CD27 and autoimmune disease: IgD+ CD38br AC cells are a type of activated B cells, often elevated in chronic inflammation or autoimmune diseases.[23] Overactivation of these cells may result in an excessive immune response, disrupting normal immune balance and increasing infection risk.[24] CD24+ CD27+ %B cells are a type of memory B cell, typically involved in secondary immune responses.[25] However, an excess of memory B cells may lead to abnormal immune reactions, raising the risk of infection.