Results Support a Relationship Between a Lower NKCC and Greater CFS Severity CFS Case Definition Number of Patients and Controls Studied Comments Reference
Yes 1988 CDC CFS: 16
Recovering from CFS: 7 Healthy: 12
NKCC of CFS pts was ↓68% compared to healthy control. In contrast, 7 patients either recovering or recovered from CFS did not exhibit a decrease in NKCC vs. the healthy controls. 51Cr-release assay, K562=target [28]
Yes 1988 CDC CFS: 10
Fatigued,non-CFS: 24
Healthy: 21 (non-fatigued controls)
2 E:T ratios
10:1 and 20:1,
51Cr-release assay, K562= target
Yes 1988 CDC Least severe CFS (n=10), more severe CFS (n=7),
most severe CFS (n=3)
Healthy: 50
Mean NKCC= 61 LU (Least severe);
18 LU (more severe);
8 LU (most severe), 51Cr-release assay, K562= target
Yes 1988 and 1994 CDC Isoprinosine treated CFS: 10 Placebo treated CFS: 6 Improvement in NKCC seen in 6 clinically improved CFS pts vs. 4 non-improved pts (p<0.03). 51Cr-release assay, K562= target [41]
Yes 1994 CDC CFS: 41 female patients classified into 2 groups
Low NKCC, n=22
Normal NKCC, n=19
CFS cohort with low NKCC had less vigor, more daytime dysfunction, and more cognitive impairment compared to the CFS cohort with normal NKCC. 51Cr- release assay, K562= target [42]
Yes 1994 CDC Severe CFS: 18
Moderate CFS: 23
Healthy: 22
3 E:T ratios
12.5:1, 25:1, 50:1 were studied using flow cytometry, K562=target
LU: Lytic Units
Table 3: Studies investigating relationship between NK cell cytotoxicity and severity of CFS.