A cough that lasted for two weeks landed Hoh Sin Jun in hospital in early 2006, sparking a 15-month ordeal for the boy and his parents. After a battery of tests over a few weeks, doctors at KK Women’s and Children’s Hospital (KKH) diagnosed the five-month-old boy with a rare condition called severe combined immunnodeficiency. This is a genetic defect that left his body unable to fight infections. Sometimes called “bubble boy disease”, the condition was made famous by David Vetter, an American who lived for 12 years in a plastic, germ-free bubble and died in 1984 after complications from an unmatched bone marrow transplant from his sister. A similar fate awaited Sin Jun unless he could get a transplant of bone marrow or cord blood that was a close genetic match.
His father, Mr Hoh Kim Youn, recalled: “We were lost and overwhelmed and couldn’t accept the diagnosis.” In the meantime, Sin Jun was infected by the tuberculosis bacteria in his lungs, arm and leg, and needed procedures to remove the infected areas. He also caught a rotavirus, which gave him severe diarrhoea. Mr Hoh quit his job on a cable ship and his wife, Ms Leong Hong Yeok, left her quantity surveyor job, to look after Sin Jun full time.
Fortunately, a match was found through the public Singapore Cord Blood Bank and Sin Jun became its first recipient of a cord blood transplant in May 2006 when he was nine months old. He is now an active five-year-old in a school for children with special needs. A side effect of the antibiotics to treat tuberculosis left him hearing impaired.
He has a cochlear implant in his right ear and wears a hearing aid on his left ear. But since the operation for cochlear implant in September 2008 – his 10th and last one – he has not needed hospitalisation. He has follow-up checks every three months and is on thyroid medication for life to prevent his gland from becoming inactive. He gets the occasional coughs and colds, but is otherwise well, said Ms Leong, 37, who returned to her previous job last year.
Mr Hoh, 36, now a service engineer, said of their only child: “We watch him closely and don’t let him run around on his own.” His wife said: “Every day, when we see him smiling or asleep, we feel a sense of gratitude.” The transplant given to Sin Jun of haemopoietic stem cells – or immature blood-forming cells contained in bone marrow or cord blood – is now the most established stem-cell therapy.
The stem cells are usually collected from the bone marrow of a relative or an unrelated donor who is a close genetic match. With advances in technology, they can also be taken from cord blood – which remains in the umbilical cord and placenta after birth – and blood circulating in the body called peripheral blood.
They can be used to treat disorders of the immune system like Sin Jun’s, and blood diseases like leukaemia and thalassaemia, in which a genetic defect leads to insufficient red blood cells or oxygen-carrying haemoglobin. A patient with blood cancer usually has chemotherapy or radiotherapy to destroy the cancer. The haemopoietic stem cells are then infused into the bloodstream. They then migrate to the bone marrow and develop into platelets, and red and white blood cells.
Bone marrow transplants have been done here since 1983 and are offered by National University Hospital, KK Women’s and Children’s Hospital (KKH), Singapore General Hospital (SGH) and doctors in private practice. SGH has done over 900 transplants in adults since 1985, while KKH has done 97 in children between 1998 and this year – largely for leukaemia.
A transplant costs $80,000 to $100,000 in a public hospital. Cord blood banking arrived here in 2001, when private cord blood bank CordLife opened. It was followed by private bank StemCord in 2002 and Singapore Cord Blood Bank in 2005. Parents pay to store their children’s cord blood in private banks for their own use later. Three leukaemia patients have retrieved cord blood from CordLife. StemCord has yet to release cord blood, but about 100 cancer patients have had transplants of stem cells taken from bone marrow and peripheral blood.
The public bank accepts donations of cord blood to be used by anyone in need, but he has to pay $2,000 to test each unit for a match, and up to $26,000 to retrieve a unit. It has facilitated 65 cord blood transplants here and overseas. Two others, besides Sin Jun, had “bubble boy’s disease”.