Transcript for Boy, 8, meets the bone marrow donor who saved his life, live on 'GMA'
ifou look at those dunes, they say six to eight feet of sand have fallen off the top of the dunes. We are trying to find out more information about that, and we will bring you a live report at noon. Live in sandwich, Josh brogadir, WCVB newscenter 5. Antoinette: Thank you. We will stay on track of time. So 70% of the time people need a bone marrow transplant, they weren't fortunate to have someone in my family like I was blessed to have woman right here and that's where be the match comes in and one of the many people it helped was a young boy named A.J. And we want to share his story with you. ??? He was a really healthy boy. All of a sudden in the middle of the night he woke up with leg pain and the following day the leg pain was so excruciating that we had to take him to the E.R. Reporter: In the hospital on his fourth birthday in January 2013 A.J. And his family received a life-changing diagnosis. We found out that it was actually leukemia. So we knew that we needed to get to Walter reed as fast as possible. Reporter: Living overseas while dad Jeff served in the military, A.J. And his family immediately flew back to the states for treatment. A.J. Was so sick, the treatment was so intense. Alexa and I were shifting each other out at the hospital. Eventually he did reach remission. Reporter: Unfortunately in the summer of 2015 A.J. Relapsed. It was another setback. It came back in two locations so that's a clear indication that the treatment wasn't working. Reporter: At that point we knew that a transplant was really his only option. The first step was for all of us to be tested. And none of us were a match. Reporter: The family turned to be the match, an organization that helps patients find their life-saving donors. And thankfully they found A.J. A match. A 22-year-old woman, that's all the family knew at the time. Meanwhile, A.J. Kept on fighting. Felt like a very long road leading up to his transplant day. He went through a lot of heavy-duty chemotherapy. Reporter: Throughout the difficult process like a typical kid A.J. Found small moments of joy in his toys and even dancing. Woo. A.J. ??? Reporter: For a.j.'s mom it was a glimmer of hope she needed. Writing to her son's donor. So I'm thinking of you as you head to the hospital today for your procedure and I thank you from the very depths of my heart for what you've done for my little boy. Reporter: After 270 days in the hospital, the best news of all, the transplant worked. A.J. Was cancer-free. ??? Happy birthday to you ??? Reporter: After 2 1/2 years, 8-year-old A.J. Is back in school. And now one more stop on his journey, meeting his donor for the first time face-to-face. Saying thank you never really feels like enough when someone saves your child's life. A.J. Alexa, his dad Jeff. Michael and I are so thrilled to have you with us. I got to tell you, how is it going, A.J.? Good. Yeah. What do you like to do? I don't know. Most of the time I like to build legos. Legos, perfect. We got a new movie coming out. We got some legos backstage for you. How is he doing. A.J. Is doing well. Going back to school and playing with his friends and, yeah, he's doing well. Alexa, A.J. Is 8 years old now and he's thriving so what does that mean to you to see him thrive in the way he is. Oh, you know, it's -- well, I just feel so much joy after a lot of dark days and it's so nice to see him running again and playing with his friends and going to school for a full day and seeing him smile again and talk. I know it had to be difficult when looking to the family and there was not a match and everybody always thinks it will be an automatic. You got a family members, it'll be the case but it's not and then to find that there was one on be the match. Yes. I remember I think my heart sank the day that none of us were a match but a lot of people were praying and fortunately we didn't have to wait very long. It was maybe two weeks afterwards we found out that A.J. Had a potential match. And what went through your head when you found out you did find a match? Relief. Relief. Yeah. Well, you know, a.j.'s match is here. You know, you've never met in person. You talked on the phone but you haven't met in person. We talked on the phone. Sent text messages back and forth. But we have not met her. So -- Are you ready to meet her? Yes. Want to meet her. Very ready. My heart is pounding. I don't know if I can take this. Get up. Everybody, give a round of applause to a.j.'s match, Alex. Come on out, Alex. Hi. Good to see you, Alex. Come on over. Good to see you. Oh, wow. Okay. This edition of "Good morning America" brought to you by Kleenex. Alex needs some herself. Look at -- something you want to say to her. Thanks for saving my life. It was my pleasure. What's it like to see each other face-to-face for the first time after all this. It's overwhelming. Of O we've thought a lot about meeting you and getting to know you more. We're so excited and so thankful. So beautiful, Alexa, something you want to say. You know, just Alex is already a part of our family and I really look forward to just sharing life with her and, you know, I've been doing that so far sending her messages and pictures of A.J. And every time he meets a milestone I'm excited to share it with her. Did you ever think when you signed up that you'd end up with a family and a new friends and all of these things? No, I thought I would be lucky if I ever met my recipient but I was prepared for the fact that I might not ever know and I had to come to terps with that but it is surreal to me. Why did you want to be a donor? Because it's the right thing to do. And it's so beautiful, I know that without even meeting him, you wrote a letter. I did. Can you read a portion of it. This boy may be somebody's -- may someday be someone's husband, someone's father, grandfather, son-in-law, maybe he will take the world by storm and find the cure for cancer or maybe he won't. The point is he is important. The point is he's important. Wow. You know, I've been overwhelmed by this moment and everybody that's here. We'll get to know more and more people and so grateful my sister was my donor. But a total stranger doing this. A total stranger and that's what we -- you've got the best smile. Can I just say that? The cutele little freckles. In the world. What is your message to people, pecially young people thinking because you guys are the sweet spot, aren't they? I mean the college -- my college campus did a swabin' for robin, a bone marrow drive because you all are really -- thank you for that. What is your message to someone. My message is don't be afraid to donate. Don't be afraid to join. You never are going to regret saving someone. There's nothing bad that can come out of donating. It's all positives. Yeah. I tell you, I'm looking at A.J. He's just staring at you. He's so happy. He's so happy and there's a big congratulations for you too, Alex. Somebody is getting married, everybody. This weekend. In three days. Oh. So you hav@ some people who may be sitting here with us who are going to the wedding. I do. Yeah. I'm very excited. Wonderful. Extension of family. Extension of family. Thank you all so much. I know it's not easy to share when you're going through something like this but it's so important to give hope to people and as I said earlier it's a privilege to be a messenger and I feel that we are. We are wrae delivering a message of hope and resilience and knowing that you just keep moving. You keep believing and we are all here today assembled and this too shall pass so thank you all very much.
This transcript has been automatically generated and may not be 100% accurate.