The functional relevance of sCD5 has not yet been elucidated; however, the fact that elevated levels of this protein have been found in certain autoimmune diseases suggests that sCD5 may be an indicator of chronic or exacerbated T cell activation, or alternatively, that it may play a role in the modulation of the immune response by interacting with the still uncharacterized endogenous CD5 ligand/s. The gene discussed is SCD5; the disease is autoimmune disease.