Association of CRTH2 Gene Polymorphisms with the Required Dose of Antihistamines in Patients with Chronic Urticaria

Abstract

Introduction: Chronic urticaria (CU), defined as the recurring incidence of wheals with or without angioedema for more than 6 weeks, is a common disorder associated with mast cell activation, degranulation, and histamine release. Considering the association between the CRTH2 gene and mast cells, we investigated the association of this gene polymorphism with the CU phenotype and antihistamine drug requirement in patients with CU. Materials & methods: Two groups consisting of 384 patients with CU and 231 patients as normal controls (NCs) were enrolled from the Department of Allergy and Rheumatology, Ajou University Hospital, Suwon, Korea. Two polymorphisms of the CRTH2 gene, -466T>C and -129C>A were genotyped using primer extension methods. Results: No significant differences were detected in the genotype and allele frequencies of the two CRTH2 polymorphisms between the CU and NC groups, and no significant associations were observed with clinical parameters, such as atopy status, serum total IgE, prevalence of autoantibodies and duration of CU. However, CU patients with homozygous TT genotypes had significantly higher dose requirements of antihistamines to control the CU symptoms (164.56 ± 115.62 vs 137.38 ± 90.15 loratadine equivalents, mg/week) than those with the CT and CC genotypes (p = 0.025). The luciferase activity was significantly enhanced in the construct containing CRTH2 466C compared with the -466T-containing construct (p < 0.001). Co-transfection experiments with GATA-3 (300 ng) and the -466T and -466C CRTH2 alleles revealed that the CRTH2 -466T allele produced a greater increase in induction of luciferase activity than the -466C allele (p < 0.001). Conclusion: The CRTH2 -466T>C gene polymorphism may not affect on the phenotype of CU, but contributes to the required dose of antihistamines in patients with CU.

KEYWORDS::

• antihistamine drugs
• chronic urticaria
• CRTH2
• polymorphism

Financial & competing interests disclosure

This study was supported by grants from the Korea Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (A050571 and A030001). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This study was supported by grants from the Korea Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (A050571 and A030001). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.