Allogeneic bone marrow transplantation: the monitoring of granulocyte macrophage colonies following the collection of bone marrow mononuclear cells and after the subsequent in-vitro cytolysis of OKT3 positive lymphocytes.

Marrow nucleated cells from eight normal allogeneic donors was layered on Ficoll-Metrizoate to isolate the mononuclear cell fraction. The cells were then washed to remove Ficoll-Metrizoate and coagulation factors prior to resuspension in a balanced salt solution and the addition of the murine anti-human T-lymphocyte monoclonal antibody OKT3 and rabbit complement. The procedures were assessed for their effect on mononuclear cell viability (mean recovery 84.4%); the ability of the cells to proliferate granulocyte-macrophage colonies (mean recovery 57.4%); the in-vitro T-lymphocytolysis (mean 75.7%) and the removal of rabbit complement (greater than 99%). Following marrow transplantation with this treated mononuclear fraction the mean day to recovery of greater than or equal to 1.0 X 10(9)/l leucocytes was 20 d, with three patients developing greater than or equal to Grade II acute graft versus host disease (GvHD). Thus, treatment of donor marrow with OKT3 and complement in a large volume system was not detrimental to subsequent engraftment, nor effective in complete T-lymphocytolysis, nor in prevention of severe GvHD.