Enteroviral RNA sequences detected by polymerase chain reaction in muscle of patients with postviral fatigue syndrome.

OBJECTIVE: To determine the presence of enteroviral sequences in muscle of patients with the postviral fatigue syndrome. DESIGN: Detection of sequences with the polymerase chain reaction in a well defined group of patients with the syndrome and controls over the same period. SETTING: Institute of Neurological Sciences, Glasgow. SUBJECTS: 60 consecutive patients admitted to the institute with the postviral fatigue syndrome who had undergone extensive investigation to exclude other conditions. 41 controls from the same catchment area without evidence of fatigue, all undergoing routine surgery. MAIN OUTCOME MEASURES: Routine investigations, serological screen for antibodies to a range of viruses, and presence of enteroviral RNA sequences in muscle biopsy specimens. RESULTS: 15 (25%) patients and 10 (24.4%) controls had important serological findings. 12 patients had neutralising antibody titres of greater than or equal to 256 to coxsackieviruses B1-5 (six positive for enteroviral RNA sequences, six negative); three were positive for Epstein-Barr virus specific IgM (two positive, one negative). Six controls had similar neutralising antibody titres to coxsackieviruses (all negative); one was positive for Epstein-Barr virus specific IgM (negative); and three had titres of complement fixing antibody greater than or equal to 256 to cytomegalovirus (all negative). Overall, significantly more patients than controls had enteroviral RNA sequences in muscle (32/60, 53% v 6/41, 15%; odds ratio 6.7, 95% confidence interval 2.4 to 18.2). This was not correlated with duration of disease, patient and age, or to raised titres of antibodies to coxsackieviruses B1-5. CONCLUSIONS: Persistent enteroviral infection of muscle may occur in some patients with postviral fatigue syndrome and may have an aetiological role.