Immunophenotyping From Blood of Patients Suffering From Chronic Degenerating Joint Diseases and Receiving LDRT

Patients suffering from chronic degenerating diseases are often treated by a plethora of NSAIDs, DMARDs, Biologicals, as well as combinations of these therapeutics. However, many patients are refractory to this treatment and suffer from chronic pain over years, leading to a worsening of the quality of live. The mobilization of these patients is one main goal in the therapy of these chronic and inflammatory diseases. Low dose radiation therapy (LDRT) is applied since more than one century for the local treatment of chronic degenerating joint diseases. The success of the treatment was described by many retrospective as well as pattern of care studies, respectively. Local (only at the painful joint) low dose irradiation of the chronic patients results in most patients in a significantly reduced pain, not only direct after the therapy, but also lasting for more than 12 month in many cases. The patients experience enhanced mobility and increased quality of life. The molecular and cellular processes leading to the pain reduction are just fragmentarily analyzed. Our group revealed that macrophages are key players in radiation-induced immune modulation. Inflammatory macrophages exposed to low doses of radiation showed a reduced inflammatory capacity and attenuated an inflammatory microenvironment. Besides macrophages further immune cells are most likely involved in reduction of inflammation following LD-RT, as in vitro already shown for neutrophils. The IMMO-LDRT01 study aims for the first time to analyze in detail the immune status of patients suffering from inflammatory, chronic joint diseases before, during and after LD-RT in a longitudinal manner. The multi-color flow cytometry-based assay will allow determining over 30 immune cell subsets and additionally their activation status. Further, biodosimetry will be performed with the whole-blood samples to get hints about dose that the immune cells are exposed to. This will be performed with national and international co-operation partners. The IMMO-LDRT01 study is a prospective and observational study not influencing the standard therapeutic scheme and will provide hints how the LDRT affects besides local cells in the irradiated area also the systemic inflammatory response.