Objectives The aim of the present study was to investigate cytokine gene-expression profile into peripheral blood cells from Bulgarian patients with ankylosing spondylitis (AS).
Methods Total RNA from peripheral blood was isolated from 12 healthy controls and 20 patients with AS with a mean disease duration of 13.2 years (range 2.9 - 26). Nine of the patients were only on first-line therapy, a non-steroidal anti-inflammatory drug (NSAID) and 11 were being treated with TNF-blocking agents. cDNAs were used for TaqMan gene expression assays of IL10, TGFB1, IL23A, IL12B, TNFA, IL18, Foxp3 and GAPDH. Relative quantitative evaluation of mRNAs was performed by the comparative ΔΔCt method and results are presented as relative quantity (RQ).
Results From all examined cytokine genes in AS, we found up-regulated most of them in the following order according to RQ values: IL12B>IL23A>TGFB>IL10>IL18. The gene expression of IL23A and IL12B was significantly higher (p=0.016; RQ=2.04; RQ=2.64, respectively) into peripheral blood cells from AS patients compared to controls, whereas TGFB, IL10 and IL18 were slightly but not significant overexpressed (RQ vary from 1.2 to 1.4.) In contrast, a significant down regulation of TNFA (RQ=0.716; p=0.02) was observed among investigated patients compared to controls. In addition, mRNA expression of FoxP3, a transcription factor driving regulatory FoxP3+ T cells was also down regulated in AS patients (RQ=0.455; p=0.0014). In terms of drug usage, the cytokine gene expression profile between AS patients treated with TNF inhibitors and those without TNF-blocking agents was comparable. A positive correlation was found between gene expression of IL23A with TNFA and IL18 in AS (r=0.67, p=0.001; r=0.456, p=0.038, respectively) and negative correlation between IL23A and TGFB1 (r=-0.58, p=0.006).
Conclusions Our results demonstrated differences in the expression of mRNA encoded regulatory and effector cytokines in peripheral blood cells of AS patients pointed on IL-23 and cytokine related transcription factor FoxP3.
Disclosure of Interest None declared