Immune response alterations in psychiatric diseases have been discussed repeatedly. The examination of the innate immune system showed alterations of the toll-like receptors (TLR) of schizophrenic patients compared to healthy controls. There was an increased amount of TLRs but decreased responsiveness after stimulation, e.g. with lipopolysaccharides (LPS), in the sense of an endotoxins tolerance, which can be seen as a result of a chronic activation of the immune system. In order to evaluate the TLR changes’ impact on the signaling cascade, we analysed the expression of central proteins of the TLR pathway.In our pilot study we recruited 25 schizophrenic patients and 16 healthy controls. Blood samples were taken once in the control group and twice in the patient group (before and 6–8weeks after medication with antipsychotics). PBMCs (peripheral blood mononuclear cells) were separated and analysed for the expression of 84 genes of the TLR pathway. The analysis was pooled for the patient and the control group and was conducted before and after stimulation with LPS.Our results on the mRNA level mostly confirmed results of previous studies on the protein and receptor level. We found a diminished capacity for response after LPS stimulation for factors which activate the TLR pathway. However, there was an increased expression of inhibiting factor of the pathway compared to healthy controls. Differences between the schizophrenic patients and healthy controls will be illustrated using the example of TLRs, MyD88, TOLLIP and IRAK4, in consideration of therapeutic effects of the antipsychotics.