Everyone has proteins, called human leukocyte antigens (HLA), on the surface of their cells. These proteins allow a person’s immune system to distinguish the body’s own cells from those of another person. Half of a child’s HLA genes are inherited from each parent. A child has one chance in four (a 25% chance) of being matched with a sibling who has the same biological parents. This pattern of inheritance explains why parents only rarely (1% of the time) match with their children. More distant relatives are even less likely to match, because they are more likely to have different HLA genes. When it is determined that an SCT might be needed, each full sibling and biological parent is HLA-typed. HLA genes come in many varieties (called alleles). Two people are considered to be a match if 8 to 12 of their alleles are identical.

We felt it was an omen that Jody’s older sister and younger brother were perfect matches. They chose Marieke because she was older; but after all of the workup and tests, they discovered that she was CMV [cytomegalovirus] positive, so they used 2-year-old Christoph’s marrow. Marieke was very disappointed.

If a match is not found in the family, the search widens to the donor registries and umbilical cord blood banks. This search will identify any potential donors with the same HLA type as your child. The registry then contacts the potential donor to ask whether he or she will donate more blood samples for additional tests.

The odds of obtaining a match from an unrelated person were once slim. However, due to the increased number of people typed and listed on various national and international marrow registries, and the development of more accurate tissue typing methods, a complete or partial match can now be found for almost 70% of children. Registries currently contain more than 10 million potential donors. Because there is a strong association of some HLA types with a person’s ethnic background, it is harder to find matches for children from certain ethnic backgrounds.

Christie had a rare HLA type, and we could not find a match in all the registries worldwide. We decided that we had to do it on our own and began a donor drive in our town, which is predominantly Italian. The Red Cross discouraged us, saying that we probably wouldn’t get a good response, that they could not process the blood without the money ($45 per person) in hand, and that it would be better to spend quality time with Christie. But when the community of Rochester found out, it just snowballed. Dave and I went on TV and advocated for Christie, stressing the importance of Christie’s bone marrow drive, and told people that this might help their own child one day. The first day of the drive, people lined up outside and stood for hours in the freezing rain and cold. The response was so overwhelming that late in the day they ran out of supplies. Large corporations became involved; one did a telethon that raised over $50,000. We typed over 4,000 people from Rochester and received letters from all over the country. It was just a beautiful thing. Christie was such a powerful little person, and she came to represent so much to our community.