Circulating levels of soluble adhesion molecules in patients with ANCA-associated vasculitis

BACKGROUND: During inflammation, activated vascular endothelial cells and other cell types express various adhesion molecules, which facilitate the binding of circulating leukocytes and their extravasation in surrounding tissue (i.e. renal tissue). The serum concentration of circulating soluble adhesion molecules is supposed to reflect the degree of this activation. OBJECTIVE: In the first part of the study, we determined if the serum levels of the soluble intercellular adhesion molecule (sICAM)-1 and the soluble endothelial cell-leukocyte adhesion molecule (sELAM)-1, in patients affected by microscopic polyangiitis (MPA), associated with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibodies (ANCA), were related to the active and the inactive vasculitis phase. In the second part of the study, we examined the changes in circulating sICAM-1 and sELAM-1 levels and the clinical outcome of renal function in these patients. METHODS: We examined 20 MPO-ANCA-positive MPA patients in an acute phase and in a remission phase, after 6 months of treatment, and 50 subjects as controls, 30 with autosomal dominant polycystic kidney disease (ADPKD) in stable chronic renal failure (CRF) and 20 healthy volunteers (HS) with normal renal function. RESULTS: Regarding serum creatinine (Cr) concentration, no significant differences were found comparing active and inactive phases in the MPA group and the CRF group. Mean serum adhesion molecule levels in the MPA group were higher in the active phase compared to the inactive phase and to the CRF and HS groups. In addition, considering the outcome of serum Cr concentrations in the MPA group, the serum adhesion molecule levels were higher and decreased more slowly in patients with final high serum Cr concentrations than in patients with final normal serum Cr concentrations. CONCLUSION: Our data suggest that in MPO-ANCA-positive MPA patients, higher sICAM-1 and sELAM-1 levels during the active phase and their slower decline during the treatment period, could be a prognostic risk factor for CRF development.