¹Department of Molecular Biology, Immunology and Genetics, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria

Correspondence: Dr S Stanilova, Department of Molecular Biology, Immunology and Genetics, Faculty of Medicine, Trakia University, Armeiska 11 St., 6000 Stara Zagora, Bulgaria. E-mail: stanilova@mf.uni-sz.bg

Received 8 December 2004; Revised 1 March 2005; Accepted 3 March 2005; Published online 28 April 2005.

Abstract

A wide array of studies has demonstrated differences in genotype and allele frequencies of cytokine gene polymorphisms depending on ethnicity and race. In this study, the frequency of Taq-I polymorphism in 3' untranslated region of IL-12B was investigated in two Bulgarian ethnic groups—Bulgarians and Turkish minority. No significant differences of genotype and allele frequencies were observed between these groups. Genotype distribution in the total group of Bulgarian citizens was: AA (61%), CA (32%) and CC (7%), and the allele frequency of 16974 A allele was 0.77. We also evaluated whether this polymorphism affects IL-12p40 production from human PBMC after stimulation. We demonstrated that association between genotype and IL-12p40 production by stimulated PBMC depends on the stimuli used. Our results indicated a significantly decreased IL-12 p40 secretion for the following order of genotypes: AA>CA>CC, after stimulation of PBMC with C3-binding glycoprotein (C3bgp) in contrast to lipopolysaccharide, phytohaemagglutinin and pokeweed mitogen.