Monocyte phenotype in blood and cerebrospinal fluid: compartment-specific pattern is unrelated to neurological...

An immunocytochemical study of surface and cytoplasmic markers of the monocyte/macrophage lineage was undertaken on peripheral blood (PB) and cerebrospinal fluid (CSF) cells in patients with multiple sclerosis (MS) or other neurological diseases (OND) and in three healthy controls. Size and granularity were assessed by means of cytofluorimetric analysis. Fewer monocytes were positive for complement receptors 1 and 3, myeloperoxidase, KiM6, IOM-3 and CD14 in CSF than in PB. Only DR-positive monocytes were present with the same frequency in the two compartments. There was no difference in the monocyte phenotype between patients and healthy controls. Furthermore, there was no difference between patients with MS or OND. Cytofluorimetric analysis showed that in CSF, regardless of clinical status, few cells displayed the physical features of blood monocytes. A population of granular and large granular cells that was not normally present among PB mononuclear cells was recognized in the CSF. A large proportion of these cells was able to adhere to plastic and--when sorted--displayed the morphology and surface markers of monocyte lineage. The results of our study demonstrate compartment-specific differences in the monocyte phenotype between CSF and PB but suggest that these changes may be unrelated to the investigated neurological diseases.