Bird flu may over-stimulate immune system

HONG KONG, Nov. 11 (UPI) -- Researchers in Hong Kong say the H5N1 bird flu virus may provoke an excessive immune reaction, explaining why it is deadly even to the young and healthy.

Laboratory tests on human cells showed that the virus caused the immune system to send proteins called cytokines to infected lung cells, a reaction that would end up damaging or destroying the tissues the immune system is meant to defend.

The tests were carried out by scientists at the University of Hong Kong, working with samples from patients who died in Vietnam. The results were published in the online medical journal Respiratory Research.

The research suggested that patients who contract bird flu may need drugs that suppress the immune response in addition to anti-viral drugs like Tamiflu. It also indicated that healthy people with strong immune systems could fare worse than others if they became infected.

The virus has killed flocks of poultry and migratory birds, particularly in Asia, in recent months, but only 124 people have been infected, through direct contact with birds. Sixty-four of them have died.

The new research may affect preparations by health officials worldwide, who fear a pandemic may occur if the virus mutates to become passed from human to human.