Alteration of -656(G/T) and -607(C/A) polymorphisms in interleukin-18 (IL-18) gene in house dust mite-sensitive allergic rhinitis patients in Thailand.

Allergic rhinitis (AR) is an IgE-mediated inflammation of the nasal membranes, which is naturally triggered by aeroallergens. House dust mites (HDM) are the most common inhalant allergens. Interleukin-18 (IL-18) has been established as an essential cytokine that can activate the generation of IgE. This randomized controlled study aimed to identify the possible relationship of the genetic variations in the IL-18 gene with AR in mite-sensitive Thai patients. Study subjects consisted of 150 AR patients and 50 normal participants. Genomic DNA of 30 randomized AR patients and 30 randomized controls were screened by sequencing for the selection of candidate single nucleotide polymorphisms (SNPs), and further analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay for all subjects. The following five SNPs were detected in the IL-18 gene: -656 G/T, -607 C/A, and -137 G/C in promoter 1 and -920 C/T and -373 C/G in promoter 2. The results showed that -656 G/T and -607 C/A SNPs were significantly correlated with IgE levels specific to Dermatophagoides pteronyssinus (Der p) allergen (P = 0.045 and P = 0.045, respectively), and significant differences were observed in the genotype distribution of AR patients when compared with controls [P = 0.044 and P = 0.044, respectively; odds ratios (ORs): 1.941 (95%CI, 1.014-3.715) and 1.941 (95%CI, 1.014-3.715), respectively]. Our findings indicate that the IL-18 alleles, -656T (rs1946519) and -607A (rs1946518), might be associated with the higher production of Der p allergen-specific IgE in mite-sensitive AR patients.

Cx26 regulates proliferation of repairing basal airway epithelial cells.

The recovery of an intact epithelium following injury is critical for restoration of lung homeostasis, a process that may be altered in cystic fibrosis (CF). In response to injury, progenitor cells in the undamaged areas migrate, proliferate and re-differentiate to regenerate an intact airway epithelium. The mechanisms regulating this regenerative response are, however, not well understood. In a model of circular wound injury of well-differentiated human airway epithelial cell (HAEC) cultures, we identified the gap junction protein Cx26 as an important regulator of cell proliferation. We report that induction of Cx26 in repairing HAECs is associated with cell proliferation. We also show that Cx26 is expressed in a population of CK14-positive basal-like cells. Cx26 silencing in immortalized cell lines using siRNA and in primary HAECs using lentiviral-transduced shRNA enhanced Ki67-labeling index and Ki67 mRNA, indicating that Cx26 acts a negative regulator of HAEC proliferation. Cx26 silencing also markedly decreased the transcription of KLF4 in immortalized HAECs. We further show that CF HAECs exhibited deregulated expression of KLF4, Ki67 and Cx26 as well enhanced rate of wound closure in the early response to injury. These results point to an altered repair process of CF HAECs characterized by rapid but desynchronized initiation of HAEC activation and proliferation.

Epidemiology and current status of allergic rhinitis and asthma in Thailand -- ARIA Asia-Pacific Workshop report.

The allergic diseases of the airway, i.e. allergic rhinitis and asthma, are on the increase in Thailand and their prevalence shows no signs of abating. When compared with a previous study, the incidence of wheezing had increased 4 fold (from 4.2% to 18.3%), and allergic rhinitis increased nearly 3 fold (from 17.9% to 44.2%). The results of the ISAAC phase III study revealed that the frequency of allergic diseases of the respiratory tract increased significantly from the ISAAC phase I survey performed in 1995; i.e. asthma increased from 12.2% to 14.5%, and allergic rhinitis from 37.9% to 50.6%. Allergic rhinitis exerts a major impact on the quality of life of Thai patients. The results of skin prick testing have indicated the leading causes of indoor (house-dust mites, house dust, cockroaches, dogs and cats) and outdoor pollen (Bermuda grass, para grass, sedge, careless weed) allergens. Molds (represented by Cladosporium), although prominent in an aeroallergen survey, returned a low percentage of positive skin prick reactions, and therefore, were considered low in allergenicity. In Thailand, there are clinical practice guidelines for both allergic rhinitis and asthma which are comparable to the international guidelines like ARIA and GINA. Sufficient kinds of pharmacotherapy are on the National List of Essential Drugs. Yet due to the limited number of trained allergists, many patients are seen by general physicians, and often, the appropriate diagnostic tests and treatments are not provided. In addition, the financial burden for quality health care may be prohibitive for those without private health insurance in spite of the implementation of a universal health care system for all Thai citizens, which is less than optimal.