On her first visit to the United States from her native Germany, 25-year-old Lisa Frömel saw the Statue of Liberty in New York City and the "Rocky" steps at the Philadelphia Museum of Art.
But the top item on her list was no tourist attraction.
"I liked to meet you," she said Thursday morning, addressing the smiling older man seated next to her at the Hospital of the University of Pennsylvania.
That was Jack Zefutie, 74, for whom the feeling was mutual.
In February 2013, after an international search that yielded just two genetic matches, the young woman donated her bone marrow stem cells to the East Windsor, N.J., man so he could beat leukemia.
The two began corresponding after that, though at first they were not allowed to learn each other's names because of rules governing donor privacy. Their messages were routed through HUP, where Zefutie received his life-saving treatment.
But after a two-year window, both said they were game for taking the next step. Plans for an in-person meeting ensued, and Frömel arrived in Philadelphia on Saturday with her boyfriend, Alessandro Zoppe.
Zefutie and his wife, Linda, picked up the couple at the airport and have since played host, hitting the Italian Market, the Jersey Shore, and Trump Tower, among other sights.
On Thursday, they went to the hospital in West Philadelphia, where Zefutie greeted his doctors and nurses warmly, and Frömel met them for the first time.
Zefutie's initial diagnosis was myelodysplastic syndrome, in which the bone marrow fails to make enough red blood cells, white blood cells, and platelets. Symptoms can include anemia, bruising, and infection, as white blood cells are soldiers of the immune system. A quarter of patients go on to develop leukemia, said Selina M. Luger, director of the leukemia program at Penn's Abramson Cancer Center.
That happened to Zefutie. At first he tried medication, which worked for a while, but Luger eventually determined he would need a transplant.
Thus began the search for a donor whose stem cells would be compatible with Zefutie's immune system, based on his human leukocyte antigens — proteins on the surface of his white blood cells. His brother was tested, but did not match, so Penn transplant coordinator Joanne Hinkle proceeded to scour international databases.
Her search turned up 80 possible matches, but further testing revealed that just two matched Zefutie's immune signature at 10 key genetic locations.
One of them was Frömel, of Heringen, a small town in central Germany. She was in the database because years earlier, she had been tested for a possible match with a German patient who needed a transplant.
In 2013, Penn relayed a message to her that her stem cells would be needed at last, an ocean away, if she were willing. She endured five days of injections to ramp up the growth of her stem cells, a painful process causing them to spill into the bloodstream, where doctors could harvest them.
She traveled three hours to Dresden and was hooked up to a pair of intravenous needles: one to remove her blood so the stem cells could be extracted, the other to return the blood back to her body.
Her precious gift was flown to the United States and injected into Zefutie the next day.
"I call her my genetic twin and my blood sister," Zefutie said.
Frömel reads English well, but is a little hesitant to speak it with strangers, so Zefutie handled the brunt of the talking on Thursday.
He recalled receiving a photograph of Frömel that she sent after they revealed their identities to each other. He had the caregivers laughing as he described what he wrote in his response:
"I liked her picture, but I said to tell her boyfriend not to worry because I was a grandfather."
Jokes aside, Zefutie was determined to meet her in person.
"Because of her letters, and her picture, and her unselfishness, I just wanted to meet her very badly," he said.
Frömel returns home Friday. But part of her is staying behind, in the form of her stem cells and the spot she holds in Zefutie's heart.