Discourse Journal of Agriculture and Food Sciences
Volume 4 Issue 4 Page 33 - 40. September 2016

Copyright 2016 Discourse Journals

 

Polymorphism in first Intron of Interferon- Gamma Gene (+874A/T) among Sudanese BCG-vaccinated Health Care Workers

1Hanaa MA Abdallah1,2,3, A. K. Bolad4, El. A. Elobied5, A.M. Babikir6,  Ali Yousif Osman7 and A. M. EL Hussien2

1Sudan Academy of Sciences,  2Central laboratory, Ministry of Science and Technology,Sudan, 3College of Science, Shagra University, KSA,   4Faculty of Medicine, University of Alneelain, 5School of Pharmacy, Ahfad University for Women, 6Institute of Nuclear Medicine, Molecular and Oncology,  University of Gezira and  7Central Veterinary Research Laboratories Sudan

Abstract

Cytokines especially interferon-gamma (IFN-γ) are largely responsible for the regulation of the protective immune response against mycobacterial infections. Several studies have clarified the importance of common variants of IFN-γ gene regarding the susceptibility to tuberculosis. Bacille Calmette-Guérin (BCG) vaccine which is used to prevent severe forms of tuberculosis could produce local and systemic side effects. This study hypothesized that assesses the level of INF-γ among BCG-vaccinated Health Care Workers (HCWs) who were tested for (Purified Protein Derivative) PPD compared with TB- unexposed individuals. One-hundred thirty-seven HCWs (20-70 years old with ratio of TB-exposed and unexposed in females and males of 7: 3) were screened by conventional methods using microscopy, (Tuberculin Skin Test) TST, (Human Immuno Virus) HIV test and Chest X-Ray). Results of these tests showed that all subjects were apparently healthy and consequently they were allocated according to the TST results into three groups (moderate TST-positive, strong TST-positive and negative groups). DNA samples were obtained from 80 TB-exposed HCWs and 20 apparently healthy individuals. Distribution of HLA-DR, DQ alleles were determined by DNA typing and the INF-γ polymorphism (+874 T → A) was assessed by Allele Specific Polymerase Chain Reaction (AS-PCR). Frequency of A/A INF-γ genotype was totally absent among the strongly positive group, while it was 8% among the TST negative group. Polymorphism at +874 was identified using AS-PCR. The variations in allelic frequencies of IFN-γ gene polymorphisms were also shown in the different population groups and genetic polymorphisms associated with tuberculosis had yielded conflicting results in different ethnic groups.

Keywords: Human leukpcyte allele (HLA), tuberculosis (TB) Bacille Calmette-Guérin (BCG), Interferon- Gamma Gene, Purified Protein Derivative (PPD)

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