CD38 and infection: Consistent with this, CD38+ CD4+ T cells displayed significantly reduced levels of both pSTAT1 and pSTAT4 compared to CD38- CD4+ T cells (p = 0.016 and p = 0.031 prior to infection, and p = 0.0002 and p = 0.0002 post-infection for pSTAT1 and pSTAT4, respectively; Fig 6A and 6B).