Suppression of natural killer cell cytotoxicity in postpartum women.
OBJECTIVE
Natural Killer (NK) cell numbers and cytotoxicity are suppressed during pregnancy. Little is known about postpartum NK number and function.


METHODS
Postpartum women (n = 39) were studied at one week and then monthly over the first six postpartum months. The standard natural killer cell cytotoxicity assay (NKCA) was performed. This is a Cr51 release assay from K562 cells cultured with peripheral blood mononuclear cells (PBMCs).


RESULTS
Data indicate suppression of NK cytotoxicity in postpartum women. Cytotoxicity at each effector:target (E:T) ratio showed a drop from 1 week postpartum, reaching a nadir at around 2 months, and a trend towards recovery of cytotoxicity from 3 to 6 months. Lytic units (LUs) from pre-incubated cells from postpartum women were lower than age-matched, non-pregnant, non-postpartum controls through the fifth postpartum month.


CONCLUSIONS
These data suggest that the postpartum period, like pregnancy, is characterized by decreased NK cytotoxicity activity. This suppressed NK cytotoxic effect may result as a response to interaction with tolerized fetal microchimeric cells accumulated during pregnancy in maternal blood and tissues.
Groer
Maureen
M
University of South Florida College of Nursing, 12910 Bruce B. Downs Blvd., Tampa, FL 33612, USA. mgroer@health.usf.edu
El-Badri
Nagwa
N
Djeu
Julie
J
Harrington
Monalisa
M
Van Eepoel
Jeanne
J
D000328:Adult; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy; D007453:Iodide Peroxidase / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D049590:Postpartum Period / Q000276:immunology*; D011247:Pregnancy; D055815:Young Adult
D007453:Iodide Peroxidase