Hong Kong's Hospital Authority said a 46-year-old woman died Wednesday of septic shock after receiving the treatment at a beauty clinic. The treatment is being tested as a method to fight cancer but in this case it was used for cosmetic purposes.
The case has raised concerns about potentially risky medical treatments at the city's numerous clinics offering procedures that claim to enhance a person's appearance.
Health Secretary Ko Wing-man promised Thursday to review regulations governing the clinics and other private medical facilities. Ko said the review would look at putting private clinics that carry out "high risk medical treatments or procedures under regulatory control."
Health authorities are investigating whether a registered doctor carried out the treatment and whether the procedure was certified by Hong Kong's Medical Council.
The four also tested positive for a rare superbug called mycobacterium abscessus, which is extremely resistant to antibiotics.
The three women in hospitals are a 64-year-old in critical condition, a 56-year-old in serious condition and a 59-year-old in stable condition.
They were among 44 people who underwent the treatment at the DR Beauty chain of clinics. The treatment costs at least 50,000 Hong Kong dollars ($6,450), according to local news reports.
The procedure, known as DC-CIK, involves the "concentration and processing" of blood by a lab before it is re-injected into the person it was drawn from, the government said. It is being tested as a way of raising the survival rate of cancer patients after they have surgery, radiation therapy or chemotherapy.
Beauty clinics offering the treatment in Hong Kong promise that it will make people look more youthful, with whiter skin and smaller pores, and strengthen their immune system. But the procedure does not appear to have any proven cosmetic effect.
Police and health officials are jointly investigating how the blood was contaminated and the relationship between the beauty clinic, the blood treatment lab and the medical practitioner who carried out the procedure.
DR Beauty said in a statement on its website that the doctor who carried out the procedures was not employed by the clinic.
Police Commissioner Andy Tsang said officers are treating the death as a criminal case and may consider manslaughter charges, according to local broadcaster RTHK.