Immunosuppressive networks in the tumour environment and their effect in dendritic cells.

The failure of the immune system to provide protection against tumour cells is an important immunological problem. It is now evident that inadequate function of the host immune system is one of the main mechanisms by which tumours escape from immune control, as well as an important factor that limits the success of cancer immunotherapy. In recent years, it has become increasingly clear that defects in dendritic cells have a crucial role in non-responsiveness to tumours.

Dendritic cells dysfunction in tumour environment.

Several studies indicate that most tumours are immunogenic and they rarely succeed to induce an efficient immune response. Many mechanisms have been involved in the tumour escape from host immune surveillance. The tumour microenvironment has emerged as an important component contributing to dendritic cells (DCs) dysfunction.

Immunological lessons learnt from patients transplanted with fully mismatched stem cells.

Fully HLA-mismatched stem cells from human fetal livers were transplanted into 17 infants and two fetuses to treat severe combined immunodeficiency disease in 1976-2000. Donor cell engraftment and immunological reconstitution were obtained in 14/19 patients, three of whom have been extensively and repeatedly studied immunologically during prolonged follow-up. T-cells were derived totally from donor cells; B-cells and antigen-presenting cells (APC) remained mainly of host origin.