World Enzyme flaw linked to fatigue
 By Richard A. Knox, Globe Staff

---

People with chronic fatigue syndrome suffer from a defect in an enzyme
the body uses to inactivate viruses, a Philadelphia-based research
group reported this week.

The discovery, if it holds up to scrutiny, lends support to the idea
that the syndrome can start with a common viral infection that leads
to a chronic, abnormal immune response.

The enzyme abnormality has shown up in all of more than 100 chronic
fatigue syndrome patients tested so far, said Robert J. Suhadolnik of
Temple University, who led the research effort. It appears in about 10
percent of healthy individuals with no sign of chronic fatigue.

Suhadolnik and his colleagues hope their discovery, which reportedly
has been confirmed by Belgian researchers, will lead to a diagnostic
test for the elusive disorder. Chronic fatigue syndrome disables
uncounted thousands of people and frustrates physicians looking for
cause or effective treatment.

The new finding could also provide clues to the physiological
mechanism of the syndrome, which has been attributed to dozens of
different immunologic, neurologic, muscular, cellular, viral,
environmental, and nutritional causes.

'Overactive and defective antiviral enzymes may be involved in the
production of fatigue, and also the cognitive symptoms,' Suhadolnik
said yesterday in an interview.

Dr. Anthony Komaroff of Brigham and Women's Hospital in Boston, a
leading authority on chronic fatigue syndrome, praised the quality of
Suhadolnik's research and said he was impressed with earlier findings
from his laboratory indicating the antiviral enzyme system is
overactive in a high percentage of fatigue patients.

However, Komaroff said many more randomly selected chronic fatigue
sufferers would have to be tested for the enzyme defect, along with
healthy subjects and individuals with other kinds of diseases, to
determine its usefulness as a diagnostic test.

'The world has been waiting for a diagnostic test, and Suhadolnik
thinks he may have it,' Komaroff said. 'But I don't see how that
claim can be made because the numbers are too small.'

In the new report, published in the current issue of the Journal of
Interferon and Cytokine Research, the enzyme defect appeared in seven
patients with confirmed chronic fatigue syndrome. It did not appear
among seven healthy individuals of the same age in one test that
measures active, functional enzymes; it sometimes appeared among
healthy subjects using a different test, but Suhadolnik believes that
is because the second test 'denatures,' or breaks down proteins.

In subsequent, unpublished tests of more than 100 chronic fatigue
patients and equal numbers of controls, or people without the
disorder, the same results appeared, the Temple University biochemist
said.

The defect is an unusually small form of an enzyme called RNase-L,
which breaks down RNA, a molecule that is the principal genetic
substance of many viruses.

Chronic fatigue syndrome involves at least six months of severe
fatigue plus four or more of the following symptoms: impairment in
short-term memory or concentration; sore throat; tender lymph nodes in
the neck or armpit; muscle pain; pain in multiple joints without
inflammation; headaches of a new type, pattern, or severity;
unrefreshing sleep; and long-lasting malaise following exertion.
 

Copyright © 1997 Globe Newspaper Company
URL:   http://www.boston.com/globe