SIGLEC1 and rheumatoid arthritis: Of particular interest was the sialic acid binding receptor sialoadhesin (CD169, siglec-1 or Sn), which is seen on activated macrophages in chronic inflammation and in tumours, e.g. on macrophages found in multiple sclerosis, atherosclerosis, and rheumatoid arthritis [3], on monocytes from HIV-1 infected patients treated with antiretroviral therapy, especially those with a high viral load [4], and on dendritic cells infected with human rhinovirus strain 14 [5].