There was a significant increase in the percentages of T and NKT-like cells expressing granzyme b and perforin in the blood of children with BE compared with controls (Fig 1) but no difference in the percentage of NK cells expressing granzyme b and perforin between groups (granzyme b: 78.0±17.3 (74.3±11.2), perforin: 81.0±13.4 (86.7±10.3) for BE (Controls) respectively p>0.05 for all). This evidence concerns the gene PRF1 and Barrett esophagus.