Immune cell discovery spells hope for chemotherapy patients

Professor Boyd and Daniel Gray, from Monash Immunology and Stem Cell Laboratories, have found that mesenchymal cells are involved in restoring a damaged thymus by supporting the growth of surrounding cells.

The thymus is a major engine room of the immune system, producing T lymphocytes, which are needed for defence against infections. Their results have been published in the latest edition of The Journal of Immunology.

Chemotherapy, necessary to kill off cancerous cells, also severely depletes the immune system and injures the thymus, affecting a cancer patient's recovery rate and level of immunity. The thymus recovers in children, but rarely if at all in adults, severely compromising the ability to fight infections and potentially help ward off the return of the cancer.

Although other researchers have examined the role of mesenchymal cells, Professor Boyd's group is the first to discover how these cells behave once the thymus has been damaged by treatments such as chemotherapy.

"We now know that mesenchymal cells act as 'immune conductors' in the thymus," Professor Boyd said. "They reduce the inflammation caused by chemotherapy in surrounding cells."

In response to chemotherapy, the mesenchymal cells increase their production of several growth factors (proteins), which help stimulate other cells to begin rebuilding the thymus.

"The research has not only shown us how the cells operate, but also how they work together. Understanding how this organ behaves, has implications for enhancing the recovery rate of a damaged thymus which we hope will increase cancer recovery rates," Professor Boyd said.

Professor Boyd, together with Professors Alan Trounson, Claude Bernard and Ban Hok Toh, currently hold a newly awarded program grant from the National Health and Medical Research Centre, which combines stem cell therapies with rebuilding the thymus to treat autoimmune diseases. Their research combines an integrated picture of immunology and stem cells.

The program grant investigates how the cells create, maintain and repair the thymus. The team will also look at how cells within the thymus and bone marrow behave through different stages of chemotherapy and work to develop therapeutics to improve recovery times.

This research is funded by the NHMRC and co-funded by the Australian Stem Cell Centre.