natural killer cells
Also written as: NK
Immune cells that may contribute to implantation failure and recurrent pregnancy loss when present in elevated numbers.
Full Definition
Natural killer (NK) cells are lymphocytes that play a role in immune surveillance and may affect reproductive outcomes when present in abnormal numbers or activity levels. In reproductive immunology, elevated peripheral or endometrial NK cells have been associated with implantation failure, recurrent pregnancy loss, and IVF failure. However, the clinical significance and appropriate testing methods remain controversial in reproductive medicine. Some practitioners measure peripheral NK cell percentages or endometrial NK cell density, while others question the validity of these tests. Treatment approaches, when pursued, may include corticosteroids, intravenous immunoglobulin, or other immunosuppressive therapies.
Usage
Usage note: Clinical utility in reproductive medicine is debated
In Context
- "Elevated natural killer cells were identified as a potential cause of recurrent implantation failure." — Immunology consultation
- "The role of natural killer cell testing in reproductive immunology remains controversial." — Clinical review article