Cytokine production by adherent and non-adherent mononuclear cells in chronic fatigue syndrome

It has been suggested that cytokines play a role in certain clinical manifestations of chronic fatigue syndrome (CFS). In this study adherent (monocytes) and non-adherent (lymphocytes) mononuclear cells were stimulated in the presence or absence of phytohemagglutinin (PHA) or lipopolysaccharide (LPS), respectively, and supernatants were assayed for IL-6, TNF-alpha, and IL-10 by ELISA. IL-6 was also measured at the mRNA level by polymerase chain reaction. The levels of spontaneously (unstimulated) produced TNF-alpha by non-adherent lymphocytes and spontaneously produced IL-6 by both adherent monocytes and non-adherent lymphocytes were significantly increased as compared to simultaneously studied matched controls. The abnormality of IL-6 was also observed at mRNA level. In contrast, spontaneously produced IL-10 by both adherent and non-adherent cells and by PHA-activated non-adherent cells were decreased. This preliminary study suggests that an aberrant production of cytokines in CFS may play a role in the pathogenesis and in some of the clinical manifestations of CFS.