Effects of intravenous methylprednisolone on mixed lymphocyte cultures in normal humans

Mixed-lymphocyte-culture response and peripheral lymphocyte counts were determined after 100 mg and 1,000 mg of methylprednisolone were administered intravenously to healthy volunteers; The MLC response was significantly suppressed in both groups for at least 12 hr. The degree of suppression of the MLC response did not differ between the two groups. Lymphocytopenia persisted for at least 24 hr. The MLC response, however, returned to its full capacity within 24 hr. In the low-dose group this response showed a marked rebound phenomenon at 24 hr. These findings indicate that methylprednisolone has a profound inhibitory effect on lymphoid cells' response to allogenic stumli in the MLC system.