Background. von Willebrant factors (vWF) represents a marker of circulating endothelial cells, which are found in circulation of patient after acute myocardial infraction (AMI). However their role is far from being understood. We aimed to investigate frequency, phenotype, cytokine/chemokine production and purification strategy of circulating vWF+ endothelial cells and their ability to affect cytotoxic mediator perforin expression in T lymphocytes in patients after AMI. Material and methods. Peripheral blood mononuclear cells (PBMCs) from 42 patients on days 1, 7 and 28 after AMI were isolated by gradient density centrifugation. Phenotype of gated vWF+ cells simultaneously labeled with monoclonal antibodies against surface HLA-DR, CD80, CD86, CD91, CCR7, or intracellular IL-15, IFN and CCL17 markers were analyzed by flow cytometry and compared to CD14+ cells. vWF+ and CD14+ were positively separated from adherent, while CD3+ T cells were negatively selected from non-adherent PBMC fraction in magnetic field. Enriched vWF+ or CD14+ cells were co- cultured with T cells and expression of perforin positive T cells was analyzed by flow cytometry. Paraffin-embedded myocardial tissue sections of patients died of AMI were double labeled for perforin and CD3 and analyzed by fluorescence microscopy. Results. The percentage of vWF+ and CD14+ cells significantly increased in patients after AMI. In the patient with STEMI treated with PCI the frequency of vWF+ cells was the highest on day 7 (approximately 5%) and statistically significantly differs from the days 1 and 28 after AMI. In NSTEMI patients without primary PCI, vWF+ cells was the lowest on day 7 (approximately 4%) when compared to the day 7 and day 28. Circulating vWF+ cells express HLA- DR as well as CD14+ cells do, while expression of CD91 receptor, CCR7, CD80 and CD86 molecules were poorer, together with low intracellular expression of IL-15, IFN- and CCL17 when compared with CD14+ cells. vWF+ cells maintained the MFI for perforin only in vWF+:CD3+ cells ratio 1:2.5, and were disable to increase the percentage of perforin expressing T cells in the culture. CD14+ cells specifically and statistically significantly increased frequency of perforin expressing 18 hours cultured T cells. Paraffin-embedded myocardial section from the patients died of AMI showed negligible fraction of perforin expressing T lymphocytes. Conclusion. The dynamic fluctuation of circulating vWF+ cells after the AMI differs regarding the type of AMI, and probably the implementation of PCI. In circulation, they might act as antigen presenting cells with regulatory properties and induce anergic T cells, contributing to down-regulation of inflammatory reaction in a short period of time immediate after acute coronary event, before own apoptosis.