The long-term survival of plasma cells.

Plasma cells sustain antibody production and hence are an essential part of immune protection. In the mucosa-associated lymphoid tissues plasma cells secrete IgA antibodies which protect the organism from invasion by pathogenic bacteria while in the bone marrow they produce the antibodies which guarantee long-term humoral immune protection. The various lymphoid organs provide specific microenvironments which support plasma cell survival. In particular, in the bone marrow, highly specialized survival niches are established by the underlying stromal reticular cells which permit plasma cells to survive for years. In some situations, however, the antibody may be detrimental to the organism. In those auto immune diseases, where plasma cells play a pathological role by producing the auto antibodies, new strategies are needed to interfere with the lifespan of plasma cells and thus to diminish their numbers. The recent finding that eosinophils are essential for the long-term survival of plasma cells in the bone marrow provides a new therapeutic target to modulate the plasma cell survival niche.