CD4 and alkaline phosphatase measurement: However, phenotypically the AP-associated T cells appear to consist mainly of CD4+ subset, whereas MAIT cells in blood or oral mucosal tissues mostly are CD8αα+ and CD4-/CD8- double-negative, respectively.15 Among the concomitant cytokines expressed, our data further suggest that TNF was associated with progression of AP and that IL-17A correlated inversely with multiple bacterial taxa within AP microbiome that likely utilise the riboflavin pathway.