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Summer 2002

Research Briefs
Following is news of current publications and research efforts underway related to chronic fatigue syndrome (CFS) — also called chronic fatigue and immune dysfunction syndrome (CFIDS).

Fibromyalgia patients show brain changes
Fibromyalgia (FM) and CFS exhibit significant overlap in female patients. Research now shows that both disorders may be marked by abnormalities in how the brain perceives pain.

FM researchers have applied a high-speed imaging technique called functional MRI to track the brain’s response to stimuli. While applying pressure to the thumbs of test subjects, researchers recorded brain function in 16 FM patients and 16 controls. The results showed marked differences in cerebral responses. FM patients reported pain at one-half the pressure level of control subjects; mild pressure resulted in much greater blood flow to pain-related centers of their brains.

Researchers say the test provides the first documentation of the differential response to pain in FM patients compared to the general population. For more on brain responses to pain in CFS, please see p. 3.

Gracely RH et al. “Functional magnetic resonance imaging evidence of augmented pain processing in fibromyalgia.” Arthritis & Rheumatism. 2002; 46:1333-43.

CFS linked to oxygen shortage
Poor cerebral oxygenation and CFS may be linked in a subset of young CFS patients, researchers report in the Journal of Pediatrics.

In the study, 16 CFS patients (ages 10-22) with orthostatic intolerance (OI) were measured for oxygenated and deoxygenated hemoglobin levels in the brain while standing and seated. Results showed that 15 of the 16 failed to show a rapid recovery in oxygenated hemoglobin shortly after standing. The same reaction was found in just six of 12 CFS patients without OI and only two of 20 healthy control subjects.

In addition, 13 of the 16 CFS patients showed prolonged reductions in oxygenated hemoglobin levels while continuing to stand. The authors say these results suggest a link between  levels of cerebral oxygenation and CFS, although they do not explain CFS symptoms in patients without OI.

Tanaka H et al. “Impaired postural hemodynamics in young patients with chronic fatigue with and without chronic fatigue.” J Pediat. April 2002; 140(4):412-417.

Chronic HHV-6 infection causes immune imbalance
CFS patients with a persistent, active Human Herpesvirus-6 (HHV-6) infection appear to show imbalanced, fluctuating immune responses and not outright immune deficiency, according to a study published in In Vivo.

Researchers tracked immune system status in 10 patients who met the 1994 International Case Definition for CFS (see back cover) and had persistent HHV-6 infection, for a period of

24 months. Changes in HHV-6 antibody titer, viral DNA load, peripheral blood T lymphocytes, CD4/CD8 cell ratios and other factors were measured.

HHV-6 presence, as measured by viral DNA copies, was variable and slightly elevated during the study period. Peripheral T lymphocytes ranged from normal to twice normal, while the CD4/CD8 ratio varied from 0.7-3.8 with considerable fluctuation. This ratio is typically high in CFS patients, and is indicative of immune system activation.

While the lymphocyte counts fluctuated, the authors note that they returned to normal limits at points during the study period. This stands in contrast to the immune response to HIV infection, which begins with variable lymphocyte levels but eventually results in complete immune deficiency.

Results of this small trial requires confirmation through larger tests, the authors note.

Krueger G et al. “Dynamics of chronic active herpesvirus-6 infection in patients with chronic fatigue syndrome: data acquisition for computer modeling.” In Vivo. 2001; 15:461-466.