The apparent increase in the blasts may have been due to the initial selective phagocytosis of the differentiated myeloid cells. Sequential bone marrow aspiration and trephine biopsy in this patient revealed severe hypoplasia with mild hemophagocytosis simulating aplastic anemia. A search for these etiological agents was conducted in our patients, but no agent could be identified. It is possible that an unidentified virus was responsible. The occurrence of hemophagocytic syndrome in apparently immunocompetent patients may be explained on the basis of transient immunoparesis.
Cytopenias are possibly secondary to hemophagocytosis and bone marrow failure.
The role of altered T-cell function and cytokines in the development of hypoplasia in RHS needs further study. Risdall RJ, McKenna RW, Nesbet ME, et al. Reactive hemophagocytic syndrome - a clinicopathologic study of 40 patients in an Oriental population. Dreyer ZE, Dowell BL, Chen H, et al. Infection associated hemophagocytic syndrome evidence of Epstein-Barr virus gene expression.