Evaluation of Immune Dysregulation in an Austrian Patient Cohort Suffering from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe multi-systemic disease characterized by debilitating fatigue that is not relieved  by rest. The causes of the disease are still largely unexplained, and no  causative treatment is currently available. Changes in the immune response are  considered as fundamental in the development of ME/CFS. Thus, we aimed to  evaluate the immunological profile of ME/CFS patients in a retrospective data  analysis. As part of the routine workup for ME/CFS patients, a differential blood  count, leukocyte subtyping, and quantification of immunoglobulins and IgG  subclasses, as well as a complement analysis, was performed. Out of 262 ME/CFS  patients, 64.9% had a reduction or deficiency in at least one of the listed  immune parameters. In contrast, 26.3% showed signs of immune activation or  inflammation. A total of 17.6% of the ME/CFS patients had an unclassified  antibody deficiency, with IgG3 and IgG4 subclass deficiencies as the most common  phenotypes. Reduced MBL (mannose-binding lectin) levels were found in 32% of  ME/CFS patients, and MBL deficiency in 7%. In summary, the present results  confirmed the relevance of immune dysfunction in ME/CFS patients underlining the  involvement of a dysfunctional immune response in the disease. Thus, immune  parameters are relevant disease biomarkers, which might lead to targeted  therapeutic approaches in the future.