CYTOTOXIC T-LYMPHOCYTE ANTIGEN 4 (CTLA-4) GENE POLYMORPHISMS IN BRONCHIAL ASTHMA.

Asthma is a polygenic, multifactorial disorder, these factors are both genetic and environmental. CTLA-4 gene is located on chromosome 2q33, a key inhibitor of T cell activation, expressed only on activated T helper cells and plays a negative regulatory role in T cell response. CTLA-4 gene polymorphisms have been linked to susceptibility to autoimmune disease as rheumatoid arthritis, celiac disease, type I diabetes, myasthenia gravis, and bronchial asthma.The aim of the current study was to analyze the relation between CTLA-4 gene SNPs (A/G polymorphism at position 49 in Exon 1 and C/T-60 polymorphism in the 3\' untranslated region) and serum IgE in bronchial asthma. This study was carried out on 62 patients with bronchial asthma attending inpatients and outpatients clinics of Thoracic Medicine Department, Mansoura University Hospital. Also 38 apparently healthy volunteers were taken as a control group. Ten ml blood was withdrawn from each individual and divided in two tubes.One formeasurement of serum IgE by ELIZA and the other for polymorphism genotyping of CTLA4 gene by PCR-RFLP. The results of the current study showed that there was no statistically significant difference between patients and control groups as regard A/G polymorphism at position 49 in Exon 1 of the CTLA4 gene. On the other hand there was a statistically significant difference between patients and control groups as regard C/T-60 Polymorphism in the 3\' untranslated region of the CTLA-4 gene. CC genotype was significantly higher in asthmatic than control group. It can be concluded that CTLA-4 gene C/T 60 polymorphisms could conferred susceptibility to bronchial asthma and could confirm the usefulness of the CTLA-4 genotyping in predicting bronchial asthma.