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Spring 2003

Research Briefs
No link between BHR, RNase L ratio

A CFS-related change in the body’s antiviral pathway appears not to be responsible for the high percentage of CFS patients with bronchial hyperresponsiveness (BHR), according to new research fromBelgium.

The study focused on 137 CFS patients, seventy-three of whom presented with BHR. This percentage is comparable to earlier research that found 60 percent of CFS patients showed signs of BHR.

All subjects were tested for the ratio between two different forms of RNase L, a key protein in the antiviral pathway. Many people with CFS have two forms, the normal 83 kilodalton (kDa) version and a lighter, 37 kDa type that is formed by the cleaving of the 83 kDa protein.

The researchers report no differences in the 83 kDa/37 kDa ratio between the BHR and non-BHR patients. There also were no differences in total lung capacity or forced expiratory/forced vital capacity measures. These results, the authors write, “refute any association” between the RNase L ratios and BHR.

Study results did indicate that CFS patients with BHR showed an overall higher immune system activation level than those without BHR.

Nijs J et al. “Associations Between Bronchial Hyperresponsiveness and Immune Cell Parameters in Patients with Chronic Fatigue Syndrome.” Chest. April 2003;123:998-1007.

Brain metabolism different in CFS

Research from Scotland finds that patients with CFS may show different metabolism characteristics than controls in the left basal ganglia region of the brain.

Eight patients with CFS and no psychiatric co-morbidity were tested for metabolic activity using proton magnetic resonance spectroscopy (H MRS), a relatively new tool for measuring brain function. Compared to controls, the patient group showed elevated levels of choline-containing compounds in the basal ganglia.

This could be an indication of higher cell membrane turnover or changes in the signaling process between separate membranes, the authors say. It is not understood why this may happen — although some researchers speculate that exposure to infectious agents or neurotoxins may result in such increased activity.

Chaudhuri A et al. “Proton magnetic resonance spectroscopy of basal ganglia in chronic fatigue syndrome.” NeuroReport. 2003;14(2):225-8.

Tilt-test studies show mixed results

Researchers may be able to differentiate female CFS patients from healthy controls using a measurement taken during the head-up tilt test.

The tilt test is commonly given to people with suspected autonomic disorders; a large percentage of CFS patients have such conditions. However, symptom presentation during the test has not proven effective in separating CFS patients from controls.

But new research has found that measuring heart rate variability (HRV), specifically a decrease in the aperiod fractal component of HRV, can be used to differentiate the patient population. In this study of 24 female CFS patients and 22 controls, researchers reached sensitivity and specificity measures of 90 percent and 72 percent, respectively.

Yamamoto Y et al. “A measure of heart rate variability is sensitive to orthostatic challenge in women with chronic fatigue syndrome.” Exp Biol Med. Feb. 2003;228(2):167-74.

In a separate study, researchers conclude that CFS patients do not have a distinctive pattern of regional cerebral blood flow when placed under orthostatic stress.

This study, from Johns Hopkins University , looked at 26 patients with CFS and 23 controls. Researchers measured blood flow volume in the middle cerebral artery (MCA) at six points during tilt-table testing. The overall results found no significant variation between the two test groups.

Some researchers have speculated that changes in regional cerebral blood flow, as measured in the MCA, may be a hallmark of CFS.

In general, CFS patients do show higher rates of neurally mediated hypotension and postural tachychardia syndrome than healthy controls on tilt testing.

Razumovsky AY et al. “Cerebral and systemic hemodynamics changes during upright tilt in chronic fatigue syndrome.” J Neuroim. Jan. 2003;13(1):57-67. 

NIH to Host CFS Research Workshop

“Neuro-Immune Mechanisms and CFS: Will understanding central mechanisms enhance the search for the causes, consequences and treatment of CFS?”

The Office of Research on Women’s Health (ORWH) of the National Institutes of Health (NIH) will host a scientific workshop designed to enhance understanding of chronic fatigue syndrome by examining the interface between the brain, immune system and symptoms of CFS and related disorders. The workshop will be held June 12-13, 2003 at the Bethesda Marriott Hotel. Dr. Leslie Crofford of the University of Michigan and Dr. Dedra Buchwald of the University of Washington will chair.

Scientists from NIH and academic institutions, representing diverse disciplines, will explore the mechanisms by which hormones, cytokines and other mediators act as intermediaries between the brain and other body systems. The potential application of new technologies in the study of these mediators and their central and peripheral actions will also be discussed. NIH intends for these deliberations to form the basis for future interdisciplinary initiatives.

Presentations will be given on the HPA axis, autonomic nervous system, neuroactive drugs, sleep, imaging studies (including PET and functional MRI scans), genomics and more. Dr. Vivian Pinn, ORWH director, will deliver opening remarks followed by introductory talks by Drs. Crofford and Buchwald.

The meeting has been organized by ORWH and the Trans-NIH Working Group for Research on CFS. Continuing medical education units will be available to medical professionals. For additional information, visit http://www4.od.nih.gov/orwh/

Note to Readers

Beginning with this issue, The CFS Research Review will be published on a twice-yearly schedule. The next issue will be mailed this fall. The Review also has changed from a 12-page to a 16-page format, to allow for more in-depth coverage of CFS issues. Thank you for your continued support.

—Editor