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).

Autoantibody tied to CFS
Japanese researchers have discovered a new autoantibody that may be linked to a subset of CFS patients with hypersomnia and cognitive complaints.

More than 13 percent of the 114 CFS patients in the study tested positive for autoantibodies to a 68/48 kDa protein. In this subset, 80 percent of subjects complained of hypersomnia, compared to 36 percent in the non-antibody group. Impaired memory and concentration complaints also were significantly higher in the subset. No control subjects showed signs of the antibody.

The study's authors say the antibodies may serve as a useful serological marker for CFS patients with sleep and cognitive difficulties.

Nishikai M et al. Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders. Rheumatology. 2001; 40(7):806-810.

Depression not cause of cognitive symptoms
Cognitive deficitsin patients with chronic fatigue syndrome (CFS) cannot be fully explained by accompanying depressive symptoms, according to a new study in the journal Applied Neuropsychology.

Researchers looked at 101 patients, 29 of whom met the modified 1994 international research case definition for CFS. The depression group included 23 non-CFS patients with a history of major depressive disorders. A third group of 24 patients had been diagnosed with clinically definite multiple sclerosis (MS). There were 25 healthy controls.

The subjects were given a battery of neuro-psychological tests. The scores were grouped into five cognitive domains: attention, memory, language, executive function and spatial ability.

In general, the depression group showed the highest levels of cognitive impairment compared to controls, followed by MS patients, then CFS patients. While CFS scores were generally worse than controls, the difference did not reach statistical significance.

After adjusting scores for CFS patients based on self-reported depressive symptoms, the authors write that the presence of depression in CFS patients "cannot solely account for the cognitive differences among the patient groups."

Daly E et al. Neuropsychological function in patients with chronic fatigue syndrome, multiple sclerosis and depression. Applied Neuropsychology. 2001; 8(1):12-22.

RNAse L variant active
A novel protein in some CFS patients' antiviral pathways is far more active than previously realized, according to a study in the June issue of the Journal of Biological Chemistry.

The protein, 37 kDa RNase L, has been identified in a subset of CFS patients, but not in fibromyalgia or depression patients. Presence of the 37 kDa RNase L has previously been correlated with the level of clinical disability in CFS patients. The new study showed that it is structurally similar to the normal 80 kDa RNase L and can be detected with the same azido photoaffinity probe, even though it is less than half the size of the 80 kDa form.

However, the 37 kDa form is at least three times faster at hydrolyzing RNA than the 80 kDa form. The authors say they will continue to study the structure of the protein and work to determine the role it plays in CFS.

Shetzline SE, Suhadolnik RE. Characterization of a 2',5'-Oligoadenylate (2-5A)-dependent 37 kDa RNase L. J Biol Chem. 2001; 276(26):23707-11.

Pre-CFS patients visit doctors often
People who develop CFS consult their physicians more frequently than other patients in the years prior to their illness, according to new British research.

The study looked at records from 14 general medical practices in Devon, England. Researchers tracked the histories of 49 CFS patients and 49 matched controls. The researchers found that CFS patients visited their doctors nearly twice as often as the controls during the 15-year period prior to diagnosis.

CFS patients were 8.5 times more likely to visit a doctor with complaints of upper respiratory tract infections than were controls. They also were seven times more likely to mention lethargy and 3.8 times more likely to complain of vertigo.

The authors offer several explanations for the increased office visits - including the possibility that the patients already had CFS and were undiagnosed.

Hamilton WT et al. Frequency of attendance in general practice and symptoms before development of chronic fatigue syndrome: a case-control study. Brit J of Gen Prac. 2001; 51:553-558.

New method finds immune differences
In the past, linear methods have proven unreliable for detecting immunological abnormalities in CFS patients versus control groups. In a recent paper, scientists describe using neural network classifiers to detect immune differences that were previously unidentified.

Neural networks are a type of nonlinear classification system that has been shown to provide optimal identification of factors in situations where the data is multilayered and multiple comparisons are being made.

Researchers looked at immunological data for 103 CFS patients and 87 healthy but sedentary controls. Multilayer neural networks showed an over 16% improvement in identifying immune differences than traditional linear methods. A sensitivity analysis of the network found differences between groups that are consistent with the hypothesis that CFS symptoms are a consequence of immune system dysregulation.

Hanson SJ et al. Detection of immunologically significant factors for chronic fatigue syndrome using neural-network classifiers. Clin Diagnostic Lab Immunol. 2001; 658-662.