MONTREAL -- By their own admission, Jessica and Joel Makuma don’t always get along. Joel likes to dance in his big sister’s bedroom, which led her to kick him out (“he had it coming,” she said with a smile). And, he recalls ruefully, “one time she told me she hates me.”

But the brother and sister are about to put aside these spats of sibling rivalry, as they become part of a milestone for Ste-Justine Hospital: they’re going to become the 1,000th stem cell transplant the hospital has performed.

Jessica, 12, suffers from sickle cell anemia, a genetic blood disorder in which crescent-shaped red blood cells cause pain, sluggishness strokes and other issues. Her eight-year-old brother doesn’t have the disorder and has compatible blood to Jessica’s, making him a prime transplant candidate.

"The plan is to get Jessica’s red cells normal," said Johanne Richer, the hospital’s bone marrow transplant coordinator. "We hope that in about a year she’s going to be off any medication."

Stem cell transplants are considered an important development in treating sickle cell anemia. They’re also used to treat leukemia, and last year a British man was reported to be free of HIV after a successful stem cell transplant.

"Clearly it’s getting better, and we make continuous progress in the way we do the transplant," said Dr. Pierre Teira.

Currently, an estimated five per cent of patients undergoing the procedure suffer complications that arise when the body rejects cells from another person. It’s a risk that’s considered low.

For the two siblings, it’s also a procedure that has brought them together. "I’m very proud of him," their mother, Nkanku Bitala said, referring to Joel. The 8-year-old chimed in that had someone else been selected to offer their cells to his sister, "I wouldn’t feel the same."

The procedure is scheduled for Wednesday.

When asked about her own opinion of being part of the hospital’s milestone, Jessica simply said "I’m more confident now that nothing bad’s going to happen to me.

“I feel special in a way.”