Patients with potentially
fatal "superbug" forms of tuberculosis
(TB) could in future be treated using stem
cells taken from their own bone marrow, according to the results of an
early-stage trial of the technique.
The finding, made by
British and Swedish scientists, could pave the way for the development of a new
treatment for the estimated 450 000 people worldwide who have multi
drug-resistant (MDR) or extensively drug-resistant (XDR) TB.
In a study in The Lancet
Respiratory Medicine journal, researchers said more than half of 30
drug-resistant TB patients treated with a transfusion of their own bone marrow
stem cells were cured of the disease after six months.
"The results ... show
that the current challenges and difficulties of treating MDR-TB are not
insurmountable, and they bring a unique opportunity with a fresh solution to
treat hundreds of thousands of people who die unnecessarily," said TB expert
Alimuddin Zumla at University College London, who co-led the study.
TB, which infects the lungs
and can spread from one person to another through coughing and sneezing, is
often falsely thought of as a disease of the past.
can TB be prevented?
In recent years,
drug-resistant strains of the disease have spread around the world, batting off
The World Health
Organisation (WHO) estimates that in Eastern Europe, Asia and South Africa 450 000
people have MDR-TB, and around half of these will fail to respond to existing
TB bacteria trigger an
inflammatory response in immune cells and surrounding lung tissue that can
cause immune dysfunction and tissue damage.
Bone marrow may be the answer
Bone-marrow stem cells are
known to migrate to areas of lung injury and inflammation and repair damaged
tissue. Since they also modify the body's immune response and could boost the
clearance of TB bacteria, Zumla and his colleague, Markus Maeurer from
Stockholm's Karolinska University Hospital, wanted to test them in patients
with the disease.
In a phase 1 trial, 30
patients with either MDR or XDR TB aged between 21 and 65 who were receiving
standard TB antibiotic treatment were also given an infusion of around 10
million of their own stem cells.
The cells were obtained
from the patient's own bone marrow, then grown into large numbers in the
laboratory before being re-transfused into the same patient, the researchers
marrow cells can help in heart failure
Safe and well tolerated
During six months of
follow-up, the researchers found that the infusion treatment was generally safe
and well tolerated, with no serious side effects recorded. The most common
non-serious side effects were high cholesterol levels, nausea, low white blood
cell counts and diarrhoea.
Although a phase 1 trial is
primarily designed only to test a treatment's safety, the scientists said
further analyses of the results showed that 16 patients treated with stem cells
were deemed cured at 18 months compared with only five of 30 TB patients not
treated with stem cells.
Maeurer stressed that
further trials with more patients and longer follow-up were needed to better
establish how safe and effective the stem cell treatment was.
But if future tests were
successful, he said, it could become a viable extra new treatment for patients
with MDR-TB who do not respond to conventional drug treatment or those with
severe lung damage.
Stem cells to boost healing
Some stem cells protect TB bacteria