Plasmarakkude

Plasmarakkude, known in English as plasma cells, are specialized antibody-secreting cells derived from B lymphocytes and essential to the adaptive immune response. They develop after B cells encounter an antigen and undergo activation, usually within germinal centers of lymphoid tissues, then migrate to the bone marrow and other tissues where they can persist long term.

Morphology and function: Plasma cells are typically large, with an eccentric nucleus and abundant basophilic cytoplasm. A prominent perinuclear region, or Golgi apparatus, reflects heavy protein production. Their primary role is the synthesis and secretion of immunoglobulins (antibodies) of various isotypes, providing targeted, specific defense against pathogens. Short-lived plasmablasts contribute to early responses, while long-lived plasma cells in the bone marrow sustain antibody levels for years.

Phenotype and markers: In humans, plasma cells commonly express high levels of surface markers such as CD38 and CD138. CD19 is often reduced or absent, and CD45 expression can be variable. These markers help distinguish plasma cells from other B-cell stages in diagnostic settings.

Clinical relevance: Abnormal proliferation or malignant transformation of plasma cells leads to conditions such as multiple myeloma and solitary plasmacytomas. Plasma cell disorders often feature a monoclonal immunoglobulin protein (M-protein) in serum or urine, bone lesions, anemia, kidney impairment, or hypercalcemia. Management depends on the disorder and may include targeted therapies, chemotherapy, radiation, or stem cell transplantation. Understanding plasmarakkude biology informs both immune function and the diagnosis of plasma cell–related diseases.