Association between the polymorphisms of IL-4 gene promoter [-590C>T], IL-13 coding region [R130Q] and IL-16 gene promoter [-295T>C] and allergic asthma

Allergic asthma is a multifactorial disease, influenced by genetic and environmental factors. Recent family-based studies have revealed evidence for linkage of human chromosomes 5q31-33, 12ql5-24, Ilql3 and 15q23.6 as regions likely to contain genes related to asthma. Among the candidate genes in these regions are the genes encoding for human interleukin-4, interleukin-13 and interleukin-16. To evaluate this linkage, we examined an Iranian population of patients with asthma. A total of 30 patients with allergic asthma and 50 normal subjects were studied. Allergic asthma was confirmed using skin prick test and spirometry. DNA was extracted from blood cells and IL-4 [-590C>T], IL-13 [R130Q] and IL-16 [-295T>C] polymorphisms were determined by PCR-RFLP method. Out of 30 patients with allergic asthma, the following genotypes for IL-4, IL-13 and IL-16 cytokines were found: IL-4 genotypes consisted of 17 [56.7%] CC, 8 [26.7%] CT and 5 [16.7%] TT; IL-13 genotypes consisted of 11 [36.7%] GG, 13 [43.3%] GA and 6 [20%] AA; IL-16 genotypes consisted of 23 [76.7%] TT and 7 [23.3%] CT. No patient showed CC genotype for IL-16. A higher proportion of case subjects with the C allele for the IL-4, G allele for the IL-13 and T allele for the IL-16 polymorphisms was found compared with the T, A and C alleles, respectively. These results suggest an influence of genetic variability at the promoter of IL-4 gene [-590C>T] and a coding region of IL-13 gene [R130Q] on the occurrence of allergic asthma and no relationship between IL-16 promoter polymorphism [-295T>C] and this disease

Association of the expression of IL-4 and IL-13 genes, IL-4 and IgE serum levels with allergic asthma

Immune and inflammatory responses mediated by cytokines, play important roles in the pathophysiology of asthma. These responses are associated with overexpression of Th2 cytokines such as IL-4 and IL-13. These two cytokines use common receptors for signaling that lead to identical immunological effects and regulation of the Th1/Th2 balance. The aim of this study was to determine whether patients with allergic asthma display overexpression of IL-4 and IL-13 genes. Using RT-PCR, we examined the expression of IL-4 and IL-13 genes in twenty asthmatic cases and twenty normal individuals. Total levels of serum IgE and IL-4 were also determined by ELISA method. Expression of IL-13 gene in 70% of patients with allergic asthma was higher than controls [P=0.01]. There was no correlation between the expression of IL-13 gene and total level of serum IgE [P=0.07]. Expression of IL-4 gene was detected in 30% of the patients and none of the normal individuals as determined by RT-PCR [P=0.01]. Mean of serum IgE levels in patients and controls were 84.9 IU/ml and 62.2 IU/ml, respectively. Level of serum IgE was more than 100 IU/ml in 30% of patients [P=0.03]. Mean of serum IL-4 levels in patients and controls were 15.73 pg/ml and 13.07 pg/ml, respectively. There was a relation between levels of serum IgE and IL-4 in 73% of cases. The results showed that there was a correlation between the expression of IL-4 gene and the level of serum IL-4. Levels of serum IgE and IL-4 were considerably higher in asthmatics than nonasthmatic controls

Association between the polymorphism of TGF- beta 1 gene promoter [-509C>T] and idiopathic chronic Urticaria

Idiopathic Chronic Urticaria [ICU], the most common form [70-80%] of chronic urticaria is supposed to have immune basis causes. It is speculated that the promoter polymorphism of TGF- beta 1 gene may be involved in ICU. This condition is thought to affect at least 0.1% of the population and often can be severe and difficult to treat. A total of 40 patients with ICU and 41 normal subjects were studied. DNA was extracted from whole blood and TGF- beta 1 promoter -509C>T polymorphism was determined by PCR-RFLP method. Out of the 40 patients with ICU, 11 [27.5%] had CC, 26 [65%] had CT and 3 [7.5%] had TT genotypes. A higher proportion of case subjects with the C allele [CT type or CC type] was found compared with the T allele. These results do suggest an influence of genetic variability at the promoter of TGF- beta 1 gene [-509C>T] on the occurrence of ICU. This polymorphism has been shown as a useful genetic change in our study. Further work is required to confirm this result