The high seroprevalence of Toxoplasma gondii infection in Blood Banks could be a potential risk for contamination of blood recipients. The discovery of new biomarkers may help to distinguish between seropositive and seronegative donors. This study determined the seroprevalence and profile of systemic immune biomarkers associated with Toxoplasma gondii infection among blood donors from Southern Brazil. Peripheral blood was collected from 510 blood donors (52.2 % male; mean age: 36.61), 310, and 200 from Erechim, and Chapecó municipalities, respectively. Specific Toxoplasma gondii IgG and IgM antibodies were detected by Eletrochemioluminescence. Nested PCR and qPCR were performed to detectToxoplasma gondii DNA. Twenty-seven inflammatory factors were analyzed using a high-performance Luminex assay. Among 310 blood donors from Erechim, 44.5 % (138/310) were IgM(-)/IgG(+), and 1.3 % (4/310) were IgM(+)/IgG(+), while out of 200 blood donors from Chapeco, 42.5 % (85/200) were IgM(-)/IgG(+), and 2 % (4/200) were IgM(+)/ IgG(+). We did not find Toxoplasma gondii DNA in the samples analyzed by Nested PCR and qPCR.Additionally, IgM(-)/IgG(+) donors presented higher levels ofdistinct systemic mediators, and were indicated to be high producers of several systemic mediators (CCL11, CCL2, CCL3, CCL4, CXCL10, IL-1β, IL-17, IFN-γ, IL-4, IL-9, IL-13, IL-10, IL-1Ra, vascular endothelial growth factor/VEGF, platelet-derived growth factor/PDGF, granulocyte-macrophage colony-stimulating factor/GM-CSF, and IL-7). However, IgM(+)/IgG(+) donors were found as high producers of CXCL8, CXCL10, CCL4, IL-1β, IL-1Ra, IL-9, IL-13, and PDGF, while IgM(-)/IgG(-) donors showed unaltered levels for the most soluble mediators evaluated. These distinct biomarker signatures might help identify potential factors to distinguish between IgM(-) and IgM(+) donors.2099-12-31