INCREASED SOLUBLE INTERLEUKIN-2 RECEPTOR CONCENTRATIONS IN SUICIDE ATTEMPTERS

Several biochemical parameters such as monoamines and corticosteroids are considered to play a role in the underlying pathogenetic mechanism s in mood disorders. It has also been proposed that disturbances of th e immune system may be responsible for mental disorders. Increased con centrations of plasma soluble interleukin-2 receptor (S-IL-2R) reflect an activation of T-lymphocytes. In plasma samples from medication-fre e suicide attempters with various psychiatric diagnoses (mainly mood d isorders), we found a median S-IL-2R concentration far above the range of healthy controls. No sex differences and no differences between di agnostic and suicidal subgroups were noted. In follow-up samples, the S-IL-2R remained at high levels. In cerebrospinal fluid samples from p atients, S-IL-2R levels were all below 200 U/ml. No samples from contr ols were available. We were unable to find pronounced associations bet ween plasma S-IL-2R and various monoaminergic measures in plasma, 24-h urine and cerebrospinal fluid. There was, however, a tendency of an a ssociation between S-IL-2R and the ratio of norepinephrine-epinephrine in 24-h urine, as well as plasma and cerebrospinal fluid 4-hydroxy-3- methoxymethylglycol. There was no significant association between post -dexamethasone plasma cortisol, 24-h urinary cortisol and plasma S-IL- 2R. Both when studied as medication-free inpatients and during follow- up as outpatients, there were no apparent associations between ratings of psychopathology and plasma S-IL-2R. This study clearly shows that an imbalance of the immune system was present in psychiatric patients studied after a suicide attempt. Furthermore, the immune dysfunction, shown as high S-IL-2R, seems to be independent of drug therapy.