Scientists have discovered how certain immune cells could be used to cure balding.

The regulatory T-cells, known as 'Tregs', are present throughout our bodies. They control inflammation by ensuring every part of the immune system is running smoothly.

Now a research team has discovered another previously unknown function of Tregs: they can trigger hair growth.

Testing mice, scientists from the University of California at San Francisco showed how Tregs in the skin send out signals that stimulate hair follicles to regenerate.

Lead researcher Dr Michael Rosenblum said the findings mark one of the biggest steps in baldness and immune system research.

Testing mice, scientists from the University of California at San Francisco showed how cells in the skin send out signals that stimulate hair follicles to regenerate - marking a possible cure

'Our hair follicles are constantly recycling: when a hair falls out, the whole hair follicle has to grow back,' he explained.

'This has been thought to be an entirely stem cell-dependent process, but it turns out Tregs are essential.

'If you knock out this one immune cell type, hair just doesn't grow.'

The research, published in the journal Cell, could lead to new treatments for alopecia areata, an autoimmune disease that causes patchy hair loss from the scalp and eyebrows.

Tregs could also play a role in other forms of baldness, including the classic 'male pattern' variety that causes men to recede and lose their hair, the team believes.

The findings highlight a growing understanding that immune cells have much broader functions than just fighting off foreign invaders.

'We think of immune cells as coming into a tissue to fight infection, while stem cells are there to regenerate the tissue after it's damaged,' Dr Rosenblum added.

'But what we found here is that stem cells and immune cells have to work together to make regeneration possible.'

The study comes amid a surge in research on baldness.

Earlier this month, cancer researchers at UT Southwestern Medical Center in Texas revealed they accidentally discovered a key protein that fuels baldness and turns hair grey.

The study, published in the Genes & Development journal, found the protein called KROX20, more commonly associated with nerve development, turned on in skin cells that become the hair shaft.

These hair precursor, or progenitor, cells then produce a protein called stem cell factor (SCF) which is essential for hair pigmentation.

When scientists deleted the SCF gene in the hair progenitor cells in mice, their hair turned white. When they deleted the KROX20-producing cells, no hair grew and the mice became bald.

Dr Lu Le, professor of Dermatology at UT Southwestern, said the chance discovery could lead to an effective treatment.

'Although this project was started in an effort to understand how certain kinds of tumours form, we ended up learning why hair turns grey and discovering the identity of the cell that directly gives rise to hair.

'With this knowledge, we hope in the future to create a topical compound or to safely deliver the necessary gene to hair follicles to correct these cosmetic problems.'