The parents of a two-year-old girl who was diagnosed with leukemia marked World Blood Donor Day by meeting a local man who has donated more than 400 times.

According to Canadian Blood Services, Maura and Alan Cosgrave's 13-month-old daughter, Sophie, was diagnosed in January 2018. As she underwent chemotherapy, Sophie needed dozens of blood products.

That's why the Cosgraves were at the Oak Street blood donation centre to thank donors like West Vancouver's John C. Lee, who has been donating blood for decades.

"Sophie, when she was in hospital, received multiple blood transfusions and that wouldn't have been possible without the donations from donor like John, who we met today, so really nice for us to connect with him," Alan told CTV News. "It's a special day for us for sure."

Lee started donating blood in 1974 as a student at the University of British Columbia.

"I donated and found out it was easy for me to do," he said in a news release. "I had no ill effects. I didn't miss the blood, and it struck me as being the ideal exchange."

Lee was once also called on to donate platelets for a leukemia patient years ago, and was one of six people supporting the patient on a weekly basis.

"I never met the person but learned that he was male and in the same wing of the same hospital at the same time, getting what I was giving him while it was still warm," Lee said. "It gave me a tremendously warm feeling being that close to the one in need we were helping and knowing he knew we were there for him."

While Sophie may have never received Lee's blood, he called finally getting to meet a recipient who has benefited from the generosity of donors like him a "meaningful" experience.

"I've donated a lot of whole blood, platelets and plasma, whatever was needed or asked of me," he said.

"I'm in good health so I continue to do so. But you're a full step removed from those receiving your donation and kind of disassociated from the end goal … Unlike donating blood, it's not disassociated and theoretical. It's real."

According to CBS, more than 100,000 are needed in Canada this year to keep up the national blood supply.