ABSTRACT
Blood and lymph node samples were obtained from patients with chronic fatigue syndrome (CFS) who had volunteered to undergo a lymph node biopsy while participating in a phase 1 clinical trial of a novel immunomodulatory therapy. The surface marker pheno-types of the peripheral blood and lymph node samples were examined using four-color flow cytometry and compared to published proportions of cells in peripheral blood and lymph nodes from control individuals. While a greater proportion of T lymphocytes from both lymph nodes and peripheral blood of control subjects are immunologically “naive” (CD45RA+), the proportions of lymphocytes with a “memory” phenotype predominate in lymph nodes and peripheral blood of CFS patients. CFS has been proposed to be a disease of autoimmune etiology and in this respect it is interesting to note that decreased proportions of CD45RA+ T (“naive”) cells are also seen in the peripheral blood of patients with autoimmune diseases.