Interferon gamma (IFNgamma) & interleukin-4 (IL-4) gene variants & cytokine levels in pulmonary tuberculosis.
OBJECTIVE
Cytokine gene polymorphisms may alter Th1/Th2 balance with major implications in tuberculosis. The aim of our study was to find out whether Interferon gamma +874A and IL-4 -590T polymorphisms were associated with susceptibility to pulmonary tuberculosis as well as the level of IFNgamma and IL-4 in south Indian population.


METHODS
Interferon gamma +874A and IL-4 -590T promoter polymorphisms were studied in 129 pulmonary tuberculosis (PTB) patients and 127 normal healthy subjects (NHS) and were associated with culture filtrate and live Mycobacterium tuberculosis induced IFNgamma and IL-4 production in peripheral blood mononuclear cells (PBMCs). IL-4 gene variants were also associated with IgG antibody levels against M. tuberculosis culture filtrate antigen.


RESULTS
The variant IFNgamma genotypes and IFNgamma levels between genotypes did not differ significantly in patients and controls. Significantly increased frequency of variant IL-4 'CT' genotype in PTB patients (P<0.05) and 'CC' genotype in control group (P<0.01) was observed. IL-4 levels were detectable in very few subjects and the IgG levels did not differ between the three IL-4 genotypes.


CONCLUSIONS
The study suggests a lack of functional association of Interferon gamma +874A polymorphism in tuberculosis in south Indian population. The higher frequency of IL-4 'CT' genotype in PTB suggests a possible association of IL-4 -590T promoter polymorphism with susceptibility to tuberculosis, and the 'CC' genotype may be associated with protection.
Vidyarani
M
M
Tuberculosis Research Centre (ICMR), Chennai, India.
Selvaraj
P
P
Prabhu Anand
S
S
Jawahar
M S
MS
Adhilakshmi
A R
AR
Narayanan
P R
PR
D000328:Adult; D001483:Base Sequence; D016022:Case-Control Studies; D017931:DNA Primers / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics*; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D014397:Tuberculosis, Pulmonary / Q000235:genetics* / Q000276:immunology*
D017931:DNA Primers; C508598:IL4 protein, human; D015847:Interleukin-4; D007371:Interferon-gamma