IEIs: inborn errors of immunity; NK: natural killer; EBV: Epstein-Barr virus; CMV: cytomegalovirus; VZV: varicella-zoster virus; HSV: herpes simplex virus.
* Refer to the UpToDate topic on the clinical manifestations and diagnosis of NK cell deficiency syndromes, section on differential diagnosis.
¶ While the chromium release assay is the "gold standard," it is increasingly difficult to access clinically and flow cytometric surrogate assays are also acceptable.
Δ Variants known to cause classical and functional NK cell deficiencies, respectively, are discussed in the text of the UpToDate topic on clinical manifestations and diagnosis of NK cell deficiency syndromes.
◊ Refer to the discussion of chronic NK cell lymphocytosis in the UpToDate topic on NK cell large granular lymphocytic leukemia.