I. Wilke et al., INVESTIGATIONS OF CYTOKINE PRODUCTION IN WHOLE-BLOOD CULTURES OF PARANOID AND RESIDUAL SCHIZOPHRENIC-PATIENTS, European archives of psychiatry and clinical neuroscience, 246(5), 1996, pp. 279-284
In an attempt to define potential immunological dysfunctions in schizo
phrenia, we determined the production of interleukin-2 (IL-2), interle
ukin-4, (IL-4), interferon-gamma (IFN-gamma), and soluble IL-2 recepto
r (sIL-2R) in a whole-blood assay after stimulation with phytohemagglu
tinin (PHA) as well as the serum concentrations of sIL-2R. Because CD(
4)(+)CD45RO(+)T cells are the main producers of IFN-gamma, we determin
ed the percentage of these cells, as well as of panT, CD4(+)T, and CD8
(+)T cells, by flow cytometry. A whole-blood count was performed in ad
dition. Two groups of patients were examined, paranoid-type and residu
al-type schizophrenics. The numbers of both monocytes and neutrophils,
but not of lymphocytes, were increased significantly in the schizophr
enic sample. The IFN-gamma production of the schizophrenics as a whole
group, and of the paranoid patients, was reduced significantly in com
parison with the control group (p less than or equal to 0.05). The res
idual patients produced less IFN-gamma than the controls, but more tha
n the paranoid patients. The latter differences did not reach statisti
cal significance. The production of IL-4, which physiologically antago
nizes the production of IFN-gamma, was not significantly higher in the
patient group. No changes in the lymphocyte subpopulations were obser
ved. The production of IL-2 showed a trend toward reduction in paranoi
d patients, but not in residual schizophrenics. The serum sIL-2R level
s were elevated slightly in schizophrenics when compared with controls
. In order to rule out a possible effect of cortisol on cytokine produ
ction, 20 schizophrenics were compared with 20 age- and gender-matched
controls. However, neither elevated cortisol levels were detected in
the schizophrenic sample, nor significant intercorrelations between co
rtisol levels and cytokine production, or levels of sIL-2R, respective
ly. In summary, our data reinforce the possibility of immune dysfuncti
on in schizophrenia and point to the possible relevance of disease sub
groups in this respect.