In CFS Patients Cells called monocytes are an essential part of the immune system. They ingest and kill invaders, they communicate with other immune system cells to indicate when an immune response should be mounted, and they make a number of enzymes that are essential to properly functioning immunity. Monocytes are the precursor cells to another very important type of immune system cell called macrophages.
Macrophages perform basically the same functions as monocytes.
Like just about every other cell in the immune system, monocytes do not work properly in CFS patients. Some research teams have found that about half of CFS patients have monocytosis, in which too many monocytes are produced. Additionally, a Spanish research team from the University of Navarra, in Pamplona, studied monocyte function in CFS patients and found it to be disturbed in a large percentage of patients. Consequently, they found, the monocytes and macrophages of CFS patients are quite dysfunctional.