OBJECTIVE: Chronic fatigue syndrome (CFS) has been hypothesized to
result from immune activation. We examined the role of serum
markers of inflammation and immune activation among patients
with CFS and in those with chronic fatigue (CF) not meeting
the case definition.
METHODS: Assays for soluble interleukin
2 (IL-2) receptor, IL-6, C-reactive protein, beta
2-microglobulin, and neopterin were performed in 153 fatigued
patients in a referral clinic. Patients were classified
according to whether they met criteria for CFS, reported onset
of illness with a viral syndrome or had a temperature > 37.5
degrees C on examination.
RESULTS: Compared to control
subjects, mean concentrations of C-reactive protein, beta
2-microglobulin, and neopterin were higher in patients with
CFS (p < or = 0.01) and CF (p < or = 0.01). Results did not
distinguish CFS from CF. IL-6 was elevated among febrile
patients compared to those without this finding (p < or =
0.001), but other consistent differences between patient
subgroups were not observed. The presence of several markers
was highly correlated (p < 0.01).
CONCLUSION: Our findings
that levels of several markers were significantly correlated
points to a subset of patients with immune system activation.
Whether this phenomenon reflects an intercurrent, transient,
common condition, such as an upper respiratory infection, or
is the result of an ongoing illness associated process is
unknown. Overall, serum markers of inflammation and immune
activation are of limited diagnostic usefulness in the
evaluation of patients with CSF and CF.
MCM: Studied soluble IL-2 receptor, IL-6, C-reactive protein,
beta-2-microglobulin, and neopterin in 98 pts w CFS and 55 w
CF as well as controls. Found soluble IL-2 receptor and IL-6
levels were not significantly different. C-reactive protein,
beta-2-microglobulin, and neopterin levels were significantly
higher in both pt groups compared to controls.