The CD27 antigen is part of the tumor necrosis factor family and plays a vital role in the proper functioning of B lymphocytes. It also plays a major role in T lymhocyte survival and NK-cell differentiation. It thus plays a significant role in anti-viral response, anti tumor immunity and alloreactivity.
Mutations in the CD27 gene can result in a form of immunodeficiency called Lymphoproliferative Syndrome 2