People infected with multidrug-resistant forms of tuberculosis could, potentially, be treated with stem cells from their own bone marrow. Even though this treatment is in the early stage of its development, the results of an early-stage trial of the technique show immense promise.
British and Swedish scientists have tested this procedure, which could introduce a new treatment strategy for the estimated 450,000 people worldwide who have multi drug-resistant (MDR) or extensively drug-resistant (XDR) TB.
This study, which was published in the medical journal, The Lancet, showed that over 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 initially infects the lungs but can rapidly spread from one person to another through coughing and sneezing. Despite its modern-day resurgence, TB is often regarded as a disease of the past. However, recently, drug-resistant strains of Mycobacterium tuberculosis, the microorganism that causes TB, have spread globally, rendering standard anti-TB drug treatments obsolete.
The World Health Organisation (WHO) estimates that in Eastern Europe, Asia and South Africa 450,000 people have MDR-TB, and close to half of these cases will fail to respond to existing treatments.
Mycobacterium tuberculosis, otherwise known as the “tubercle bacillus, trigger a characteristic inflammatory response (granulomatous response) in the surrounding lung tissue that elicits tissue damage (caseation necrosis).
Bone-marrow stem cells are known to migrate to areas of lung injury and inflammation. Upon arrival, they initiate the repair of damaged tissues. Since bone marrow stem cells also they also modify the body’s immune response, they can augment the clearance of tubercle bacilli from the body. Therefore, Zumla and his colleague, Markus Maeurer from Stockholm’s Karolinska University Hospital, wanted to test bone marrow stem cell infusions in patients with MDR-TB.
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 bone marrow-derived stem cells.
The cells were obtained from the patient’s own bone marrow by means of a bone marrow aspiration, and then grown into large numbers in the laboratory before being re-transfused into the same patient.
During six months of follow-up, Zumla and his team found that the infusion treatment was generally safe and well tolerated, and no serious side effects were observed. The most common non-serious side effects were high cholesterol levels, nausea, low white blood cell counts and diarrhea.
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 their own 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, this could become a viable extra new treatment for patients with MDR-TB who do not respond to conventional drug treatment or for those patients with severe lung damage.