White blood cells and bone marrow in typhoid fever.

Leukopenia and/or neutropenia are thought to be characteristic findings in patients with typhoid fever. In a study of 29 children 8 months to 15 years of age mild neutropenia was found in 1 (3%) and leukopenia in 6 (20%) patients. These findings are similar to those reported recently. Epinephrine stimulation tests done in 3 patients excluded the possibility of excessive margination as a cause of neutropenia or leukopenia. In 3 neutropenic or leukopenic patients bone marrow examination showed hemophagocytosis with an increased number of histiocytes that had phagocytized neutrophils, red blood cells and platelets. This phenomenon was not seen in the bone marrow of 3 patients with normal white blood cell counts. Hemophagocytosis is an important mechanism in producing neutropenia, anemia and thrombocytopenia in several infectious and noninfectious disorders.