IL2 and graft versus host disease: Interestingly, elimination of a lethal challenge of BCL1 inoculated in (BALB/c X C57BL/6)F1 mice following infusion of recipients with IL-2 activated C57BL/6 lymphocytes resulted in cure, in sharp contrast to similar treatment using IL-2 activated BALB/c spleen cells, although both IL-2 activated BALB/c or C57BL/6 spleen cells could result in equal GVHD against F1 recipients (Cohen et al. 1993).