EOSINOPHILIA AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION USING THE BUSULFAN AND CYCLOPHOSPHAMIDE PREPARATIVE REGIMEN

Eosinophilia may complicate allogeneic bone marrow transplantation (BM T) after treatment with preparative regimens that include total body i rradiation (TBI). This complication is of uncertain significance and h as not been reported after treatment protocols which do not contain TB I. We reviewed our experience using busulfan and cyclophosphamide (CY) , instead of TBI, as the preparative regimen for allogeneic BMT to stu dy the incidence and relationship to graft-versus-host disease (GVHD) of post-treatment eosinophilia. Fifty-five consecutive patients receiv ing busulfan 16 mg/kg and CY 120 mg/kg for the treatment of leukemia w ere reviewed. All patients received non-T cell-depleted, HLA-matched s ibling or unrelated donor marrow 2 days after chemotherapy was complet e. Cyclosporine (CYA) and methylprednisolone were given to prevent GVH D. Thirty-nine patients surviving 100 days post-transplant were evalua ted; 11 (28%) patients developed eosinophilia (defined as an absolute eosinophil count of > 500 x 10(6)) after transplant. Only 2 patients w ere still taking methylprednisolone at the onset of eosinophilia. At t he onset of eosinophilia 5 of these 11 patients (45%) and GVHD that wo rsened within 2 months. In the other 6 patients (55%), GVHD was not pr esent initially but developed in all 6 patients at a median of 4 month s after the onset of eosinophilia. We conclude that eosinophilia can c omplicate allogeneic BMT not preceded by TBI and that it often heralds the onset of worsening of, or de novo, GVHD.