Association of interleukin-6 and interleukin-10 expression, gene polymorphisms, and Takayasu arteritis in a Chinese Han population

Takayasu arteritis (TA) is a chronic inflammatory disease. Interleukin (IL)-6 and IL-10 are important cytokines involved in the immune response of TA in some ethnicities. We investigated whether the single-nucleotide polymorphism (SNP) of IL-6 and IL-10 genes and their expressions were associated with TA in a Chinese Han population. One hundred eighty-four TA patients and 235 healthy controls (HC) were recruited. DNA and RNA were extracted from peripheral blood cells. Genotyping of IL-6 and -10 was performed using polymerase chain reaction-ligase detection reaction (PCR-LDR). The mRNA levels of IL-6 and IL-10 were semi-quantified using reverse transcription polymerase chain reaction (RT-PCR) and real-time polymerase chain reaction (real-time PCR). Plasma levels of them were examined by enzyme-linked immunosorbent assay (ELISA). The mRNA levels of IL-6 in active phase of TA were higher than those in stable phase (p=0.015); the IL-10 in active phase was lower compared with stable phase (p=0.046). Plasma levels of IL-6 in TA were higher than those in HC (p=0.024). Plasma levels of IL-10 showed no difference between the two groups (p=0.264). Plasma levels of IL-6 in active phase were increased than those in stable phase (p=0.043) while those of IL-10 were decreased in active phase (p=0.041). We found no significant differences between TA and HC in the frequency of any of the variations in the SNPs of IL-6 and IL-10 genes. The expression levels of both cytokines were associated with the disease status, indicating that they may serve as potential biomarkers for monitoring disease activity.