Transplantation of animal organs, living cells and tissues into humans is termed xenotransplantation. Recent experiments have shown that the transplantation of organs from genetically modified pigs into baboons can yield moderate to good results and this raises hopes for the future of organ transplantation from pigs to humans.
However these, along with existing claims of treatments for diabetes or neurodegenerative disorders such as Parkinson’s disease, are still at a very embryonic phase. Apart from a few simple, established procedures such as the treatment of severe burns with human skin cells cultured with mouse cells, xenotransplantation today is only acceptable in very tightly controlled human trials, warns the World Health Organisation (WHO).
An advisory group of international experts recently met at the WHO to discuss progress made in xenotransplantation. The main objective of the meeting was to propose ways in which the health agency can assist countries to implement stronger policies to control the practice and enforce quality and safety measures while still promoting further research into its potential uses.
The main risk in xenotransplantation is the transmission of diseases. Many serious infections in human history have originated in animals. Once a new pathogen is introduced in one individual, it may spread to the larger population.
To manage that risk, several countries have developed rigorous guidelines and oversight procedures for the performance of xenotransplantation. However, xenotransplantation is also carried out in countries that lack such oversight and where materials and procedures used have not undergone any quality and safety controls. This means there is no proof of the quality of source animals and no monitoring of the recipient, leaving no guarantee of the safety of the procedures for the patient. The problem is globalized when individuals travel to a country where xenotransplantation has no adequate oversight. The WHO advisory group notes that any xenotransplantation performed in countries without adequate oversight poses unacceptable infectious public health risks and should be stopped.
The potential for such risks led the Member States of WHO to adopt a resolution addressing xenotransplantation in 2004. The resolution urges member States "to allow xenotransplantation only when effective national regulatory control and surveillance mechanisms overseen by National Health Authorities are in place."
The WHO advisory group and WHO experts have concluded that stronger measures need to be put in place by countries to stop the illegal performance of xenotransplantation and to promote harmonized quality and safety controls.
Guidance on xenotransplantantation and its effective regulation is available from WHO at www.who.int/transplantation/xeno.
