Endothelial cells in infantile haemangiomas originate from the child and not from the mother (a fluorescence in situ hybridization-based study).

Background: Infantile haemangiomas are benign vascular tumours of infancy of unknown origin. Their aetiological relationship to maternal cells has been questioned given that they develop during the neonatal period.

Objectives: As endothelial cells in the placenta may be of maternal or fetal origin, we questioned whether vascular haemangioma cells originated from fetal or maternal tissue.

HLA-G*0105N null allele encodes functional HLA-G isoforms.

Expression of the nonclassical HLA class I antigen, HLA-G, is associated with immune tolerance in view of its role in maintaining the fetus in utero, allowing tumor escape, and favoring graft acceptance. Expressed on invasive trophoblast cells, HLA-G molecules bind inhibitory receptors on maternal T lymphocytes and NK cells, thereby blocking their cytolytic activities and protecting the fetus from maternal immune system attack. The HLA-G gene consists of 15 alleles, including a null allele, HLA-G*0105N.

Skin carcinoma arising from donor cells in a kidney transplant recipient.

The incidence of skin cancer is increased in transplant recipients. UV radiation, papillomaviruses, and immunosuppression participate in the pathogenesis of these tumors. In addition, donor cells may leave the grafted organ, reach peripheral tissues and either induce immune phenomena or possibly take part in tissue remodeling.

HLA-G up-regulates ILT2, ILT3, ILT4, and KIR2DL4 in antigen presenting cells, NK cells, and T cells.

The nonclassical HLA class I antigen HLA-G is an inhibitory molecule involved in immune tolerance and immune escape. HLA-G exerts its inhibitory functions via interaction with inhibitory receptors ILT2, ILT4, and KIR2DL4, differentially expressed by NK, T, and antigen-presenting cells. Cells expressing HLA-G and cells expressing its receptors are often found in the vicinity of each other, but the mechanisms responsible for this colocalization are still unknown.

Selective expression of HLA-G in malignant and premalignant skin specimens in kidney transplant recipients.

The HLA-G molecule has been implicated in the escape from the host antitumor immune response. Besides, this molecule appears also to be detected in transplant recipient's tissues, mainly those with fewer rejection episodes. Since skin carcinomas develop frequently in organ transplant recipients, we asked whether HLA-G could be expressed in these lesions, therefore allowing tumor development in such patients.