Immune Molecule Key to Preventing Organ Rejection

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MONDAY, June 23 (HealthDay News) -- An immune molecule called HLA-G dimer plays a powerful role in preventing the immune system from rejecting transplanted organs and tissue, Medical College of Georgia researchers say.

They found that HLA-G helped prolong skin graft survival in mice and are currently studying whether this molecule is at work in kidney transplant patients who don't experience organ rejection.

"This is a molecule with huge potential to regulate immune response," Dr. Anatolij Horuzsko, a reproductive immunologist at the Medical College of Georgia Center for Molecular Chaperone/Radiobiology and Cancer Virology, said in a prepared statement.

He and his colleagues found that when HLA-G dimer binds with its inhibitory receptor ILT4, it triggers a signaling pathway in which immune molecules IL-6 and STAT3 play a major role.

"Biologically, this is an interaction that requires several important suppressive molecules," said Horuzsko, corresponding author of the study, which was published online in the journal Proceedings of the National Academy of Sciences.

The researchers looked at the resulting strong signal in culture and then assessed its impact on skin graft survival in mice.

Horuzsko and colleagues believe HLA-G dimer's action can be boosted in order to suppress immune activity in people with organ transplants and autoimmune diseases, and turned down in order to increase immune system activity against tumors. Measuring levels of HLA-G dimer may also help doctors identify transplant patients who require little, if any, immune system suppression.

More information

The MedlinePlus Medical Encyclopedia has more about transplant rejection.