(WSVN) - A worldwide search is on for an extremely rare blood type to help save the life of a South Florida toddler.

Two-year-old Zainab is battling an aggressive form of cancer called neuroblastoma. OneBlood says her dire situation is complicated by her blood type since she is missing a common antigen that most people carry in their red blood cells.

The antigen is called “Indian B.” For a person to be a possible match for Zainab, they must also be missing the Indian B antigen or the little girl’s body will reject the blood.

The only people who are likely to be a match for Zainab are people of Pakistani, Indian or Iranian descent, OneBlood said. Of these populations, less than 4 percent of the people are actually missing the Indian B antigen.

According OneBlood, the following conditions must be met for anyone to be a possible match for Zainab:

Must be exclusively Pakistani, Indian or Iranian descent – meaning the donor’s birth parents are both 100 percent Pakistani, Indian or Iranian.

Must be blood type “O” or “A.”

Donors must reach out to OneBlood in advance to ensure the additional compatibility testing is performed.

OneBlood said it’s working closely with other blood centers as well as the American Rare Donor Program, which helps search the globe for donors with rare blood types.

So far, three matching donors have been found worldwide, including a donor in the United Kingdom. The organization said it is the first time they have ever had an international donor for a local patient.

While three donors have been found, OneBlood said they are looking for seven to 10 more compatible donors since the little girl will need blood transfusions for the foreseeable future.

For more information on how to become a potential donor for Zainab, click here.

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