EXPRESSION OF PAX5 GENE IN HUMAN HEMATOPOIETIC-CELLS AND TISSUES - COMPARISON WITH IMMUNODEFICIENT DONORS

In mice, Pax5 gene is indispensable for B cell development. Pax5-defic ient mice fail to produce mature B cells owing to complete arrest of B cell development at a precursor stage. However, the lineage and stage of human Pax5 gene expression have remained elusive. In this investig ation expression of the human Pax5 gene was studied. Pax5 gene express ion was detected in B cell lines but not in myeloma cell lines. CD19 e xpression was correlated with Pax5 gene expression. Adult spleen and b one marrow and fetal spleen and Liver showed strong Pax5 gene expressi on, as did the corresponding mouse tissues, as reported previously. In common variable immunodeficiency (CVID) peripheral blood lymphocytes (PBL) with a decreased number of B cells, no Pax5 gene expression was detected. Some CVID PBL stimulated with IL-2, IL-IO and anti-CD40 mono clonal antibody, expressed the Pax5 gene. Defect of Pax5 gene expressi on in CVID may be caused by regulatory T cell disorder.