Fucosylation of serum alpha1-acid glycoprotein in rheumatoid arthritis patients treated with infliximab.

To analyze fucosylation of alpha(1)-acid glycoprotein (AGP) and to identify relations between AGP fucosylation and clinical and biochemical indices of disease activity in patients with rheumatoid arthritis (RA) treated with monoclonal antitumor necrosis factor (TNF) antibody infliximab, we examined 22 patients with RA who underwent a 54-week treatment with infliximab according to ATTRACT protocol. Blood samples were collected at baseline and before every infusion of infliximab. AGP fucosylation was measured using lectin-binding enzyme-linked immunosorbent assay utilizing fucose-specific lectin Aleuria aurantia (AAL). Moreover, the clinical status/activity, erythrocyte sedimentation rate, serum C-reactive protein (CRP), antitrypsin, alpha(1)-antichymotrypsin, AGP reactivity with concanavalin A, serum C3 and C4 complement components, and serum concentrations of TNF and soluble TNF type 1 and type 2 receptors were determined. In most patients, the fucosylation of AGP decreased rapidly after first infusion of infliximab and remained low during the 54-week therapy (p < 0.001). The decrease in AGP affinity to AAL closely followed changes in clinical and laboratory activity of RA and correlated with pretreatment concentrations of CRP (r = 0.4986, p < 0.05) and TNF (r = 0.5181, p < 0.05). The fucosylation of AGP can be a part of a negative feedback loop regulating migration of inflammatory cells and collagenase-3 activity in RA. The decrease in AGP fucosylation accompanied by improvement in clinical and biochemical parameters of RA could possibly reflect reduced migration of inflammatory cells to inflamed joints and AGP-mediated inhibition of collagenase-3 as a response to infliximab treatment.