CD52, also known as Campath-1 antigen, is a small surface glycoprotein composed of 12 amino acids. It is a glycosylphosphatidylinositol (GPI)-anchored antigen. Its physiological role on lymphocytes is unclear, but it may be involved in lymphocyte transendothelial migration, costimulation of CD4+ T cells, T-cell activation and proliferation [1,2]. CD52 is expressed on a wide range of immune cells such as lymphocytes, monocytes, eosinophils, dendritic cells, and neutrophils, as well as in the male genital tract [1,2].

Higher CD52 mRNA expression is associated with favorable overall survival in non-immune checkpoint blockade (ICB)-treated melanoma and with progression-free survival and disease control in ICB-treated melanoma. CD52 expression is also associated with features of ICB response in melanoma [3]. Alemtuzumab, an anti-CD52 monoclonal antibody, is used to treat lympho-proliferative disorders, multiple sclerosis, and is used in organ transplantation, but it increases the risk of infections [2,4,5]. High preoperative CD52 levels in kidney transplantation patients are associated with higher rates of acute rejection, delayed graft function, and BK virus infection and lower rates of graft survival [6]. In ibrutinib-treated mantle cell lymphoma, treatment-persisting cells have increased CD52 expression, and targeting CD52 may be an efficient way to minimize the risk of survival of ibrutinib-resistant cells [7].

In conclusion, CD52 plays a role in lymphocyte-related functions and is associated with various diseases. Research on CD52, especially through the use of agents like alemtuzumab targeting it, has implications for treating diseases such as multiple sclerosis, lympho-proliferative disorders, and in transplantation settings. However, potential side-effects like increased infection risk need to be considered.