mononucleaire

Mononucleaire, or mononuclear in English, refers to cells or tissues that contain a single nucleus. The term is used in biology, medicine, and pathology to distinguish these cells from multinucleated or polyploid cells, which have more than one nucleus. Mononuclear cells include lymphocytes (T cells, B cells, and natural killer cells) and monocytes in peripheral blood, as well as macrophages and dendritic cells in tissues, all originating from hematopoietic lineages.

In laboratory and clinical practice, peripheral blood mononuclear cells (PBMCs) are commonly isolated for research and diagnostic purposes. They are typically separated from other blood cells by density gradient centrifugation and used in immunology, genetics, and cell biology studies. The mononuclear phagocyte system also encompasses tissue-resident macrophages and related cells derived from monocytes.

Mononuclear leukocytes are contrasted with polymorphonuclear leukocytes, such as neutrophils, eosinophils, and basophils, which have nuclei with multiple lobes. This distinction is routinely observed in blood smears, flow cytometry, and other cytometric analyses.

Clinical notes often mentioned in relation to mononuclear cells include infectious mononucleosis, a syndrome typically associated with Epstein-Barr virus infection that can cause lymphocytosis and atypical lymphocytes; the disease is defined by clinical and laboratory features rather than the presence of a single nucleus per se. In various languages, including French, the term mononucleaire is used similarly, with mononuclear as the standard English term.