The importance of monocyte and granulocyte activation in rheumatoid arthritis and primary Sjögren's syndrome

Sammanfattning: Macrophages and neutrophils infiltrate the synovium and synovial fluid in rheumatoid arthritis (RA). These cells are considered to contribute to the destructive process in RA.The expression of adhesion and phagocytosis receptors on the surface of peripheral granulocytes and monocytes was increased in patients with RA. Elevation of the serum concentration of the mononuclear and the neutrophil derived granula proteins lysozyme and MPO and not of the neutrophil derived proteins HNL and lactoferrin suggest a stimulated activity of mononuclear phagocytes in RA. Measurement ofserum lysozyme, as a potential indicator of monocyte/macrophage activity, might beof clinical value in studies of the disease activity in RA.Low dose prednisolone treatment decreased the activation level of monocytes and eosinophils but only had minor effects on peripheral blood neutrophils. Patients with RA were treated with metyrapone in order to lower the concentration of the endogenous cortisol. This lowering of endogenous cortisol level had minor impact onmonocyte and eosinophil expression of adhesion receptors.C-reactive protein (CRP) stimulated the granulocyte respiratory burst induced by E.coli and PMA, and the granulocyte phagocytosis of opsonized and non-opsonized E.coli. Granulocyte adhesion to E-selectin and neutrophil expression of CD44 (p =  0.058) were decreased by CRP. The neutrophil expression of the receptor antigen CD11b (p < 0.05) was increased by CRP.The adhesion of peripheral blood neutrophils and eosinophils was enhanced in primary Sjögren's syndrome (pSS). Accordingly results from earlier studies of impaired neutrophil adhesion in pSS were not confirmed.