Researchers have identified an effective and rapid response to protect the patient from developing multiple infections at once and the patients who receive bone marrow transplant are vulnerable to fatal infections.
Scientists are developing a way to inject designer immune cells into transplant patients to help fight off severe viral infections. Broad-spectrum T cells appear to effectively treat the viral infections that commonly follow a hematopoietic stem cell transplant, researchers reported.
Bone marrow transplants save thousands of lives but patients are vulnerable to infection for months until their new immune system kicks in. Anti-viral medications don’t work very well. Scientists have long wanted to treat those patients with virus fighting T cells from healthy donors but it requires a custom-made dose that is too complicated and costly to be practical.
Now, researchers at Baylor College of Medicine report a faster and easier way. They brewed T cells in a laboratory that could fight five different viruses at once and took just 10 days to create. The next step is trying to create a bank of these cells that could provide off-the-shelf treatment.
“These viruses are a huge problem, and there’s a huge need for these products,” said Dr. Ann Leen, who leads a team at Baylor College of Medicine and Texas Children’s Hospital that found an easier way to produce these long-desired designer T cells.
Healthy people have an army of T cells that roams the body, primed to recognize and fight viruses. People with suppressed immune systems such as those undergoing a bone marrow transplant to treat leukemia or other diseases lack that protection. It can take anywhere from four months to more than a year for marrow stem cells from a healthy donor to take root and start producing new immune cells for the recipient. When patients get sick before then, today’s antiviral medications don’t always work and cause lots of side effects.
The new method employs virus specific immune cells dubbed T cells, a Baylor College of Medicine news release reported. These cells help the body fight infections by recognizing viruses and destroying infected cells in patients who have undergone a bone marrow transplant these cells are lacking.
Bone marrow transplants are often given to cancer patients who have undergone intensive chemotherapy or radiation. Severe infections occur in between 17 and 20 percent of those who have had the procedure. Antiviral medications used to treat these infections are expensive and often ineffective.
For many viruses, there are no specific treatments and while T cell approaches have been shown to work in some cases, making the cells is a long, complicated and costly process.
Leen and colleagues derived T cells specific to five viruses i.e. cytomegalovirus, adenovirus, Epstein-Barr virus, BK virus and human herpesvirus 6 by stimulating peripheral blood mononuclear cells with overlapping peptide libraries of viral antigens.
The number of viruses recognized by a given cell line was correlated with the donors’ age, they reported, possibly a reflection of exposure to a larger number of pathogens in older donors.
All of the patients who got the cells prophylactically between 38 and 43 days after transplant remained free of infection by all of the viruses for more than 3 months, Leen and colleagues reported.