Age-associated B cells, key players in autoimmune pathogenesis.

Age-associated B cells (ABC) are a unique subset of antigen-experienced B cells that were first identified in old female mice. ABC have both physiological and pathological roles in humans and they are important in the progression of some immune disorders, chronic infections, and even in the aging process. These cells are differentiated from other B cell subsets by the expression of transcription factors T-bet and surface markers such as CD11c+, CD21/35−, CD23−. ABCs are heterogeneous cell populations that are involved in the development of autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis by producing inflammatory cytokines and autoantibodies, antigen-presenting to T cell, and developing a specific humoral response and memory. Discovering the exact function of ABCs and their related regulatory factors can be effective in introducing them as therapeutic targets and diagnostic biomarkers. In this manuscript, we aimed to explain the role of these cells and their function in autoimmune diseases so that by reviewing past studies, a new window can be opened towards a better therapy approach of mentioned autoimmune diseases, in the future.