Infections associated with haemophagocytic syndrome

Abstract

Haemophagocytic syndrome or haemophagocytic lymphohistiocytosis is a rare disease that is often fatal despite treatment. Haemophagocytic syndrome is caused by a dysregulation in natural killer T-cell function, resulting in activation and proliferation of lymphocytes or histiocytes with uncontrolled haemophagocytosis and cytokine overproduction. The syndrome is characterised by fever, hepatosplenomegaly, cytopenias, liver dysfunction, and hyperferritinaemia. Haemophagocytic syndrome can be either primary, with a genetic aetiology, or secondary, associated with malignancies, autoimmune diseases, or infections. Infections associated with haemophagocytic syndrome are most frequently caused by viruses, particularly Epstein-Barr virus (EBV). We present a case of EBV-associated haemophagocytic syndrome in a young adult with no known immunosuppression. We briefly review haemophagocytic syndrome and then discuss its associated infections, particularly EBV and other herpes viruses, HIV, influenza, parvovirus, and hepatitis viruses, as well as bacterial, fungal, and parasitic organisms.

Figure 1

Truncated extremities in a patient with Holt-Oram syndrome and EBV-associated haemophagocytic syndrome

Figure 2

Autopsy results with evidence of EBV-associated haemophagocytosis (A) Haematoxylin-eosin stain of bone marrow sample obtained on autopsy showing rare phagocytic cells with engulfed haematopoietic elements (arrows). (B) CD68 (macrophage marker) staining by immunohistochemistry showing presence of abundant macrophages within lymph nodes. (C) EBV staining by immunohistochemistry showing numerous infected cells (arrows) within lymph node.