Immunological, physical and social functioning in varying cases of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis

Abstract

Objectives: The purpose of this study is to determine whether immunological, physical and social functioning varies in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) patients that meet different diagnostic criteria for the illness, and healthy controls. Methods: A total of 35 patients diagnosed with CFS/ME and 22 healthy controls from the South East Queensland region of Australia provided a blood sample for standard screening of illness and immunological analysis. Participants also completed a diagnostic questionnaire, the Short-Form General Health Survey (SF-36), and the World Health Organization Disability Adjustment Schedule 2.0 (WHO DAS 2.0). Results: Eighteen patients were classified as 1994 Centers for Disease Control (1994 CDC) cases, and 17 were classified as International Consensus Criteria (ICC) cases. No differences were found between the two groups for standard blood tests. Natural Killer (NK) cell activity was consistently and significant decreased, while regulatory T cells (Tregs) were significantly increased in both CFS/ME subgroups, in comparison to healthy controls. Salient differences between 1994 CDC and ICC groups were also detected in human neutrophil antigens and expression of NK cell receptors. ICC patients however, were found to report significantly lower SF-36 scores for physical functioning, physical role, bodily pain, and social functioning. These findings were also supported by the WHO DAS 2.0 scores with ICC patients reporting greater impairment across all measures. Conclusion: These preliminary findings suggest suggest that the ICC case definition identifies a subgroup found within 1994 CDC patients, with more severe impairment to their physical and social functioning. Further, the ICC may be more effective at detecting salient differences in the immune system found in CFS/ME. Further investigation is required into the clinical presentation of these patients to determine whether more profound and specific relationships can be found. The presence of immune abnormalities combined with clear clinical measures could potentially serve as an important diagnostic tool for the illness.