ABSTRACT
We report increased numbers of hematogones in a 7-year-old girl with pancytopenia due to Shwachman-Diamond syndrome. Her hematogones expressed the T-cell marker CD5 as well as CD19, CD10, and CD20, and terminal deoxynucleotidyl transferase and HLA-DR. These findings suggest that hematogones are precursors of both CD5-positive B cells and CD5-negative B cells. Thus CD5-positive B cells in bone marrow may be derived from bone marrow stem cells, and not from the residual fetal B cells of yolk sac/liver origin. The finding of CD5 expression on hematogones also raises the possibility that neoplastic B cells of chronic lymphocytic leukemia, which characteristically co-express CD5 and CD19, may be derived from CD5-positive B-cell precursors in bone marrow and not from mature B cells in lymph nodes.
Subject(s)
B-Lymphocytes/pathology , CD5 Antigens/biosynthesis , Exocrine Pancreatic Insufficiency/pathology , Hematopoietic Stem Cells/pathology , B-Lymphocytes/metabolism , Bone Marrow Cells/metabolism , Bone Marrow Cells/pathology , Child , DNA Nucleotidylexotransferase/biosynthesis , Exocrine Pancreatic Insufficiency/diagnostic imaging , Exocrine Pancreatic Insufficiency/metabolism , Female , Flow Cytometry , Growth Disorders , HLA-DR Antigens/biosynthesis , Hematopoietic Stem Cells/metabolism , Humans , Immunoenzyme Techniques , Immunophenotyping , In Situ Hybridization, Fluorescence , Leukemia, Lymphocytic, Chronic, B-Cell/etiology , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Pancreas/diagnostic imaging , Pancreas/pathology , Syndrome , Tomography, X-Ray ComputedABSTRACT
Monoclonal antibody purified factor IX concentrate, Mononine (Armour Pharmaceutical Company, Kankakee, Illinois, USA), is a recently developed replacement factor concentrate for the treatment of patients with hemophilia B. The pharmacokinetic properties of monoclonal antibody purified factor IX concentrate (MAb Factor IX concentrate) have been evaluated in only small samples of patients, and little is known about those factors that might influenced in vivo recovery of factor IX after infusion is a larger patient population. In vivo recovery of factor IX was therefore evaluated for 80 different indications in 72 patients who received MAb Factor IX concentrate for the management of spontaneous or trauma-induced bleeding, or as prophylaxis with surgery. The average recovery after infusions for presurgical pharmacokinetic analysis (mean +/- standard deviation) was 1.28 +/- 0.56 U/dl rise per U/kg infused (range 0.41-2.80), and the average recovery after all infusions for treatment was 1.23 +/- 0.49 U/dl rise per U/kg infused (range - 0.35-2.92). Recovery values for multiple MAb Factor IX doses in a given patient were also variable; the average recovery was 1.22 +/- 0.53 U/dl rise per U/kg given, and standard deviations ranged from 0.03 to 1.26. Patient age, weight, and MAb Factor IX concentrate dose minimally but significantly influenced factor IX recovery. There was no significant effect of either race, history of previous thrombotic complications during treatment with other replacement factor concentrates, or bleeding state on recovery. All of the patients treated with this preparation experienced excellent hemostasis, and no thrombotic complications were observed.
