Unravelling Intracellular Immune Dysfunctions in Chronic Fatigue Syndrome: Interactions between Protein Kinase R Activity, RNase L Cleavage and Elastase Activity, and their Clinical Relevance

This study examined possible interactions between immunological abnormalities and symptoms in CFS. Sixteen CFS patients filled in a battery of questionnaires, evaluating daily functioning, and underwent venous blood sampling, in order to analyse immunological abnormalities. Ribonuclease (RNase) L cleavage was associated with RNase L activity (r s =0.570; p=0.021), protein kinase R (PKR) (r s =0.716; p=0.002) and elastase activity (r s =0.500; p=0.049). RNase L activity was related to elastase (r s =0.547; p=0.028) and PKR activity (r s =0.625; p=0.010). RNase L activity (r s =0.535; p=0.033), elastase activity (r s =0.585; p=0.017) and RNase L cleavage (r s =0.521; p=0.038) correlated with daily functioning. This study suggests that in CFS patients an increase in elastase activity and subsequent RNase L cleavage is accompanied by increased activity of both the PKR and RNase L enzymes. RNase L and elastase activity are related to daily functioning, thus evidence supporting the clinical importance of these immune dysfunctions in CFS patients was provided.