Burst-promoting activity in anemia and polycythemia.

Burst-promoting activity (BPA) in the sera of patients with various types of anemia and polycythemia was compared with that of normal subjects by an in vitro method using mouse bone marrow cells. The control culture contained normal human AB serum instead of sample materials. Results were expressed as a percentage of burst numbers in control cultures. Serum erythropoietin (Epo) levels were determined by a radioimmunoassay. Serum BPA in patients with aplastic anemia (155.4 +/- 56.7%, mean +/- SD) was significantly higher than that in normal subjects (112.1 +/- 29.1%, Wilcoxon's rank sum test, P less than 0.05). However, serum BPA in patients with uremic anemia (122.2 +/- 26.5%), polycythemia vera (101.9 +/- 19.5%) and stress polycythemia (115.5 +/- 25.6%) was not significantly different from normal subjects. There was a correlation between serum BPA and Epo titers in patients with aplastic anemia and paroxysmal nocturnal hemoglobinuria (r = 0.81, t test, P less than 0.001).