Four Ebola patients received care at Emory University Hospital, presenting a unique opportunity to examine the cellular immune responses during acute Ebola virus infection. We found striking activation of both B and T cells in all four patients. Plasmablast frequencies were 10-50% of B cells, compared with less than 1% in healthy individuals. Many of these proliferating plasmablasts were IgG-positive, and this finding coincided with the presence of Ebola virus-specific IgG in the serum. Activated CD4 T cells ranged from 5 to 30%, compared with 1-2% in healthy controls. The most pronounced responses were seen in CD8 T cells, with over 50% of the CD8 T cells expressing markers of activation and proliferation. Taken together, these results suggest that all four patients developed robust immune responses during the acute phase of Ebola virus infection, a finding that would not have been predicted based on our current assumptions about the highly immunosuppressive nature of Ebola virus. Also, quite surprisingly, we found sustained immune activation after the virus was cleared from the plasma, observed most strikingly in the persistence of activated CD8 T cells, even 1 mo after the patients' discharge from the hospital. These results suggest continued antigen stimulation after resolution of the disease. From these convalescent time points, we identified CD4 and CD8 T-cell responses to several Ebola virus proteins, most notably the viral nucleoprotein. Knowledge of the viral proteins targeted by T cells during natural infection should be useful in designing vaccines against Ebola virus.Ebola infection | human immune response | immune activation | plasmablasts | T cells
SUMMARY
Among the survivors of Ebola virus disease (EVD), complications that include uveitis can develop during convalescence, although the incidence and pathogenesis of EVD-associated uveitis are unknown. We describe a patient who recovered from EVD and was subsequently found to have severe unilateral uveitis during convalescence. Viable Zaire ebolavirus (EBOV) was detected in aqueous humor 14 weeks after the onset of EVD and 9 weeks after the clearance of viremia.
West Africa is currently experiencing the largest outbreak of Ebola virus disease (EVD) in history. Two patients with EVD were transferred from Liberia to our hospital in the United States for ongoing care. Malaria had also been diagnosed in one patient, who was treated for it early in the course of EVD. The two patients had substantial intravascular volume depletion and marked electrolyte abnormalities. We undertook aggressive supportive measures of hydration (typically, 3 to 5 liters of intravenous fluids per day early in the course of care) and electrolyte correction. As the patients' condition improved clinically, there was a concomitant decline in the amount of virus detected in plasma.
It is unclear what role the experimental drug and convalescent plasma had in the recovery of these patients. Prospective clinical trials are needed to delineate the role of investigational therapies in the care of patients with EVD.
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