MODIFICATION OF SURFACE MARKER EXPRESSION ON CD14 MONOCYTES OF ALLERGIC PATIENTS AFTER LYSIS OR FICOLL PURIFICATION

It has been observed that peripheral blood monocytes are often in a pr imed or activated state in inflammatory diseases such as asthma. Howev er, the majority of these studies have been performed using cells whic h have been purified by density gradient centrifugation on Percoll or Ficoll-Hypaque. Using cytofluorimetry, we compared the expression of m onocyte surface markers of monocytes from untreated blood with monocyt es purified by erythrocyte lysis or density centrifugation using the F icoll technique. Monocytes from two groups of subjects were analyzed: healthy subjects and allergic patients. When compared with untreated b lood, the percentage of CD16-positive cells, and the sMFI was signific antly greater after monocyte purification (lysis or Ficoll). The expre ssion of CD62L (percentage and sMFI) was modified after monocyte purif ication. Such modification of these two surface markers was predominan tly observed on monocytes from allergic patients, and not on monocytes from healthy subjects. This study suggests that surface marker analys is should be performed on unfractionated whole blood in order to avoid modification of monocyte antigens.