D. Couriel

241Predominance of resistant gram positive isolates as sources of bacteremia in GVHD patients treated with infliximab

and screening laboratory investigations. At Princess Margaret Hospital we perform bone marrow aspirates when screening stern cell donors. Bone marrow samples are examined for morphology and hemopoietic progenitor cell reserve using colony forming unit (CFU)-GEM~M assay. We report two potential donors with occult hematological malignancies on screening bone marrow aspirate. Neither patient had features of malignancy on history, physical examination or screening laboratory investigations. The first patient was a 65 year old man considered as donor for his brother with multiple myeloma. His past medical history and physical examination were unremarkable. Laboratory investigations demonstrated a normal CBC and biochemistry. A bone marrow aspirate demonstrated the presence of 12 % atypical plasma cells. Fnrther investigations showed a monoclonal paraprotein igG kappa of 19.6 g/1. Cytogenetic analysis was normal. This was most consistent with either monoclonal gammopathy of unknown significance or smoldering multiple myeloma. CFUGEMM assay evaluation showed 144 CFU-C, 151 BFU-E, 12 CFU-Meg and 4 CFU-GEMM. The second patient was a 72 year old man whose brother had chronic lymphocytic leukemia (CLL)in Richters transformation. His past history and physical examination were unremarkable. Laboratory investigations demonstrated a normal CBC with a norma] lymphocyte count. Bone marrow aspiration showed increased cellularity with 5060% small lymphocytes. A repeat bone marrow aspirate and biopsy confirmed these findings. Flow cytometry was consistent with CLL. CFU-GEMM assay showed 50 CFU-C, 43 BFU-E, 0 CFU-Meg and 8 CFU-GEMM. Occult hematologic maligancies in these two donors were only demonstrated on bone marrow aspirates. C F U G E M M assays showed decreased numbers of henmpoietic progenitors in both potential donors particularly in the patient with CLL. In conclusion, in views of the relatively innocuous nature of bone marrow aspiration we consider it advis able to screen particularly older stem cell donors with a bone marrow aspirate prior to donations. CFU-GEMM assays may contribute to the identification of bone marrow problems in potential donors.