CD4 and melanoma: A study found that when compared to normal plasma, melanoma tumour interstitial fluid had higher concentrations of the mono and di‐phosphates guanosine di‐phosphate (GDP) and uridine di‐phosphate (UDP) and that this was associated with an increase in CD4+, CD25+, FOXP3‐, nuclear factor‐kappa B (NF‐kB), and an increase in the cytokines; interferons, T‐bet, and IL17, and a decrease in IL13 expression.