Antibody responses in early graft rejection in pig-to-primate renal xenotransplantation

Hepatocyte cell therapy in liver disease

Liver disease is a leading cause of morbidity and mortality. Liver transplantation remains the only proven treatment for end-stage liver failure but is limited by the availability of donor organs. Hepatocyte cell therapy, either with bioartificial liver devices or hepatocyte transplantation, may help address this by delaying or preventing liver transplantation. Early clinical studies have shown promising results, however in most cases, the benefit has been short lived and so further research into these therapies is required. Alternative sources of hepatocytes, including stem cell-derived hepatocytes, are being investigated as the isolation of primary human hepatocytes is limited by the same shortage of donor organs. This review summarises the current clinical experience of hepatocyte cell therapy together with an overview of possible alternative sources of hepatocytes. Current and future areas for research that might lead towards the realisation of the full potential of hepatocyte cell therapy are discussed.

T-cell-based immunosuppressive therapy inhibits the development of natural antibodies in infant baboons

BACKGROUND

We set out to determine whether B-cell tolerance to A/B-incompatible alloantigens and pig xenoantigens could be achieved in infant baboons.

METHODS

Artery patch grafts were implanted in the abdominal aorta in 3-month-old baboons using A/B-incompatible (AB-I) allografts or wild-type pig xenografts (pig). Group 1 (Gp1) (controls, n=6) received no immunosuppressive therapy (IS) and no graft. Gp2 (n=2) received an AB-I or pig graft but no IS. Gp3 received AB-I grafts+IS (Gp3A: n=2) or pig grafts+IS (Gp3B: n=2). IS consisted of ATG, anti-CD154mAb, and mycophenolate mofetil until age 8 to 12 months. Gp4 (n=2) received IS only but no graft.

RESULTS

In Gp1, anti-A/B and cytotoxic anti-pig immunoglobulin-M increased steadily during the first year. Gp2 became sensitized to donor-specific AB-I or pig antigens within 2 weeks. Gp3 and Gp4 infants that received anti-CD154mAb made no or minimal anti-A/B and anti-pig antibodies while receiving IS.

DISCUSSION

The production of natural anti-A/B and anti-pig antibodies was inhibited by IS with anti-CD154mAb, even in the absence of an allograft or xenograft, suggesting that natural antibodies may not be entirely T-cell independent. These data are in contrast to clinical experience with AB-I allotransplantation in infants, who cease producing only donor-specific antibodies.