Elevated levels of IL-6 and IL-9 in the sera of patients with AAA do not correspond to their production by peripheral blood mononuclear cells

Abstract Background Abdominal Aortic Aneurysm (AAA) is the stable local dilatation of abdominal aorta. AAA is an inflammatory condition in which cytokines may play a pathogenic role. Methods Peripheral Blood Mononuclear cells (PBMCs) were isolated from 5 men, with confirmed diagnosis of AAA and aortic dilation greater than 5.5 cm, and 5 men with normal/insignificant angiography, CT-Scan and Ultrasonography results. The supernatant of PBMCs, rested overnight in RPMI containing 10%-FBS, removed to measure IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, IL-22, IFN-γ and TNF-α using a commercial fluorescent-labeled bead assay. Results The mean serum IL-6 and IL-9 levels were significantly higher in patients than controls (P = 0.007 and P = 0.007, respectively). PBMCs from patients produced lower levels of IL-6 and IL-9 compared to controls but the differences were not significant. While serum TNF-α level was not different between groups, its production by PBMCs of patients was significantly lower than controls (P = 0.047). The mean serum levels of IL-10 and IFN-γ in patients were marginally higher than controls (P = 0.055, P = 0.055, respectively). Mean serum IL-2 level was not different between the groups but its production by PBMCs of patients was significantly higher than the control group (P = 0.047). Conclusions Our study showed alteration in the levels of cytokines from inflammatory, Th1, Th2 and Th17 subtypes in the sera of patients with AAA. The production of IL-6, IL-9, IFN-γ and IL-10, however, was not solely attributed to the PBMCs. Therefore, participation of other cells in the tissue or blood should be considered in their production.