This question can no longer be ignored, said Dr. Connie Davis in an editorial in the Lancet, even if it decides premature to draw conclusions about the need for a tri recipients. The analysis, led by Professor Alois Gratwohl (University Hospital Basel, Switzerland) and his colleagues in Heidelberg (Germany), brought back on the registration during the period 1985-2004 to 195.51'6 recipients of kidneys (deceased donors) from 400 transplant centers.

The authors have found quite complex interactions. Thus, the rejection of the transplant is more common with kidneys from women as from men kidneys, the first year after transplant and ten years later. By contrast, women recipients have a lower failure rate of transplantation between the end of the first year and the tenth year of transplantation.

But compared with the three other combinations of sex (HH, FF, F-H), kidney transplant on a man recipients is associated with an increase of 8% risk of failure of the graft in the first year following the intervention. This effect on the rejection of the transplanted organ has come from a "antigen" compatibility, called "HY" linked to the male Y chromosome, which causes a reaction in immunology from the recipient. "We need to know why the transplant of a kidney from a man gives poorer results in some patients and not in others," are the perpetrators.

Future research should address in detail the mechanisms and possibilities for preventing the release associated with this type of minor histocompatibility antigen, "note the authors.

For organ transplants such as kidney or heart, the risk of rejection usually based primarily on the major histocompatibility system, HLA (for Human 'Leucocyte antigens). The more different HLA, the greater the rejection reactions are important.