Case example: Rheumatoid arthritis and infectious diseases
Patients with autoimmune diseases like rheumatoid arthritis (RA) not only suffer from autoimmunity but also from frequent and more severe infectious diseases. The higher risk for infections can either be caused by the immunosuppressive therapy or by an intrinsic defect of their immune system. To investigate whether RA patients have an intrinsic immune defect, scientists of the TWINCORE and the Clinic for Immunology and Rheumatology of the MHH initiated a comprehensive study. To this end the function of T helper cells was monitored in RA patients that were treated with different immunosuppressive therapies. Since T helper cells play a vital role in both, the defense against invading pathogenic infections, as well as the causative origin of RA, they are important targets of immunosuppressive therapy.
Indeed, this study revealed that T helper cells of RA patients show signs of functional exhaustion. After isolation of patients’ blood, exhausted T cells show reduced response upon stimulation as it might occur upon infection. Importantly, one specific drug was identified, which significantly reverted T cell exhaustion. RA patients treated with Abatacept showed significantly enhanced T cell functionality compared with RA patients treated with TNF-alpha blocking agents (Frenz 2016). Currently, we continue to investigate whether Abatacept-treated patients also show increased responses upon vaccinations.