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

Citation:

Sharma P, Singh AK, Singh BP, Gaur SN, Arora N. Allergenicity assessment of osmotin, a pathogenesis-related protein, used for transgenic crops. J Agric Food Chem. 2011; 59 (18): 9,990-9,995.

PubMed ID: 21838306
 
Study Design:
Non-Controlled Trial
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
The purpose of this study was to assess the allergenicity of osmotin protein using bioinformatic and immunobiochemical methods.
Inclusion Criteria:
  • Patients with allergic rhinitis and asthma aged 15 to 50 years
  • Provided informed consent.
Exclusion Criteria:
Not described.
Description of Study Protocol:

Recruitment

  • Patients with allergic rhinitis and asthma aged 15 to 50 years were skin prick tested with various pollens, fungi, insects and food allergen extracts to detect sensitization
  • The patients having any two of the symptoms, i.e., sneezing, rhinorrhea, nasal blockage, postnasal drip, etc., for most of the time in the last two years were diagnosed with rhinitis
  • Blood samples (sera) were collected from patients showing marked positive skin reactions to different food extracts at the outpatient department, V.P. Chest Institute, Delhi, a referral chest hospital.

Design

Non-controlled trial.

Blinding Used

Implied with measurements.

Intervention

  • Bioinformatic analysis of osmotin was performed using SDAP and Farrp allergen databases
  • Osmotin was cloned in pET22b+ vector, purified to homogeneity and analyzed for digestibility, heat stability and IgE binding using atopic patients' sera.

Statistical Analysis

  • Statistical analysis for the specific IgE values of the patients showing positive SPT to food extracts and normal human sera against osmotin was performed using Epiinfo
  • Analysis of variance revealed a significant difference in concentration of IgE between the patients and the control sera samples
  • A P-value of less than or equal to 0.05 was considered significant.
Data Collection Summary:

Timing of Measurements

Measurements made in all subjects.

Dependent Variables

Allergenicity of osmotin protein: Specific IgE against purified osmotin protein was determined by ELISA
  • 250ng of osmotin protein was intubated in carbonate buffer (250ng per 100mcl per well) overnight at four degrees Celsius in a microtiter plate
  • The plate was washed and incubated with antihuman IgE-horseradish peroxidase for three hours at 37° Celsius.

Independent Variables

Patients with allergic rhinitis or asthma vs. non-allergic controls.
Description of Actual Data Sample:
  • Initial N: A total of 117 patients' sera were screened against osmotin protein by ELISA. Of these, 22 serum samples from patients positive to different foods showed significant IgE binding to osmotin protein.
  • Attrition (final N): 22 patients and four controls
  • Age: Not described
  • Ethnicity: Not described
  • Other relevant demographics: Not described
  • Anthropometrics: Not described
  • Location: India.
Summary of Results:

Key Findings

  • Osmotin showed 40% to 92% and 48% to 75% homology with allergens in the Structural Database of Allergenic Proteins (SDAP) and Farrp databases, respectively
  • These cross-reactive allergens were from apple, tomato, peach, capsicum, kiwi, fruit and cypress
  • Osmotin was resistant to pepsin digestion and heat treatment at 90° Celsius for one hour
  • Osmotin protein showed dose-dependent inhibition with pooled patients sera
  • It showed significant IgE-binding with 22 of 117 patients' sera who were sensitized to tomato and apple, thus indicating cross-reactivity among tomato, apple and osmotin allergens.
Author Conclusion:
In conclusion, osmotin seems to be a potential allergen based on bioinformatics, SGF, heat stability and immunobiochemical studies and showed cross-reactivity with tomato and apple allergens.
Funding Source:
Other: Indian Agricultural Research Institute
Reviewer Comments:
  • Small sample size
  • Subjects 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? ???
  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? ???
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? Yes
  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? No
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