Purified choline oxidase showed complete degradation with SGF
  • Skin prick test of native and GM mustard extract on respiratory allergic patients showed significant correlation (P<0.05)
  • ELISA with 96 patients' sera showed comparable IgE reactivity.
Author Conclusion:
  • Genetically modified mustard with the codA gene possessed allergenicity similar to that of native mustard and no enhancement of IgE binding was observed due to genetic manipulation
  • In conclusion, both GM and native mustard showed same allergenicity with no enhancement in IgE binding due to genetic manipulation.
Funding Source:
Government: Department of Biotechnology, Government of India
Reviewer Comments:
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? Yes
  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? Yes
  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? No
  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? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  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)? Yes
  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