[Bone marrow stromal damage mediated by immune response activity]. / Ostecenje strome kostne srzi u uslovima aktivnosti imunskog odgovora.

The aim of this work was to estimate influence of activated immune response on hematopoiesis in vitro, using the experimental model of BCG immunized BALB/c mice and in patients with chronic immunoactivation: long-lasting infections, autoimmunity or malignancy. We correlated changes in long term bone marrow cultures (Dexter) and NBT reduction with appearance of anemia in patients and experimental model of immunization by BCG. Increased spontaneous NBT reduction pointed out role of macrophage activation in bone marrow stroma damage. Long-term bone marrow cultures showed reduced number of hematopoietic cells, with predomination of fibroblasts and loss of fat cells. This results correlated with anemia and leucocytosis with stimulated myelopoiesis in peripheral blood. Activation of immune response, or acting of any agent that directly changes extracellular matrix and cellularity of bone marrow, may result in microenviroment bone marrow damage that modify hematopoiesis.

[Effect of exanguinotransfusion on the immune system of neonate]. / Uticaj eksangvinotransfuzije na imunski sistem novoredjenceta.

Exanguinotransfusion is commonly used during therapeutic procedure in neonates with hyperbillirubinemia risking to cause brain injury of the neonate. This therapy without alternative may couse anemia, hyper or hypotonus, and behavior problems. Those disturbances are not clearly understood yet, but it appears that this process is mediated by the immune system. In order to confirm this hypothesis parallely with clinical examination, we performed the following laboratory investigations: red blood cell count, hemoglobin, hematocrite, white blood cells, natural killer cells, T lymphocyte subsets, ability of the peripheral blood phagocytes to reduce NBT, the phagocytic ability and hemiluminescent response. In the clinical examination the most common finding was hypertonus or hypotonus of the muscules. The values of hemoglobin and hematocrite were reduced, red blood cell count was similar, while the white blood cell particularly the monocyte count was increased compared to the control. The absolute number of T lymphocytes defined by CD2 and CD3 surface marker expression was depleted, while the number of DR positive cells as well as the number of NK cells was increased in group treated with exanguinotransfusion. We have also found an increase of NBT positive cells in the same group. There were no differences in the number of NBT positive cells, when they were prestimulated by PMA. Phagocytic ability was lower compared to the control, while hemiluminescent response was faster remaining on high level for a long time. All those differences remained for several months after exanguinotransfusion.