Researchers from the RIKEN Center for Integrative Medical Sciences and Keio University in Japan report that a type of lymphocyte may be able to overcome resistance to steroids in severe asthma patients.
According to the results of their research, the anti-psychotic drug Pimozide can be used to overcome resistance to steroids in severe asthma patients because of the drug’s ability to restore the effects of steroids on natural helper (NH) cells.
In an asthmatic lung, NH cells and T lymphocytes produce proteins named interleukin (IL)-5 and IL-13, causing severe airway inflammation. Inhaled steroids suppress both T lymphocytes and NH cells, reducing the inflammation.
In corticosteroid-resistant patients, a protein called interleukin-33 (IL-33) is also produced in the airways; IL-33 strongly activates NH cells to produce IL-5 and IL-13, leading to severe airway inflammation that does not respond to standard treatments.
For this research, investigators used a mouse model to demonstrate that NH resistance to steroids is induced by the protein thymic stromal lymphopoietin (TSLP), which is present in the airways of severe asthma patients. The team found one drug, pimozide, was able to restore the effects of steroids on NH cells. Pimozide is an anti-psychotic approved for the treatment of Tourette’s syndrome.