The aim of this study is to examine the associations between inflammatory disease activity and endothelial function in rheumatoid arthritis (RA) and spondyloarthritis patients treated with methotrexate and Tumor Necrosis Factor alpha (TNFalpha)inhibitor in combination or methotrexate or TNFalpha-inhibitor alone. Further, to look for improvement in endothelial function, and decrease in bone and cartilage destruction during treatment with the combination therapy of TNFalpha-inhibitor and methotrexate in RA and Psoriatic Arthritis (PSA) patients. Last, examine the TNFalpha inhibitors influence on endothelial function and levels of bone and cartilage markers in patients with Ankylosing Spondylitis (AS).