Ellie White’s battle against leukemia is facing another obstacle.

The seven-year-old Hampstead girl relapsed after receiving a bone marrow transplant in February.

White received a wave of support from Montrealers after CTV first shared her story.

It led to over 900 people signing up with Hema-Quebec to be potential bone marrow donors in a three-day span.

The normal rate is 3,000 per year.

White started Grade 2 this week.

“We spent all summer getting her tutored and catching her up,” said her mother Amanda Sokoloff.

The family received the news of the relapse on Wednesday. Sokoloff says they spent the summer doing every activity Ellie wanted to try including hosting her dream birthday, sending her to dance camp and playing mini-golf.

Finding a match was a huge hurdle, Hema-Quebec compared it to finding a needle in a haystack.

White went through an intense round of chemotherapy before the transplant.

The Children's Hospital, where Ellie is a patient, performs between 15 and 20 of these procedures every year.

"The bone marrow is given like a transfusion, just like an IV, and the cells find their way to the bone marrow," explained Dr. David Mitchell, a pediatric haematologist who performs most of the transplants.

Her mother says there is no clear protocol at this moment for what happens next but is appealing to the public for any contacts specializing in pediatric high-risk acute myeloid leukaemia (AML) bone marrow transplant.