Analysis of human peripheral blood samples from fatal and nonfatal cases of Ebola (Sudan) hemorrhagic fever: cellular responses, virus load, and nitric oxide levels.
Peripheral blood samples obtained from patients during an outbreak of Ebola virus (Sudan species) disease in Uganda in 2000 were used to phenotype peripheral blood mononuclear cells (PBMC), quantitate gene expression, measure antigenemia, and determine nitric oxide levels. It was determined that as the severity of disease increased in infected patients, there was a corresponding increase in antigenemia and leukopenia. Blood smears revealed thrombocytopenia, a left shift in neutrophils (in some cases degenerating), and atypical lymphocytes. Infected patients who died had reduced numbers of T cells, CD8(+) T cells, and activated (HLA-DR(+)) CD8(+) T cells, while the opposite was noted for patients who survived the disease. Expression levels of cytokines, Fas antigen, and Fas ligand (TaqMan quantitation) in PBMC from infected patients were not significantly different from those in uninfected patients (treated in the same isolation wards), nor was there a significant increase in expression compared to healthy volunteers (United States). This unresponsive state of PBMC from infected patients despite high levels of circulating antigen and virus replication suggests that some form of immunosuppression had developed. Ebola virus RNA levels (virus load) in PBMC specimens were found to be much higher in infected patients who died than patients who survived the disease. Similarly, blood levels of nitric oxide were much higher in fatal cases (increasing with disease severity), and extremely elevated levels (>/=150 microM) would have negatively affected vascular tone and contributed to virus-induced shock.
Sanchez
Anthony
A
Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. ASanchez1@cdc.gov
Lukwiya
Matthew
M
Bausch
Daniel
D
Mahanty
Siddhartha
S
Sanchez
Angela J
AJ
Wagoner
Kent D
KD
Rollin
Pierre E
PE
D000956:Antigens, Viral / Q000097:blood; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000382:microbiology; D016207:Cytokines / Q000032:analysis; D029043:Ebolavirus / Q000302:isolation & purification / Q000502:physiology*; D053222:Fas Ligand Protein; D019142:Hemorrhagic Fever, Ebola / Q000097:blood / Q000276:immunology / Q000401:mortality / Q000821:virology*; D006801:Humans; D007108:Immune Tolerance; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000502:physiology*; D007970:Leukopenia; D008214:Lymphocytes / Q000166:cytology; D008562:Membrane Glycoproteins / Q000032:analysis; D009504:Neutrophils / Q000166:cytology; D009569:Nitric Oxide / Q000097:blood*; D012367:RNA, Viral / Q000097:blood; D013601:T-Lymphocytes / Q000166:cytology; D013921:Thrombocytopenia; D014454:Uganda / Q000453:epidemiology; D019562:Viral Load; D014766:Viremia; D019014:fas Receptor / Q000032:analysis
D000956:Antigens, Viral; D016207:Cytokines; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D012367:RNA, Viral; D019014:fas Receptor; D009569:Nitric Oxide