In any given family, 25 percent of siblings have an identical match, 50 percent share the same HLA with their mothers and 50 percent with their fathers. In an average-sized family, a patient has a 1 in 3 chance of a complete match.
"That means two-thirds of individuals are disenfranchised," said Dr. Neal Flomenberg, chair of the department of medical oncology at Thomas Jefferson Hospital and founder of the blood and marrow transplant program.
Now, in a haplo or half-match transplant, siblings and parents who have one, but not both, of the same gene types can be donors.
The procedure doubles the number of potential donors for cancer patients, particularly among hard to match minorities like Muniz, according to Flomenberg.
The procedure is not new, but its timing was perfected at Thomas Jefferson to reduce transplant toxicity.
Because the immune system is weakened by chemotherapy, cancer patients can die during the transplant process -- when infections set in or due to host-graft disease, which damages the lungs or liver.
The half-match procedure, the only one in the region, reduces toxicity and about 80 percent of the patients go into cancer remission.
Patients receive their transplant in two steps. First, after radiation, they are given a specified dose of infection-fighting T cells from their half-matched family donor. Next, they receive the drug cyclophosphamide to help the newly infused donor T cells to be better tolerated in the patient's body.
In the second step, patients receive a dose of their donors' stem cells to help their blood counts return to normal and further strengthen their new immune system.
"Outcomes have exceeded our wildest expectations at this point," he said. "The success rate is mind-blowing."
"The immune system recovers promptly and they may develop some mild host-graft disease, but it's easily managed," said Flomenberg.
In Muniz's case, doctors selected her 34-year-old sister Anna, a twin, as her half-match donor. Even though she was the smallest of the three siblings, her T-cells were stronger, according to Muniz.
"She was my little angel," she said.
Meanwhile, Tomko, who owns his own photography studio, had waged his own medical battle at Thomas Jefferson. The 57-year-old had been diagnosed in 2007 with a virulent form of stomach cancer.
"I was doing 52 weddings that year," he said. "On July 30, they told me I had cancer and on Aug. 15, I was on the operating table and they took 80 percent of my stomach out."
Tomko endured three and a half months of chemotherapy and 25 radiation treatments, but within four to six weeks after his surgery, he was back to his 31-year career as a wedding photographer.
"It was the brides who kept me going," he said. "Personally, I didn't feel I could let them down."
At first, the hospital didn't seem to know how to use his talent, but last year at a Philadelphia Eagles football game, Tomko met a woman who worked for an oncologist at Thomas Jefferson and said, "We have the perfect person."
When he finally met Muniz, she looked at Tomko and said, "There's no charge? This is free?"
Today, Muniz shows no signs of leukemia.
"I feel great and I am starting to get my energy back," she said. "I am eating better, have gained weight and am definitely stronger."
But she gets teary when she talks about others with the disease.
"I see a lot of patients are on the waiting list now to get bone marrow because they don't have a match," she said. "That's very emotional for me. I had a chance."
On Feb. 8, Tomko escorted Muniz and Jones around the city for a series of stunning photos. Even a lightly falling snow didn't dampen their spirits.
"Words can't explain, how I feel about my wedding pictures," she said afterwards. "Jerry is great. I was nervous at first, but he made me feel like I knew him forever and he will always have a special place in our heart. ... I felt like we were getting married again."