Down-regulation of CXCR1 and CXCR2 on neutrophils by IL-8 and TNFα. Isolated neutrophils from HC were pre-incubated with serial doses of IL-8 (A, left figure), TNFα (B, left figure), ANGPT-1 (C) or ANGPT-2 (D). Isolated neutrophils from AAV patients were pre-incubated with serial doses of IL-8 (A, right figure) and TNF α (B, right figure). Membrane expression of CXCR1 (black dots) and CXCR2 (black diamonds) was measured by flow cytometry. Expression of CD177 (open dots) was measured in parallel as control for stimulation. Results are presented as percentages compared to control incubation with normal medium (ctrl). CXCR1 and CXCR2 are equally down-regulated by TNFα (overlapping graphs in panel B). Results are the mean (± SD) of three experiments, *, P < 0.05; **, P < 0.01 (CXCR1 and CD177). #, P < 0.01 (CXCR2). AAV, ANCA-associated vasculitides; ANCA, anti-neutrophil cytoplasmic autoantibody; ANGPT, angiopoietin; IL; interleukin; TNF, tumor necrosis factor.
Hu et al. Arthritis Research & Therapy 2011 13:R201 doi:10.1186/ar3534