Methods for Treating or Ameliorating Fibrosis by Inhibiting the Interaction between IL-21 Receptor (IL-21R) and IL-21

This invention includes methods for treating or ameliorating fibrosis by inhibiting the interaction between IL-21 Receptor (IL-21R) and IL-21 using either anti-IL-21R monoclonal antibodies (or binding fragments of anti-IL-21R mAbs), anti-IL-21 monoclonal antibodies (or binding fragments of anti-IL-21 mAbs) or soluble IL-21R (or binding fragments of IL-21R). It is believed that the TH2 immune response, induced by IL-21, plays a major role in the in the pathogenesis of tissue fibrosis. Antagonism of IL-21R by anti-IL-21R monoclonal antibodies or the sequestration of IL-21 by soluble IL-21R or anti-IL-21 monoclonal antibodies has been demonstrated to reduce TH2 immune responses associated with fibrosis in animal models.

The causes of chronic tissue fibrosis are diverse and the market for a therapeutic that targets fibrosis is large. Fibrosis is associated with diverse causes which include: genetic diseases (such as cystic fibrosis); autoimmune diseases (such as scleroderma); chronic viral infections (such as hepatitis), parasitic infections (such as schistosomiasis); and occupational exposures to causative agents (such as asbestosis). Additionally, many cases of tissue fibrosis are idiopathic.