Changes in hemopoietic and regulator levels in mice during fatal or nonfatal malarial infections. II. Nonerythroid populations.

Levels of mature lymphocytes, granulocytes, macrophages, platelets, their progenitor cells, and cytokines were monitored in the blood, marrow, and spleen during fatal or nonfatal murine malarial infections. In all four malaria models, before anemia developed, there was a lymphopenia, a rapid lymphocyte depletion in the marrow with a compensating rise in spleen lymphocytes, thrombocytopenia with increased megakaryocytic progenitor cell numbers, and monocyte increases in the bone marrow and later the spleen. The development of anemia was associated with a monocytosis and neutropenia, an increase in granulomonocytic progenitor cells in the spleen, and a reduction of spleen lymphocytes. Spleen granulocytes, monocytes, and their progenitor cells increased two- to threefold more in nonfatal than in fatal malaria and the spleen lymphocyte pool became severely depleted in fatal malaria. The data suggest that a defective effector cell response was of importance for the fatal outcome of the disease. Other than an early rise in serum macrophage colony stimulating factor levels in fatal infections, changes in levels of the regulators of these effector cells did not correlate well with the outcome of the infection.