TABLE OF CONTENTS
Following is news of
current publications and research
efforts underway related to chronic fatigue syndrome (CFS), also called chronic fatigue and immune dysfunction
Herpesviruses and CFS
Centers for Disease
Control and Prevention study published in the July issue of Clinical Infectious Diseases found
that the human herpesviruses (HHV) 6 and HHV-7 are not likely to cause CFS, in contrast to other studies.
The study looked at 26 CFS patients and 52 non-fatigued matched controls. The researchers used
serum samples, lymphocyte assays and three different polymerase chain reaction (PCR) methods to identify
All patients and control subjects tested positive for HHV-6, although the antibody
titer was not significantly different between patients and controls. Neither HHV-6 nor HHV-7 was isolated
from peripheral blood lymphocytes of patients or control subjects, a sign that no active infection or
viral reactivation was involved.
HHV-6 (A or B) DNA was detected in 17 (22.4%) of 76 samples and
there were no significant differences between patients and control subjects. HHV-7 DNA was detected in
14 subjects. Although the controls (24%) were more likely than patients (7.7%) to be positive for HHV-7,
the difference was not statistically significant.
The researchers concluded that there was no evidence
active or latent infection with HHV-6A, HHV-6B, HHV-7 or any combination of these viruses is associated
with CFS. At least seven other studies on HHV-6 or HHV-7 infection and CFS have been published, and reported
widely differing results, but it is difficult to compare them with the CDCís study because of the different
Reeves et al. Human herpesviruses 6 and 7 in chronic fatigue syndrome:
a case-control study. Clin Inf Dis. 2000; 31: 48-52.
Response to exercise
study conducted by St.
Bartholomewís and the Royal London School of Medicine and Dentistry has shown that CFS patients have a
significantly reduced exercise capacity (see also article on exercise
intolerance in this issue).
Researchers measured the strength, aerobic capacity and functional
capacity of 66 CFS patients who had not been diagnosed with a psychiatric disorder, 30 healthy but sedentary
controls and 15 patients with major depressive disorders. Exercise capacity and efficiency were assessed
by monitoring peak and submaximal oxygen uptake, heart rate, blood lactate, duration of exercise and perceived
exertion during a treadmill test.
The study found that the CFS patients were physically weaker
than the sedentary and depressed controls and as unfit as the sedentary controls. They also showed lower
aerobic capacity and lower maximum heart rate than the controls.
The researchers speculate that
improved physical fitness after exercise therapy was associated with increased exercise capacity and that
a program to reverse deconditioning may help improve physical functioning in some patients.
KY and White PD. Strength and physiological response to exercise in patients with chronic fatigue syndrome.
J Neurol Neurosurg Psychiatry. 2000; 69: 302-7.
Co-morbidity of CFS,
FM and MCS
Many of the
symptoms associated with CFS are also characteristic of other poorly understood medical conditions, including
fibromyalgia (FM) and multiple chemical sensitivities (MCS). A study from DePaul University has examined
illness co-morbidity rates for the three illnesses as well as characteristics related to fatigue severity
Thirty-two individuals with symptoms of CFS received medical and psychiatric evaluations
to confirm the diagnosis. Of the 32, 40.6% met criteria for MCS and 15.6% met criteria for FM. Thirteen
of the 32 (40.6%) had CFS without any other coexisting illness.
These rates for coexisting disorders
are lower than those reported in prior studies; the researchers speculated that the discrepancy may in
part be the differences in sampling procedures.
The researchers noted that having co-morbid conditions
does affect a patientís functionality. Individuals with more than one diagnosis reported more mental and
physical fatigue than those with no diagnosis and were less likely to be working.
et al. Chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities in a community-based
sample of persons with chronic fatigue syndrome-like symptoms. Psychosomatic Med. 2000; 62:655-63.
More evidence of OI involvement
from the State University of New York Health Sciences Center have provided additional evidence that delayed
orthostatic intolerance (OI) is an important physical disorder found in many patients with moderate to
The blood pressure, heart rate and circulating erythrocyte and plasma volumes of 15
CFS patients were measured every minute for 30 minutes supine and 60 minutes standing. Eleven of the 15
showed excessive reductions in systolic and diastolic blood pressure, orthostatic tachycardia and presyncopal
symptoms after standing for 60 minutes. None of the controls showed symptoms of OI.
circulating erythrocyte volumes were subnormal in 12 of the 14 CFS patients and plasma noriepinephrine
concentration rose excessively after standing for 10 minutes. Lower body compression with MAST (military
antishock trousers) restored all orthostatic measurements to normal and overcame presyncopal symptoms
within 10 minutes in the CFS patients.
Streeten DH and Bell DS. The roles of orthostatic hypotension,
orthostatic tachycardia, and subnormal erythrocyte volume in the pathogenesis of chronic fatigue syndrome.
Am J Med Sci. 2000; 320:1-8.