CD20+ T cells: an emerging T cell subset in human pathology

Introduction Although CD20 is classically a B cell marker, in the last three decades, dim expression has been noted on a subset of T cells as well that has been independently verified by a number of groups. Our understanding of these cells and their function is not well established. Methods A thorough review of original articles on CD20(+)T cells was undertaken of Pubmed by using combination of phrases including CD20(+), CD20-positive and T cells. Articles in English were considered, and there was no time restriction. Results CD20(+)T cells express the standard T cell markers and, in comparison to CD20 over bar T cells, appear to express greater inflammatory cytokines and markers of effector function. Although the ontogeny of these cells is still being established, the current theory is that CD20 may be acquired by trogocytosis from B cells. CD20(+)T cells may be found in healthy controls and in a wide range of pathologies including autoimmune diseases, haematological and non-haematological malignancies and human immunodeficiency virus (HIV) infections. One of the best studied diseases where these cells are found is multiple sclerosis (MS) where a number of therapeutic interventions, including anti-CD20 depletion, have been shown to effectively deplete these cells. Conclusion This review summarises the latest understanding of CD20(+)T cells, their presence in various diseases, their putative function and how they may be an ongoing target of CD20-depleting agents. Unfortunately, our understanding of these cells is still at its infancy and ongoing study in a wider range of pathologies is required.

Automated summary

Although CD20 is primarily known as a B cell marker, it has been observed in a subset of T cells as well. These CD20(+)T cells appear to express more inflammatory cytokines and markers of effector function compared to CD20(-)T cells. The current understanding is that CD20 may be acquired from B cells through trogocytosis. CD20(+)T cells can be found in various diseases including autoimmune diseases, malignancies, and HIV infections. Multiple sclerosis is one of the best-studied diseases where CD20(+)T cells are found and therapeutic interventions targeting CD20 have shown promise in depleting these cells.