• anti-tumour necrosis treatment
• cytokine network
• adhesion molecules
• chemokines
• angiogenesis
• inflammation

Preclinical studies based on in vitro cell systems and in vivo models had established a position for tumour necrosis factor (TNF) α as a pivotal molecule regulating cellular activation and interactions in rheumatoid inflammation by 1992. That neutralisation of TNFα has a profound impact on the biology of inflammation is reflected by the rapid reduction in the concentration of C reactive protein (CRP), an acute phase protein, associated with a fall in the level of its well known inducer, interleukin (IL) 6. This supports the hypothesis that TNFα is a critical part of a regulatory cytokine network.

The reduction in clinical signs of inflammation were soon shown by arthroscopic examination and synovial biopsies of knee joints to be a consequence of reduction in the density of infiltrating lymphocytes and macrophages. Circulating numbers of lymphocytes increased transiently after infliximab in a dose dependent fashion, associated with a reduction in soluble adhesion molecules E selectin, ICAM-1, and density of cells staining for these and VCAM-1 in synovial biopsies. The dynamics of cell trafficking have been examined by tracking the fate of the indium¹¹¹ labelled polymorphonuclear cells injected intravenously in rheumatoid arthritis (RA) patients. These experiments show a reduction in uptake of radioactivity in joints after anti-TNF treatment indicating reduced adhesiveness and retention of the leucocytes in joints.

The results of anti-TNF treatment on the progression of damage to cartilage, bone and other connective tissue components is not yet established in RA, although in collagen induced arthritis in DBA/1 mice, joint protection was reported. Measurement of circulating matrix metalloproteinases, MMP-1 and MMP-3, in their inactive form, has been noted following infliximab in patients. Recently we have documented a reduction in raised concentrations of serum VEGF, an important angiogenic factor after infliximab treatment. More direct evidence of a reduction in angiogenesis has been …