CCL4 and rheumatoid arthritis: Increased concentrations of MIP-1α and MIP-1β were detected in various systemic diseases, such as osteoarthritis,17 rheumatoid arthritis,17 congestive heart failure,18 multiple myeloma,19 and asthma.20 It was suggested that MIP-1α and MIP-1β were expressed by subchondral bone marrow stromal cells isolated from osteoarthritis and rheumatoid arthritis.18 The MIP-1α has been implicated in the pathogenesis of many diseases, and high levels of it in systemic circulation as a result of periodontal diseases may increase the risk for atherosclerosis and the other diseases mentioned above.