A patient suspected of having a natural killer cell deficiency should be evaluated according to a diagnostic algorithm.
Patient selection: clinical suspicion of natural killer cell deficiency (such as frequent herpesvirus or papilloma virus infections)
Testing may include:
(1) NK cell quantification by flow cytometry
(2) cytotoxicity testing using the 51Cr release assay
(3) advanced functional and phenotypic evaluation
Testing should be repeated about 1 month later.
Classic NKCD has:
(1) no or very low numbers of NK cells on flow cytometry
(2) shows no activity on cytotoxicity testing
Functional NKCD:
(1) has some natural killer cells on flow cytometry
(2) has impaired results on cytotoxicity testing
(3) may warranted additional functional and phenotypic evaluation
Other causes of immunodeficiency should be considered:
(1) some natural killer cells are present in flow cytometry
(2) shows normal cytotoxicity testing
