CD4 and diabetes mellitus: This discrepancy between in vivo and ex vivo data appears not to result from the transfer of fewer p509 or p530-expanded CD4+CD25+ T cells compared to those expanded by p524, as even a 3–5 fold increase (e.g. 3−5×106) in p509 or p530-expanded CD4+CD25+ T cells failed to inhibit transfer of diabetes (Figure 4).