Figure 1: Comparison of percent decrease in NKCC/NK cell activity for CFS patients vs. normal controls for two populations of CFS patients defined by either the CDC 1988 or 1994 CD shows a significant difference (p<0.01). Each symbol represents an individual study from Tables 1 or 2 that reported actual values which could be presented as a percent decrease in NKCC in the first column and used either the CDC 1988 or 1994 CD (n=12), but not both CDs (n=1) as shown in the second column. The two percent decreases in NKCC values for Masuda [26], ↓75% (E:T=10:1) and ↓72% (E:T=20:1) were averaged. Two studies in Table 1 reporting a decrease in NKCC did not provide a NKCC numerical value and therefore could not be included in Figure 1 (Wemm [25]; Ojo- Amaize [27]). The initial baseline evaluation was used from the longitudinal study of Brenu [40]. For Brenu [13] data from the E:T=50:1 evaluation were used. ●= 5 studies that used the CDC 1988 CD (all 5 studies used the 51Cr release assay); ▲= 3 studies that used the CDC 1994 CD and the 51Cr release assay; ■= 4 studies that used the CDC 1994 CD and flow cytometry.