Serum IgG Responses to Food Antigens in the Italian Population Evaluated by Highly Sensitive and Specific ELISA Test

Common misconceptions and controversies in the management of irritable bowel syndrome

Despite an increase in our understanding of the pathophysiology of irritable bowel syndrome (IBS), in the context of abnormal gut-brain axis communication, and advances in both pharmacological and non-pharmacological treatment of the disorder, there remain areas in which there are misconceptions and controversies in the clinical management of IBS. This Perspective aims to highlight some of the most common misconceptions and controversies in IBS management, including those that the scientific literature has resolved, but for which further education of clinicians dealing with patients with IBS might be required to implement the findings from medical research. Areas of remaining contention are also discussed, as are suggestions as to how these issues could be addressed, both by advances in clinical practice and by further research.

A Novel, IBS-Specific IgG ELISA-Based Elimination Diet in Irritable Bowel Syndrome: A Randomized, Sham-Controlled Trial

BACKGROUND & AIMS

Personalized dietary therapies for irritable bowel syndrome (IBS) are needed and an immunoglobulin (Ig)G-antibody-based elimination diet presents a potential solution. However, existing studies have serious methodological limitations. This study aimed to assess the efficacy of an elimination diet by using a novel IBS-specific IgG assay.

METHODS

We conducted a randomized, double-blind, sham-controlled trial enrolling subjects with IBS from 8 centers. Subjects positive for ≥1 food on an 18-food IgG assay and an average daily abdominal pain intensity score between 3.0 and 7.5 on an 11.0-point scale during a 2-week run-in period were randomized to either an experimental antibody-guided diet or sham diet for 8 weeks. The primary outcome was a ≥30% decrease in abdominal pain intensity for ≥2 of the last 4 weeks of the treatment period.

RESULTS

Among 238 randomized subjects with IBS, 223 were included in the modified intention-to-treat analysis. A significantly greater proportion of subjects in the experimental diet group met the primary outcome than those in the sham diet group (59.6% vs 42.1%, P = .02). Subgroup analysis revealed that a higher proportion of subjects with constipation-predominant IBS and IBS with mixed bowel habits in the experimental diet group met the primary endpoint vs the sham group (67.1% vs 35.8% and 66% vs 29.5%, respectively).

CONCLUSIONS

Subjects on an IgG-guided elimination diet were more likely to achieve the primary endpoint than those on a sham elimination diet. Subgroup analysis suggests a more robust benefit for subjects with constipation-predominant IBS and IBS with mixed bowel habits. This highlights the potential effectiveness of a personalized elimination diet based on a novel IBS-specific IgG assay. A larger study is warranted to validate these observations. (ClinicalTrials.gov, Number NCT03459482.).

Small bowel stomas are associated with higher risk of circulating food-specific-IgG than patients with organic gastrointestinal conditions and colostomies

OBJECTIVE

The effects of food sensitivity can easily be masked by other digestive symptoms in ostomates and are unknown. We investigated food-specific-IgG presence in ostomates relative to participants affected by other digestive diseases.

DESIGN

Food-specific-IgG was evaluated for 198 participants with a panel of 109 foods. Immunocompetency status was also tested. Jejunostomates, ileostomates and colostomates were compared with individuals with digestive tract diseases with inflammatory components (periodontitis, eosinophilic esophagitis, duodenitis, ulcerative colitis, Crohn's disease and appendicitis), as well as food malabsorption due to intolerance. A logistic regression model with covariates was used to estimate the effect of the experimental data and demographic characteristics on the likelihood of the immune response.

RESULTS

Jejunostomates and ileostomates had a significant risk of presenting circulating food-specific-IgG in contrast to colostomates (OR 12.70 (p=0.002), 6.19 (p=0.011) and 2.69 (p=0.22), respectively). Crohn's disease, eosinophilic esophagitis and food malabsorption groups also showed significantly elevated risks (OR 4.67 (p=0.048), 8.16 (p=0.016) and 18.00 (p=0.003), respectively), but not the ulcerative colitis group (OR 2.05 (p=0.36)). Individuals with profoundly or significantly reduced, and mild to moderately reduced, levels of total IgG were protected from the formation of food-specific IgG (OR 0.09 (p=<0.001) and 0.33 (p=0.005), respectively). Males were at higher risk than females.

CONCLUSION

The strength of a subject's immunocompetence plays a role in the intensity to which the humoral system responds via food-specific-IgG. An element of biogeography emerges in which the maintenance of a colonic space might influence the risk of having circulating food-specific-IgG in ostomates.

Specific Dog Allergen Immunoglobulin G Antibodies in Patients with Allergic Conjunctivitis

Purpose:

The purpose of the study was to examine the role of total tear IgE, and specific serum dog IgG and IgE antibodies on the severity of allergic conjunctivitis.

Methods:

This study enrolled healthy subjects (control group, N=13), the patients with seasonal allergic conjunctivitis (seasonal group, N=13), and patients with perennial allergic conjunctivitis (perennial group, N=13). Skin prick test, tear IgE level, and serum specific dog IgE and IgG levels were examined. The severity of allergic conjunctivitis using a grading score (0-30) was also examined.

Results:

The levels of serum dog-specific IgE and IgG, and total tear IgE of the seasonal and perennial groups were higher as compared to those of the control group (all p<0.05). The levels of serum dog-specific IgG of the perennial group were higher than those of the seasonal group (0.4 ± 0.6 vs. 0.0 ± 0.0). Multivariate analysis confirmed that the skin prick test result for dog allergen was related to the serum dog-specific IgG levels, but not IgE levels (p<0.01). The severity of allergic conjunctivitis was related to the serum level of dog-specific IgG antibodies (p<0.01).

Conclusion:

It was concluded that dog-specific IgG antibodies level may be associated with the severity of dog-related perennial allergic conjunctivitis.

Fabrication of Microarrays for the Analysis of Serological Antibody Isotypes against Food Antigens

Food intolerance is delayed adverse food reactions which follow consumption of specific foods. The underlying mechanisms are not well understood, but food intolerance is often considered as a type 2 hypersensitivity reaction mediated by immunoglobulin G (IgG) antibody. To understand the causes of food intolerance, it is important to investigate sensitization patterns of food-specific IgGs (sIgG) in relation to dietary patterns and physical conditions. Conventional approaches to measure serological IgGs often require large volumes of serum, thus are not suitable for highly multiplexed assays. To overcome this impracticality, we developed a highly sensitive method to screen the sIgGs and other antibody isotypes against 66 antigens with minimal amount of serums. We prepared a microarray by immobilizing food antigens on activated glass slides. Human sera and their dietary information were obtained from 30 subjects. Aliquots (200 nl) of sera were analyzed against 66 food antigens in parallel. sIgG levels were determined and analyzed in relation to subjects' dietary patterns. The levels of antibody isotypes were also examined to understand the relationship between allergy and food intolerance. The developed microarray showed exceptional performances in antibody screening and demonstrated the potential to be used as an automated assay system.

Detection of serum and salivary IgE and IgG1 immunoglobulins specific for diagnosis of food allergy

Given the growing incidence and prevalence of life-threatening food allergies, health concerns have raised new perspectives for in vivo and in vitro diagnostic methodologies, pointing to saliva as a promising material, already used to diagnose other pathologies. Based on the above considerations, this study aimed to verify the possible use of saliva for the detection of IgE and IgG₁ in the diagnosis of food allergy. This was a randomized, cross-sectional clinical study with a quantitative approach, developed at a hospital referral center in allergy in the state of Ceará, from January to July 2015. The sample consisted of 36 children of both sexes, aged between 1 and 60 months, with a diagnosis of cow's milk protein allergy (CMPA) by the RAST test. Children hospitalized or under immunosuppressive drugs were excluded from the study. Serum and saliva samples of the participants were collected and subsequently subjected to the indirect immunoenzymatic assay (ELISA) for the detection of specific serum and salivary immunoglobulins for food: corn, papaya, cow's milk, egg white, wheat, soybeans, peanuts, nuts, kiwi, cacao, fish, shrimp, bananas and tomatoes. For comparison of serum and saliva results, the T-test of independent samples and Mann-Whitney were adopted, for samples with normal and non-normal distribution respectively. A confidence interval of 95% was adopted for significant results. It was observed that 100% (n = 36) of the participants presented cow's milk allergy through the indirect ELISA, detecting IgE or IgG₁ in serum and saliva. When serum IgE and IgG₁ concentrations were compared, there was no statistical difference (p > 0.05) in 12 of the 14 foods evaluated. The same amount (n = 12) of non-significant differences (p > 0.05) was observed in the comparison of the 14 foods under IgE and IgG₁ contractions in saliva. In the verification of the average values of IgE present in the serum and saliva of the foods, only cow's milk, fish and papaya showed statistically significant differences (p < 0.05). Of the total food evaluated, only the average levels of IgG₁ present in serum and saliva showed a significant value (p < 0.05) in banana and tomato. These findings indicate that the detection of IgE and IgG₁ in saliva proves to be as efficient as in the serum. The use of the salivary technique for use in the diagnosis of food allergy is suggested.

Immune suppression of IgG response against dairy proteins in major depression

BACKGROUND

Interactions between the digestive system, brain functions and immunoglobulin G (IgG) mediated immunity against food antigens became recently a topic of growing interest in psychiatry research. Psychological stress can activate hypothalamic-pituitary-adrenal axis (HPA) with subsequent hypercortisolemia. It can also influence intestinal permeability and dynamics of IgG response. Major depression can by accompanied either by activation of inflammatory response or by immune suppression (e.g. decreased antibody production) where hypercortisolemia is a significant immune modulator. The aim of our study was to assess IgG immune response against 44 food products in depressed patients and controls along with markers of psychological stress, inflammation, psychometric and dietary parameters.

METHODS

Serum IgG concentrations against 44 food antigens, plasma cortisol, TNF-α, IL-6, IL-1b concentrations were measured and psychometric parameters were evaluated using Hamilton Depression Rating (HAM-D 17), Perceived Stress (PSS-10), and Symptom Checklist (SCL-90) scales in 34 depressed patients and 29 controls. Dietary parameters such as frequency of exposure to food antigens, appetite and weight change were assessed.

RESULTS

There was a significantly lower IgG concentration against dairy in depressed patients compared to controls (post hoc p < 0.05) when there was a high exposure (consumption) to dairy. Our research revealed a significant interaction of IgG concentration against dairy proteins and exposure to dairy between groups (F (2.63) = 3.92, p = 0.025, η² = 0.12). There was no significant difference in mean IgG concentration against food antigens between patients and controls. We found increased concentration of cortisol in depressed patients (t (1.61) = 2.37, p = 0.02) compared to controls. Patients with melancholic depression had significantly higher (M _rank  = 21.27) concentration of cortisol (U = 41, p = 0.006), when compared with the non-melancholic group of patients (M _rank  = 12.16). Cortisol concentration significantly positively correlated with HAM-D 17 (r = 0.442, p = 0.009) and with phobias in SCL-90 scale in patients' group (r = 0.531, p = 0.001). There was decreased concentration of TNF-α (t = 4.256, p < 0.001) in depressed patients compared to controls. IgG concentration of 38.63% food products positively correlated with TNF-α concentration in depressed patients compared to 9.09% of those in healthy controls.

CONCLUSIONS

We observed an immune suppression of IgG response to dairy proteins in depressed patients. Hypercortisolemia with involvement of decreased concentration of TNF-α might play a significant role in suppression of IgG response in depressed patients.

Food IgG4 antibodies are elevated not only in children with wheat allergy but also in children with gastrointestinal diseases

BACKGROUND

Food sIgG and sIgG4 are highly individually versatile. We put a hypothesis that one of the responsible factors is the presence of gastrointestinal inflammatory diseases. The objectives were: 1. An analysis of wheat and rice sIgG and sIgG4 in healthy children, children with IgE-mediated wheat allergy (WA), coeliac disease (CD) and Helicobacter pylori infection (HP). 2. Usability of wheat sIgG and sIgG4 in the WA diagnostics.

METHODS

We compared 388 each wheat and rice sIgG and sIgG4 in a group of 200 children: 50 WA (diagnosis, diet treatment, tolerance), 50 CD (diagnosis and remission), 50 HP and 50 healthy. SIgE, sIgG, sIgG4 were determined with the FEIA method (Pharmacia CAP System).

RESULTS

In healthy children food sIgG were the lowest; no sIgG4 were found. In the CD diagnosis group wheat and rice sIgG and rice sIgG4 were the most common and their concentrations were the highest (p < .001, p < .05). Wheat sIgG4 were the highest in WA children (diagnosis and tolerance) to fall during the elimination diet (p < .05). Wheat and rice sIgG remained the same in all allergy phases. Rice sIgG also did not differ in the class G4.

CONCLUSIONS

1. Serum concentrations of wheat and rice sIgG and sIgG4 are elevated in children with CD, HP and WA. 2. Sub-clinical incidence of some gastrointestinal inflammatory diseases may be responsible for high individual versatility of food sIgG and sIgG4 concentrations in serum. 3. Wheat sIgG and sIgG4 in children do not correlate with WA clinical picture.

The Impact of a Food Elimination Diet on Collegiate Athletes' 300-meter Run Time and Concentration

BACKGROUND

Optimal human function and performance through diet strategies are critical for everyone but especially for those involved in collegiate or professional athletics. Currently, individualized medicine (IM) is emerging as a more efficacious approach to health with emphasis on personalized diet strategies for the public and is common practice for elite athletes. One method for directing patient-specific foods in the diet, while concomitantly impacting physical performance, may be via IgG food sensitivity and Candida albicans analysis from dried blood spot (DBS) collections.

METHODS

The authors designed a quasi-experimental, nonrandomized, pilot study without a control group. Twenty-three participants, 15 female, 8 male, from soccer/volleyball and football athletic teams, respectively, mean age 19.64+0.86 years, were recruited for the study, which examined preposttest 300-meter run times and questionnaire responses after a 14-day IgG DBS-directed food elimination diet based on IgG reactivity to 93 foods. DBS specimen collection, 300-meter run times, and Learning Difficulties Assessment (LDA) questionnaires were collected at the participants' university athletics building on campus. IgG, C albicans, and S cerevisiae analyses were conducted at the Great Plains Laboratory, Lenexa, Kansas.

RESULTS

Data indicated a change in 300-meter run time but not of statistical significance (run time baseline mean=50.41 sec, run time intervention mean=50.14 sec). Descriptive statistics for frequency of responses and chi-square analysis revealed that 4 of the 23 items selected from the LDA (Listening-Memory and Concentration subscale R=.8669; Listening-Information Processing subscale R=.8517; and General Concentration and Memory subscale R=.9019) were improved posttest.

CONCLUSION

The study results did not indicate merit in eliminating foods based on IgG reactivity for affecting athletic performance (faster 300-meter run time) but did reveal potential for affecting academic qualities of listening, information processing, concentration, and memory. Further studies are warranted evaluating IgG-directed food elimination diets for improving run time, concentration, and memory among college athletes as well as among other populations.

Specific IgG for cat allergens in patients with allergic conjunctivitis

Immunoglobulin G (IgG) antibodies are involved in type II and type III hypersensitivity. We evaluated the relation between perennial allergic conjunctivitis and serum levels of specific IgG for cat allergens. A prospective study was conducted in patients with seasonal allergic conjunctivitis (seasonal group, n = 10), patients with perennial allergic conjunctivitis (perennial group, n = 10), and healthy control subjects (control group, n = 10). Serum levels of specific IgE and IgG for cat allergens and total tear IgE were measured, and a skin prick test was also performed. In addition, a severity score associated with allergic conjunctivitis was calculated (0-30). The positive rates and scores of for total tear IgE, serum cat-specific IgE, and serum cat-specific IgG were all higher in the seasonal and perennial groups than in the control group (all p < 0.05). Serum cat-specific IgG levels were higher in the perennial group than in the seasonal group (p = 0.0156), but there was no significant difference in the grade of cat-specific IgE between the two groups (p = 0.3008). On multivariate analysis, the mean wheal diameter for cat allergen was associated with the serum level of cat-specific IgG (not IgE) in all patients [odds ratio (OR) = 31.979, p < 0.0001]. Multivariate analysis revealed that the total objective score was strongly associated with serum cat-specific IgG (OR = 23.015, p < 0.0001). These findings suggest that specific IgG antibodies may be involved in perennial allergic symptoms caused by indoor allergens such as cat allergens.

Randomised controlled trial of food elimination diet based on IgG antibodies for the prevention of migraine like headaches

BACKGROUND

Research suggests that food intolerance may be a precipitating factor for migraine like headaches.

AIM

To evaluate the effectiveness of the ELISA (Enzyme Linked Immuno-Sorbent Assay) Test and subsequent dietary elimination advice for the prevention of migraine like headaches.

DESIGN

Randomised controlled trial.

SETTING

Community based volunteers in the UK.

PARTICIPANTS

Volunteers who met the inclusion criteria for migraine like headaches and had one or more food intolerance were included in the study. Participants received either a true diet (n = 84) or a sham diet (n = 83) sheet. Participants were advised to remove the intolerant foods from their diet for 12 weeks.

MAIN OUTCOME MEASURES

Number of headache days over a 12 week period (item A MIDAS questionnaire). Other measures includes the total MIDAS score and total HIT-6 score.

RESULTS

The results indicated a small decrease in the number of migraine like headaches over 12 weeks, although this difference was not statistically significant (IRR 1.15 95% CI 0.94 to 1.41, p = 0.18). At the 4 week assessment, use of the ELISA test with subsequent diet elimination advice significantly reduced the number of migraine like headaches (IRR 1.23 95%CI 1.01 to 1.50, p = 0.04). The disability and impact on daily life of migraines were not significantly different between the true and sham diet groups.

CONCLUSIONS

Use of the ELISA test with subsequent diet elimination advice did not reduce the disability or impact on daily life of migraine like headaches or the number of migraine like headaches at 12 weeks but it did significantly reduce the number of migraine like headaches at 4 weeks.

Subunit and whole molecule specificity of the anti-bovine casein immune response in recent onset psychosis and schizophrenia

Previous studies show increased antibody levels to bovine casein in some individuals with schizophrenia. The immunogenicity of specific domains of bovine casein varies among people with milk sensitivities and thus could vary among different neuropsychiatric disorders. Using ELISAs and immunoblotting, we characterized IgG class antibody specificity to whole bovine casein and to the alpha(s), beta, and kappa subunits in individuals with recent onset psychosis (n=95), long-term schizophrenia (n=103), and non-psychiatric controls (n=65). In both patient groups, we found elevated IgG to casein proteins, particularly to whole casein and the alpha(s) subunit (p<or=0.0001). Odds ratios of casein seroprevalence for recent onset psychosis (age-, gender-, race-, smoking-adjusted) were significant for whole casein (8.13, p<or=0.0001), and the alpha(s) (7.89, p<or=0.0001), beta (5.23, p<or=0.001) and kappa (5.70, p<or=0.0001) subunits. Odds ratios for long-term schizophrenia were significant for whole casein (7.85, p<or=0.0001), and the alpha(s) (4.78, p<or=0.003) and kappa (4.92, p<or=0.004) subunits. Within the recent onset group, odds ratios were particularly significant for a subgroup of people with psychotic disorders that included major depressive disorders (8.22-16.48, p<or=0.0001). In a different recent onset subgroup (schizophrenia-spectrum disorders), PANSS scores for negative symptoms were correlated with casein antibody levels for the alpha(s) and kappa subunits (p<or=0.001-0.01). Immunoblotting patterns also exhibited group specificity, with kappa predominant in recent onset and alpha(s) in schizophrenia (Fisher's Exact Test, p<or=0.001). The elevated IgG and unique patterns of antibody specificity to bovine casein among diagnostic groups provide a rationale for clinical trials to evaluate efficacies of dietary modifications in individuals with neuropsychiatric diseases.