TNF-α levels linked to lithium response in BD patients

Jul 10 2012

By Mark Cowen

Patients with bipolar disorder (BD) who have a poor response to lithium treatment have significantly higher serum levels of tumor necrosis factor (TNF)-α than those with a good response, researchers report.

Furthermore, the team observed a trend toward increased TNF-α levels in BD patients who have a partial response to treatment compared with those with a good response.

"The present findings suggest that TNF-α level may impact on the clinical response to lithium and suggest that a continuous immune imbalance in poor lithium responders may be related to treatment resistance," comment Sinan Guloksuz (Maastricht University Medical Centre, the Netherlands) and team.

The findings come from a study 60 euthymic BD patients who were receiving lithium treatment.

The participants were divided into poor (n=20), partial (n=23), and good (n=17) responders based on Alda lithium response scale (LRS) scores of 0-1, 2-6, and 7-10, respectively.

Blood samples were collected from all of the participants and assessed for TNF-α levels using enzyme-linked immunosorbent assay.

Analysis revealed that mean TNF-α levels in poor, partial, and good lithium responders were 4.29, 3.50, and 2.75 pg/mL, respectively.

The difference in TNF-α levels between poor and good responders was significant (standardized effect size=0.48), and remained so after accounting serum lithium level and other factors. The difference between partial and good responders was not significant.

The researchers note that LRS scores were significantly negatively associated with TNF-α levels after adjustment for confounding factors.

Guloksuz et al conclude in the Journal of Affective Disorders: "Although these findings require further replication and cannot be taken to indicate that TNF-α represents a biomarker for response in clinical practice, further studies are warranted that focus on immune alterations in treatment resistant bipolar patients in order to clarify the association between treatment response and inflammation."

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