MURINE SCHISTOSOMIASIS-MANSONI - EXPERIMENTAL-ANALYSIS OF BONE-MARROWAND PERIPHERAL MYELOPOIESIS

In schistosomiasis a systemic hyperplasia of the monomacrophagic cell lineage is associated with its mild modifications in myelograms and he mograms. We monitored the in vitro proliferation of myeloid precursors obtained from bone marrow, blood, spleen, and liver. The macrophage c olony-forming unit (M-CFU) numbers were stable in bone marrow but incr eased progressively in spleen and in liver, reaching in each organ the values equivalent to one femur. The bone marrow had an increased prod uction and enhanced capacity to release M-CFU. Their quantitative incr ease in blood and in peripheral tissues of schistosome-infected mice w as associated with their qualitative modifications: augmented prolifer ative capacity, enhanced adhesion, and accelerated differentiation. Th e accelerated release of monomacrophage progenitors and their enhanced proliferation in peripheral tissues potentially account for the relat ively low involvement of the bone marrow and for an efficient in situ production of phagocytes, which participate in host reactions to paras ites.