A 46-year-old woman in Hong Kong has died after having a blood transfusion that was supposed to enhance her looks and immune system.
Three other women, aged 56, 59 and 60, fell ill after receiving the treatment at a beauty parlour. The 60-year-old is in a critical condition.
Hong Kong authorities plan to review the lack of regulations relating to private health care procedures and cosmetic treatment.
The blood transfusion, which took place in the DR beauty chain, involved an amount of the woman's blood being drained to isolate and culture specific types of immune cells. The cells, along with the blood, were then injected back into her.
Experts said the treatment had not been found to have any appearance-enhancing properties and was, at best, an experimental cancer treatment.
The patient, who has not been named, went into septic shock, which is normally caused by bacterial infection. The other women quickly became ill with fever, dizziness and diarrhoea.
A post-mortem examination revealed the presence of the superbug Mycobacterium absecessus, although an official cause of death has not been confirmed.
William Chui, president of the Society of Hospital Pharmacists in Hong Kong, said: "They now have to find out where the bacterial contamination occurred in this whole process.
"Did it happen when the blood was drawn, during the culture process, or when it was re-injected back into the body?"
The woman who died had paid £4,000 for the procedure. DR said the transfusion had been carried out by a doctor who was not an employee of the firm.
Felice Lieh-Mak, a former chairman of the medical council, said: "We hope that this tragedy will result in some attempt at making legislation, or at least work towards legislating and defining what medical treatment is."
According to China Daily, 44 people have had the DC-CIK treatment.