Decreased erythropoiesis: the origin of the BCG induced anaemia in mice.

Transient anaemia follows a high dose of viable BCG given intravenously to mice. The anaemia was dependent upon the dose, viability and the route of injection of the BCG. The evidence of an absolute anemia was based on red cell mass decrease. Serum iron concentration and red cell life span were unchanged in the first 14 d after BCG infection. The erythropoietin level increased 20-fold. Despite the high level of this hormone and the appearance of increased erythropoiesis in the spleen, the production of erythrocytes was decreased presumably because of a decrease in numbers of erythropoietin-responsive cells.