The Rampant Abuse Of Natural Killer (NK) Cell Testing

THE USE AND ABUSE OF NATURAL KILLER CELL TESTING IS RAMPANT IN THE FIELD OF REPRODUCTIVE MEDICINE AND IN THE REALM OF EVALUATING COUPLES WITH PREGNANCY LOSSES. This following study and other articles recently cast tremendous doubt on the entire way in which this is managed by IVF programs and office practices. Patients need to be aware of this and recognize that the medical community consensus is highly dubious of how these patients are currently being addressed.

The article below suggests that IF there is any validity to natural killer cell testing (NK tests) the results can be FALSELY influenced by several factors:

  • the time of the menstrual cycle in which the blood is drawn
  • the environment in which the blood is drawn
  • and simply the stress during the blood draw itself or stress the patient may be experiencing at the time of the blood sampling

Thus, these factors need to be considered and can easily lead to FALSE POSTIVE results and unnecessary treatments—quite simply there are better ways to manage these couples and the significant majority of patients do not benefit from this costly testing…It is clearly time for a different, new approach to these couples and patients need proper knowledge of these issues.

For more info and articles please contac me.

Peter Ahlering, MD

MCRM Fertility Medical Director

High NK cell activity in recurrent miscarriage: what are we really measuring?

Keren Shakhar1, Ella Rosenne1, Ron Loewenthal2, Guy Shakhar1, Howard Carp3,4 and Shamgar Ben-Eliyahu1,5

Human Reproduction, vol 21, No9 ( pp 2421-2425)

BACKGROUND: Several studies have shown that women with unexplained recurrent miscarriage (RM) have increased numbers and activity of peripheral blood NK cells and that elevated levels of these cells predict subsequent miscarriages in women with RM. Because catecholamines rapidly mobilize NK cells into the circulation, such increases may not reflect a steady state of overactive immunity but may result from a transient increase in the number of NK cells because of the stress associated with blood withdrawal.

METHODS: Blood was drawn from 22 controls and 38 RM patients immediately after vein cannulation, and again 20 min later. The percentage of NK cells within lymphocytes, their concentration per microlitre of blood and their activity were assessed.

RESULTS: All three indices of NK cells did not change in the controls across the two samples. However, women with RM had elevated levels in all three NK indices in the first blood sample, but these levels declined to values similar to those seen in the controls. This decline was mainly observed in primary aborters whose NK activity was highest in the first blood withdrawal. Accordingly, there was a high correlation between the magnitude of the decline and the initial NK cell indices in women with RM. The change in activity highly correlated with the change in the concentration of NK cells.

CONCLUSION: The increased NK number and activity previously observed in RM patients may result from a transient stress response at the time of blood withdrawal. Patients with primary RM may be characterized by exaggerated acute stress responses in other circumstances.

(Complete Article Available Here)