ABSTRACT
Whole-blood cyclosporine (CsA) concentration was monitored using radioimmunoassay with a polyclonal nonspecific antibody until 1988, when a new monoclonal-specific assay was introduced. This chapter evaluates the relation between whole-blood CsA concentration and acute graft-versus-host disease (GVHD), in 91 consecutive allogeneic bone marrow transplantation patients, using both immunoassays. All patients received marrow grafts from genotypically HLA-identical sibling donors, after treatment with cyclophosphamide plus fractionated total-body irradiation as the conditioning regimen. GVHD diagnosis was always demonstrated histologically and its severity graded according to the Seattle group’s criteria. To analyze the results, the mean trough CsA concentration for each patient was calculated during 7 and 10 days before the onset of GVHD. Mean day-to-day CsA levels on the 10 days before the onset of GVHD in patients monitored by the polyclonal antibody were irregular, with a high dispersion. This was similar in all the groups studied, contrasting with those of patients monitored by the specific antibody.
