A 37 kDa 2-5A binding protein as a potential biochemical marker for chronic fatigue syndrome

PURPOSE: Recent studies have revealed abnormalities in the ribonuclease L p athway in peripheral blood mononuclear cells of patients with the chronic f atigue syndrome. We conducted a blinded study to detect possible difference s in the distribution of 2-5A binding proteins in the cells of patients wit h chronic fatigue syndrome and controls. PATIENTS AND METHODS: We studied 57 patients with chronic fatigue syndrome and 53 control subjects (28 healthy subjects and 25 patients with depressio n or fibromyalgia). A radioactive probe was used to label 2-5A binding prot eins in unfractionated peripheral blood mononuclear cell extracts and to co mpare their distribution in the three groups. RESULTS: A 37 kDa 2-5A binding polypeptide was found in 50 (88%) of the 57 patients with chronic fatigue syndrome compared with 15 (28%) of the 53 con trols (P <0.01). When present, the amount of 37 kDa protein was very low in the control groups. When expressed as the ratio of the 37 kDa protein to t he 80 kDa protein, 41 (72%) of the 57 patients with chronic fatigue syndrom e had a ratio >0.05, compared with 3 (11%) of the 28 healthy subjects and n one of the patients with fibromyalgia or depression. CONCLUSION: The presence of a 37 kDa 2-5A binding protein in extracts of pe ripheral blood mononuclear cells may distinguish patients with chronic fati gue syndrome from healthy subjects and those suffering from other diseases. (C) 2000 by Excerpta Medica, Inc.