The World Health Organization has named two newly identified alleles that will hopefully enhance the success rates of bone marrow transplants for leukemia patients.

The alleles, HLA-B*5614 and HLA-B*5136, were identified recently by transfusion experts with the Zhejiang provincial blood center, said Prof. Yan Lixing, head of the research team based in the provincial capital Hangzhou.

HLA-B encodes a protein for human leukocyte antigen (HLA) located on the surface of white blood cells and other tissues.

Prof. Yan and his colleagues have found the new alleles while examining blood samples from more than 2,000 people, using high-resolution molecular biological technologies.

The finding will be reported in the upcoming issues of Tissue Antigen, Human Immunology and European Journal of Immunogenetics, says Steven Marsh, an expert with WHO's HLA naming committee, in a letter addressed to Prof. Yan.

The new alleles will match more adequate types of bone marrow for leukemia and other fatal blood disease sufferers, for whom the best therapy available so far is bone marrow transplant.

In China, leukemia patients increase by 40,000 each year, and currently, there are more than four million patients waiting for bone marrow transplants.

A successful transplant depends on how well the donor's human leukocyte antigen matches that of the receptor.

The results of the Chinese scientist's research may also help organ transplant patients find ideal donors. It may also enable doctors to explain why some women often have miscarriages for no obvious reason, according to Yan.

These are not the only new alleles identified by Chinese scientists. A group of researchers in southern China's city of Shenzhen discovered one new allele in 2001 and another two in 2002.

Last year, Chinese scientists identified a new allele named HLA-B*5516 in a girl in southwest China's Sichuan Province.

About 80 percent of the 1,013 known alleles of HLA-A, B, DRB1 were discovered by American scientists. Identification of unknown alleles is a hotspot for worldwide scientists and the competition is extremely high, said Wu Guoguang, director of Shenzhen's Institute of Transfusion Medicine.

(Xinhua News Agency October 19, 2004)