BACKGROUND Human monocytic ehrlichiosis (HME) and Rocky Mountain spotted fever (RMSF) are caused by Ehrlichia chaffeensis and Rickettsia rickettsii, respectively. The pathogenesis of RMSF relates to rickettsia-mediated vascular injury, but it is unclear in HME. METHODS To study histopathologic responses in the lymphatic system for correlates of immune injury, lymph nodes from patients with HM...

Hemophagocyticlymphohistiocytosis (HLH) is a hyper inflammatory disorder which results from immune dysfunction, either from primary immune deficiency or acquired failure of normal immune homeostasis. There is often phagocytosis by macrophages of blood cells, hence the name “hemophagocytosis” [1]. HLH may be inherited (known as familial hemophagocyticlymphohistiocytosis), or it may occur seconda...

A previously healthy 12-year-old girl was admitted to the intensive care unit with severe pulmonary bleeding. Her history revealed that she had suffered from high fever, fatigue, sore throat, myalgia and generalized rash for two weeks. Physical examination revealed hepatosplenomegaly. Laboratory investigation showed pancytopenia associated with unusual high levels of serum ferritin, triglycerid...

All trans-retinoic acid (ATRA) is a targeted therapy, used in Acute Promyelcytic leukemia (APL) and causes the abnormal promyelocytes to differentiate in to mature leucocytes, however their clearance in vivo is not known. ATRA has been found to be associated with hemophagocytosis, but sometimes one may find phagocytosis of differentiated cells by histiocytes without the overt manifestations of ...

Reactive hemophagocytic syndrome (HPS) is characterized by hemophagocytosis by activated histiocytes, resulting in pancytopenia and liver dysfunction. We describe a patient with adult onset Still's disease (AOSD) in whom HPS developed. An 80-year-old Japanese woman with high fever, arthralgia, skin rash, and pleuritis was admitted to our hospital for further examination. She was diagnosed with ...

The authors report four autopsy cases of previously healthy children with dengue shock syndrome complicated with infection-associated hemophagocytosis and invasive aspergillosis. Hemophagocytosis is confirmed by histopathology of autopsied reticuloendothelial organs. All four children were identified to have invasive aspergillosis by histopathology and three cases were positive on fungal cultur...

The diagnosis of tuberculosis in immunocompromised hosts is often difficult as the hosts have atypical tuberculosis symptoms. The current study presents a case of scrofula and pulmonary tuberculosis with acute myelocytic leukemia (AML). As the disease became aggravated, the patient presented with fever, hemophagocytosis in the bone marrow, lymphadenopathy of the supraclavicular fossa, and media...