Immunoglobulin M memory B cell decrease in inflammatory bowel disease

Memory B cells represent 30-60% of the B cell pool and can be subdivided in IgM memory and switched memory. IgM memory B cells differ from switched because they express IgM and their frequency may vary from 20-50% of the total memory pool. Switched memory express IgG, IgA or IgE and lack surface expression of IgM and IgD. Switched memory B cells derive from the germinal centres, whereas IgM memory B cells, which require the spleen for their survival and/or generation, are involved in the immune response to encapsulated bacteria. Since infections are one of the most frequent comorbid conditions in inflammatory bowel disease, we aimed to verify whether IgM memory B cell pool was decreased in Crohn's disease and ulcerative colitis patients