Person with rare blood type rediscovered in Jiangsu

A person with an extremely rare blood type has been rediscovered by a doctor in Taizhou, Jiangsu province, after more than a decade.

Cao Guoping, head of transfusion at Taixing People's Hospital in Taizhou, revealed the discovery on Jan 4 to the Xiandai Kuaibao newspaper, saying the person's unique nucleotide sequence had significant clinical value.

The person has the blood type "p" in the P blood group system, Cao said, adding that it is even rarer than the Rh-negative type, often referred to as "panda blood" in China.

Human blood is generally grouped by analyzing different antigens in the red blood cells. The ABO group system, the most commonly used one, divides people into A, B, AB and O blood types.

The Rh system categorizes people into the Rh-positive and Rh-negative types. Only about 0.4 percent of members of the Han Chinese ethnic group have Rh-negative blood.

The P blood group system examines antigens in the red blood cells known as P, P1 and Pk, with people generally having at least two of the three. The p type, which means that the blood has none of the three but has a peculiar antibody called anti-Tja, is extremely rare, with only about 10 cases documented in China, Cao said.

He said he first encountered such a blood sample more than a decade ago, but did not conduct any further analysis. Last year, he found the special type again.

"You can't ask for such things to happen, and this is a once-in-a-lifetime situation," he said, adding that he went to check records to see if it was the same person, which it turned out to be.

"Clinically, we usually just do tests on ABO and Rh blood groups, and only under extremely rare circumstances — when the blood sample is not compatible with every regular type, for example — will we conduct extra tests to determine the rare type," Cao said.

He said the further test also revealed a nucleotide sequence that had never been documented before, which was of great clinical value.

Xie Jinhui, director of immunohematology at the Tianjin Blood Center, said a blood phenotype is considered rare if it is found in less than one in a thousand people.

Experts said people with rare blood types should make preparations before medical procedures or hospital admission, as incompatible blood types bring risks during transfusions or pregnancies.

Cao said people with the p phenotype have a higher chance of miscarriage, as the anti-Tja antibody may attack the uterus due to an incompatible blood type. He added that people with the p phenotype may only accept blood of exactly the same type during a transfusion.

"For people with such a special blood type, an early discovery would lead to better preparation," Cao said.

Xie told People's Daily that individuals with rare blood types should arrange for their blood to be stored in advance, and also suggested the country establish a national network for rare blood allocation to enable smooth dispatch in case of emergency.