Cell-mediated immune function and the outcome of chronic fatigue syndrome

This study examined the importance of cell-mediated immunity in determining the long-term outcome of patients diagnosed with chronic fatigue syndrome (CSF). A total of 103 patients (74%) of 139 previously enrolled in one of two treatment trials conducted within a university hospital referral center was reviewed a mean of 3.2 yr after trial entry. Ongoing symptom severity, levels of disability and immunological function were assessed at follow-up. The relationship between immunological function at trial entry and measures of outcome was also evaluated. Sixty-five patients (63%) had improved, while only 6 (6%) reported no current symptoms. Thirty-one subjects (30%) were unable to perform any form of work and 26 (25%) were on a disability benefit directly attributable to CFS. Cell-mediated immune function, as measured at trial entry or follow-up, did not appear to affect outcome. Whilst improvement occurred in the majority of patients with CFS, a substantial proportion (37%) remained functionally impaired. Impairment of cell-mediated immunological function measured during the course of the illness may not be an important factor in determining long-term outcome.