Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) exert various effects on immune cells. Here we studied, whether they influence the cytokine expression pattern in peripheral blood mononuclear cells (PBMCs) or antigen specific T-cells. In PBMCs BDNF and NGF had interindividually variable effects on T helper cell type (Th)1- and Th2-cytokines. However, there was a high correlation between the modulating properties of these neurotrophins (r=0.97) concerning the expression of interleukin (IL) 4, transforming growth factor-beta and tumour necrosis factor-alpha mRNA at a concentration of 100 ng/ml. In myelin basic protein-specific T-cell lines BDNF and NGF increased interferon -gamma mRNA to a moderate extent, but not IL4. No major effects were detected at the cytokine protein level. In conclusion, our results suggest a partial effect of neurotrophins on immune cells, which may be modified by other signals.