China's drug regulator said on Monday it has found problems in some batches of the human immunoglobulin that has been linked to six deaths in east Jiangxi Province.

Initial testing has shown that some of the products have problems, but the cause was not yet identified, said Yan Jiangying, spokeswoman of the State Food and Drug Administration (SFDA).

She gave no details of the problems, but said further investigation was underway by a team dispatched from the SFDA, and local public security authorities were also looking into the case.

Six people died from May 22 to 28 at the No. 2 Hospital Affiliated with Nanchang University, in Nanchang, capital of Jiangxi Province, after being given human immunoglobulin produced by Jiangxi Yabo Bio-pharmaceutical Co.(JYBC), with batch number 20070514.

SFDA has called a stop on the sales and use of the human immoglobulin made by JYBC and urged the manufacturer to recall the products with the same batch number, while local authorities had sealed all the human immunoglobulin of the producer.

No details about the victims and the dates of their deaths are available so far and adverse drug reactions related to the same batch of drugs have not been reported elsewhere.

Human immunoglobulins are proteins produced from human plasma cells and lymphocytes, and play an essential role in the body's immune system. They attach to foreign substances, such as bacteria, and assist in destroying them.

They are commonly used in the treatment of autoimmune diseases such as newborn sepsis, idiopathic thrombocytopenic purpura (ITP) and Kawasaki disease.

(Xinhua News Agency June 3, 2008)