INTRODUCTION. Dendritic cells (DCs) as professional antigen presenting cells possess the unique ability to present antigens to naive T cells and thus play a key role in the polarization of immune response towards the Th1 or Th2 profile. Allergy is caused by an excessive development of Th2 profile in immune response to environmental allergens. Mycobacteria as strong Th1 inducers are potent candidates to redress the Th1/Th2 balance in allergic disorders. Still little is known about the activity of memory T cells in response to mycobacterial antigens presented by DCs in the context of house dust mite allergy. AIM. We asked a question whether in the presence of Der p 1, the major allergen of Dermatophagoides pteronyssinus house dust mite, Mycobacterium bovis BCG vaccine and a recombinant BCG producing human IL-18 (rBCGhIL-18) were able to polarize Th2 towards Th1 memory T cell response. MATERIALS AND METHODS. Monocyte-derived dendritic cells (MoDC), prepared from asthmatic patients who responded to Der p 1 in skin prick test and healthy BCG vaccinated donors, were stimulated with M. bovis BCG or rBCGIL-18 bacilli in the presence/absence of Der p 1. The response of memory T cells to pulsed MoDC was evaluated by determining the IL-10 production by ELISA test. RESULTS. Memory T cells from allergic patients produced significantly more intensively IL-10 in response to BCG and rBCGhIL-18-pulsed DCs, as compared to the identically stimulated memory T cells from healthy donors. This effect was also observed when BCG and rBCGhIL-18-pulsed DCs were in the presence of Der p 1 allergen. This process was independent of IL-18. CONCLUSIONS. Our results indicate that memory T cells from allergic patients are more receptive to downregulating signals from BCG.