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S075-3

Pro-Inflammatory Cytokines in Bipolar Disorder

Ya-Mei Bai

Taipei Veterans General Hospital, Taiwan

Background/Objective: Pro-inflammatory cytokines have gained increased attention as potential
mediators of interaction with the immune and neuroendocrine systems and specific pathways
involved in mood, energy, and activity control. Both bipolar disorder and unipolar depression are
reported to be related to inflammatory dysregulation, and inflammatory cytokines have been
suggested to be the trait or state markers of bipolar disorder, but with inconsistent results. This may
be related to small sample sizes and poor control of some important confounding factors.

Method: Gender/age-matched outpatients with bipolar disorder, unipolar depression and normal
controls were enrolled. The clinical symptoms were rated using the Montgomery Åsberg Depression
Rating Scale and Young Mania Rating Scale. Inflammatory cytokines, including soluble
interleukin-6 receptor (sIL-6R), soluble interleukin-2 receptor (sIL-2R), C-reactive protein (CRP),
soluble tumor necrosis factor receptor type 1 (sTNF-R1), soluble p-selectin receptor (sP-selectin),
and monocyte chemotactic protein-1 (MCP-1), were assessed by enzyme-linked immunosorbent
assays.

Result: 130 patients with bipolar disorder (BD), 149 patients with unipolar depression (UD), and
130 normal controls (NC) were enrolled. The BD group had significantly higher levels of sIL-6R,
CRP, sTNF-R1, and MCP-1 than the UD group after controlling smoking, medical comorbidity, body
mass index, and duration of illness. Among the 130 BD patients, the bipolar II patients had
significantly lower levels of sTNF-R1 than the bipolar I patients ; and the patients in a depressive
state had significantly lower levels of sTNF-R1 than the patients in manic/hypomanic and euthymic
states with controlling of age, gender, BMI, smoking, duration of illness, and medication grouping.

Conclusion: The results suggested bipolar disorder is with a more severe inflammatory
dysregulation than the unipolar disorder, and sTNF-R1 may be a potential biomarker for staging
bipolar disorder.