Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of anemia affecting the precursors to red blood cells but not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. There are multiple etiologies that can cause PRCA. The condition has been first described by Paul Kaznelson in 1922. Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of anemia affecting the precursors to red blood cells but not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. There are multiple etiologies that can cause PRCA. The condition has been first described by Paul Kaznelson in 1922.