CD38 and influenza: For influenza-specific B cells, CD27 mRNA was not detected on day 42 samples from Groups C, D, and E. CD38 mRNA was detected in 1 of 3 influenza-vaccinated foals from non-vaccinated mares (Group C), 2 of 8 vaccinated foals from vaccinated mares (Group D), and in 2 of 4 foals from non-vaccinated mares (Group E) (Fig 8).