Chemotactic and adhesive properties of neutrophils from rheumatoid arthritis patients and influence of different treatments

Author(s)

Venina Marcela Dominical

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2010-03-08

Examining board members

Nicola Amanda Conran Zorzetto; Lilian Tereza Lavras Costallat; Alessandra Gambero

• Advisor: Nicola Amanda Conran Zorzetto; Fernando Ferreira Costa

Abstract

Rheumatoid arthritis (RA) is a chronic inflammatory disease that is autoimmune and systemic, and characterized by a symmetric polyarthritis, affecting mainly the wrists, hands and feet. The pathological process that explains RA remains unknown. The induction of an immune response, characteristic of the disease, results from an inflammation of the joints through the infiltration of inflammatory cells that are recruited to the synovial tissue, where they adhere to endothelial cells and transmigrate through the synovial sublayer, forming complexes that produce inflammatory cytokines. These complexes induce hyperplasia of the synovial layer and stimulate the further production of cytokines and enzymes, leading to the degradation of the bone matrix, and resulting in the destruction of affected joints. In the synovial fluid, neutrophils are the main cell type and are attracted to the inflamed joints by chemoattractants, such as LTB4, C5a, IL-8 and TGF-?, and exposed to a variety of local pro-inflammatory cytokines such as IL-1?, TNF -?, GM-CSF, IL-6 and IL-18. Studies have shown that neutrophils play a role in inducing the generation of inflammation, and efforts to understand the mechanisms deployed by neutrophils in this disease may be a key point for the development of pharmacological interventions to ameliorate symptoms and disease severity. Thus, this study evaluated the chemotactic and adhesive properties of neutrophils in patients with RA and the influence of different drugs, currently used in the treatment of this pathology, on these properties. One hundred and twenty-three patients with active RA or in disease remission were enrolled and divided into three groups; patients not treated with drugs specifically for RA (AR nt), patients treated with disease-modifying antirheumatic drugs (AR dm) and patients treated with biological agents (AR ab); healthy individuals were used as controls (Con). Neutrophils were separated from peripheral blood and static adhesion assays and cell chemotaxis assays were performed in vitro. We verified the gene and surface expression of some proteins involved in the adhesive process. Moreover, chemokines involved in the recruitment of neutrophils and L-selectin, a cellular adhesion molecule expressed in leukocytes, were quantified in the serum and synovial fluid of these patients. Neutrophils from the peripheral blood of RA patients with active disease demonstrated no difference in adhesive properties, compared to healthy subjects. Furthermore, patients on therapy with biological agents had increased migratory properties, compared to patients without specific RA treatment. Interestingly, neutrophils from RA patients in remission of disease presented reduced adhesive and migratory capacity in the absence of stimulus. Nevertheless, no differences were observed in these properties with IL-8 stimulus. The synovial fluid of RA patients with active disease has a high chemotactic potential for neutrophils and presented significantly higher levels of IL-8 and ENA-78 in this fluid, as well as in the peripheral blood. An increased gene expression of L-selectin in RA patients with active disease was observed, but interestingly, we found no differences in surface expression or presence in the serum of this molecule. Of note, a significant decrease in the surface expression of neutrophil L-selectin and LFA-1 was observed in patients in remission of disease. Results suggest that the remission of the RA inflammatory state appears to be associated with significant alterations in major neutrophil-attracting chemokines in the circulation of individuals, contributing possibly, to neutrophils function alteration in these individuals and the consequent amelioration of the disease (AU)