Stem cells transplant trick immune system to accept organs

Of 8 kidney transplant patients who have been treated with this new approach of stem cell transplant, 5 have managed to avoid taking anti-rejection drugs a year after their surgery. One patient is totally free of anti-rejection drugs nearly 2 years after her kidney transplant.

With conventional transplants, recipients need to take pills to suppress immune system for the rest of their lives. These drugs can cause side effects, including high blood pressure, diabetes, infection, heart disease & cancer. This new approach would potentially offer a better quality of life & fewer health risks for recipients.

But some experts say the procedure, in which patients undergo a bone marrow transplant from an unmatched organ donor, is too risky, especially given the relative of kidney transplants. According to one Dr., since the current treatment is so stable, it really has to be safe. The new approach was done by Noble laureates of 1960, who discovered that the immune system in animals can be trained to acquire tolerance of foreign tissue. But it has been a long road to bring this about in people. To get recipients to accept the organ, the team needs to “condition” them by suppressing their bone marrow with chemotherapy & radiation before transplanting the donor’s bone marrow. Bone marrow contains immature blood forming stem cells that give rise to all blood cells, including immune system.

“The idea here is to try to use donor-derived stem cells to achieve engraftment, a state we call chimerism” said a doctor. “Here what we’re trying to do is get donor & recipient cells to peacefully co-exist”.

About a month before transplant surgery, kidney donors must inject themselves with a medication for several days that forces stem cells & other key cells called “facilitating cells” into their blood stream, from where they can be collected & sent off to the University of Louisville for processing.

The doctor said that these facilitating cells are naturally occurring cells that help create amore favourable environment for the stem cells & allow engraftment to occur safely.

Ildstad has developed a process for enriching these cells & formed a company called Regenerex LLC, which is developing the patented technology.

Meanwhile, the transplant recipient is given radiation & chemotherapy to suppress the immune system, a process intended to prepare them for accepting the donor’s stem cells.

The patients then undergoes a kidney transplant, & a day later, get transplanted with the enriched mix of the donor’s stem cells & facilitating cells with the hope offorming 2 bone marrow systems that can exist & function in one person.

Following these procedures, the recipient starts off taking anti-rejection drugs, but is gradually weaned off them with the goal of stopping entirely a year after the transplant.

The doctor said, patients developed tolerance to the graft, eliminating the need for anti-rejection drugs, even when donor recipients were mismatched & unrelated. The team is enrolling patients in the clinical trials, which aims to include 40 subjects.