Diamine oxidase levels in different chronic urticaria phenotypes

Predictors of Response to Oral Medications and Low-Histamine Diet in Patients with Chronic Urticaria

Background

Chronic urticaria (CU) is comprised of diverse phenotypes, and thus, a shift towards a precision medical approach is warranted in its management.

Methods

This study enrolled 78 patients with CU. Serum erythrocyte sedimentation rate, hemoglobin, hematocrit, eosinophil count, IgE, antinuclear antibody (ANA), and serum diamine oxidase (DAO) levels of the patients were measured and were compared according to the patient's response to second-generation antihistamines (sgAH), corticosteroids, leukotriene receptor antagonist (LTRA), H₂ blockers, and low-histamine diet.

Results

Age- and sex-adjusted logistic regression analysis showed that patients with duration of CU > 3 years (adjusted odd ratio [aOR] = 4.39) and a DAO level < 10 U/mL (aOR = 3.90) were significantly associated with a good sgAH response. Age > 50 years (aOR = 0.02), duration of chronic urticaria > 3 years (aOR =0.06), and an ANA titer ≥ 1 : 80 (aOR = 0.03) were significantly and inversely associated with corticosteroid response. A low-histamine diet response was significantly associated with LTRA response (aOR = 67.29). In addition, a DAO level < 5.4 U/mL (aOR = 71.95) was significantly associated with H₂ blocker response. Furthermore, concomitant angioedema (aOR = 10.56), multiple food triggers (aOR = 11.69), and a DAO level < 5.4 U/mL (aOR = 3.78) were significantly associated with a low-histamine diet response. Conversely, dermatographic urticaria and a hematocrit level < 36% were significantly and inversely associated with low-histamine diet response.

Conclusions

Several promising biomarkers were identified in this study to predict the efficacy of chronic urticaria treatment. DAO could be a novel biomarker for predicting the efficacy not only of dietary intervention but also for antagonists of H₁ and H₂ receptors.

Nutrition and urticaria

Urticaria is a distressing dermatologic condition for many. Although the wheals of urticaria are characteristically evanescent, lasting less than 24 hours, patients tend to have recurrent episodes. Hives that last less than 6 weeks are considered acute urticaria. Acute urticaria does not routinely require supplementary work-up because the history often identifies a convincing, inciting allergen. Chronic urticaria is defined as episodes that occur for longer than 6 weeks, and there is often not an easily identifiable trigger. For both acute and chronic urticaria, patients frequently report food as a precipitating cause. For acute urticaria, the foods that are associated with true allergies, such as nuts and shellfish, are the most frequent offenders. The relationship between diet and chronic urticaria is not as firmly defined. Many patients unnecessarily restrict their diets, so it becomes the role of dermatologists to help patients identify if there is a reproducible link between their symptoms and their dietary exposures. The literature suggests that diets free from pseudoallergens and histamine-releasing foods may attenuate urticaria. Supplements such as fats, vitamin D, iron, and flavonoids have also been studied and may diminish symptoms.

Two generation reproduction toxicity study of GmDREB3 gene modified wheat in Wistar rats

To study reproductive toxicity of gene modified wheat generated by introducing DREB3 (drought response element binding protein 3) gene, Wistar rats of were allocated into 3 groups and fed with DREB3 gene modified wheat mixture diet (GM group), non-gene modified wheat mixture diet (Non-GM group) and AIN-93 diet (Control group) from parental generation (F0) to the second offspring (F2). GM wheat and Non-GM wheat, Jimai22, were both formulated into diets at a ratio of 69.55% according to AIN93 diet for rodent animals. Compared with non-GM group, no biologically related differences were observed in GM group rats with respect to reproductive performance such as fertility rate, gestation rate, mean duration, hormone level, reproductive organ pathology and developmental parameters such as body weight, body length, food consumption, neuropathy, behavior, immunotoxicity, hematology and serum chemistry. In conclusion, no adverse effect were found relevant to GM wheat in the two generation reproduction toxicity study, indicating the GM wheat is a safe alternative for its counterpart wheat regarding to reproduction toxicity.

Diamine oxidase enzyme: a novel biomarker in respiratory allergy

BACKGROUND

Well-known allergy tests are used to evaluate and diagnose allergic diseases. The aim of this study was to assess the role of serum level diamine oxidase (DAO) enzyme as a diagnostic marker in respiratory allergy.

METHODS

This case-control study included 40 patients with respiratory allergies (atopic asthma and allergic rhinitis) as well as 40 age- and sex-matched controls. A detailed past medical history of allergy was collected from each participant including family history of allergy. Physical examination, pulmonary function test (PFT) and measurement of serum levels of total immunoglobulin E (IgE) and DAO were performed. Skin-prick test and specific IgE to common aeroallergens were also carried out.

RESULTS

DAO levels were higher in patients than controls. There was a positive correlation between severity of disease and DAO. No significant association was found between DAO level and age, type of respiratory allergy, duration of disease, PFT, eosinophilia, and total IgE. DAO had a high negative predictive value (94.7%) and high sensitivity (97.5%).

CONCLUSION

DAO may be helpful in the assessment of severity and in ruling out respiratory allergy.

Possible Allergenic Role of Tropomyosin in Patients with Adverse Reactions after Fish Intake

In a recent case report, patient's anti-fish tropomyosin IgE was associated with gastrointestinal symptoms. We aimed to demonstrate on a wider scale that the panallergen tropomyosin should not be limited to invertebrate species and that clinically relevant reactions could be elicited by vertebrate tropomyosin. On the whole, 19 patients with adverse reactions after fish intake and showing negative skin tests with commercial fish extracts were included. Fish tropomyosin was recognized by 10/19 patients' IgE by immunoblotting. All patients with gastrointestinal complaints after fish intake (6/6) showed an IgE band matching with tropomyosin. Cod, albacore, and swordfish tropomyosins were recognized by most patients although 3/10 patients did not claim adverse reactions to these fish species. Immunoblotting with a battery of antigens from different fish species have a high yield of positivity at a band matching with tropomyosin molecular weight, even if they have not been claimed to be causative agents of symptoms. Tropomyosin is therefore a good candidate to be investigated as a clinically relevant fish allergen in patients who report adverse reactions after fish intake.

A Histamine-Free Diet Is Helpful for Treatment of Adult Patients with Chronic Spontaneous Urticaria

Background

In adult patients with chronic urticaria (CU), the prevalence of food allergy is low compared to childhood patients. However, there are many patients who report food-related aggravation of CU, and some of them may have histamine intolerance.

Objective

The aim of this study was to evaluate the role of ingested histamine and to investigate the effect of a histamine-free diet in adult patients with CU.

Methods

Twenty-two adult patients with CU were enrolled. Foods with high amounts of histamine were prohibited to all patients for four weeks. The degree of severity of the urticaria was evaluated using the urticaria severity score (USS) and urticaria activity score (UAS). Plasma histamine levels and diamine oxidase (DAO) activity were determined and compared before (baseline) and after the histamine-free diet.

Results

Twenty-two adult patients were recruited and completed four weeks of histamine-free diet. The USS and UAS scores each showed significant differences before and after the histamine-free diet (p=0.010, p=0.006). There was a significant reduction in plasma histamine level after the histamine free-diet, compared with baseline (p=0.010). However, DAO activity did not change after the histamine-free diet (p=0.165).

Conclusion

Our study suggested that ingested histamine might be related to CU severity and that a histamine-free diet is helpful for treatment of adult patients with CU.