LYMPHOCYTE DISORDERS IN DIAMOND-BLACKFAN ANAEMIA (DBA) 155

DBA is considered to be an isolated failure of erythropoiesis without involvement of lymphoid and myeloid cell lines. Recently, a broad panel of monoclonal antibodies has allowed to assess of T, B and NK subpopulation as well as an expression of surface receptors and adhesive molecules. Using mo ab(Dako and Coulter) and flow cytometry (Epics XL, Coulter) we performed evaluation of PBL from 7 children with DBA and 7 healthy children of the same age as a control. We have found higher percentage of CD3 and CD5 cells and lower percentage of CD19 and CD20 cells in DBA children in comparison to the control. Inside of CD3 population the percentage of CD4 was decreased but CD8, in particular CD8CD11(LFA+) was increased in DBA group. In this group more CD3CD4 cells expressed CD29 (Th) and CD45RA (sup. in.). In the blood of DBA children NK cells (CD8CD56) were not found. In both investigated groups the percentage of CD5CD20 and CD122 was on comparable level. The quantitative lymphocyte disorders were associated with disfunction of proliferative response inducted by PWM and SAC but not by PHA. Presented results support the hypothesis that in DBA the cellular defect is not restricted to erythroid progenitors and that CD8CD11 eytotoxic effectors may be involved in DBA pathogenesis.