Elevation of cerebrospinal fluid interleukin-1ß in bipolar disorder.
BACKGROUND
In recent years, a role for the immune system in the pathogenesis of psychiatric diseases has gained increased attention. Although bipolar disorder appears to be associated with altered serum cytokine levels, a putative immunological contribution to its pathophysiology remains to be established. Hitherto, no direct analyses of cerebrospinal fluid (CSF) cytokines in patients with bipolar disorder have been performed.


METHODS
We analyzed CSF cytokine concentrations in euthymic patients with diagnosed bipolar disorder type I (n = 15) or type II (n = 15) and healthy volunteers (n = 30) using an immunoassay-based protein array multiplex system.


RESULTS
The mean interleukin (IL)-1ß level (4.2 pg/mL, standard error of the mean [SEM] 0.5) was higher and the IL-6 level (1.5 pg/mL, SEM 0.2) was lower in euthymic bipolar patients than in healthy volunteers (0.8 pg/mL, SEM 0.04, and 2.6 pg/mL, SEM 0.2, respectively). Patients with 1 or more manic/hypomanic episodes during the last year showed significantly higher levels of IL-1ß (6.2 pg/mL, SEM 0.8; n = 9) than patients without a recent manic/hypomanic episode (3.1 pg/mL, SEM 1.0; n = 10).


CONCLUSIONS
All patients were in an euthymic state at the time of sampling. Owing to the large variety of drugs prescribed to patients in the present study, influence of medication on the cytokine profile cannot be ruled out.


CONCLUSIONS
Our findings show an altered brain cytokine profile associated with the manifestation of recent manic/hypomanic episodes in patients with bipolar disorder. Although the causality remains to be established, these findings may suggest a pathophysiological role for IL-1ß in bipolar disorder.
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Johan
J
Söderlund
Sara K
SK
Olsson
Martin
M
Samuelsson
Lilian
L
Walther-Jallow
Christian
C
Johansson
Sophie
S
Erhardt
Mikael
M
Landén
Göran
G
Engberg
D000328:Adult; D001714:Bipolar Disorder / Q000134:cerebrospinal fluid*; D006801:Humans; D007118:Immunoassay; D053583:Interleukin-1beta / Q000134:cerebrospinal fluid*; D015850:Interleukin-6 / Q000134:cerebrospinal fluid; D008297:Male; D008875:Middle Aged
D053583:Interleukin-1beta; D015850:Interleukin-6