A person taking an oral sulfonamide is found to have a markedly decreased peripheral blood neutrophil count, but the numbers of platelets and erythrocytes are normal. If the peripheral neutropenia is the result of antineutrophil antibodies being produced in response to taking the sulfonamide, then this patient would be expected to have
An atrophic spleen Decreased vitamin B12 levels Hypoplasia of the bone marrow myeloid series Hyperplasia of the bone marrow myeloid series